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WO2024260907A1 - Système de balayage intrabuccal pour déterminer un signal de couleur visible et un signal infrarouge - Google Patents

Système de balayage intrabuccal pour déterminer un signal de couleur visible et un signal infrarouge Download PDF

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Publication number
WO2024260907A1
WO2024260907A1 PCT/EP2024/066772 EP2024066772W WO2024260907A1 WO 2024260907 A1 WO2024260907 A1 WO 2024260907A1 EP 2024066772 W EP2024066772 W EP 2024066772W WO 2024260907 A1 WO2024260907 A1 WO 2024260907A1
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WO
WIPO (PCT)
Prior art keywords
light
infrared
visible light
color
filtered
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PCT/EP2024/066772
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English (en)
Inventor
Philip Grabow WESTERGAARD
Alexander Bruun Christiansen
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3Shape AS
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3Shape AS
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Publication of WO2024260907A1 publication Critical patent/WO2024260907A1/fr
Anticipated expiration legal-status Critical
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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
    • G01B11/2509—Color coding
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/00002—Operational features of endoscopes
    • A61B1/00004—Operational features of endoscopes characterised by electronic signal processing
    • A61B1/00009—Operational features of endoscopes characterised by electronic signal processing of image signals during a use of endoscope
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/00163—Optical arrangements
    • A61B1/00186—Optical arrangements with imaging filters
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/00163—Optical arrangements
    • A61B1/00194—Optical arrangements adapted for three-dimensional imaging
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/04—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances
    • A61B1/045—Control thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/06—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements
    • A61B1/0638—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements providing two or more wavelengths
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/06—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements
    • A61B1/0646—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements with illumination filters
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/24—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor for the mouth, i.e. stomatoscopes, e.g. with tongue depressors; Instruments for opening or keeping open the mouth
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
    • A61B5/0082—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes
    • A61B5/0088—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes for oral or dental tissue
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/45—For evaluating or diagnosing the musculoskeletal system or teeth
    • A61B5/4538—Evaluating a particular part of the muscoloskeletal system or a particular medical condition
    • A61B5/4542—Evaluating the mouth, e.g. the jaw
    • A61B5/4547—Evaluating teeth
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C9/00—Impression cups, i.e. impression trays; Impression methods
    • A61C9/004—Means or methods for taking digitized impressions
    • A61C9/0046—Data acquisition means or methods
    • A61C9/0053—Optical means or methods, e.g. scanning the teeth by a laser or light beam
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C9/00—Impression cups, i.e. impression trays; Impression methods
    • A61C9/004—Means or methods for taking digitized impressions
    • A61C9/0046—Data acquisition means or methods
    • A61C9/0053—Optical means or methods, e.g. scanning the teeth by a laser or light beam
    • A61C9/006—Optical means or methods, e.g. scanning the teeth by a laser or light beam projecting one or more stripes or patterns on the teeth
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C9/00—Impression cups, i.e. impression trays; Impression methods
    • A61C9/004—Means or methods for taking digitized impressions
    • A61C9/0046—Data acquisition means or methods
    • A61C9/0053—Optical means or methods, e.g. scanning the teeth by a laser or light beam
    • A61C9/0066—Depth determination through adaptive focusing
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/90—Determination of colour characteristics

Definitions

  • the disclosure relates to an intraoral scanning system. More specifically, the disclosure relates to one or more processors of the system that is configured to determine An infrared signal based on a subtraction of combined filtered light signals with one or more color lights.
  • ionizing radiation e.g., X-rays
  • X-ray bitewing radiographs are often used to provide non-quantitative images of the teeth's internal structures.
  • images are typically limited in their ability to show early tooth mineralization changes (e.g. initial caries) resulting in underestimation of the demineralization depth; they are unable to assess the presence or not of micro-cavitation; they result in frequent overlap of the approximal tooth surfaces which requires repetition of radiograph acquisition and thus may involve a lengthy and expensive procedure.
  • NIR near-infrared
  • a handheld intraoral scanner that is configured to emit light pulses at different wavelengths, such as visible wavelengths and non-visible wavelengths.
  • the cycling between the different light sources may be provided by switching on and off the different light sources or by applying a mechanical filter in-front of the different light sources which provides an equivalent on- and-off switching of the different light sources by blocking the unwanted emitted wavelengths.
  • the mechanical filter may be a filter wheel with different blocking filters.
  • the slower movement of the handheld intraoral scanner is needed if wanting an optimal image quality for both surface information and inner region information for generating a three-dimensional model of the dental object being scanned which includes both surface and inner region information.
  • the on-off switching such as electronically swithing, creates unwanted transients on the emitted light pulses, and additionally, the on-off switching creates timing issues between the light sources.
  • mechanical filtering will result in a bulky solution that will lead to a larger handheld intraoral scanner that eventually will result in an uncomfortable scanner experience for the patient.
  • an intraoral scanning system may be configured to determine 3D data of a dental object in an oral cavity.
  • the intraoral scanning system may comprise a handheld intraoral scanner that includes a projector unit configured to emit visible light and infrared light, a filter unit configured to receive visible light signals and infrared light signals from at least the dental object caused by the emitted visible light and the emitted infrared light, respectively.
  • the filter unit may be configured to transmit filtered visible light signals and combined filtered light signals, wherein the combined filtered light signals include a combination of a first color light of the visible light signals and infrared light of the infrared light signals.
  • the first color light may be one or more of following red, green, blue and white.
  • the filter unit may comprise a plurality of single-color channels configured to output the filtered visible light signals, and a plurality of combined-color channels configured to output the combined filtered light signals.
  • the filter unit may be Bayer filter or a combined filter that includes a Bayer filter and an infrared blocker filter that is configured to block or partly block the infrared reflections for certain areas on the Bayer filter.
  • the system may comprise an image sensor unit configured to acquire the filtered visible light signals and the combined filtered light signals.
  • the image sensor unit may be a high-speed camera which has a frame rate of above 60 frames per seconds.
  • the image sensor unit may be a very high-speed camera which has a frame rate of above 500 frames per seconds.
  • the system may include one or more processors configured to determine an infrared signal based on a subtraction of the combined filtered light signals with one or more color lights of the filtered visible light signals and to determine the 3D data of the dental object based on at least the filtered visible light signals.
  • the one or more color lights may correspond to the first color light which is combined with infrared in the combined filtered light signals.
  • the infrared light may include wavelengths from between 750 nm and 1500 nm.
  • One or more of the plurality of single-color channels may be configured to transmit infrared light and block visible light.
  • the image sensor unit may include multiple cameras, such as, high speed cameras. In one example, the multiple cameras may be arranged around the projector unit or next to the projector unit.
  • the advantage with the system is that on-off switching between visible light and infrared light is avoided, and thereby, a real-time determination of the infrared signal and the 3D data are obtained without having the user to slow down the movement of the handheld intraoral scanner during the scanning of the dentition of a patient with both visible and infrared light.
  • the one or more processors may be configured to determine the 3D data of the dental object based on at least the filtered visible light signals and the first color light of the combined filtered light signals.
  • the first color light of each of the plurality combined-color channels may be determined based on an average of output from neighboring single-color channels to each of the plurality combined-color channels, and wherein the output includes a color-output that is the same as the first color light.
