WO2018126497A1 - Tip-modulated endoscopic polarization imaging system and measuring method - Google Patents

Abstract

A tip-modulated endoscopic polarization imaging system and an endoscopic polarization imaging measuring method thereof. The system comprises: a light source (400), a polarization generating device (110), a polarization analyzing device (120), an imaging device (310), a mechanical tip-fixing component (100), a movement controller (200), an image acquisition device (300), and a data processing terminal (500). The polarization generating device (110) and the polarization analyzing device (120) are installed at the mechanical tip-fixing component (100) and are integrated with the light source (400) and the imaging device (310) into a tip of an endoscope. The system integrates a polarization modulating device and a demodulating device with the tip of the endoscope to form a single component, enabling flexible and convenient access to different locations for large-scale polarization detection in various endoscopic areas. Incident polarized light is modulated, and demodulated polarized light is received, both without passing through other light transmission media, significantly reducing the impact of a transmission path and the external environment on light polarization. The system has the advantages of a highly integrated tip, a small structure and quick imaging.

Description

End-end modulation endoscopic polarization imaging system and measuring method Technical field

The present invention relates to the field of endoscopic imaging measurement, and in particular to a head-end modulated endoscopic polarization imaging system and a measurement method.

Background technique

Polarized optical imaging methods have the advantages of no damage, high resolution, and functional imaging of the measured tissue. Existing studies have shown that polarized optical imaging methods can provide more obvious organization than traditional unpolarized optical imaging methods. Contrast resolution, which can visually reflect differences in tissue microstructure and morphology, and has shown potential for early cancer diagnosis.

Endoscopic detection provides a more convenient, quicker, and more efficient method of examination than traditional biopsy methods, and does not cause significant trauma to individuals. Most of the current traditional endoscopic detection methods use ordinary optical imaging, which does not distinguish well between diseased tissue and normal tissue. Therefore, some techniques for combining polarized optical imaging with endoscopic detection have emerged.

The invention disclosed in the publication No. CN104161493A, entitled "Polarization Imaging Endoscope System and Endoscopic Imaging Method" discloses a polarization imaging system using a liquid crystal phase retardation wave plate as a polarizing device with a focal plane as a detection mode And imaging methods.

"Ji Q, Elson D SA high definition Mueller polarimetric endoscope for tissue characterisation. [J]. Scientific Reports, 2016, 6." discloses an endoscopic polarization measurement system and method for polarization modulation and demodulation using external rotation .

The above two measurement methods rely on the rigid endoscope as a light guiding and imaging medium, and the light source and the imaging end are far from the end of the endoscope, which is very sensitive to the external environment due to the transmission of polarized light in the medium, and Since the rigid endoscope cannot be bent, the use of the above two measurement methods in practice is limited.

"Vizet J, Manhas S, Deby S, et al. Demonstration of Mueller polarimetry through an optical fiber for endoscopic applications [C]//CLEO: Applications and Technology. 2014: 3047-54.", "Vizet J, Manhas" S, Tran J, et al. Optical fiber-based full Mueller polarimeter for endoscopic imaging using a two-wavelength simultaneous measurement method. [J]. Journal of Biomedical Optics, 2016, 21(7)." and the literature "Rivet S, Bradu A, Podoleanu A.Fast full 4x4 Mueller polarimeter for Endoscopic applications[C]//SPIE BiOS.2016." Announced the use of optical fiber as a light-guided and imaging medium for endoscopic polarization measurement methods, both of which require mechanical displacement devices at the head end for surface imaging, otherwise only single Point measurement.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the above drawbacks, and provide a head-end modulated endoscopic polarization imaging system and a measuring method, which realize polarization polarization modulation and demodulation functions at the end of the endoscope, and can perform polarization imaging on the measured tissue.

In order to achieve the above object, the present invention is achieved by the following technical solutions:

A head-end modulated endoscopic polarization imaging system includes a light source, a polarization generating device, a polarization analyzing device, an imaging device, a head end mechanical fixture, a motion controller, an image acquisition device, and a data processing terminal.

