A static opt imaging system and acquisition control method thereof

Abstract

The application discloses a kind of static OPT imaging systems, it is related to optical projection tomography technical field, including projection data acquisition host computer, image acquisition processing unit, acquisition control unit, display unit, wherein, projection data acquisition host computer is used to obtain projection image, including N camera, N backlight, an imaging container, a water tank;Image acquisition processing unit is used to collect, save, handle projection image, and according to logical timing diagram to acquisition control unit sends control signal;Acquisition control unit realizes the control to camera and backlight according to control signal, and acquisition control unit includes pulse trigger, light source controller;Display unit includes data acquisition real-time display, three-dimensional reconstruction result dynamic display and tomographic image dynamic display.The application adopts multi-source stationary OPT imaging system, realizes under the premise of not rotating sample simultaneously obtains multiple projection images, realizes real-time imaging to moving sample, growth change sample.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical projection tomography technology, and in particular to a static OPT imaging system and an acquisition control method thereof. BACKGROUND

[0002] Optical projection tomography (OPT) as a mesoscopic imaging technology has made outstanding contributions in imaging of semi-transparent objects (such as biological embryos, in-vitro organs, live small animals, gels, etc.). The principle of the OPT imaging technology is to reconstruct optical attenuation images of a substance by using different degrees of attenuation of light by different semi-transparent substances, so as to realize three-dimensional tomographic imaging of the semi-transparent object.

[0003] The OPT imaging technology is a computer tomography technology in the optical waveband, and the framework of the OPT imaging system is similar to that of the traditional X-CT system, the main difference being that the OPT imaging system uses visible light, near-infrared light, etc. instead of traditional X-rays to irradiate the sample, and uses photodiodes or CCD sensors as detectors to collect the attenuated projection signals at the signal receiving end.

[0004] Compared with other semi-transparent object imaging systems, the OPT imaging system is low in price, fast in speed, and free of ionizing radiation, and provides a new type of imaging means for semi-transparent objects.

[0005] Most of the existing OPT imaging systems are applied to biological tissues that are transparentized by chemical cleaning or biological embryos that are imaged in vitro after being treated by transgenic processing. To the best of our knowledge, single-source OPT imaging equipment is usually used on the market to achieve the above imaging requirements, but the imaging sample needs to be kept relatively static during the imaging process. In order to achieve this purpose, the existing technology needs to anesthetize the imaging sample or make the sample lose activity by chemical means. However, anesthetizing the sample will cause the sample to have a stress reaction, causing irreversible damage, especially to the embryo sample; and chemical treatment of the sample will directly kill the sample, resulting in the inability to observe the dynamic information of the sample and record the continuous growth changes of the same sample. In addition, the traditional OPT equipment is a single-source device using a square water tank, which is not suitable for multi-source scenarios.

[0006] Therefore, the skilled in the art is committed to developing a static OPT imaging system and an imaging method thereof, which can image a moving live sample without harming the live sample. SUMMARY

[0007] In view of the above defects of the prior art, the technical problem to be solved by the present application is how to image a moving sample in real time.

[0008] In order to achieve the above object, the application provides a static OPT imaging system, comprising a projection data acquisition host, an image acquisition processing unit, an acquisition control unit and a display unit, wherein the projection data acquisition host is used to acquire projection images and send the acquired projection images to the image acquisition processing unit, the projection data acquisition host comprises N cameras, N backlight sources, an imaging container and a water tank;

[0009] The image acquisition processing unit is used to acquire, save and process the projection images acquired by the projection data acquisition host and send the projection images to the display unit; the image acquisition processing unit comprises a multi-channel data acquisition, a high-speed data transmission, a control and calculation host; the control and calculation host sends control signals to the acquisition control unit according to a logical timing diagram, and the logical timing diagram is designed according to the acquisition requirement;

[0010] The acquisition control unit controls the cameras and the backlight sources according to the control signals; the acquisition control unit comprises a pulse trigger and a light source controller; the pulse trigger controls the exposure of the N cameras, and the pulse trigger controls the lighting of the N backlight sources through the light source controller; the pulse trigger is based on FPGA;

[0011] The display unit comprises real-time display of data acquisition, dynamic display of three-dimensional reconstruction results and dynamic display of tomographic images.