  • An inner region of the dental object may be determined by the one or more processors based on the infrared signal.
  • the inner region may include information about dental features that are arranged within the dental object.
  • the dental feature may be one or more of an anatomy feature, a disease feature and a mechanical feature.
  • the anatomy feature may be an enamel, a dentine, or a pulp.
  • the disease feature may be plaque, crack or caries.
  • the mechanical feature may be a filling and/or a composite restoration.
  • the one or more color lights of the filtered visible light signals may include one or more of following colors red, green, blue, and white.
  • the projector unit may include multiple light sources that are configured to emit the one or more colors lights and the infrared light.
  • the multiple light sources may be arranged within a single module that includes multiple Light Emitting Diodes (LED) that are configured to emit different wavelengths within the visible and non-visible wavelength ranges.
  • the light source i.e. one or more LEDs, that is configured to emit infrared light may be arranged separated from the light source that is configured to emit the visible light.
  • the image sensor unit may include a plurality of pixels, wherein each of the plurality of single-color channels and each of the plurality of combined-color channels is aligned to each of the plurality of pixels.
  • each of the channels overlaps with a pixel of the image sensor unit or with a group of pixels of the image sensor unit.
  • the filter unit may include a pixel-pattern filter that includes the plurality of single-color channels, and an infrared filter that is configured to block or partly block the infrared light signals for a first group of the plurality of single-color channels.
  • the infrared filter may be further configured to transmit the infrared light signals for a second group of the plurality of single-color channels, and wherein the second group of the plurality of single-color channels corresponds to the plurality of combined filter channels.
  • the filter unit may be constructed in a way that allows to be aligned and arranged in front of the image sensor unit, and which eventually, results in a compact filter unit.
  • the pixelpattern filter may include a first pixel-pattern surface and a second pixel-pattern surface that is opposite to the first pixel-pattern surface.
  • the infrared filter may be arranged on or in vicinity to the first pixel-pattern surface and the image sensor may be arranged on or in vicinity to the second pixel-pattern surface.
  • the infrared filter may include a first infrared surface and a second infrared surface that is opposite to the first infrared surface, and wherein the pixel-pattern filter is arranged on or in vicinity to the first infrared surface, and the image sensor unit may be arranged on or in vicinity to the second infrared surface.
  • the pixel-pattern filter may be a Bayer filter.
  • the 3D data includes 3D geometry data of the dental object and/or color data of the dental object.
  • the 3D data may include a plurality of sub-scans that have been acquired by the handheld intraoral scanner, and the plurality of sub-scans have been stitched together or otherwise related to form the 3D data.
  • the 3D geometry data may include the 3D shape of teeth and gingiva, and the color data includes the color of the teeth and the gingiva. Furthermore, the 3D data may include shade values of the teeth.
  • the one or more processors may be configured to determine in parallel the 3D data and the inner region of the dental object based on the infrared signal and/or a combination of the infrared signal and the visible light signals, and/or a combination of the infrared signal, visible light signal being white and fluorescence green and fluorescence red.
  • the one or more processors may be configured to receive the infrared signal and the filtered visible light signals sequentially from the image sensor unit and process the received signals in parallel but with a slight delay between the initiation of the processing of the two signals caused by the sequential receival of the infrared signals and the filtered visible light signals.
  • the image sensor unit is configured to output the filtered visible light signals and the combined filtered light signals in parallel such that no delay will appear between the processing of the two signals.
  • the filtered visible light signals for determining the 3D data may include a summation of red, green and blue wavelengths, and the first color light which is combined with the reflected infrared light in the combined filtered light signals may be green.
  • the one or more processors is configured to determine a virtual visible light signal from each of the combined filtered light signals, wherein the virtual visible light signal includes green wavelengths.
  • the virtual visible light signal is determined by interpolating between the filtered visible light signals of neighbouring single-color channels in relation to each of the combined-color channels, and wherein the filtered visible light signals of the neighbouring single-color channels include green wavelengths.
  • the virtual visible light signal corresponds to the first color light.
  • the first color light of the combined filtered light signals may be determined by interpolating between the first group of the plurality of single-color channels.
  • the one or more processors may then be configured to combine the virtual visible light signal of each of the combined filtered light signals with the filtered visible light signals to determine the 3D data.
  • all pixels that are aligned with the plurality of single-color channels and the plurality of combined-color channels are used for determining the 3D data. Thereby, no reduction in the resolution of the 3D data is sufferd in comparison to the example where the one or more processors is disregarding the plurality of combined filtered light signals for determining 3D data.
  • the one or more processors may be configured to change a pulse repetition rate of the emitted visible light from the projector unit based on the wavelength of the emitted visible light.
  • the one or more processors may be configured to improve the signal -to-noise ratio of the filtered visible light signal by increasing a pulse repetition rate of the emitted visible light from the projector unit. For example, in a situation where the emitted light of the projector unit includes wavelengths between 350 nm and 500 nm, the one or more processors is configured to increase the pulse repetition rate of the emitted visible light. Since the infrared light is constant on throughout a scanning sequence of a patient, then no pulse repetition rate is defined for the emitted infrared light.
  • the pulse duration of emitted visible light pulses may be around 0.4 ms.
  • the switching period between the two colors may be around 0.8 ms, corresponding to a pulse repetition rate (PRR) of 1.25 kHz. This will be the PRR of the white visible light pulses.
  • PRR pulse repetition rate
  • the PPR for the blue visible light pulses is only occurring every fourth pulse, and the PPR is then reduced to 625 Hz for the blue pulses.
  • the one or more processors may be configured to change a gain level of the image sensor unit based on a wavelength and/or a power level of the emitted light from the projector unit. To further improve the signal-to-noise ratio of the filtered visible light signal, the one or more processors is configured to increase a gain level of the emitted light from the projector unit.
  • the projector unit may be configured to constantly emit the infrared light while emitting the visible light.
  • the on-off switching of the emitted infrared light is avoided, and thereby, unwanted transients on the emitted infrared light are avoided.
  • any timing issue between the visible light and the infrared light are also avoided.
  • the determination of the infrared signal is performed by the one or more processors.
  • the one or more processors may be configured to generate a color light magnitude signal from the filtered visible light signals, and wherein the color light magnitude signal may be one or more of red light, green light and blue. If combining red, green and blue then the color light magnitude signal corresponds to white light. Then, the one or more processors may be configured to generate a combined light magnitude signal from a combined filtered signal of the combined filtered signals, wherein the combined light magnitude signal may be a sum of infrared light and the first color that includes one or more colors of the color light magnitude signal. The one or more processors may then be configured to determine the infrared signal by subtracting the color light magnitude signal from the combined light magnitude signal.
  • the color light magnitude signal may be a sum of red light, green light and blue light, and wherein the combined light magnitude signal is a sum of infrared light and red light, green light and blue light.
  • the color light magnitude signal includes green light, and wherein the combined light magnitude signal is a sum of infrared light and green light.
  • the color light magnitude may be generated based on filtered visible light signals from a first group of the plurality of single-color channels, and the combined light magnitude signal may be generated based on a single combined-color channel of the plurality of combined-color channels, and wherein the first group of the plurality of single-color channels is arranged in vicinity to the single combined-color channel.
  • the first group may be arranged as neighbour channels to the single combined-color channel.