The light emitted by the light source is scattered on the object to be measured by the polarization generating device, is imaged by the polarization analyzing device, and is collected by the image capturing device and transmitted to the data processing terminal.

The polarization generating device and the polarization analyzing device are mounted on the head end mechanical fixing member, and are integrated with the light source and the imaging device at the end of the endoscope.

The data processing terminal connects and controls the motion controller to respectively control a polarization generating state of the polarization generating device and a polarization detecting state of the polarization analyzing device.

The polarization generating device includes a polarizing plate, a polarizing bearing, a polarizing transmission member, a polarizing transmission member, and a polarizing micromotor.

The polarizing transmission member and the polarizing transmission member are friction transmission wheels.

The polarizing transmission member and the polarizing transmission member are gears or belt transmission wheels.

The polarizing micromotor is mounted and fixed on the head end mechanical fixing component, and the polarizing transmission component is mounted on the output shaft of the polarizing micromotor, and the polarizing transmission component is assembled and assembled with the deflection component by the transmission component. The transmission component is fixed on the outer ring of the polarizing bearing, and the inner ring of the polarizing bearing is mounted and fixed on the mechanical fixing member of the head end, and the polarizing plate is fixedly attached to the outer ring of the polarizing bearing.

The rotation of the polarizing bearing is driven by the rotation of the polarizing micromotor to change the polarization state of the initial polarizing plate for modulating the light into linearly polarized light of different preset polarization states.

The polarization analysis device includes an analyzer polarizing plate, a polarization detecting bearing, a deviation detecting transmission member, a deviation detecting transmission member, and a polarization detecting micro motor.

The deviation detecting transmission member and the deviation detecting transmission member are friction transmission wheels.

The deviation detecting transmission member and the deviation detecting transmission member are gears or belt transmission wheels.

The detecting micromotor is mounted on the head end mechanical fixing component, and the detecting transmission component is mounted on the output shaft of the detecting micromotor, and the detecting transmission component and the detecting bias are fitted and assembled by the transmission component, and the biasing is transmitted by the transmission component. It is fixed on the outer ring of the differential bearing. The inner ring of the differential bearing is mounted on the head end mechanical fixing member, and the polarizing plate is fixedly attached to the outer ring of the detecting bearing.

The polarization of the polarization detecting plate is changed by the rotation of the differential motor to detect the polarization state of the polarization detecting plate, and is used for detecting linearly polarized light of different polarization states after being scattered by the object.

The light source includes a broadband source proximal end for generating broadband light, a band pass filter for filtering the broadband light to generate preset narrowband light, a light guiding medium for narrowband optical transmission, and A distal end of the light source that exits the narrowband light transmitted through the light guiding medium.

The polarizing angle θ _{1 of the} polarizing plate has a value range of [0, π], and the data processing terminal calculates the need for the polarizing micro motor according to the angle θ ₁ and the gear ratio of the polarizing gear and the polarizing transmission gear. The angle of rotation sends a command to the motion controller to control the tilting of the micromotor to the specified position.

The polarization angle θ _{2 of the} polarizing plate has a value of [0, π], and the data processing terminal calculates the differential motor according to the angle θ ₂ and the gear ratio of the analyzer gear and the analyzer gear. The angle of rotation is required to send a command to the motion controller to control the tilting of the micromotor to the specified position.

The data processing terminal is a computer or an embedded processing system.

The invention also provides a head-end modulation endoscopic polarization imaging measuring method, the measuring steps are as follows:

a. The light emitted by the light source is polarized by the polarization generating device and then irradiated onto the object to be tested;

b. The polarization analysis device detects light that has been scattered and detected by the object to be detected and is intensity-informed by the imaging device;

c. Change the polarization state of the polarized state N and the polarization polarization state M times in steps a and b, respectively, and take the surface polarization image of the MN image, and establish a system equation about the incident light and the outgoing light of the object to be measured. Mueller matrix information of the surface of the object.

