Large field of view skin tomography device

Abstract

The utility model provides a skin tomography device with a large field of view, which includes a portable imaging unit and a control unit. The portable imaging unit includes a probe module and a wide-field imaging auxiliary module. Therefore, while performing tomography on the skin to obtain multiple groups of tomography images, a large-field image of the skin surface can be obtained as a wide-field auxiliary positioning image, so that the multiple groups of tomography images can be spliced ​​with the assistance of the wide-field auxiliary positioning image to obtain a three-dimensional tomography image with a larger field of view. With the assistance of the wide-field auxiliary positioning image with a large field of view, the problem of incorrect splicing direction of the tomography image with a small field of view can be avoided, and a true tomography image with a large field of view can be obtained. In addition, since the wide-field imaging auxiliary module is only used to image the skin surface, there is no need to consider zooming, so the design of the optical system is simpler, which is conducive to the miniaturization of the portable imaging unit.

Description

Technical Field

[0001] The utility model relates to the field of skin tomography detection based on the reflection confocal microscopic imaging principle, in particular to a skin tomography device with a large field of view. Background Art

[0002] Portable skin tomography is an advanced skin imaging instrument based on the principle of reflective laser scanning confocal optical imaging and computer three-dimensional tomography imaging technology. It can realize non-invasive, real-time, in vivo (living), and dynamic observation of the occurrence, development, efficacy, and skin lesions of skin diseases layer by layer with cellular resolution. Skin tomography, including portable and desktop skin tomography, although its main optical working principle is basically the same as that of reflective laser confocal scanning microscope, but because the skin tomography can be conveniently used to detect the skin of the patient's face, hands, body and other parts, it needs to adopt a compact miniaturized design. It cannot use a microscope workbench and an electric stage like a large reflective laser confocal scanning microscope. Therefore, the imaging field of existing skin tomography is generally very small. For example, the imaging field of the few portable skin tomography on the market is usually only 750×750μm 2 Since the imaging field of view is very small, it is difficult to obtain the pathological correlation information of the entire lesion when using such a portable skin tomography device for skin disease detection. It can be seen that increasing the imaging field of the skin tomography device is of great significance for the detection of skin diseases.

[0003] At present, the method to increase the imaging field of view of the skin tomography instrument is mainly to stitch the small field of view images, that is, after obtaining multiple sets of small field of view tomography images of multiple detection positions through the skin tomography instrument, the multiple sets of small field of view tomography images are stitched together using a pure image algorithm. For example, the patent "High Reliability and Fault Tolerance Skin CT Large Field of View Image Stitching Method and System" (Application No.: 202111152470.6) proposes such a stitching method, in which M rows × N columns of skin CT images are stitched according to the grid shape based on algorithms such as image feature point matching, thereby obtaining a skin CT image with a large field of view. However, the above stitching method cannot be applied to portable skin tomography for two main reasons: first, when detecting skin diseases, portable skin tomography can move in any direction on the surface of human skin, and its movement is irregular, that is, the multiple sets of small field of view tomography images obtained are not regularly arranged in the form of M rows × N columns. The actual situation is often that multiple sets of small field of view tomography images are not only translated but also rotated with each other, which significantly increases the difficulty of the stitching algorithm; second, the images obtained by the skin tomography are usually black and white images of cells of skin tissue, and the cell morphology in the images is often very similar. The above two points will cause a set of small field of view tomography images to be spliced ​​on the edge of the wrong direction of another set when executing the image feature point matching algorithm to splice the edges of the two sets of small field of view tomography images, resulting in the spliced ​​large field of view image being an erroneous pseudo image. Utility Model Content

[0004] The utility model is designed to solve the above problems, and aims to provide a large-viewing-field skin tomography device that can perform large-viewing-field tomography of the skin tissue to be tested, effectively ensure the accuracy of imaging, and is easy to operate. The utility model adopts the following technical solutions:

[0005] The utility model provides a large-field skin tomography device, characterized in that it comprises: a portable imaging unit, used for imaging the skin tissue to be tested, wherein the portable imaging unit at least comprises: a probe module, used for performing tomography on the skin tissue to be tested; and a wide-field imaging auxiliary module, used for performing wide-field imaging on the surface of the skin tissue to be tested, wherein the wide-field imaging auxiliary module has an illumination light source for providing illumination for the wide-field imaging, and the illumination light source is an incoherent light source.

[0006] The large-field-of-view skin tomography device provided by the utility model may also have such a technical feature, wherein the field of view size of the wide-field auxiliary positioning image is 3 to 5 times the field of view size of a single tomography image.