  • the first group of single-color channels constitutes a color filter-channel neighbourhood
  • the color filter-channel neighbourhood is one of following a 4-neighborhood color filter channel arrangement, a diagonal neighbourhood color filter channel arrangement, or a 8-neighborhood color filter channel arrangement.
  • a 2D infrared image or a composed scan image may be determined based on the infrared signal, and to obtain an optimal resolution quality of the 2D infrared image, the ratio between the plurality of combined-color channels and the plurality of single-color channels is determined to be between 1/16 and 1/2.
  • the handheld intraoral scanner may be configured to scan a patient during a scan sequence, and during the scan sequence, the projector unit may be configured to emit visible light and infrared light such that a 3D model is real time determined and displayed based on the 3D data. Furthermore, the infrared signal may also be determined in realtime.
  • the one or more processors may be configured to determine and display a 2D or a 3D infrared image based on the infrared signal, or, to determine and display a composed scan image based on the infrared signal.
  • the one or more processors is configured to determine a 3D model in real-time that includes one or more of following information of a dental object or a dentition: 3D geometry, color information, shade information, and inner region information determined from at least the infrared signal.
  • the one or more processors may be configured to control the projector unit during the scan sequence, and wherein the scan sequence includes at least a first time period and a second time period, wherein during the first time period the emitted visible light includes a first visible light that is turned on at a constant power level while the infrared light is turned on at a constant power level, and during the second time period the emitted visible light includes a second visible light that is turned on and off with a second pulse repetition rate while the infrared light is turned on at a constant power level. Furthermore, during the second time period, the first visible light is turned on and off asynchronously to the on/off switching of the second visible light, and wherein the first visible light is turned on and off with a first pulse repetition rate.
  • both the 3D data and the infrared signal are determined during the first time period, and during the second time period but the 3D data and fluorescence data, either 2D or 3D, are determined along with the infrared signal.
  • the first visible light may include white, green or red wavelengths
  • the second visible light may include blue wavelengths for the purpose of exciting susceptible molecules on the dental object to excite red and green fluorescence signals.
  • the one or more processors may be configured to determine a composed scan image based on the infrared light, the first visible light and/or the second visible light.
  • the one or more processors may be configured to change the signal -to-noise ratio of the filtered visible light signal by changing the pulse repetition rate during a time period of the emitted visible light.
  • the one or more processors may be configured to change the signal-to-noise ratio of the filtered visible light signal by changing the first pulse repetition rate during the second time period based on a scan mode. For example, in a scan mode where the projector unit does emit both the visible light and infrared light, the pulse repetition rate of the visible light is increased in relation to a scan sequence where infrared light is turned on constantly during the scan sequence.
  • the scan sequence may include a repetition of the first time period and the second time period, and wherein the first time period and the second time period are repeated throughout the scan sequence, and wherein the second time period is repeated within 100 ms, 200 ms or 500 ms.
  • the first time period may be longer than the second time period.
  • the first time period may be between 100 ms and 500 ms, or between 100 ms and 250 ms.
  • the second time period may be between 30 ms and 50 ms, 30 ms and 40 ms, about 30 ms or about 40 ms about or about 50 ms.
  • the scan sequence would provide sufficient amount of visible light signals and infrared signals for the one or more processors to determine the 3D data and the infrared signals that would inevitably result in a 3D model with the necessary quality for the user to investigate the dentition for plaque, caries, cracks and other dental features within and on a dental object of the dentition.
  • the scan sequence may be a full scan of at least an upper jaw and/or a lower jaw of the oral cavity of the patient.
  • the projector unit may be configured to emit during the scan sequence a first visible light that includes white light and a second visible light that includes blue light, and wherein a first pulse repetition rate of the first visible light is different from a second pulse repetition rate of the second visible light, and wherein the infrared light is emitted constantly during the scan sequence.
  • the one or more processors may be configured to adjust the first and the second repetition rate based on a scan mode of the handheld intraoral scanner. The first pulse repetition rate may be faster than the second pulse repetition rate.
  • the one or more processors may be configured to determine fluorescence information of the dental object from the filtered visible light signals.
  • the filtered visible light signals may include excited fluorescence red light and fluorescence green light that have been excited by the emitted blue light.
  • the one or more processors may be configured to determine the 3D data based on two or more different colors of the filtered visible light signals.
  • the 3D data may be determined based on white light which may include a summation red light, blue light and green light, or, the 3D data may be determined based on blue light, green light or red light, or a combination of both blue light, green light and red light.
  • a power level of the infrared light may be constant throughout a scan sequence of at least an upper jaw and/or a lower jaw of the oral cavity.
  • the power level of the infrared light may be set to a first power level during a primary time period and to a second power level during a secondary time period, wherein the first power level is lower than the second power level.
  • the primary time period may correspond to the first time period of the scan sequence which implies mainly the capturing of visible light signal for determining the 3D data.
  • the secondary time period corresponds to the second time period of the scan sequence which implies mainly the capturing of scattered visible light for determining fluorescence information and scattered infrared light.
  • the first power level may be between 50% and 90% of the second power level, between 10 % and 50 % or between 5 % and 40 %.
  • the first power level may provide a signal above a noise floor level of the image sensor unit.
  • the emitted visible light may include visible light pulses, and wherein the emitted infrared light is not a pulse as the emitted infrared light is constantly on throughout the complete scan sequence of a jaw of the patient.
  • the one or more processors may be configured to determine an infrared signal based on the subtraction of the combined filtered light signals with the one or more color lights of the filtered visible light signals, and the inner region is determined by composed scan information that includes a difference between the infrared signal and the one or more color lights of the filtered visible light signals.
  • the composed scan information includes enhanced contrast between the dental features, wherein the enhanced dental features may be depicted on or in a 3D model determined by the 3D data and the composed scan information.
  • the one or more processors may be configured to determine a first difference between the infrared signal and the green fluorescence information and a second difference between the infrared signal and the red fluorescence information, and wherein the composed scan information includes a summation of the first difference and/or the second difference.
  • the contrast between the dental features would be improved even more.
  • the composed scan information may include a summation of the infrared signal, the green fluorescence information and the red fluorescence information, and in this example, the dentin-enamel junction is more enhanced, and thereby, easier to distinguish from other dental features of the dental object.
  • the composed scan information provides an enhanced visualization of caries of teeth in such a manner that it becomes easier for the dentist to identify and treat caries.
  • the intraoral scanning system may be configured to enhance the visualization of restorations of teeth in such a manner that it becomes easier for the dentist to identify and treat secondarycaries, and, to identify the type of restoration, such as type of fillings, inlays, onlays, crowns and/or sealants.
  • the intraoral scanning system may be configured to enhance the visualization of "dentinenamel junction” (DEJ) of teeth in such a manner that it becomes easier for the dentist to identify the dentin-enamel junction for clinical assessment.
  • DEJ denoted "dentinenamel junction”
  • the intraoral scanning system may be configured to generate or update a three- dimensional 3D model while determining composed scan information with the use of different wavelength modalities.
  • yet a further aspect of the present disclosure is to detect incipient caries at stages where preventive measures are likely to effect remineralization, repairing damage done by the caries infection at a stage well before more complex restorative measures are necessary.
  • the disclosure can be accurate at an earlier stage of caries infection than has been exhibited using existing fluorescence or near-infrared approaches.