The system equation of the mueller matrix for solving the surface of the object to be measured in step c can be described as AM _'s = P, where A is a MN x 9-order matrix, which is a combination of the polarization generation state and the polarization analysis state set according to step c. The determined coefficient matrix, P is a MN×1 order column vector, each row of the vector represents the intensity value of the polarization image obtained for each measurement, and the system equation can be obtained to obtain the mueller matrix of the measured object represented by the 9×1 order vector. M' _s , after the elements are rearranged, the mueller matrix M _{s of the} measured object is obtained.

The invention has the beneficial effects that: compared with the prior art, the invention integrates the polarization modulation and demodulation device on the end of the endoscope to make it a whole, and can flexibly and conveniently perform a wide-range endoscopic region for different positions. The polarization detection, the modulation of the incident polarized light and the reception of the demodulated polarized light do not pass through other optical transmission media, greatly reducing the influence of the transmission path and the external environment on the polarization state of the light, and improving the imaging quality.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram of the system structure of a specific embodiment of the present invention.

FIG. 2 is a schematic structural view of the polarization measuring head end of FIG. 1. FIG.

3 is a schematic structural view of the light source of FIG. 1.

4 is a schematic structural view of the imaging end of FIG. 1.

Figure 5 is a schematic view showing the structure of the head end mechanical fixing member of Figure 2;

detailed description

The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings, in which the advantages and features of the invention can be more readily understood by those skilled in the art.

1 and 2, the head-end modulation-based endoscopic polarization imaging system described in the present invention includes a medical cold light source 400, a polarization generating device 110, a polarization analyzing device 120, an imaging device 310, a head end mechanical fixture 100, and motion. The controller 200, the image acquisition device 300, and the data processing terminal 500.

The light generated by the medical cold light source 400 enters the polarization generating device 110, the light passing through the polarization generating device becomes linearly polarized light, is irradiated to the measured tissue 600, is scattered by the measured tissue, and is detected by the polarization analyzing device 120 to enter the imaging device 310. The polarization analyzing device 120 detects linearly polarized light of a predetermined angle.

The polarization generating device 110 and the polarization analyzing device 120 are controlled by the motion control device 200 to rotate the polarizing plate to a predetermined angle to generate different polarizing and detecting states.

The distal end 402 of the medical cold light source, the polarization generating device 110, the polarization analyzing device 120, and the imaging device 310 are all fixed on the head end mechanical fixture 110 to form an endoscopic polarization measuring head end. The image acquired by the imaging device 310 is collected by the image acquisition device 300 and transmitted to the data processing terminal 500 for recording and processing.

Referring to FIG. 2, a preferred polarization generating device includes a polarizing plate 114, a polarizing bearing 115, a polarizing gear 113, a polarizing transmission gear 112, and a polarizing micromotor 111 for communicating The incident light passing through the device is modulated into linearly polarized light of a specified polarization state.

A preferred mounting method is that the polarizing micromotor 111 is mounted and fixed on the base 101 of the head end mechanical fixing member 110. The polarizing transmission gear 112 is mounted on the output shaft of the polarizing micromotor 111, and the polarizing transmission gear 112 is The polarizing gear 113 is fitted and assembled, and the polarizing gear 113 is fixed to the outer ring of the polarizing bearing 115. The inner ring of the polarizing bearing 115 is mounted and fixed on the head end mechanical fixing base 111, and the polarizing plate 114 is fixedly attached to the polarizing plate 114. The outer ring of the polarizing bearing 115.

Referring to FIG. 2, a preferred polarization analysis apparatus includes an analyzer polarizing plate 124, an analyzer bearing 125, an analyzer gear 123, an analyzer transmission gear 122, and an analyzer micromotor 121 for passing the device. The received light specifies the linearly polarized light of the polarization state.

