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WO2025220458A1 - Procédé de traitement d'image, dispositif de traitement d'image et programme - Google Patents

Procédé de traitement d'image, dispositif de traitement d'image et programme

Info

Publication number
WO2025220458A1
WO2025220458A1 PCT/JP2025/012249 JP2025012249W WO2025220458A1 WO 2025220458 A1 WO2025220458 A1 WO 2025220458A1 JP 2025012249 W JP2025012249 W JP 2025012249W WO 2025220458 A1 WO2025220458 A1 WO 2025220458A1
Authority
WO
WIPO (PCT)
Prior art keywords
image
image processing
polar coordinate
talbot
processing method
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2025/012249
Other languages
English (en)
Japanese (ja)
Inventor
泰憲 坪井
生馬 太田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Konica Minolta Inc
Original Assignee
Konica Minolta Inc
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Filing date
Publication date
Application filed by Konica Minolta Inc filed Critical Konica Minolta Inc
Publication of WO2025220458A1 publication Critical patent/WO2025220458A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
    • G01N23/041—Phase-contrast imaging, e.g. using grating interferometers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
    • G01N23/046—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material using tomography, e.g. computed tomography [CT]
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis

Definitions

  • the present invention relates to an image processing method, an image processing device, and a program.
  • inspections have been conducted on the state of resin flow that occurs during molding, such as on resin gears manufactured by injection molding.
  • the state of resin flow is checked between normal and abnormal locations, and between normal lots and abnormal lots.
  • inspections use tools such as X-ray Talbot-Lau interferometers and microfocus CT.
  • the Talbot effect is a phenomenon in which, when coherent light passes through a first grating with slits at a regular interval, a grating image is formed at a regular interval in the direction of light travel. This grating image is called a self-image, and a Talbot interferometer places a second grating at the position where the self-image is formed, and measures the Moiré fringes that occur when the second grating is slightly shifted.
  • the X-ray Talbot imaging device can simultaneously obtain multiple Talbot images, such as absorption images, differential phase images, small-angle scattering images, and orientation analysis images.
  • the orientation angle image can confirm the orientation of fibers in a certain direction.
  • Talbot CT imaging which generates three-dimensional images (tomographic images) has also been developed by extending the Talbot imaging that generates the above-described two-dimensional images to three dimensions.
  • a subject is rotated by a predetermined angle, and two-dimensional Talbot images captured at multiple angles in three dimensions are used to calculate the signal value of each voxel, thereby obtaining a three-dimensional Talbot image.
  • Patent Documents 1 and 2 describe how arc-shaped cartilage can be linearized by polar coordinate conversion of medical images, which are differential phase images taken with a Talbot camera, making it easier to examine the thickness of the cartilage.
  • Patent Documents 1 and 2 describe polar coordinate conversion of medical images, which are differential phase images, but this is a simple polar coordinate conversion based on an origin set at a certain location. Therefore, even if Patent Documents 1 and 2 are applied to radially arranged parts, it does not necessarily make inspection easier.
  • the objective of the present invention is to facilitate the inspection of samples in which the microstructure within the material has either or both radial and radial components, or samples that have shapes that approximate circles and arcs centered on a certain point.
  • the image processing method of the present invention comprises: An image processing method in which an information processing device processes a Talbot image of a sample whose microstructure in a material has components in either or both of a radial direction and a radial direction, or a sample whose shape is close to a circle or a circular arc with a certain point as a center, A first step of obtaining the origin of polar coordinates; a second step of performing polar coordinate transformation based on the polar coordinate origin; Includes:
  • the image processing device of the present invention further comprises: An image processing device that processes Talbot images of a sample whose microstructure in a material has components in either or both of a radial direction and a radial direction, or a sample whose shape is close to a circle or a circular arc with a certain point as a center, an acquisition unit for acquiring a polar coordinate origin; a conversion unit that performs polar coordinate conversion based on the polar coordinate origin; Equipped with.
  • the program of the present invention also includes: A computer of an image processing device that processes Talbot images of a sample whose microstructure in the material has components in either or both of a radial direction and a radial direction, or a sample whose shape is close to a circle or a circular arc with a certain point as a center, A first step of obtaining the origin of polar coordinates; a second step of performing polar coordinate transformation based on the polar coordinate origin; Execute the following.
  • the present invention facilitates the inspection of samples in which the microstructure within the material has either or both radial and radial components, or has shapes that approximate circles and arcs centered at a point.