[0007] The large-field skin tomography device provided by the utility model may also have such technical features, wherein the probe module has an objective lens and a dichroic mirror for performing the tomography, the objective lens is arranged on the light transmission path of the dichroic mirror, and the wide-field imaging auxiliary module includes: an illumination light source for generating illumination light; an illumination lens for making the illumination light become a uniform illumination light beam; a narrow-band filter for performing narrow-band filtering on the illumination light beam; a beam splitter, arranged on the light transmission path of the dichroic mirror, for splitting the filtered illumination light beam; a wide-field imaging lens, arranged on the light transmission path of the dichroic mirror, for performing wide-field imaging on the surface of the skin tissue to be measured to form an imaging light beam; and a planar array detector for receiving the imaging light beam.

[0008] The large-field-of-view skin tomography device provided by the utility model may also have such technical features, and also includes: a light source module, used to provide a light source for the portable imaging unit, wherein the light source module adopts a laser light source with a wavelength of 830nm or 980nm, and the illumination light source is an incoherent light source with a wavelength of more than 550nm.

[0009] The large-viewing-field skin tomography device provided by the utility model may also have such a technical feature, wherein the illumination light source is an LED light source.

[0010] The large-field-of-view skin tomography device provided by the utility model may also have such a technical feature, wherein the portable imaging unit has a light source output module, a flexible output optical fiber is arranged between the light source module and the light source output module, and the output optical fiber serves as the light source output end of the light source output module.

[0011] The large-field-of-view skin tomography device provided by the utility model may also have such technical features, and also include: a reflective scanning module, including a MEMS galvanometer, for two-dimensionally deflecting the light beam to make it a deflected light beam, wherein the probe module also includes a conversion lens group, for converting the deflected light beam to match the objective lens.

[0012] The large-field-of-view skin tomography device provided by the utility model may also have such technical features, wherein the reflective scanning module also includes a reflector, the portable imaging unit has a light source output module, and the light beam emitted by the light source output module is incident on the working surface of the MEMS galvanometer after being reflected by the reflector.

[0013] The large-viewing-field skin tomography device provided by the utility model may also have such technical features, and further include: a zoom driver for driving the objective lens to zoom; and a zoom control circuit for controlling the zoom driver.

[0014] The large-field-of-view skin tomography device provided by the utility model may also have such technical features, wherein the zoom driver is a stepping motor, the probe module also includes an optical protection plate arranged at the front end of the lens of the objective lens, the objective lens includes an objective lens housing, an objective lens inner housing movably arranged in the objective lens housing, and an objective lens optical element arranged in the objective lens inner housing, and the moving rod of the stepping motor is connected to the objective lens inner housing.

[0015] Function and effect of utility model

[0016] According to the large-field skin tomography device and large-field skin tomography method of the utility model, the device includes a portable imaging unit, and the portable imaging unit includes a probe module and a wide-field imaging auxiliary module. Therefore, the device can obtain a large-field image of the surface of the skin to be tested as a wide-field auxiliary positioning image while performing tomography on the skin tissue to be tested to obtain multiple groups of tomography images, so that multiple groups of tomography images can be spliced ​​based on the assistance of the wide-field auxiliary positioning image to obtain a three-dimensional tomography image with a larger field of view, and the extension of the original small-field tomography image can be achieved. With the assistance of the wide-field auxiliary positioning image with a large field of view, the problem of the wrong splicing direction of the tomography image of the small field of view can be avoided, and a real large-field tomography image can be obtained. In addition, since the wide-field imaging auxiliary module is only used to image the skin surface, there is no need to consider zooming, so the design of its optical system is simpler, which is also conducive to the miniaturization of the portable imaging unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of a skin tomography device with a large field of view in an embodiment of the utility model;

[0018] Figure 2 It is a structural schematic diagram of a wide-field imaging auxiliary module and a probe module in an embodiment of the utility model;

[0019] Figure 3 This is a flow chart of performing large-viewing-field tomography using a large-viewing-field skin tomography device in an embodiment of the utility model;

[0020] Figure 4 It is a schematic diagram of a tomographic image and a wide-field auxiliary positioning image of a first detection position in an embodiment of the utility model;

[0021] Figure 5 It is a schematic diagram of a tomographic image and a wide-field auxiliary positioning image at a first detection position and a second detection position in an embodiment of the utility model.