A preferred mounting method is that the differential micromotor 121 is mounted and fixed on the base 101 of the head end mechanical fixing member 110, and the differential transmission gear 122 is mounted on the output shaft of the analyzer micromotor 121, and the differential transmission gear 122 is The analyzer gear 123 is assembled and assembled, and the analyzer gear 123 is fixed to the outer ring of the analyzer bearing 125. The inner ring of the analyzer bearing 125 is mounted and fixed on the head end mechanical fixture base 101, and the polarizing plate 124 is fixedly attached thereto. The outer ring of the bearing 125 is detected.

In this embodiment, the polarizing plate and the polarizing plate are both thin film polarizers, but those skilled in the art can understand that the polarizing plate and the polarizing plate can use linear polarizing plates of other materials. . The transmission mode adopted in the embodiment is a gear-fitting transmission mode, and in addition to this, a non-gear transmission mode such as a belt transmission or a rolling friction transmission can be employed.

In the embodiment shown in FIG. 3, medical cold light source 400 includes a light source back end 401, a narrow band filter 402, a light directing medium 403, and a light source head end 404. The broadband light emitted from the rear end 401 of the light source passes through the narrow band filter 402 to become narrow band light, and the narrow band light is transmitted to the light source head end 404 through the light guiding medium 403. In this embodiment, the rear end 401 of the light source is a wide-spectrum xenon lamp, but is not limited thereto and may use other light sources, such as LEDs or tributary lamps; the filter 402 is a 632 nm narrow-band optical filter, but is not limited to only This band; the light guiding medium 404 is a fiber bundle, but is not limited thereto, and other light guiding media such as a liquid optical waveguide beam may be employed.

In the embodiment shown in FIG. 4, the composition of the imaging device 310 includes a wide-angle CMOS head-end imaging lens 311 and a CMOS chip 312.

Referring to a preferred head end mechanical fastener shown in Figure 5(a), a mount base 101 and a mount cover 102 are included. The fixing base 101 includes a fixing hole C110 of the polarizing micro motor, a head end shaft passing hole K111 of the polarizing micro motor, a positioning hole C109 of the polarizing gear, a fixing hole C106 of the differential detecting micro motor, and a head end of the differential detecting micro motor. Shaft through hole K108, placement hole C107 of the analyzer gear, and fixing of the light source The hole K104, the polarizing bearing, the positioning hole C102 of the polarizing gear and the polarizing plate, the CMOS mounting hole C105, the CMOS head end imaging lens 311 pass through the fixing hole K103, and the polarization detecting bearing, the analyzer gear, and the polarization detecting polarizer Place the hole C101. The fixture cover shown in FIG. 5(b) includes a light-emitting aperture K202 for emitting light emitted from the light source and a reception aperture K201 for receiving the scattered light of the measured tissue.

The polarization generating device and the polarization analyzing device used in the conventional polarization imaging method are both large, so they are generally disposed outside the body, and the polarization state of the polarized light changes during the transmission of the light guiding medium to the distal end of the endoscope, thereby measuring The result is interference. In this embodiment, the polarization generating device, the polarization analyzing device, the light source, and the imaging device are all mounted at the head end of the endoscope, which can overcome the influence of the above transmission problem.

The present invention also provides an endoscopic polarization imaging method based on head-end modulation, which is described in conjunction with a preferred embodiment:

The steps for performing endoscopic polarization measurements are as follows:

a. The light emitted from the light source 400 is polarized by the polarization generating device 110 and then irradiated onto the tissue to be tested.

b. Light scattered by the measured tissue is detected by the polarization analyzing device 120 and intensity imaging is performed by the imaging device 310.

c. Change the polarization state N (N ≥ 3) times in step a and the polarization polarization state M (M ≥ 3) times in b, respectively, and take a polarization image of the surface of the measured tissue of MN and store it in the data processing terminal. In 500, a system equation is established for the incident and exit of the measured tissue, and the mueller matrix information of the surface of the measured tissue is obtained.

The motion controller 200 is controlled by the data processing terminal 500 to transmit a specified number of pulses to the corresponding polarizing micromotor 111 and the analyzer micromotor 121, thereby realizing the polarization states of the polarization generating device 110 and the polarization analyzing device 120 of steps a and b. After the micromotor and the differential micromotor are rotated to the designated position, the current surface of the measured tissue and the polarization of the measured surface are recorded.