  • the intraoral scanning system may be configured to provide a composed scan data based on captured visible light and the determined infrared signal.
  • the infrared signal may include mainly reflection from inside a tooth, i.e. internal region of a dental object, and significantly less of surface reflection of a tooth.
  • the visible light signals may include mainly surface reflection of a tooth and significantly less reflection from inside a tooth, i.e. internal region of a dental object.
  • the infrared signal may include information about dental condition from within a tooth and not just superficial.
  • a composed scan information does not include an overlay of two 2D images where each of the two 3D images relates to different emitted wavelengths from the projector unit. In this example, no enhancement of internal structure information is provided.
  • the composed scan information may be a combination of intensity levels of each pixel of the 2D images that relates to different wavelengths. For example, at a first time period, the image sensor unit captures light information that relates to visible wavelength, and at a second time period, the image sensor unit captures light information that relates to infrared, and the intensity levels of the two time periods are recorded and combined for enhancing a dental condition, i.e. a dental feature such as dentine, enamel, dentine-enamel junction, plaque, caries, cracks etc.
  • the combination of the intensity levels may be done digitally by subtraction and/or addition of the intensity levels.
  • the intensity levels may be captured and recorded during at least three time periods for at least three different wavelengths, such as white-coloured wavelength, blue-coloured wavelength and infrared wavelength.
  • the infrared wavelength may be between 750 nm and 1500 nm.
  • the one or more processors may be configured to display the composed scan information and the 3D model on a displaying unit of the system.
  • the one or more processors may be configured to utilize the filtered visible light signals for both generating or updating the 3D model and for determining the composed scan information that includes enhanced internal structures in the form of enhanced contrast between the dental features, such as a caries lesion, and tooth structures.
  • the surface of a dental object are mainly provided by the visible light information, and the inner region of the dental object are mainly provided by the composed scan information or the infrared signal determined by the one or more processors.
  • a handheld intraoral scanning device first performs a scan for generating or updating a 3D model and then afterwards performs another scan for determining composed scan information would result in a more complicated way of aligning the position of the composed scan information on the 3D model in comparison to the present disclosure.
  • FIGs. 1 A and IB illustrate an example of the intraoral scanning system
  • FIGs 2A, 2B and 2C illustrate different examples of a filter unit
  • FIGs 3 A, 3B, 3C and 3D illustrate different examples on how the filter unit is configured;
  • FIGs. 4A and 4B illustrate different examples of a scan sequence;
  • FIG. 5 illustrates an example of a scan sequence
  • FIG. 6 illustrates an example of a scan sequence
  • FIG. 7 illustrates an example on how a gain of an image sensor unit is changing according to a wavelength of the emitted light
  • FIGs 8A, 8B, 8C and 8D illustrate different examples on a composed scan information
  • FIG. 9 illustrates an example of a shadow component arranged within a tip of a handheld intraoral scanner.
  • the electronic hardware may include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure.
  • Computer program shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.
  • a scanning for providing intra-oral scan data may be performed by a dental scanning system that may include an intraoral scanning device such as the TRIOS series scanners from 3 Shape A/S.
  • the dental scanning system may include a wireless capability as provided by a wireless network unit.
  • the scanning device may employ a scanning principle such as triangulation-based scanning, confocal scanning, focus scanning, ultrasound scanning, x-ray scanning, stereo vision, structure from motion, optical coherent tomography OCT, or any other scanning principle.
  • the scanning device is capable of obtaining surface information by operated by projecting a pattern and translating a focus plane along an optical axis of the scanning device and capturing a plurality of 2D images at different focus plane positions such that each series of captured 2D images corresponding to each focus plane forms a stack of 2D images.
  • the acquired 2D images are also referred to herein as raw 2D images, wherein raw in this context means that the images have not been subject to image processing.
  • the focus plane position is preferably shifted along the optical axis of the scanning system, such that 2D images captured at a number of focus plane positions along the optical axis form said stack of 2D images (also referred to herein as a sub-scan) for a given view of the object, i.e.
  • the scanning device is generally moved and angled relative to the dentition during a scanning session, such that at least some sets of sub-scans overlap at least partially, in order to enable reconstruction of the digital dental 3D model by stitching overlapping subscans together in real-time and display the progress of the virtual 3D model on a display as a feedback to the user.
  • the result of stitching is the digital 3D representation of a surface larger than that which can be captured by a single sub-scan, i.e. which is larger than the field of view of the 3D scanning device.
  • Stitching also known as registration and fusion, works by identifying overlapping regions of 3D surface in various sub-scans and transforming sub-scans to a common coordinate system such that the overlapping regions match, finally yielding the digital 3D model.
  • An Iterative Closest Point (ICP) algorithm may be used for this purpose.
  • Another example of a scanning device is a triangulation scanner, where a time varying pattern is projected onto the dental arch and a sequence of images of the different pattern configurations are acquired by one or more cameras located at an angle relative to the projector unit.
  • Color texture of the dental arch may be acquired by illuminating the object using different monochromatic colors such as individual red, green and blue colors or my illuminating the object using multichromatic light such as white light.
  • a 2D image may be acquired during a flash of white light.
  • the process of obtaining surface information in real time of a dental arch to be scanned requires the scanning device to illuminate the surface and acquire high number of 2D images.
  • a high speed camera is used with a framerate of 300-2000 2D frames pr second dependent on the technology and 2D image resolution.
  • the high amount of image data needed to be handled by the scanning device to eighter directly forward the raw image data stream to an external processing device or performing some image processing before transmitting the data to an external device or display. This process requires that multiple electronic components inside the scanner is operating with a high workload thus requiring a high demand of current.
  • the scanning device comprises one or more light projectors configured to generate an illumination pattern to be projected on a three-dimensional dental arch during a scanning session.
  • the light projector(s) preferably comprises a light source, a mask having a spatial pattern, and one or more lenses such as collimation lenses or projection lenses.
  • the light source may be configured to generate light of a single wavelength or a combination of wavelengths (mono- or polychromatic). The combination of wavelengths may be produced by using a light source configured to produce light (such as white light) comprising different wavelengths.
  • the light projector(s) may comprise multiple light sources such as LEDs individually producing light of different wavelengths (such as red, green, and blue) that may be combined to form light comprising the different wavelengths.
  • the light produced by the light source may be defined by a wavelength defining a specific color, or a range of different wavelengths defining a combination of colors such as white light.
  • the scanning device comprises a light source configured for exciting fluorescent material of the teeth to obtain fluorescence data from the dental arch.
  • a light source may be configured to produce a narrow range of wavelengths.
  • the light from the light source is infrared (IR) light, which is capable of penetrating dental tissue.
  • the light projector(s) may be DLP projectors using a micro mirror array for generating a time varying pattern, or a diffractive optical element (DOF), or back-lit mask projectors, wherein the light source is placed behind a mask having a spatial pattern, whereby the light projected on the surface of the dental arch is patterned.
  • the back-lit mask projector may comprise a collimation lens for collimating the light from the light source, said collimation lens being placed between the light source and the mask.
  • the mask may have a checkerboard pattern, such that the generated illumination pattern is a checkerboard pattern. Alternatively, the mask may feature other patterns such as lines or dots, etc.
  • the scanning device preferably further comprises optical components for directing the light from the light source to the surface of the dental arch.