  • FIG. 1 is a schematic diagram illustrating an overall view of an X-ray Talbot imaging device.
  • FIG. 1 is a block diagram illustrating a schematic configuration of an information processing device.
  • FIG. 10 is a flowchart illustrating image processing.
  • 1 is an example of a scattering intensity image.
  • 1 is an example of an orientation angle image.
  • FIG. 1 is a schematic diagram of fiber orientation. 1 shows an example of a scattering intensity image and a guideline. 1 shows an example of a scattering intensity image and a guideline.
  • 10 is an example of a scattering intensity image after polar coordinate transformation.
  • 10 is an example of an orientation angle image after polar coordinate transformation and orientation angle correction.
  • FIG. 1 is a schematic diagram of fiber orientation.
  • FIG. 10 is an image diagram of normalization.
  • FIG. 10 is an image diagram of normalization. This is an image of polar coordinate transformation and joining after region division.
  • FIG. 1 is an image of a tomographic orientation CT of a helical gear
  • the analysis system 1 shown in FIG. 1 includes an X-ray Talbot imaging device 10 , a controller 19 , and an information processing device 20 .
  • the X-ray Talbot imaging device 10 is connected to an information processing device 20 via a controller 19 and a communication network N.
  • the communication network N is a LAN (Local Area Network), a WAN (Wide Area Network), the Internet, or the like.
  • the subject H is a part (sample) whose microstructure within the material affects the performance of the part, and is a sample whose microstructure within the material has either or both radial and radial components, or a sample having a shape that is close to a circle or arc centered at a certain point.
  • the materials include fiber reinforced plastics in general, resins in general, resins with added fillers in general, foam materials such as sponge, and casting materials such as aluminum die casting.
  • known materials include CFRP (Carbon-Fiber-Reinforced Plastics), CFRTP (Carbon Fiber Reinforced Thermo Plastics), and FRP (Fiber-Reinforced Plastics) such as GFRP (Glass-Fiber-Reinforced Plastics), which use carbon fiber or glass fiber as reinforcing fibers, and CMC (Ceramic Matrix Composites), which use ceramic fiber as a reinforcing material.
  • CFRP Carbon-Fiber-Reinforced Plastics
  • CFRTP Carbon Fiber Reinforced Thermo Plastics
  • FRP Fiber-Reinforced Plastics
  • GFRP Glass-Fiber-Reinforced Plastics
  • CMC Ceramic Matrix Composites
  • the term may also include composite materials made of multiple types of wood, such as plywood.
  • Resins used as materials include, but are not limited to, general-purpose plastics, engineering plastics, and super engineering plastics. Resins are often used as resin composites to which fillers with micro- or nano-sized structures are added to impart specific properties such as strength, and are used as plastic molded products. Fillers include organic materials, inorganic materials, magnetic materials, and metal materials. For example, when strength and rigidity are required in plastic molded products, composite materials such as PPS, POM, PA, PC, and PP as resins and aramid fiber, talc, and cellulose fiber as fillers may be used. Furthermore, when the plastic molded product is a plastic-magnet, composite materials such as nylon as resins and strontium ferrite and samarium cobalt as fillers may be used.
  • Microstructures include the orientation of fiber fillers such as CF (Carbon Fiber) and GF (Glass Fiber), and the orientation of long fiber CF woven into a matrix.
  • Other examples of microstructures include the orientation of flat fillers such as talc, the localized distribution of fine particles, mixed or added fine bubbles, voids, welds (seams in the resin flow), and blowholes (defective structures caused by fine bubbles that occur in aluminum castings).
  • samples that have a shape close to a circle or arc with a certain point as their center include rotating shafts, bearings, circular gears, sector gears, rollers, cams, etc.
  • Subject H is manufactured by injection molding or the like.
  • Other manufacturing methods include autoclave molding, RTM (Resin Transfer Molding), and SMC (Sheet Molding Compound) molding for FRP (Fiber Reinforced Plastics).
  • Other manufacturing methods include casting and die casting for metals.
  • the present invention is effective when applied to subject H manufactured using a molding method that causes molten resin or metal material to flow during manufacturing, or to such molded products that have been subjected to secondary processing (cutting, drilling, grinding, polishing).
  • the present invention is more effective when the subject H is a sample whose material has a microstructure having components in either or both of the radial and radial directions.