[0022] Reference numerals:

[0023] Light source module A; light source output module B; probe module C; wide-field imaging auxiliary module D; semiconductor laser 1; shaping lens 2; coupling focusing lens 3; optical fiber 4; collimating lens group 5; pupil filter 6; first focusing lens group 7; zoom lens group 8; laser filter 9; polarization beam splitter prism 10; quarter-wave plate 11; reflector 12; micro-electromechanical system (MEMS galvanometer) 13; conversion lens group 14; dichroic mirror 15; objective lens 16; optical protection plate 17; protective cover 18; second focusing lens group 19; pinhole component 20; first photodetector 21; second photodetector 22; laser safety protection circuit 23; stepping motor (zoom driver) 24; data acquisition control circuit 25; computer 26; illumination light source 31; illumination lens 32; narrow-band filter 33; beam splitter 34; wide-field imaging lens 35; array detector 36. DETAILED DESCRIPTION

[0024] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the large-field-of-view skin tomography device of the present invention is specifically described below in conjunction with the embodiments and drawings.

[0025] <Example>

[0026] This embodiment provides a skin tomography device with a large field of view, which can achieve skin tomography with a larger field of view compared to existing skin tomography devices.

[0027] Figure 1 Schematic diagram of the structure of the large-field-of-view skin tomography device in this embodiment.

[0028] like Figure 1 As shown, the large-field-of-view skin tomography device includes a light source module A, a portable imaging unit, and a control unit.

[0029] The light source module A is used to generate a laser light source. The portable imaging unit is used to perform tomographic imaging of the patient's skin tissue to be tested based on the laser light source to obtain multiple tomographic images at different positions and / or different depths, and it is a portable small unit. The control unit is used to control the operation of the portable imaging unit.

[0030] The light source module A includes a semiconductor laser 1, a shaping lens 2, a coupling focusing lens 3 and a heat sink (not shown) arranged in sequence. The semiconductor laser 1 is used to generate an emission laser, and the divergence angles of the emission laser generated by it in two orthogonal directions are not equal, so it needs to be shaped by the shaping lens 2. After being shaped by the shaping lens 2, the emission laser becomes a circular light beam with a circular cross-section and uniform light intensity distribution on the cross-section. The coupling focusing lens 3 couples and focuses the circular light beam so that the focused circular light beam can be efficiently coupled into the output optical fiber 4. The heat sink is used to dissipate heat from the semiconductor laser 1.

[0031] The light source module A is relatively large in size due to the need to provide a heat sink, and is therefore designed independently from the portable imaging unit.

[0032] The portable imaging unit includes an output optical fiber 4, a light source output module B, a reflection scanning module, a probe module C and a wide-field imaging auxiliary module D.

[0033] The light source module A and the light source output module B are connected via an output optical fiber 4, which serves as the light source output end of the optical system portion of the light source output module B. The use of output optical fiber facilitates the flexible layout of the overall optical path, and the spot size output by the optical fiber is fixed and uniform, which is equivalent to a fixed and uniform light source surface size for the subsequent optical system portion, which is very important for the subsequent optical system portion to achieve higher optical resolution and imaging depth performance indicators.

[0034] The light source output module B includes a collimating lens group 5, a pupil filter 6, a first focusing lens group 7, a zoom lens group 8, a laser filter 9, a polarization beam splitter prism 10, a quarter wave plate 11, a second focusing lens group 19, a pinhole component 20, a first photodetector 21 and a second photodetector 22.

[0035] The collimating lens group 5 is used to collimate the output laser of the output optical fiber 4. The pupil filter 6 is used to improve the optical resolution of the subsequent optical system part. The zoom lens group 8 is used to cooperate with the first focusing lens group 7 to achieve the scaling of the cross-sectional size of the parallel light beam so that it is compatible with the reflective scanning module. Among them, the rear focal plane of the collimating lens group 5 coincides with the front focal plane of the first focusing lens group 7, the rear focal plane of the first focusing lens group 7 coincides with the front focal plane of the zoom lens group 8, and the pupil filter 6 is located at the front focal plane of the first focusing lens group 7. The laser filter 9 is used to filter the scaled parallel light beam, and its output light beam is a non-polarized light beam, which can reduce the chromatic aberration of the subsequent optical system part. The polarization beam splitter prism 10 is used to split the non-polarized light beam into two polarized light beams, one polarized light beam is incident on the 48-1 wave plate 11, and the other polarized light beam is incident on the second photodetector 22, and the second photodetector 22 is used to cooperate with the laser safety protection circuit 23 to realize the power control of the semiconductor laser 1. The quarter wave plate 11 is used to convert one polarized light beam into two circularly polarized light beams to provide to the reflective scanning module. The second focusing lens group 19 is used to focus the other polarized light beam, and the pinhole on the pinhole component 20 filters the focused polarized light beam. The filtered polarized light beam is incident on the first photodetector 21, and the first photodetector 21 is used to realize the imaging of skin tissue.