  • the specific arrangement of the optical components depends on whether the scanning device is a focus scanning apparatus, a scanning device using triangulation, or any other type of scanning device.
  • a focus scanning apparatus is further described in EP 2 442 720 Bl by the same applicant, which is incorporated herein in its entirety.
  • the light reflected from the dental arch in response to the illumination of the dental arch is directed, using optical components of the scanning device, towards the image sensor(s).
  • the image sensor(s) are configured to generate a plurality of images based on the incoming light received from the illuminated dental arch.
  • the image sensor unit may be a high-speed image sensor such as an image sensor configured for acquiring images with exposures of less than 1/1000 second or frame rates in excess of 250 frames pr. second (fps).
  • the image sensor may be a rolling shutter (CCD) or global shutter sensor (CMOS).
  • the image sensor(s) may be a monochrome sensor including a color filter array such as a Bayer filter and/or additional filters that may be configured to substantially remove one or more color components from the reflected light and retain only the other non-removed components prior to conversion of the reflected light into an electrical signal.
  • additional filters may be used to remove a certain part of a white light spectrum, such as a blue component, and retain only red and green components from a signal generated in response to exciting fluorescent material of the teeth.
  • the network unit may be configured to connect the dental scanning system to a network comprising a plurality of network elements including at least one network element configured to receive the processed data.
  • the network unit may include a wireless network unit or a wired network unit.
  • the wireless network unit is configured to wirelessly connect the dental scanning system to the network comprising the plurality of network elements including the at least one network element configured to receive the processed data.
  • the wired network unit is configured to establish a wired connection between the dental scanning system and the network comprising the plurality of network elements including the at least one network element configured to receive the processed data.
  • the dental scanning system preferably further comprises a processor configured to generate scan data (such as extra-oral scan data and/or intra-oral scan data) by processing the two-dimensional (2D) images acquired by the scanning device.
  • the processor may be part of the scanning device.
  • the processor may comprise a Field- programmable gate array (FPGA) and/or an Advanced RISC Machines (ARM) processor located on the scanning device.
  • the scan data comprises information relating to the three- dimensional dental arch.
  • the scan data may comprise any of: 2D images, 3D point clouds, depth data, texture data, intensity data, color data, and/or combinations thereof.
  • the scan data may comprise one or more point clouds, wherein each point cloud comprises a set of 3D points describing the three-dimensional dental arch.
  • the scan data may comprise images, each image comprising image data e.g. described by image coordinates and a timestamp (x, y, t), wherein depth information can be inferred from the timestamp.
  • the image sensor(s) of the scanning device may acquire a plurality of raw 2D images of the dental arch in response to illuminating said object using the one or more light projectors.
  • the plurality of raw 2D images may also be referred to herein as a stack of 2D images.
  • the 2D images may subsequently be provided as input to the processor, which processes the 2D images to generate scan data.
  • the processing of the 2D images may comprise the step of determining which part of each of the 2D images are in focus in order to deduce/generate depth information from the images.
  • the internal depth information may be used to generate 3D point clouds comprising a set of 3D points in space, e.g., described by cartesian coordinates (x, y, z).
  • the 3D point clouds may be generated by the processor or by another processing unit.
  • Each 2D/3D point may furthermore comprise a timestamp that indicates when the 2D/3D point was recorded, i.e., from which image in the stack of 2D images the point originates.
  • the timestamp is correlated with the z-coordinate of the 3D points, i.e., the z-coordinate may be inferred from the timestamp.
  • the output of the processor is the scan data, and the scan data may comprise image data and/or depth data, e.g. described by image coordinates and a timestamp (x, y, t) or alternatively described as (x, y, z).
  • the scanning device may be configured to transmit other types of data in addition to the scan data. Examples of data include 3D information, texture information such as infra-red (IR) images, fluorescence images, reflectance color images, x-ray images, and/or combinations thereof.
  • IR infra-red
  • FIG.1A illustrates an example of the intraoral scanning system 1.
  • the system 1 includes a handheld intraoral scanner 10 that can be handheld and used for scanning a patient’s mouth and one or more processors 2.
  • the handheld intraoral scanner may include a projector unit 3 that is configured to emit 8 visible light and infrared light and a filter unit 5 that is configured to receive visible light signals 9 and infrared light signals 9 from at least the dental object caused by the emitted visible light 8 and the emitted infrared light 8, respectively.
  • the filter unit 3 is configured to transmit filtered visible light signals and combined filtered light signals, wherein the combined filtered light signals include a combination of a first color light of the visible light signals and infrared light of the infrared light signals.
  • the filter unit may comprise a plurality of single-color channels 11 configured to output the filtered visible light signals, and a plurality of combined-color channels (12A,12B) configured to output the combined filtered light signals.
  • the handheld intraoral scanner 10 may include an image sensor unit 4 configured to acquire the filtered visible light signals by pixels 14 that are aligned 16 to one or more of the single-color channels 11 of the plurality of single-color channels, and to acquire the combined filtered light signals by pixels 15 that are aligned 16 to one or more of the combined-color channels (12A,12B) of the plurality of combined-color channels.
  • each of plurality of single-color channels 11 and each of the plurality of combined-color channels (12A,12B) are aligned 16 to each of the pixels (14,16) of the image sensor unit 4.
  • FIG. IB illustrates another example of the system 1 and the one or more processors 2.
  • the one or more processors 2 receives the filtered visible light signals 40 and the combined filtered light signals 41, wherein the one or more processors is configured to determine 42 the infrared signal based on a subtraction of the combined filtered light signals 41 with one or more color lights of the acquired filtered visible light signals 42.
  • the one or more processors 2 is further configured to determine 43 an inner region of the dental object based on the infrared signal.
  • the one or more processors is configured to determine 44 the 3D data of the dental object based on at least the filtered visible light signals 40.
  • the one or more processors 2 is then configured to determine 45 a 3D model that includes one or more of following information of a dental object or a dentition: 3D geometry, color information, shade information and inner region information determined based on at least the infrared signal.
  • the one or more processors 2 is configured to determine in parallel the 3D data and an inner region of the dental object based on the infrared signal.
  • the 3D model and the inner region may be determined in parallel.
  • the system 1 includes a display unit (46A,46B).
  • the example illustrates two different ways of displaying the 3D model (45A,45B) and the inner region 43 A.
  • the one or more processors 2 is configured to display the 3D model (46A,46B) and/or the inner region in real-time.
  • the displayed 3D model includes both the 3D data 44 and the inner region 43 which in this example is in 3D.
  • the displayed 3D model 45B includes the 3D data, and the inner region 43 A is displayed in 2D and next to the 3D model 45B.
  • FIGS. 2A, 2B 2C illustrate different examples of the filter unit 5.
  • the filter unit 5 includes a plurality of combined-color channels (12A,12B), which in this specific example includes two combined-color channels (12A, 12B).
  • the filter unit 5 includes a plurality of single-color channels (11,11A,1 IB).
  • the combined-color channels (12A, 12B) is configured to output combined filtered light signals that include a combination of green light and infrared light where wavelengths within the blue and red spectrum are blocked from being output through the combined-color channels (12A,12B).
  • the first color light of the combined-color channels (12A,12B) includes green wavelengths.