  • the X-ray Talbot imaging device 10 uses a Talbot-Lau interferometer equipped with a source grating 12. Note that it is also possible to use an X-ray Talbot imaging device using a Talbot interferometer equipped only with a first grating 14 and a second grating 15, without the source grating 12. Furthermore, the X-ray Talbot imaging device 10 may be configured so that an imaging jig (not shown) for fixing the subject H in a predetermined orientation is provided on the subject table 13, and the subject H can be rotated three-dimensionally to perform Talbot CT imaging.
  • FIG. 1 is a schematic diagram showing an overall view of an X-ray Talbot imaging device 10.
  • the X-ray Talbot imaging device 10 includes an X-ray generator 11, a source grating 12, a subject table 13, a first grating 14, a second grating 15, an X-ray detector 16, a support 17, and a base 18.
  • the grating directions of the source grating 12, the first grating 14 and the second grating 15 are the same.
  • a moiré image Mo of a subject H at a predetermined position relative to the subject table 13 can be captured using a method based on the principles of the fringe scanning method, and the moiré image Mo can be analyzed using the Fourier transform method, thereby reconstructing at least three types of images (two-dimensional images) (referred to as reconstructed images). That is, there are three types of images: an absorption image (same as a normal X-ray absorption image) that visualizes the average component of the moiré fringes in the moiré image Mo; a differential phase image that visualizes the phase information of the moiré fringes; and a small-angle scattering image that visualizes the visibility of the moiré fringes.
  • the sine wave graph is a graph in which the horizontal axis represents the relative angle ⁇ between the sample and the grating, and the vertical axis represents the small-angle scattering signal value of a certain pixel.
  • the sine wave graph is expressed as in the following equation (1):
  • the fitting parameters are the amplitude A, average B, and phase C of the sine wave in the above formula (1).
  • the image showing the amplitude value for each pixel is called the orientation image
  • the image showing the average value for each pixel is called the scattering intensity image
  • the image showing the phase for each pixel is called the orientation angle image.
  • the orientation angle image provides the distribution of fiber orientation relative to the main direction.
  • the images (orientation degree image, scattering intensity image, and orientation angle image) generated by recombining the reconstructed images will be referred to as an orientation analysis image.
  • the small-angle scattering image and the differential phase image have angle dependency with respect to the lattice direction. Therefore, as described above, differential phase images or small-angle scattering images taken at multiple (three or more) grating facing angles are used, and after aligning the images, a sine wave is fitted for each pixel to extract fitting parameters.
  • the sine wave graph is a graph in which the horizontal axis represents the relative angle ⁇ between the sample and the grating, and the vertical axis represents the differential phase signal value or small-angle scattering signal value of a certain pixel.
  • the sine wave graph is expressed as shown in Equation (1) above.
  • the differential phase image fitting is performed on the absolute value of the differential phase signal value of a pixel, or the sign of A is inverted according to ⁇ .
  • the differential phase signal value or small-angle scattering signal value of a pixel at a certain relative angle ⁇ can be obtained.
  • Talbot photography which generates various two-dimensional images using a Talbot interferometer and a Talbot-Lau interferometer.
  • Talbot CT imaging is a three-dimensional extension of Talbot imaging, which generates various two-dimensional images.
  • the CT rotation axis is rotated by a predetermined angle (e.g., 1°) to obtain Moiré fringe images of 180° or 360°, and processing is performed based on a fringe scanning method or a Fourier transform method to generate two-dimensional projection images (absorption image, small-angle scattering image, differential phase image).
  • the two-dimensional projection images (absorption image, small-angle scattering image, differential phase image) are used to calculate the signal value of each voxel, thereby generating three-dimensional CT images (absorption tomography image, small-angle scattering tomography image, phase tomography image) corresponding to the two-dimensional projection images.
  • the control unit 51 performs CT reconstruction and image processing using small-angle scattering images taken with the subject oriented in multiple directions relative to the CT rotation axis to generate three-dimensional orientation analysis images (orientation degree tomographic image, orientation angle tomographic image, and scattering intensity image).
  • Talbot photography will refer to not only the photography of the moiré image Mo, but also the generation of the above-mentioned reconstructed image, orientation analysis image, 3D CT image, 3D orientation analysis image, and secondary image.
  • the reconstructed image, the orientation analysis image, the three-dimensional CT image, the three-dimensional orientation analysis image, and the secondary image will be collectively referred to as Talbot images.