[0036] The reflective scanning module includes a reflective mirror 12 and a micro-electromechanical system (MEMS) galvanometer 13 .

[0037] The reflector 12 is used to reflect the circularly polarized light beam emitted by the quarter wave plate 11 to achieve optical path folding, thereby reducing the overall size of the optical system. The MEMS galvanometer 13 is used to deflect the incident circularly polarized light beam in two dimensions at high speed to make it a deflected light beam, thereby achieving two-dimensional high-speed laser scanning. The MEMS galvanometer 13 has a working surface (mirror), a scanning control circuit for driving the high-speed two-dimensional deflection scanning of the working surface, and a timing circuit for controlling the frequency of the deflection scanning. Since the size of the working surface is very small, the cross-sectional size of the scaled parallel light beam is matched with the size of the working surface through the above-mentioned focusing lens group 7, pupil filter 6 and zoom lens group 8.

[0038] The light source output module B outputs a circularly polarized light beam to the MEMS galvanometer 13 . The use of circularly polarized light can make the focusing spot of the objective lens 16 circular, and the same optical resolution can be obtained in two orthogonal directions during two-dimensional scanning imaging by the MEMS galvanometer 13 .

[0039] The probe module C includes a conversion lens group 14 , a dichroic mirror 15 , an objective lens 16 , an optical protection plate 17 and a protection cover 18 .

[0040] The conversion lens group 14 is used to convert the deflected light beam of the two-dimensional scanning so that the cross-sectional size of the light beam matches the size of the objective lens 16. The dichroic mirror 15 is a short-wave dichroic mirror, which allows the light beam with a wavelength lower than the cut-off wavelength to be almost completely transmitted, and at the same time, the light beam with a wavelength higher than the cut-off wavelength is almost completely reflected. The objective lens 16 is used to image the skin tissue to be measured. The box on the upper part of the objective lens 16 in the figure represents the entrance pupil of the objective lens 16. The objective lens 16 is arranged on the light transmission path of the dichroic mirror 15. The optical protection plate 17 is installed in front of the lens of the objective lens 16, and is used to cooperate with the objective lens 16 to achieve focusing. The objective lens 16 has an objective lens housing, an objective lens inner housing movably arranged in the objective lens housing, and an objective lens optical element installed in the objective lens inner housing. By moving the objective lens inner housing, the distance between the objective lens optical element and the optical protection plate 17 can be adjusted, thereby achieving focusing. The protective cover 18 is installed on the optical protection plate 17 to protect it. In this embodiment, the optical protection plate 17 and the protection cover 18 are also part of the lens of the objective lens 16 , and the contact between the protection cover 18 and the skin surface means that the lens of the objective lens 16 is in contact with the skin surface.

[0041] When scanning the patient's skin, the circularly polarized light emitted by the quarter wave plate 11 is reflected by the reflector 12 and incident on the working surface of the micro-electromechanical system 13. The working surface realizes high-speed two-dimensional deflection scanning under the drive of the driving circuit, so that the circularly polarized light beam forms a deflected light beam. The deflected light beam is sequentially converted by the conversion lens group 14, reflected by the second reflector 15, and focused on the human skin tissue to be tested by the objective lens 16 and the optical protection plate 17. The scattered light at the focal point of the light beam on the human skin tissue returns to the quarter wave plate 11 along the original optical path and becomes linearly polarized light, wherein the light beam with a wavelength higher than the cut-off wavelength is reflected to the conversion lens group 14 by the dichroic mirror 15. The linearly polarized light emitted by the quarter wave plate 11 is sequentially incident on the first photodetector 21 after passing through the polarization beam splitter prism 10, the second focusing lens group 19, and the pinhole on the pinhole component 20. The first photodetector 21 generates a corresponding electrical signal after receiving the incident light. After signal acquisition and data reconstruction of the electrical signal, a three-dimensional tomographic image (hereinafter referred to as tomographic image) of a small field of view of the skin tissue can be obtained.

[0042] The field of view of a single tomographic image is very small. In this embodiment, the field of view of each tomographic image is about 750 μm×750 μm.

[0043] The wide-field imaging auxiliary module D is used to obtain a wide-field image of the surface of the skin tissue to be tested as a wide-field auxiliary positioning image. The wide-field auxiliary positioning image can be used to stitch multiple small-field tomography images to obtain a real three-dimensional tomography image of the skin tissue with a large field of view.

[0044] Figure 2Schematic diagram of the structure of the wide-field imaging auxiliary module and the probe module in this embodiment.