  • the plurality of single-color channels 11 are configured to output filtered visible light signals that include blue, green and red light.
  • the one or more processors 2 is configured to determine the infrared signal by subtracting the green light outputted by the neighbouring single-color channels (11 A,1 IB) in relation to the respective composed-color channels (12A,12B) from the combined filtered visible light signals.
  • the combined-color channels (12A, 12B) is configured to output combined filtered light signals that include a combination of white light and infrared light.
  • the one or more processors 2 is then configured to determine the infrared signal by subtracting the green light, red light and blue light outputted by the neighbouring singlecolor channels (11 A,1 IB) in relation to the respective composed-color channels (12A,12B) from the combined filtered visible light signals.
  • the two composed-color channels (12A,12B) are sharing two single-color channels (11A+1 IB).
  • the one or more processors 2 is configured to generate a color light magnitude signal (11A,1 IB) from the filtered visible light signals, and wherein the color light magnitude signal (11 A,1 IB) is one or more of red light, green light and blue.
  • the color light magnitude signal (11 A,1 IB) corresponds to green light
  • the color light magnitude signal (11 A,1 IB) corresponds to a summation of red, green and blue light.
  • the one or more processors is configured to generate a combined light magnitude signal from a combined filtered signal of the combined filtered signals, and wherein the combined light magnitude signal is a sum of infrared light and the first color light that includes one or more colors of the color light magnitude signal.
  • the first color light is green
  • the first color is white.
  • the one or more processors is further configured to determine the infrared signal by subtracting the color light magnitude signal from the combined light magnitude signal.
  • the color light magnitude is generated based on filtered visible light signals from a first group (11 A,1 IB) of the plurality of single-color channels 11, and the combined light magnitude signal is generated based on a single combined-color channel (12A,12B) of the plurality of combined-color channels, and wherein the first group (11 A,1 IB) of the plurality of single-color channels 11 is arranged in vicinity to the single combined-color channel (12A,12B).
  • the one or more processors 2 is configured to determine the color light magnitude signal by averaging the filtered visible light signals from the first group (11A,1 IB) or by interpolation between the filtered visible light signals from the first group (11,1 IB).
  • the determined color light magnitude signal is an approximation of the first color that is combined with the infrared light in the plurality of combined-color channels.
  • FIG. 2C illustrates different examples of how the first group (11A,1 IB) of the plurality of single-color channels 1 is arranged relative to each of the combined-color channels (12A,12B).
  • the first group (11A,1 IB) of single-color channels (11) constitutes a color filter-channel neighbourhood, and the color filter-channel neighbourhood is as following:
  • the color filter-channel neighbourhood 11A is a four-neighbourhood color filter channel arrangement, wherein each of the single filterchannels 11 A of the four-neighbourhood outputs green light which also corresponds the first color of the combined filtered light signal.
  • the color filter-channel neighbourhood 11A is a diagonal neighbourhood color filter channel arrangement
  • the color filter-channel neighbourhood 11A is an eight-neighbourhood color filter channel arrangement.
  • FIGS. 3 A,3B,3C and 3D illustrate different examples on how the filter unit 5 is configured together with the image sensor unit 4.
  • the filter unit 5 includes a pixel pattern 5B filter that includes the plurality of single-color channels 11, and an infrared filter 5 A that is configured to block or partly block the infrared light signals for a first group of the plurality of single-color channels 11.
  • the infrared filter 5 A is further configured to transmit the infrared light signal for a second group of the plurality of single-color channels 11, and wherein the second group of the plurality of single-color channels 11 corresponds to the plurality of combined filter channels (12A,12B).
  • FIGS. 3 A and 3B illustrate an example where the pixel-pattern filter 5B includes a first pixel-pattern surface 30A and a second pixel-pattern surface 3 OB that is opposite to the first pixel-pattern surface 30A.
  • the infrared filter 5A is arranged on, see FIG. 3B, or in vicinity to, see FIG. 3 A, the first pixel-pattern surface 30A, and the image sensor 4 is arranged on, see FIG. 3B or in vicinity to, see FIG. 3A, the second pixel-pattern surface 30B.
  • 3C and 3D illustrate an example where the infrared filter 5 A includes a first infrared surface 31 A and a second infrared surface 3 IB that is opposite to the first infrared surface 31 A, and wherein the pixel-pattern filter 5B is arranged on, see FIG. 3D, or in vicinity to, see FIG. 3C, the first infrared surface 31 A, and the image sensor unit 4 is arranged on, see FIG. 3D, or in vicinity to, see FIG. 3C, the second infrared surface 3 IB.
  • the projector unit 3 includes multiple light sources, a primary light source configured to emit the visible light and a secondary light source configured to emit infrared light.
  • the primary light source may include a first primary light source configured to emit a first visible light
  • the projector unit 3 includes the first and a second primary light source configured to emit a second visible light source.
  • the first visible light source is configured to emit pattern visual light, e.g. white light, that is used for determining 3D data of a dental object
  • the second visible light source is configured to emit pattern visual light, e.g. including blue wavelengths, that is used for exciting red and green fluorescence signals of the dental object.
  • the second primary light source is further configured to emit pattern visual light, e.g.
  • the secondary light source may include multiple Light Emitting Diodes (LED) that are all configured to emit light with infrared wavelengths. The emitted infrared light may be unpatented.
  • the primary light source may also include multiple of LEDs.
  • the secondary light source may be arranged within the handheld intraoral scanner 10 and distantly away from the primary light source, or, on a rack that includes both the primary and the secondary light source.
  • FIGS. 4A and 4B illustrate different examples of a scan sequence 50.
  • the projector unit emits both visible light (51 A, 5 IB) and infrared light 52.
  • the visible light includes a first modality 51 A, e.g. white light and a second modality 5 IB, e.g. blue light.
  • the infrared light 52 is constant on at a constant power level, and the one or more processors 2 is configured to synchronize the on and off switching of the first modality 51 A and the second modality 5 IB.
  • the pulse repetition rate for the first modality 51 A is higher than for the second modality 5 IB which is ideal for determining the 3D data with sufficient quality for a 3D model to be displayed with the level of quality which the dentist needs for being able to diagnose a dental disease, e.g. a disease feature.
  • the pulse repetition rate of the first 51 A and the second 5 IB modality is the same.
  • FIG. 5 illustrates another example of a scan sequence 50 that includes a first time period (56A,56B) which have been repeated in the scan sequence 50. Furthermore, the scan sequence 50 includes a second time period (55A,55B,55C) which also have been repeated in the scan sequence.
  • the one or more processors is configured to switch between the first time period (56A,56B) and the second time period (55A,55B,55C) according to a wanted quality of the 3D data, fluorescent information and infrared signals. Throughout the whole scan sequence 50 the infrared light 52 is constant at a power level above the noise floor of the image sensor unit 4.
  • FIG. 5 illustrates two examples ((I), (II)) of the second time period 55.
  • the pulse repetition rate for the first modality 51 A is higher than for the second modality 5 IB which is ideal for determining the 3D data with sufficient quality for a 3D model to be displayed with the level of quality which the dentist needs for being able to diagnose a dental disease, e.g. a disease feature.
  • the pulse repetition rate of the first 51 A and the second 5 IB modality is the same.