  • the fringe scanning method is a method of obtaining a high-resolution reconstructed image by moving one of multiple gratings in the direction of the slit period by 1/M of the grating slit period (M is a positive integer, M>2 for absorption images, M>3 for differential phase images and small-angle scattering images) and capturing M images M times, then reconstructing the images using the resulting moiré images Mo.
  • the Fourier transform method involves capturing a single moiré image (Mo) using an X-ray Talbot imaging device in the presence of a subject, and then performing a Fourier transform on the moiré image (Mo) during image processing to reconstruct and generate an image such as a differential phase image.
  • This embodiment is a so-called vertical type, with the X-ray generator 11, source grating 12, subject table 13, first grating 14, second grating 15, and X-ray detector 16 arranged in this order in the z direction, which is the direction of gravity.
  • the z direction is the direction of X-ray irradiation from the X-ray generator 11.
  • the X-ray generator 11 is equipped with an X-ray source 11a, such as a Coolidge X-ray source or a rotating anode X-ray source, which are widely used in medical settings. Other X-ray sources can also be used.
  • the X-ray generator 11 of this embodiment is designed to irradiate X-rays in a cone beam shape from a focal point. In other words, as shown in Figure 1, the X-rays are irradiated so that they spread out the further away from the X-ray generator 11, with the X-ray irradiation axis Ca coinciding with the z direction as the central axis (i.e., the X-ray irradiation range).
  • the controller 19 (see Figure 1) is configured as a computer with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), input/output interface, etc. (not shown) connected to a bus.
  • the controller 19 is also provided with appropriate means and devices, such as input means including an operating unit, output means, storage means, and communication means (not shown).
  • the controller 19 performs overall control of the X-ray Talbot imaging device 10. That is, for example, the controller 19 is connected to the X-ray generator 11, and is able to set the tube voltage, tube current, irradiation time, etc. for the X-ray source 11a.
  • the information processing device 20 includes a control unit 21, an operation unit 22, a communication unit 23, a storage unit 24, and a display unit 25.
  • the control unit 21 is configured with a CPU (Central Processing Unit), a RAM (Random Access Memory), etc.
  • the CPU of the control unit 21 reads out various programs stored in the storage unit 24, loads them into the RAM, and executes various processes (e.g., image processing, which will be described later) in accordance with the loaded programs, thereby controlling the operation of each unit of the information processing device 20.
  • the control unit 21 functions as an acquisition unit that acquires the origin of polar coordinates.
  • the control unit 21 functions as a conversion unit that performs polar coordinate conversion based on the origin of polar coordinates.
  • the operation unit 22 includes a keyboard equipped with cursor keys, numeric input keys, and various function keys, a pointing device such as a mouse, and a touch panel laminated on the surface of the display unit 25.
  • the operation unit 22 is configured to be operable by the operator.
  • the operation unit 22 also outputs various signals to the control unit 21 based on operations performed by the operator.
  • the communication unit 23 is capable of sending and receiving various signals and data to and from other devices connected via the communication network N.
  • the storage unit 24 is composed of non-volatile semiconductor memory, a hard disk, etc., and stores various programs executed by the control unit 21, parameters required for executing the programs, various data (e.g., Talbot images), etc.
  • the display unit 25 is composed of a monitor such as an LCD (Liquid Crystal Display), and displays various screens according to the instructions of the display signal input from the control unit 21.
  • a monitor such as an LCD (Liquid Crystal Display)
  • LCD Liquid Crystal Display
  • Image processing of the Talbot image in the information processing device 20 will be described with reference to FIG. Image processing starts when the control unit 21 receives a signal to start image processing input by the user using the operation unit 22 . It is assumed that the Talbot image has been sent from the X-ray Talbot imaging device 10 to the information processing device 20 and has already been stored in the storage unit 24 before the start of image processing.
  • the control unit 21 acquires a Talbot image from the storage unit 24 (step S1).
  • the control unit 21 causes the display unit 25 to display the Talbot image (step S2).
  • the scattering intensity image P1 shown in FIG. 4 or the orientation angle image P2 shown in FIG. 5 is acquired by Talbot photography of the subject H, which is a gear manufactured by injection molding.
  • the gate GT is the gate location during injection molding that appears in the scattering intensity image P1.
  • the weld line WL is the weld line that occurred during injection molding that appears in the scattering intensity image P1.