According to the polarization state and the polarization state of the acquired image, the local coordinate system determined by the endoscopic probe can determine the gray value (m, n) of each pixel of the currently captured image and the measured tissue. The linear equation between the mueller matrix elements.

According to the principle of polarization measurement, the incident light will scatter after being irradiated onto the measured tissue after passing through the polarizing device, and the scattered light will carry polarization information related to the optical properties of the tissue, and the image is processed by the imaging device after being screened by the analyzer. This process can be described as:

I _out (m,n) and I _in (m,n) correspond to the intensity values received by the point (m,n) on the imaging device and the intensity of the light emitted by the light source, respectively, for each pixel on the imaging device. It is said that I _in (m, n) does not change during the measurement, and I _out (m, n) will vary with the polarization state of the polarizing device and the analyzer, which is the modulation of the light intensity signal. . A denotes the instrument mueller matrix corresponding to the polarization state of the polarizing device, P denotes the mueller matrix of the polarization state of the analyzer, u _ij = a _i p _j is the ith matrix element of the first row of A and the first of P The product of the j matrix elements of the column expands M _s into a 9 × 1 order column vector M' _s , and the above expression can be expressed as:

The linear equation can be simplified as: UM _s (i,j)=I' _out (i,j), for the mueller matrix M _s (i,j) to be solved, the pseudo-inverse method can be obtained by the linear equations:

M' _s (i,j)=(U ^T U) ^-1 U ^T ·I' _out (i,j);

The 9×1 order column vector M′ _s (i,j)=[m ₁₁ , m ₁₂ , m ₁₃ , m ₂₁ , m ₂₂ , m ₂₃ , m ₃₁ , m ₃₂ , m ₃₃ ] ^T is rearranged to obtain The mueller matrix M _s (i, j) of the sample being tested.

In particular, in the embodiment, N=4 is selected, and the angles of the polarizing plate and the polarizing plate relative to the preset horizontal position of the endoscope end are respectively set to θ ₁ =0°, 45°, 90°, 135°, θ ₂ =0°, 45°, 90°, 135°. Thus, the linear relationship between M _s (i, j) and a particular pixel point value vector I' _out (i, j) in the acquired gray image can be solved, and the pixel coordinates can be changed to perform the same operation to obtain the entire image. Mueller matrix M _s .

The above is only the embodiment of the present invention, and is not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformation of the present invention and the contents of the drawings may be directly or indirectly applied to other related technologies. The fields are all included in the scope of patent protection of the present invention.

Claims (10)