  • FIG. 6 illustrates another example of a scan sequence 50 that includes a first time period (56A,56B) which have been repeated in the scan sequence 50. Furthermore, the scan sequence 50 includes a second time period (55A,55B,55C) which also have been repeated in the scan sequence.
  • the one or more processors is configured to vary the power level of the infrared light 52 between a first time period (56A,56B) and a second time period (55A,55B,55C). The varying of the power level is for improving the power consumption of the handheld intraoral scanner 10.
  • the one or more processors is configured to switch between the first time period (56A,56B) and the second time period (55A,55B,55C) according to a wanted quality of the 3D data, fluorescent information and infrared signals.
  • the infrared light 52 is constant at different power level above the noise floor of the image sensor unit 4.
  • both the first modality 51 A and the infrared light 52 is constant on and at a constant power level
  • the one or more processors 2 is configured to switch between the first modality 51 A and the second modality 5 IB.
  • FIG. 6 illustrates two examples ((I), (II)) of the second time period 55.
  • the pulse repetition rate for the first modality 51 A is higher than for the second modality 5 IB which is ideal for determining the 3D data with sufficient quality for a 3D model to be displayed with the level of quality which the dentist needs for being able to diagnose a dental disease, e.g. a disease feature. Furthermore, it is clearly seen that the power level of the infrared signal is increased to a level which is optimal for acquiring infrared images based on the infrared signals. In example (II), the pulse repetition rate of the first 51 A and the second 5 IB modality is the same. FIG.
  • the one or more processors 2 which is configured to synchronize a gain level of the image sensor unit 4 according to a wavelength of the emitted light (51A,51B, 52) from the projector unit 3.
  • the one or more processors 2 is configured to increase the gain to around 4 when the emitted wavelength from the projector unit 3 is between 350 nm and 500 nm or above 800 nm.
  • the gain level is turned down to 1.
  • FIGS. 8A, 8B,8C, and 8D illustrate example on composed scan image 20 determined based on the infrared signal 24 and the visible signals (51 A, 5 IB).
  • the filtered visible light signals 22 includes surface reflection, i.e. surface information, provided by white coloured light 51 A emitted by the handheld intraoral scanning device 10, and the infrared signal 24 provided by the emitted infrared light 52.
  • the composed scan information 20 includes a subtraction of the infrared signal 24 with filtered visible light signals 22, and wherein the filtered visible light signals 22 are used for determining a 3D surface model 29 of the dentition 80.
  • the composed scan information 20 includes enhanced internal structure that is represented by a restoration 26A that is not seen in the infrared signal 24 but can easily be identified in the composed scan information 20.
  • the composed scan information 20 may be mapped onto the 3D surface model 29 by the one or more processors 2, such that the composed scan information provides three-dimensional information regarding the inner region of the dentition 80.
  • the filtered visible light signals 22 includes excited fluorescence information that is provided by blue coloured light 5 IB emitted by the handheld intraoral scanning device 10, and in this example, the composed scan information 20 includes a subtraction of the infrared signal 24 with the filtered visible light signals 22, and wherein the filtered visible light signals 22 are used for applying fluorescence information onto the 3D surface model 29 of the dentition 80.
  • the infrared image 24 the caries lesion 27 can barely be seen, however, on the composed image 20 the visibility of the caries lesion has improved.
  • FIG. 8C illustrates a similar example as FIG. 8B, however, the composed scan information 20 in FIG. 8C is composed differently. In FIG.
  • the composed scan information 20 includes a summation of the green coloured fluorescence information 22 and the infrared signals 24.
  • the composed scan information 20 includes enhanced textural information about the enamel 28A and dental 28B, and thereby, the Dentin-Enamel- Junction (DEJ) has become easier to see due to an improved contast in the composed scan information image 20. It is easily seen that the enamel 28A and the dental 28B are more clearly seen in the composed scan information image 20 than in the infrared signal 24.
  • DEJ Dentin-Enamel- Junction
  • the composed scan information includes a summation of the infrared signals 24, the green fluorescence information 22 and the red fluorescence information 22, and the composition, has also shown to improve the visibility of DEJ in relation to a regular or enhanced fluorescence information (, or, in relation to the infrared signal 24).
  • FIG. 8B illustrates an example where the projector unit 5 emits visible lights that includes blue wavelengths 5 IB and white wavelengths 51 A, and non-visible light that includes infrared wavelengths.
  • the emitted blue wavelengths 5 IB excites greencoloured fluorescence information 22B and red-coloured fluorescence information 22C.
  • the filtered visible light signals (22A,22B, 22C) include surface information provided by the emitted white wavelengths 22A and green 22B and red 22C fluorescence provided by the emitted blue wavelengths. The surface information is used for generating or updating the 3D model 29, and the fluorescence information (21 A, 21 C) are used for determining a composed scan information 20.
  • the one or more processors 2 is configured to determine a first difference between the infrared signals 24 and the green fluorescence information 22B and a second difference between the infrared signals and the red fluorescence information 22C, and the composed scan information 20 includes a summation of the first difference and the second difference.
  • the enhance internal structure relates to a caries lesion that has become more visible in comparison to the infrared signal 24 and in the example illustrated in FIG. 8B.
  • the secondary light source 90 may be arranged within and at a tip of the handheld intraoral scanner 10 just above a window of the tip.
  • the tip is inserted partly or fully into the patient’s mouth during scanning of the patient’s dentition, while the emitted light and reflected light is passing through the window.
  • the main contributor to the stray light is the window.
  • a shadow component 92 is arranged between the secondary light source 90 and the image sensor unit 4.
  • the shadow component 92 is arranged next to the secondary light source 92.
  • the shadow component 92 may be a box with following dimensions; a width of 1.5 mm to 3 mm, preferably around 2.2 mm +/-0.1 mm, a length of 2,5 and 4,5 mm, preferably around 3.5 +/-0.2 mm, a height of 1.5 mm to 2.5, and preferably around 1.9 mm +/-0.1 mm.
  • connection or “coupled” as used herein may include wirelessly connected or coupled.
  • the term “and/or” includes any and all combinations of one or more of the associated listed items. The steps of any disclosed method is not limited to the exact order stated herein, unless expressly stated otherwise.
  • An intraoral scanning system configured to determine 3D data of a dental object in an oral cavity, the intraoral scanning system comprising;
  • a handheld intraoral scanner including; o a projector unit configured to emit visible light and infrared light, o a filter unit configured to receive visible light signals and infrared light signals from at least the dental object caused by the emitted visible light and the emitted infrared light, respectively, and wherein the filter unit is configured to transmit filtered visible light signals and combined filtered light signals, wherein the combined filtered light signals include a combination of a first color light of the visible light signals and infrared light of the infrared light signals, and wherein the filter unit comprising:
  • ⁇ a plurality of single-color channels configured to output the filtered visible light signals
  • ⁇ a plurality of combined-color channels configured to output the combined filtered light signals
  • o an image sensor unit configured to acquire the filtered visible light signals and the combined filtered light signals
  • processors configured to: o determine an infrared signal based on a subtraction of the acquired combined filtered light signals with one or more color lights of the acquired filtered visible light signals, and o determine the 3D data of the dental object based on at least the acquired filtered visible light signals.