  • FIG. 6 is a schematic diagram SD1 that visualizes the fiber orientation for each specified region in terms of line direction.
  • the control unit 21 specifies the origin of polar coordinates on the Talbot image (step S3; first step).
  • the user may use the operation unit 22 to select an arbitrary position with a cursor.
  • the control unit 21 may perform a Hough transform on the Talbot image, detect arcs at multiple locations, and display the centers of the arcs on the display unit 25 as candidate points for selection, allowing the user to select from the candidate points.
  • the origin of the polar coordinates may be set not only near the center of the subject H but also at the position of the gate GT of the subject H.
  • the range of polar coordinate conversion in the Talbot image may be specified after specifying the polar coordinate origin O.
  • An example of a method for the user to specify the range of polar coordinate conversion will be described with reference to FIG.
  • the user can specify the range to be converted to polar coordinates by moving the start guideline G2 and the end guideline G3.
  • the user can also specify the direction of rotation from the start guideline G2 to the end guideline G3. If the rotation direction is specified as clockwise, the larger area between the start guideline G2 and the end guideline G3 is specified as the range to be converted to polar coordinates. If the rotation direction is specified as counterclockwise, the smaller area between the start guideline G2 and the end guideline G3 is specified as the range to be converted to polar coordinates.
  • the control unit 21 converts the Talbot image into polar coordinates (step S4; second step).
  • the control unit 21 causes the polar coordinate converted Talbot image to be displayed on the display unit 25 (step S5; third step).
  • the formula for converting the XY coordinate system I(x, y) into the polar coordinate system I( ⁇ , ⁇ ) is shown below.
  • 9 is a scattering intensity image P4 after polar coordinate conversion.
  • the gate GT and weld line WL are also converted and appear in the scattering intensity image P4. In this way, the teeth of the subject H, which is a gear, are aligned side by side, making inspection easier.
  • the control unit 21 determines whether the Talbot image has directionality (step S6). If it is determined that the Talbot image has directionality (step S6; YES), the control unit 21 advances the image processing to step S7. If it is determined that the Talbot image does not have directionality (step S6; NO), the control unit 21 advances the image processing to step S9.
  • a Talbot image having directionality means that the value of each pixel in the Talbot image is set based on a certain direction.
  • directional Talbot images include small-angle scattering images, differential phase images, and orientation angle images.
  • the control unit 21 corrects the direction angle of the Talbot image (step S7; fourth step).
  • the control unit 21 causes the display unit 25 to display the Talbot image whose direction angle has been corrected (step S8; fifth step).
  • the upward direction of the paper surface is defined as 0°.
  • the orientation angle image P2 has been converted to polar coordinates in step S4, and the polar coordinate converted orientation angle image and the orientation image P3 do not correspond. Therefore, the orientation angle of the polar coordinate converted orientation angle image needs to be converted from XY coordinates to polar coordinates.
  • the orientation angle is corrected (converted) by setting the radial direction from the polar coordinate origin to 0° and obtaining the orientation direction relative to the radial direction.
  • 10 is an orientation angle image P5 after polar coordinate transformation and orientation angle correction.
  • the orientation angle image P5 corresponds to an image P6 in which the orientation angle has been corrected and which shows the orientation.
  • Figure 11 is a schematic diagram SD2 that visualizes the fiber orientation for each specified region using line directions.
  • the orientation of the fibers can be easily recognized, as indicated by the arrows in the figure.
  • the signal component in the radial direction (I r ') perpendicular to the radial direction (I c ') can be explicitly separated and extracted into two and depicted as shown in the following equations (3) and (4).
  • nearest neighbor interpolation or the like can be applied as a method for interpolating signal values between pixels when polar coordinate transformation is performed, rather than linear interpolation, polynomial interpolation, or spline interpolation.
  • step S9 determines whether or not normalization is required. If normalization is required (step S9; YES), the control unit 21 proceeds to step S10 for image processing. If normalization is not required (step S9; NO), the control unit 21 terminates image processing.
  • the control unit 21 normalizes the polar coordinate converted Talbot image (step S10; sixth step).
  • the control unit 21 causes the display unit 25 to display the normalized Talbot image (step S11; seventh step).
  • normalization of the Talbot image after polar coordinate transformation will be described.
  • the distance from the origin of the polar coordinates to the periphery (edge) of the subject H is not necessarily constant.