[0045] like Figure 2 As shown, the wide-field imaging auxiliary module D includes an illumination light source 31 , an illumination lens 32 , a narrow-band filter 33 , a beam splitter 34 , a wide-field imaging lens 35 and an array detector 36 .

[0046] The illumination light source 31 is used to provide illumination for shooting wide-field auxiliary positioning images. The illumination light source 31 is a short-wavelength incoherent light source, and its wavelength matches the working band of the objective lens of the portable skin tomography imager. In principle, the shorter the wavelength of the illumination light source, the higher the resolution of the optical imaging system, and the easier it is for the wide-field imaging auxiliary module D to obtain a high-resolution wide-field auxiliary positioning image. However, the wavelength of the illumination light source cannot be too short and must match the working band of the objective lens of the portable skin tomography imager. For example, a portable skin tomography imager usually uses a laser light source with a wavelength of 830nm or 980nm, and the working band of its objective lens is usually 830nm to 980nm. Correspondingly, selecting an illumination light source 31 with a wavelength of more than 550nm can reduce the coating width of the objective lens (the wider the coating width, the more difficult the processing technology and the more expensive the price) and the design difficulty of the wide-field imaging lens 35 in the wide-field imaging auxiliary module D. In addition, it is not suitable to use coherent laser as the illumination light source 31, as laser illumination can easily cause coherent noise in wide-field imaging, thereby significantly reducing the resolution of the wide-field auxiliary positioning image.

[0047] In this embodiment, the illumination light source 31 is an LED light source.

[0048] The illumination lens 32 is used to form the illumination light generated by the illumination light source 31 into a uniform illumination light beam.

[0049] The narrowband filter 33 is used to perform narrowband filtering on the illumination beam to obtain an illumination beam with a narrower wavelength, which helps to reduce the chromatic aberration of the wide-field imaging lens 35 in the wide-field imaging auxiliary module D, thereby making it easier to obtain a high-resolution wide-field auxiliary positioning image.

[0050] The beam splitter 34 is used to split the light beam into two sub-beams with the same wavelength.

[0051] The wide-field imaging lens 35 is used to perform wide-field imaging of the surface of the skin tissue to be tested, and the wide-field imaging lens 35 and the objective lens 16 constitute the optical system of the wide-field imaging module D. In this embodiment, the wide-field imaging auxiliary module D is used to obtain a high-resolution image of the surface of the skin tissue as a wide-field auxiliary positioning image, and is not used for deep skin imaging. Therefore, the object plane of the wide-field imaging lens 35 is the first layer of skin to be imaged, and there is no need to consider the objective lens zoom when performing deep skin testing, which can significantly reduce the design difficulty and complexity of the wide-field imaging lens 35.

[0052] The area array detector 36 is used to cooperate with the wide-field imaging lens 35 to achieve wide-field imaging. The wide-field imaging lens 35 outputs an imaging light beam, and the area array detector 36 receives the output imaging light beam and generates a corresponding electrical signal.

[0053] While the probe module C and other modules perform tomographic imaging of the skin tissue, the wide-field imaging auxiliary module D performs wide-field imaging of the skin surface. Specifically, when performing tomographic imaging, the scattered light at the focal point of the light beam on the human skin tissue returns along the original optical path through the dichroic mirror 15, wherein the light beam with a wavelength lower than the cut-off wavelength passes through the dichroic mirror 15 and is incident on the beam splitter 34, and passes through the beam splitter 34 and the wide-field imaging lens 35 to become an imaging beam and is incident on the area array detector 36, thereby obtaining a wide-field auxiliary positioning image; at the same time, the illumination light generated by the illumination light source 31 passes through the illumination lens 32 and the narrow-band filter 33 to become a narrow-band illumination beam, and then passes through the beam splitter 34 and the wide-field imaging lens 35 to be incident on the area array detector 36, thereby providing sufficient illumination for forming a wide-field auxiliary positioning image.

[0054] In this embodiment, the field of view of the wide-field auxiliary positioning image is about 3 to 5 times the field of view of a single tomographic image; the resolution of the wide-field auxiliary positioning image depends on the performance of the wide-field imaging lens 35 and the wavelength of the illumination light source 31, and its resolution may be slightly lower than that of the tomographic image, but it has no effect on wide-field imaging. The field of view of the wide-field auxiliary positioning image should not be too large or too small. Further increasing its field of view will significantly increase the design difficulty and complexity of the wide-field imaging lens 35. If its field of view is set too small, it will increase the difficulty of operation when extending the tomographic image with a large field of view.

[0055] The control unit is used to control the process of wide-field imaging.