  • the one or more processors is configured to determine the 3D data of the dental object based on at least the filtered visible light signals and the first color light of the combined filtered light signals, and wherein the first color light of each of the plurality combined-color channels is determined based on an average of output from neighboring single-color channels to each of the plurality combined-color channels, and wherein the output includes a color that is the same as the first color light.
  • the image sensor unit includes a plurality of pixels, wherein each of the plurality of singlecolor channels and each of the plurality of combined-color channels is aligned to each of the plurality of pixels.
  • an infrared filter that is configured to block or partly block the infrared light signals for a first group of the plurality of single-color channels, the infrared filter is further configured to transmit the infrared light signals for a second group of the plurality of single-color channels, and wherein the second group of the plurality of single-color channels corresponds to the plurality of combined filter channels.
  • the pixel-pattern filter includes a first pixel-pattern surface and a second pixelpattern surface that is opposite to the first pixel-pattern surface, and the infrared filter is arranged on or in vicinity to the first pixel-pattern surface, and the image sensor is arranged on or in vicinity to the second pixel-pattern surface, or, • the infrared filter includes a first infrared surface and a second infrared surface that is opposite to the first infrared surface, and wherein the pixel-pattern filter is arranged on or in vicinity to the first infrared surface, and the image sensor unit is arranged on or in vicinity to the second infrared surface.
  • the 3D data includes 3D geometry data of the dental object and/or color data of the dental object.
  • the one or more processors is configured to increase a pulse repetition rate of the projector unit when the emitted visible light includes wavelengths between 350 nm and 500 nm.
  • the one or more processors is configured to synchronize a gain level of the image sensor unit according to a wavelength and/or a power level of the emitted light from the projector unit.
  • the projector unit is configured to constantly emit the infrared light while emitting the visible light.
  • the one or more processors is configured to:
  • the color light magnitude signal is a sum of red light, green light and blue light
  • the combined light magnitude signal is a sum of infrared light and red light, green light and blue light.
  • the filter unit includes a ratio between the plurality of combined-color channels and the plurality of single-color channels that is between 1/16 and 1/2 or 1/8 and 1/2.
  • the one or more processors is configured to control the projector unit during a scan sequence, and wherein the scan sequence includes at least a first time period and a second time period, wherein during:
  • the emitted visible light includes a first visible light that is turned on at a constant power level while the infrared light is turned on at a constant power level
  • the emitted visible light includes a second visible light that is turned on and off with a second pulse repetition rate while the infrared light is turned on at a constant power level, and the first visible light is turned on and off asynchronously to the on/off switching of the first visible light, and wherein the first visible light is turned on and off with a first pulse repetition rate.
  • the projector unit is configured to emit during a scan sequence a first visible light that includes white light and a second visible light that includes blue light, and wherein a first pulse repetition rate of the first visible light is different from a second pulse repetition rate of the second visible light, and wherein the infrared light is emitted constantly during the scan sequence.
  • the one or more processors is configured to determine an infrared signal based on the subtraction of the combined filtered light signals with the one or more color lights of the filtered visible light signals, and the inner region is determined by composed scan information that includes a difference between the infrared signal and the one or more color lights of the filtered visible light signals.
  • the one or more processors is configured to determine a first difference between the infrared signal and the green fluorescence information and a second difference between the infrared signal and the red fluorescence information, and wherein the composed scan information includes a summation of the first difference and the second difference.
  • the intraoral scanning system according to item 31 wherein the composed scan information includes a summation of the infrared signal, the green fluorescence information and the red fluorescence information.
  • the one or more processors is configured to determine the 3D data based on one or more colors of the filtered visible light signals.
  • a power level of the infrared light is set to a first power level during a primary time period and set to a second power level during a secondary time period, wherein the first power level is lower than the second power level.
  • the intraoral scanning system according to item 37 wherein the first power level is between 50% and 90% of the second power level, between 10 % and 50 % or between 5 % and 40 %. 39. The intraoral scanning system according to item 37, wherein the first power level is above a noise floor level of the image sensor unit.
  • the emitted visible light includes visible light pulses, and wherein the emitted infrared light is not a pulse.

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Abstract

La présente invention concerne un système de balayage intrabuccal conçu pour déterminer des données 3D d'un objet dentaire dans une cavité buccale. Le système de balayage intrabuccal comprend un dispositif de balayage intrabuccal portatif comprenant : une unité de projecteur conçue pour émettre une lumière visible et une lumière infrarouge, une unité de filtrage conçue pour recevoir des signaux de lumière visible et des signaux de lumière infrarouge provenant au moins de l'objet dentaire provoqués par la lumière visible émise et la lumière infrarouge émise, respectivement, l'unité de filtrage étant conçue pour transmettre des signaux de lumière visible filtrés et des signaux de lumière filtrés combinés, les signaux de lumière filtrés combinés comprenant une combinaison d'une première lumière de couleur des signaux de lumière visible et de la lumière infrarouge des signaux de lumière infrarouge, et l'unité de filtrage comprenant : une pluralité de canaux de couleur unique conçus pour délivrer les signaux de lumière visible filtrés, et une pluralité de canaux de couleurs combinées conçus pour délivrer les signaux de lumière filtrés combinés. Le système comprend en outre une unité de capteur d'image conçue pour acquérir les signaux de lumière visible filtrés et les signaux de lumière filtrés combinés, et un ou plusieurs processeurs configurés pour : déterminer un signal infrarouge sur la base d'une soustraction des signaux de lumière filtrés combinés avec une ou plusieurs lumières de couleur des signaux de lumière visible filtrés, et déterminer les données 3D de l'objet dentaire sur la base d'au moins les signaux de lumière visible filtrés.
PCT/EP2024/066772 2023-06-19 2024-06-17 Système de balayage intrabuccal pour déterminer un signal de couleur visible et un signal infrarouge Pending WO2024260907A1 (fr)

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DKPA202370304 2023-06-19
DKPA202370304 2023-06-19

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WO2024260907A1 true WO2024260907A1 (fr) 2024-12-26

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8659698B2 (en) * 2007-05-17 2014-02-25 Ilya Blayvas Compact 3D scanner with fixed pattern projector and dual band image sensor
EP2442720B1 (fr) 2009-06-17 2016-08-24 3Shape A/S Appareil d'exploration à focalisation
US20210140763A1 (en) * 2018-04-25 2021-05-13 Dentlytec G.P.L. Ltd. Properties measurement device
CN113936095A (zh) * 2021-09-28 2022-01-14 先临三维科技股份有限公司 扫描仪和扫描方法
WO2023004147A1 (fr) * 2021-07-23 2023-01-26 Align Technology, Inc Scanner intra-buccal avec séquençage d'éclairage et polarisation commandée

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8659698B2 (en) * 2007-05-17 2014-02-25 Ilya Blayvas Compact 3D scanner with fixed pattern projector and dual band image sensor
EP2442720B1 (fr) 2009-06-17 2016-08-24 3Shape A/S Appareil d'exploration à focalisation
US20210140763A1 (en) * 2018-04-25 2021-05-13 Dentlytec G.P.L. Ltd. Properties measurement device
WO2023004147A1 (fr) * 2021-07-23 2023-01-26 Align Technology, Inc Scanner intra-buccal avec séquençage d'éclairage et polarisation commandée
CN113936095A (zh) * 2021-09-28 2022-01-14 先临三维科技股份有限公司 扫描仪和扫描方法

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