  • the portion corresponding to the periphery of the subject H will not be located at a constant position in a certain direction (for example, the r direction, which is the upward direction on the paper).
  • the portion corresponding to the periphery of the subject H is corrected (normalized) so that it is located at a constant position in a certain direction in the Talbot image after the polar coordinate conversion. This makes inspection easier. Specifically, if the origin of the polar coordinates is set at the gate, the flow direction can be explicitly analyzed in the arc direction and the radial direction.
  • FIG. 12 shows an image I1 of the Talbot image, an image I2 after polar coordinate conversion, and an image I3 after normalization.
  • the subject H is shown as a circle.
  • the origin O of the polar coordinates is not at the center of the subject H. Therefore, the distance from the origin O of the polar coordinates to the periphery of the subject H is not constant, as indicated by the arrow. Therefore, the value of the radial direction r is not constant, as shown in image I2. Therefore, the control unit 21 normalizes the value of the radial direction r to make it constant, thereby correcting it as shown in image I3.
  • Figure 12 has been described using a circular subject H, this is not limiting.
  • subject H may be rectangular.
  • Figure 13 also shows image I4 of the Talbot image, image I5 after polar coordinate conversion, and image I6 after normalization.
  • steps S4-5 and S6-8 may be reversed.
  • control unit 21 may perform a comparative analysis of the repetitive shape of the subject H for the Talbot image after polar coordinate conversion.
  • the repetitive shape of the subject H is, for example, the teeth of a gear (subject H).
  • the control unit 21 calculates a region of interest (ROI) of a certain size for each repetitive shape in the Talbot image after polar coordinate conversion.
  • the ROI is set as an ROI (interest) and analyzed for each ROI, thereby performing repeated analysis of similar shapes in the horizontal direction (polar coordinate ⁇ direction).
  • the ROI may be set automatically by image analysis performed by the control unit 21, or manually by the user using the operation unit 22.
  • the control unit 21 may cause the display unit 25 to display the distribution of the orientation angles for each ROI.
  • the control unit 21 may cause the display unit 25 to display the difference between each ROI and a reference image created by obtaining an average/median value from a plurality of ROIs.
  • the control unit 21 may obtain the frequency of occurrence for each ROI of the orientation angle arbitrarily set by the user, and cause the display unit 25 to display a bar graph or the like for each ROI. This makes it easier to determine which parts are abnormal relative to other parts in a repeating shape.
  • control unit 21 may store settings including the polar coordinate origin, the polar coordinate start point and end point, and the rotation direction in the storage unit 24. Then, in step S4, the control unit 21 may perform polar coordinate conversion within a set range based on the stored settings. This eliminates the need for the user to set the same settings.
  • the control unit 21 may divide the Talbot image (step 8), perform polar coordinate conversion for each divided Talbot image, and combine the images after the polar coordinate conversion (step 9). Note that angle correction and normalization may be performed as necessary.
  • the division and combination will be explained using Fig. 14.
  • the original Talbot image I7 is divided at the position of the dashed line as in Talbot image I8, and each is subjected to polar coordinate conversion to obtain Talbot images I9 and I10 after polar coordinate conversion. By combining these two, a combined Talbot image I11 after polar coordinate conversion is obtained.
  • the user selects the division position of the Talbot image on the Talbot image using the operation unit 22 . In this way, even if the curvature of the object H is not constant, such as when the object H is a cam, the Talbot image after polar coordinate conversion will be one, making inspection easier.
  • the present invention is also applicable to cases where the subject H is a helical gear.
  • a method for applying the present invention will be specifically described with reference to Fig. 15.
  • the left diagram of Fig. 15 is a side view of the helical gear HG
  • the right diagram of Fig. 15 is a front view of the helical gear HG.
  • the control unit 21 acquires a reference axis A that passes through the vicinity of the center of the helical gear HG.
  • the control unit 21 performs Talbot CT imaging on planes L1, L2, and L3 orthogonal to the reference axis A, and obtains three-dimensional CT images and three-dimensional orientation analysis images in three orthogonal coordinate systems.
  • step S3 the control unit 21 sets the intersection point with the reference axis A as the origin of polar coordinates in the three-dimensional CT image and the three-dimensional orientation analysis image.
  • step S4 the control unit 21 adjusts the polar coordinate positions of the same tooth portion by changing the 0-degree position of the polar coordinates using the helix angle of the helical gear HG and the acquisition positions of the 3D CT image and the 3D orientation analysis image in the direction of the reference axis A. Then, the control unit 21 performs polar coordinate conversion. This allows comparison of the same tooth portion.