[0056] like Figure 1 As shown, the control unit includes a stepping motor 24 , a data acquisition control circuit 25 and a computer 26 .

[0057] The stepper motor (zoom driver) 24 is used to drive the inner shell of the objective lens to move. The moving rod of the stepper motor 24 is connected to the inner shell of the objective lens 16. When the moving rod moves along the optical axis direction of the objective lens 16, the distance between the objective lens 16 and the optical protection plate 17 can be changed, thereby realizing the zoom of the objective lens 16. In this embodiment, the step distance of the stepper motor 24 is 5μm when the objective lens 16 is zoomed, that is, the vertical resolution of the portable wide-field skin tomography is 5μm. In addition, the control unit also includes a stepper motor control circuit (zoom control circuit, not shown in the figure), which is used to control the stepper motor 24 and obtain the feedback electrical signal of the stepper motor 24.

[0058] The data acquisition control circuit 25 is used for data acquisition and control.

[0059] For tomographic images, the data acquisition control circuit 25 receives the electrical signal output by the first photodetector 21 and converts it into a discrete photodetector data signal, collects the feedback electrical signal of the stepper motor 24 and converts it into a motor data signal, and simultaneously obtains the timing signal from the timing circuit of the MEMS galvanometer 13. Thereafter, the photodetector data signal, the motor data signal and the corresponding timing signal are transmitted to the computer 26 via a data line.

[0060] For wide-field auxiliary positioning images, the data acquisition control circuit 25 receives the electrical signal output by the area array detector 36 and converts it into a discrete area array detector data signal, and at the same time obtains the timing signal from the timing circuit of the MEMS galvanometer 13. Thereafter, the area array detector data signal and the corresponding timing signal are transmitted to the computer 26 via a data line.

[0061] The computer 26 is used to reconstruct the collected data signals to obtain tomographic images and wide-field auxiliary positioning images, and after the detection is completed, the wide-field auxiliary positioning images are used to splice multiple groups of tomographic images of different detection positions to obtain a three-dimensional tomographic image with a large field of view.

[0062] When performing skin detection, the lens of the objective lens 16 moves in contact with the skin surface. When the lens of the objective lens 16 leaves the skin surface, the resolution of the wide-field auxiliary positioning image will drop significantly. Therefore, based on the similarity between the current wide-field auxiliary positioning image and the previous one, it can be determined whether the lens of the objective lens 16 leaves the skin surface. Leaving the skin surface usually means the end of the detection.

[0063] In this embodiment, the wide-field skin tomography device enters the wide-field working mode by default when it is started, and determines in real time whether to continue working in this mode. In an alternative solution, the user can also be allowed to select the working mode when the device is started. When the user selects the wide-field working mode, the above detection and judgment are performed; when the user selects the normal working mode, the above detection and judgment are not performed.

[0064] In this embodiment, the above functional units are arranged in the computer 26. In an alternative solution, the functions of some of the above functional units may also be arranged on a control board having a control chip, and the control board may be installed in the portable imaging unit.

[0065] The following will exemplarily illustrate the process of acquiring a skin tomography image with a large field of view by using the above-mentioned skin tomography imaging device with a large field of view.

[0066] Figure 3 4 is a flow chart of performing large-field-of-view tomography using a large-field-of-view skin tomography device in this embodiment.

[0067] like Figure 3As shown, for example, a large field of view tomographic image can be obtained by the following steps:

[0068] Step S1, start the large-viewing-field skin tomography device, and bring the lens of the objective lens 16 into contact with the surface of the skin tissue to be measured.

[0069] Step S2, a group of tomographic images at the detection position are obtained by the portable imaging unit, and a corresponding wide-field auxiliary positioning image is obtained by the wide-field imaging auxiliary module D.

[0070] Figure 4 Schematic diagram of a tomographic image of a first detection position and a wide-field auxiliary positioning image in this embodiment.

[0071] like Figure 4 As shown, when the wide-field skin tomography device focuses on the first detection position on the skin surface, a wide-field auxiliary positioning image P1 of the skin surface and a tomography image p11 of the first layer on the skin surface are obtained. Then, the device zooms and focuses on the second layer of the skin and obtains a tomography image p12 of the second layer. Then, the device zooms again and focuses on the third layer of the skin and obtains a tomography image p13 of the third layer, and so on, until the tomography image p1n of the nth layer is obtained, completing the detection of the first detection position.

[0072] Step S3, changing the detection position on the surface of the skin tissue to be tested and repeating step S2 until the multiple detection positions completely cover the predetermined detection area on the surface of the skin tissue to be tested, so as to obtain multiple groups of tomographic images and corresponding multiple wide-field auxiliary positioning images.