A head-end modulated endoscopic polarization imaging system, comprising a light source, a polarization generating device, a polarization analyzing device, an imaging device, a head end mechanical fixing member, a motion controller, an image collecting device, and a data processing terminal; The light emitted by the light source is scattered on the object to be measured by the polarization generating device, is imaged by the polarization analyzing device, and is collected by the image capturing device and transmitted to the data processing terminal; It is characterized by: The polarization generating device and the polarization analyzing device are mounted on the head end mechanical fixing member, and integrated with the light source and the imaging device at the end of the endoscope; The data processing terminal connects and controls the motion controller to respectively control a polarization generating state of the polarization generating device and a polarization detecting state of the polarization analyzing device. The head-end modulated endoscopic polarization imaging system of claim 1 wherein: The polarization generating device includes a polarizing plate, a polarizing bearing, a polarizing transmission component, a polarizing transmission component, and a polarizing micromotor; The polarizing transmission member and the polarizing transmission member are friction transmission wheels, and preferably, the deflection transmission member and the polarizing transmission member are gears or belt transmission wheels; The polarizing micromotor is mounted and fixed on the head end mechanical fixing component, and the polarizing transmission component is mounted on the output shaft of the polarizing micromotor, and the polarizing transmission component is assembled and assembled with the deflection component by the transmission component. The transmission component is fixed on the outer ring of the polarizing bearing, the inner ring of the polarizing bearing is mounted and fixed on the mechanical fixing member of the head end, and the polarizing plate is fixedly attached to the outer ring of the polarizing bearing; The rotation of the polarizing motor is driven by the rotation of the polarizing micromotor to change the initial polarizing plate Polarization state, used to modulate light into linearly polarized light of different preset polarization states. The head-end modulated endoscopic polarization imaging system of claim 1 wherein: The polarization analysis device includes a polarization detecting polarizer, a polarization detecting bearing, a deviation detecting transmission component, a deviation detecting transmission component, and a polarization detecting micro motor; The detection biased transmission component and the deviation detecting transmission component are friction transmission wheels; The detecting micromotor is mounted on the head end mechanical fixing component, and the detecting transmission component is mounted on the output shaft of the detecting micromotor, and the detecting transmission component and the detecting bias are fitted and assembled by the transmission component, and the biasing is transmitted by the transmission component. Fixed on the outer ring of the detecting bearing, the inner ring of the detecting bearing is mounted on the mechanical fixing member of the head end, and the polarizing plate is fixedly attached to the outer ring of the detecting bearing; The polarization of the polarization detecting plate is changed by the rotation of the differential motor to detect the polarization state of the polarization detecting plate, and is used for detecting linearly polarized light of different polarization states after being scattered by the object. A head-end modulated endoscopic polarization imaging system according to claim 3, wherein: The deviation detecting transmission member and the deviation detecting transmission member are gears or belt transmission wheels. The head-end modulated endoscopic polarization imaging system of claim 1 wherein: The light source includes a broadband source proximal end for generating broadband light, a band pass filter for filtering the broadband light to generate preset narrowband light, a light guiding medium for narrowband optical transmission, and A distal end of the light source that exits the narrowband light transmitted through the light guiding medium. A head-end modulated endoscopic polarization imaging system according to claim 2, wherein: The polarizing angle θ _{1 of the} polarizing plate has a value range of [0, π], and the data processing terminal calculates the need for the polarizing micro motor according to the angle θ ₁ and the gear ratio of the polarizing gear and the polarizing transmission gear. The angle of rotation sends a command to the motion controller to control the tilting of the micromotor to the specified position. A head-end modulated endoscopic polarization imaging system according to claim 3, wherein: The polarization angle θ _{2 of the} polarizing plate has a value of [0, π], and the data processing terminal calculates the differential motor according to the angle θ ₂ and the gear ratio of the analyzer gear and the analyzer gear. The angle of rotation is required to send a command to the motion controller to control the tilting of the micromotor to the specified position. The head-end modulated endoscopic polarization imaging system of claim 1 wherein: The data processing terminal is a computer or an embedded processing system. A method for measuring endoscopic polarization imaging using the head-end modulated endoscopic polarization imaging system of claim 1 is characterized in that it comprises the following steps: a. The light emitted by the light source is polarized by the polarization generating device and then irradiated onto the object to be tested; b. The polarization analysis device detects light that has been scattered and detected by the object to be detected and is intensity-informed by the imaging device; c. Change the polarization state of the polarized state N and the polarization polarization state M times in steps a and b, respectively, and take the polarization image of the surface of the MN image to establish the incident light and the emission of the object to be tested. The system equation of light obtains the mueller matrix information of the surface of the object under test. The spectroscopy imaging measuring method according to claim 5, wherein the system equation of the mueller matrix for solving the surface of the object to be measured in step c can be described as AM _'s = P, wherein A is a MN x 9-order matrix, It is a coefficient matrix determined according to the combination of the polarization generation state and the polarization analysis state set in step c, P is a MN×1 order column vector, and each row of the vector represents the intensity value of the polarization image obtained per measurement, and the system equation is solved. mueller matrix M can be obtained in the measured object 9 × 1 vector representing the column order of _'s, can be obtained through rearranging the elements mueller matrix M _s analyte.

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