  • the control unit 21 may stack the three registered 3D CT images and 3D orientation analysis images in the polar coordinate system and reconstruct them as volume data.
  • the image processing method is an image processing method in which an information processing device processes Talbot images of a sample whose internal microstructure has components in either or both of the radial and radial directions, or a sample whose shape is close to a circle or arc with a certain point as its center.
  • the image processing method includes a first step (step S3) of acquiring the origin of polar coordinates, and a second step (step S4) of performing polar coordinate transformation based on the origin of polar coordinates. This facilitates the examination of samples in which the microstructure within the material has either or both radial and radial components, or has shapes that approximate circles and arcs around a point.
  • the subject is a gear
  • the subject has a functional shape that you want to observe at the edge, the above comparison of any shape becomes easy.
  • the image processing device processes Talbot images of a sample whose microstructure in the material has components in either or both of the radial and radial directions, or a sample whose shape is close to a circle or arc with a certain point as its center.
  • the image processing device includes an acquisition unit (control unit 21) that acquires the origin of polar coordinates, and a conversion unit (control unit 21) that performs polar coordinate conversion based on the origin of polar coordinates. This facilitates the examination of samples in which the microstructure within the material has either or both radial and radial components, or has shapes that approximate circles and arcs around a point.
  • the program also causes a computer in an image processing device (information processing device 20) that processes Talbot images of a sample whose microstructure within the material has components in either or both of the radial and radial directions, or a sample whose shape is close to a circle or arc centered at a certain point, to execute a first step (step S3) of acquiring the polar coordinate origin and a second step (step S4) of performing polar coordinate conversion based on the polar coordinate origin.
  • a first step S3 of acquiring the polar coordinate origin and a second step (step S4) of performing polar coordinate conversion based on the polar coordinate origin.
  • This disclosure can be used in image processing methods, image processing devices, and programs.

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Abstract

La présente invention facilite l'inspection d'un échantillon dans lequel une structure fine dans un matériau présente une composante dans la direction du vecteur radial et/ou une composante dans la direction radiale, ou un échantillon ayant une forme circulaire et une forme presque arquée centrée sur un certain point. L'invention concerne un procédé de traitement d'image permettant de traiter une image de Talbot d'un échantillon dans lequel une structure fine dans un matériau présente une composante dans la direction du vecteur radial et/ou une composante dans la direction radiale, ou un échantillon ayant une forme circulaire et une forme presque arquée centrée sur un certain point, le procédé de traitement d'image comprenant une première étape (étape S3) permettant d'acquérir une origine de coordonnées polaires, et une seconde étape (étape S4) permettant d'effectuer une conversion de coordonnées polaires sur la base de l'origine de coordonnées polaires.
PCT/JP2025/012249 2024-04-16 2025-03-26 Procédé de traitement d'image, dispositif de traitement d'image et programme Pending WO2025220458A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004178976A (ja) * 2002-11-27 2004-06-24 Hitachi High-Technologies Corp 試料観察方法
JP2015104441A (ja) * 2013-11-29 2015-06-08 コニカミノルタ株式会社 医療用画像撮影システム
JP2017225644A (ja) * 2016-06-23 2017-12-28 コニカミノルタ株式会社 医療用画像処理装置及び医療用画像撮影システム
JP2018060453A (ja) * 2016-10-07 2018-04-12 グローリー株式会社 貨幣分類装置及び貨幣分類方法
JP2021089195A (ja) * 2019-12-04 2021-06-10 コニカミノルタ株式会社 成型支援装置および成型支援方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004178976A (ja) * 2002-11-27 2004-06-24 Hitachi High-Technologies Corp 試料観察方法
JP2015104441A (ja) * 2013-11-29 2015-06-08 コニカミノルタ株式会社 医療用画像撮影システム
JP2017225644A (ja) * 2016-06-23 2017-12-28 コニカミノルタ株式会社 医療用画像処理装置及び医療用画像撮影システム
JP2018060453A (ja) * 2016-10-07 2018-04-12 グローリー株式会社 貨幣分類装置及び貨幣分類方法
JP2021089195A (ja) * 2019-12-04 2021-06-10 コニカミノルタ株式会社 成型支援装置および成型支援方法

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