[0073] That is, the lens of the objective lens 16 is kept in contact with the skin surface, and the position where the lens contacts the skin surface is changed. Since the field of view of a single tomographic image is larger than about 750 μm×750 μm, and the field of view of the wide-field auxiliary positioning image is 3 to 5 times of that, the translation distance is preferably about 0.5 mm each time the detection position is changed. In addition, it should be noted that at each detection position, it is necessary to wait for the imaging of multiple tomographic images of all depths of the position to be completed before moving to the next detection position.

[0074] Figure 5 3 is a schematic diagram of a tomographic image and a wide-field auxiliary positioning image at a first detection position and a second detection position in this embodiment. The tomographic image and the wide-field auxiliary positioning image at the first detection position are shown by dotted lines in the figure.

[0075] like Figure 5As shown in the figure, after the detection of the first detection position is completed, the position where the device contacts the skin is translated by about 0.5 mm to reach the second detection position, and similarly, the wide-field auxiliary positioning image P2 of the second detection position and the tomographic images p21 to p2n of the first to nth layers are obtained. It can be seen that since the moving distance is less than 750 μm, the edges of the tomographic images of the corresponding layers of the first detection position and the second detection position have overlapping parts, and the tomographic images p21 to p2n of the second detection position are also located within the range of the wide-field auxiliary positioning image P1 of the first detection position.

[0076] Step S4, the detection is completed (the lens of the objective lens 16 leaves the skin surface), and the control unit uses the wide-field auxiliary positioning image as an aid to stitch the multiple groups of tomographic images in layers to obtain a three-dimensional tomographic image with a large field of view.

[0077] like Figure 5 As shown, since the field of view of the wide-field auxiliary positioning image is 3 to 5 times that of the tomographic image, most of the wide-field auxiliary positioning images P1 and P2 of the two detection positions are the same, with a lot of overlapping parts, and the tomographic image p11 is basically located at the center of the corresponding wide-field auxiliary positioning image P1, and the tomographic image p21 is basically located at the center of the corresponding wide-field auxiliary positioning image P2. Therefore, after the two wide-field auxiliary positioning images of the two detection positions are matched and aligned by the image processing method in the prior art, the translation amount and rotation direction of the tomographic image of the second detection position relative to the tomographic image of the first detection position can be easily obtained, and the center line of the tomographic image p11 and the tomographic image p21 represents the motion trajectory from the first detection position to the second detection position. Then, based on the translation amount, rotation direction and motion trajectory, the tomographic images of the corresponding layers of the two detection positions can be effectively spliced ​​to form a tomographic image with a larger field of view, and the problem of incorrect splicing direction can be prevented.

[0078] Functions and Effects of the Embodiments

[0079] According to the large-field skin tomography device and large-field skin tomography method provided in this embodiment, the device includes a portable imaging unit and a control unit, wherein the portable imaging unit includes a probe module C and a wide-field imaging auxiliary module D, so that the device can obtain a large-field image of the surface of the skin to be tested as a wide-field auxiliary positioning image while performing tomography on the skin tissue to be tested to obtain multiple groups of tomography images, and splice the multiple groups of tomography images based on the assistance of the wide-field auxiliary positioning image to obtain a three-dimensional tomography image with a larger field of view, thereby realizing the extension of the original small-field tomography image, and with the assistance of the wide-field auxiliary positioning image of the large field of view, the problem of the wrong splicing direction of the tomography image of the small field of view can be avoided, and a real large-field tomography image can be obtained. In addition, since the wide-field imaging auxiliary module D is only used to image the skin surface, there is no need to consider zooming, so the design of its optical system is simpler, which is also conducive to the miniaturization of the portable imaging unit.

[0080] In the embodiment, the field of view of the wide-field auxiliary positioning image is 3 to 5 times that of a single small-field tomography image. With such a field of view size setting, there is a field of view of sufficient size to facilitate the operation of changing the detection position when the field of view is extended (the changed detection position does not exceed the field of view of the wide-field auxiliary positioning image), and at the same time, the structure of the wide-field imaging lens 35 in the wide-field imaging auxiliary module D can be avoided from being too complicated.

[0081] In the embodiment, the probe module C adopts a dichroic mirror 15, and the optical system of the wide-field imaging auxiliary module D also utilizes the dichroic mirror 15 and the objective lens 16 of the probe module C. That is, the dichroic mirror 15 and the objective lens 16 have multiple functions, which can reduce the number of components in the optical system and realize further miniaturization of the portable imaging unit.