[0012] Further, the number of the cameras is equal to the number of the backlight sources, the N cameras and the N backlight sources are alternately arranged to form a ring structure, and one camera and the backlight source opposite to it constitute an imaging source.

[0013] Further, the imaging container is arranged at the center of the ring structure formed by the N cameras and the N backlight sources; the imaging container is used to place an imaging sample; and the imaging container is a cylindrical transparent container.

[0014] Further, the water tank comprises a water tank bottom and a water tank side wall; the water tank side wall comprises N long sides and N short sides, the long sides correspond to the backlight sources, and the short sides correspond to the cameras; the water tank is arranged inside the ring structure formed by the N cameras and the N backlight sources, the lenses of the cameras and the backlight sources are close to the water tank; and the water tank is made of transparent acrylic or glass material.

[0015] Further, the multi-channel data acquisition is used to acquire the projection images acquired by each camera and send the projection images to the control and calculation host through the high-speed data transmission; and the control and calculation host comprises camera image acquisition, image preprocessing and image reconstruction.

[0016] Further, the camera image acquisition is to save all projection images of the cameras according to the serial numbers of the cameras; and the image preprocessing includes grayscale correction and non-motion area cropping.

[0017] Further, the image reconstruction includes:

[0018] After the positions of the cameras, the water tank and the imaging container are fixed, the positions of the cameras in a world coordinate system are determined;

[0019] The three-dimensional projection angles of each projection view are obtained.

[0020] The three-dimensional image reconstruction under sparse angles is realized by using an analytical algorithm, an iterative algorithm or deep learning.

[0021] Further, the data acquisition real-time display unit is used to display the multi-frame data collected by each camera in real time, so as to realize real-time observation of the projection images.

[0022] The three-dimensional reconstruction result dynamic display is used to observe the three-dimensional image reconstruction result of the selected single frame from multiple angles, and the three-dimensional reconstruction result dynamic display is used to display the three-dimensional image reconstruction results of multiple frames in the form of a video after the three-dimensional image reconstruction results of multiple frames are projected into two-dimensional images according to the observation angles.

[0023] The tomographic image dynamic display is used to randomly select a cutting surface in an arbitrary direction in the sample motion space by a user, and display the two-dimensional tomographic image of the sample on the cutting surface in real time.

[0024] A collection control method of a static OPT imaging system, the method comprising the following steps:

[0025] Step 1, set the control mode of the light source controller to an external trigger mode, the lighting time is equal to the duration of the external trigger high level, and the light intensity of each channel is set; set the camera to a rising edge external trigger mode and a camera exposure time;

[0026] Step 2, design a logic timing diagram according to the collection requirements and the performance of the matching hardware;

[0027] Step 3, the control and calculation host writes a logic timing program according to the logic timing diagram using a hardware description language, and exports the logic timing program to the pulse trigger;

[0028] Step 4, the pulse trigger sends a pulse to the light source controller according to the logic timing program, and the light source controller controls the lighting of the backlight source;

[0029] Step 5, the pulse trigger sends a pulse to the camera according to the logic timing program to control the exposure of the camera.

[0030] Further, the time of all the cameras being exposed once and all the backlights being lighted once is a frame period, the same number of projection images as the source number is obtained in a frame period, three-dimensional sample reconstruction data of a frame is obtained according to the projection images; one to all of the backlights and the cameras are lighted at the same time according to the motion speed of different imaging samples.

[0031] Compared with the prior art, the present application has at least the following beneficial technical effects:

[0032] 1. The present application adopts a multi-source static OPT imaging system, so that multiple projection images are obtained at the same time without rotating the sample, and real-time imaging of a moving sample or a growing sample is realized.

[0033] 2. The present application designs a polygonal water tank according to the source number of the system, so that the refraction and deviation of light after projecting through the imaging sample is small, the distortion of the projection image is small, and the system occupies no additional space.