[0082] Furthermore, the light source module A of the portable imaging unit adopts a laser light source, and the wide-field imaging auxiliary module D adopts a corresponding incoherent light source with a wavelength of more than 550nm, which can reduce the coating width of the objective lens 16, thereby reducing its process difficulty and cost, and can avoid the generation of coherent noise in wide-field imaging, thereby obtaining a high-resolution wide-field auxiliary positioning image.

[0083] The above embodiments are only used to illustrate the specific implementation of the utility model, and the utility model is not limited to the description scope of the above embodiments. The technicians in this industry should understand that the utility model is not limited by the above embodiments. The above embodiments and the description are only to illustrate the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model will have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection of the utility model is defined by the attached claims and their equivalents.

[0084] For example, in the above embodiment, the wide-field imaging auxiliary module is applied to a portable small-scale skin tomography device. In an alternative solution, the wide-field imaging auxiliary module can also be similarly applied to a large-scale imaging instrument without a motorized stage (which cannot automatically translate the sample being measured) based on the working principle of a reflective laser confocal scanning microscope.

[0085] In the above embodiment, the wide-field imaging auxiliary module utilizes the objective lens in the probe module to form its optical system, so as to reduce the number of components and make the device more compact. In an alternative solution, the wide-field imaging auxiliary module may also be equipped with a separate objective lens.

Claims

1. A skin tomography device with a large field of view, characterized in that: include: A portable imaging unit for imaging the skin tissue to be tested. Wherein, the portable imaging unit at least comprises: A probe module, used for performing tomographic imaging of the skin tissue to be tested to obtain a tomographic image; and A wide-field imaging auxiliary module is used to perform wide-field imaging on the surface of the skin tissue to be tested to obtain a wide-field auxiliary positioning image. The wide-field imaging auxiliary module has an illumination light source for providing illumination for the wide-field imaging, and the illumination light source is an incoherent light source.

2. The large-field-of-view skin tomography device according to claim 1, characterized in that: in, The field of view of the wide-field auxiliary positioning image is 3 to 5 times the field of view of a single tomographic image.

3. The large-field skin tomography device according to claim 1 or 2, Features: in, The probe module has an objective lens and a dichroic mirror for performing the tomographic imaging, wherein the objective lens is arranged on the light transmission path of the dichroic mirror. The wide-field imaging auxiliary module comprises: An illumination light source, used for generating illumination light; An illumination lens, used to make the illumination light a uniform illumination beam; A narrowband filter, used for performing narrowband filtering on the illumination light beam; A beam splitter, arranged on the light transmission path of the dichroic mirror, for splitting the filtered illumination light beam; A wide-field imaging lens, arranged in the light transmission path of the dichroic mirror, for performing wide-field imaging on the surface of the skin tissue to be tested to form an imaging beam; and The area array detector is used to receive the imaging light beam.

4. The large-field-of-view skin tomography device according to claim 3, characterized in that: Also includes: a light source module, used to provide light source for the portable imaging unit, The light source module adopts a laser light source with a wavelength of 830nm or 980nm, and the illumination light source is an incoherent light source with a wavelength of more than 550nm.

5. The large-viewing-field skin tomography device according to claim 4, characterized in that: in, The lighting source is an LED light source.

6. The large-field-of-view skin tomography device according to claim 4, characterized in that: in, The portable imaging unit has a light source emission module. A flexible output optical fiber is arranged between the light source module and the light source output module. The output optical fiber serves as the light source output end of the light source output module.

7. The large-field-of-view skin tomography device according to claim 3, characterized in that: Also includes: The reflective scanning module includes a MEMS galvanometer, which is used to deflect the light beam in two dimensions to make it a deflected light beam. Wherein, the probe module also includes a conversion lens group for converting the deflected light beam to match the objective lens.

8. The large-viewing-field skin tomography device according to claim 7, characterized in that: in, The reflective scanning module also includes a reflector. The portable imaging unit has a light source emission module. The light beam emitted by the light source output module is incident on the working surface of the MEMS galvanometer after being reflected by the reflector.

9. The large-field-of-view skin tomography device according to claim 3, characterized in that: Also includes: A zoom driver, used for driving the objective lens to zoom; as well as The zoom control circuit is used to control the zoom driver.

10. The large-field-of-view skin tomography device according to claim 9, characterized in that: in, The zoom driver is a stepping motor. The probe module also includes an optical protection plate, which is arranged at the front end of the lens of the objective lens. The objective lens comprises an objective lens housing, an objective lens inner housing movably arranged in the objective lens housing, and an objective lens optical element arranged in the objective lens inner housing. The moving rod of the stepping motor is connected to the inner shell of the objective lens.

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