[0034] 3. The present application builds a pulse trigger circuit based on FPGA, realizes accurate lighting and exposure of multiple light sources and multiple cameras, and obtains multi-angle projection data of the sample in 1 frame.

[0035] The concept, specific structure and generated technical effects of the present application will be further described below with reference to the accompanying drawings, so as to fully understand the purpose, features and effects of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a system structure block diagram of a preferred embodiment of the present application;

[0037] Figure 2 is a projection data acquisition host structure schematic diagram of a preferred embodiment of the present application;

[0038] Figure 3 is a backlight camera ring structure schematic diagram of a preferred embodiment of the present application;

[0039] Figure 4 is a backlight camera ring structure top view schematic diagram of a preferred embodiment of the present application;

[0040] Figure 5 is a structure schematic diagram of any number of backlight camera arrangements of a preferred embodiment of the present application;

[0041] Figure 6 is a water tank structure schematic diagram of a preferred embodiment of the present application;

[0042] Figure 7is a schematic diagram of the acquisition control unit structure of a preferred embodiment of the present application.

[0043] Figure 8 is a timing diagram based on the sequential acquisition control mode of a preferred embodiment of the present application. DETAILED DESCRIPTION

[0044] The present application is described in more detail below with reference to the accompanying drawings, which show several preferred embodiments of the present application, so that the technical content of the present application is more clear and easy to understand. The present application can be embodied in many different forms, and the scope of protection of the present application is not limited to the embodiments described herein.

[0045] In the drawings, components of the same structure are denoted by the same reference numerals, and components having similar structures or functions are denoted by similar reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present application is not limited to the size and thickness of each component. In order to make the drawing clearer, the thickness of some components is appropriately exaggerated in some places in the drawing.

[0046] The present embodiment provides a static OPT imaging system, as shown in Figure 1 including a projection data acquisition host, an acquisition control unit, an image acquisition processing unit, and a display unit.

[0047] The projection data acquisition unit is the hardware body of data acquisition, as shown in Figure 2 including N cameras 1, N backlights 2, an imaging container 3, and a water tank 4.

[0048] In order to ensure the consistency of the projection data under each projection angle, the imaging container 3 should be a cylindrical transparent container. The container wall of the container is made of a material with high transparency and thin thickness, and the container wall should ensure uniform thickness and flatness without protrusions. In the actual placement process, the container can be fixed through the upper end or the lower end of the imaging container 3, and the fixing device should not block the side surface of the container wall. Pure water or salt water suitable for the survival of marine organisms needs to be added in the container during the data acquisition process, and the imaging sample also needs to be placed in the imaging container 3.

[0049] The core part of the projection data acquisition unit is the camera 1 and the backlight 2. The camera 1 adopts an industrial camera. The front end of each camera 1 is matched with a fixed focal length lens according to the camera sensor size, imaging distance and imaging field of view. During the debugging process, all cameras 1 maintain similar aperture size and focusing to ensure that each camera 1 can clearly image the imaging area. Each camera 1 has two external connection lines. One line is to ensure power supply to the camera 1 and data transmission after camera exposure; the other line is to realize hard trigger control of the camera 1 by the acquisition control unit. The backlight 2 adopts white light. The backlight 2 is composed of multiple rows of uniformly distributed led white lights and a diffuse reflection plate, which can ensure the uniformity of light intensity distribution. The size of the backlight 2 is determined according to the distance from the backlight 2 to the opposite camera 1 and the size of the imaging field of view. During imaging, the background of the imaging field of view should be completely covered by the light field, that is, the area of the backlight 2 in the camera 1 should be larger than the imaging field of view, and there should be no black shadow frame part not illuminated by the backlight at the periphery of the imaging field of view.

[0050] As shown in Figure 3 , Figure 4 The N cameras 1 and the N backlights are arranged in an alternating manner. The outermost lens of the camera 1 lens and the diffuse reflection plate of the backlight 2 form a ring structure. One camera 1 and its opposite backlight 2 are called a group of imaging sources. During data acquisition, each camera 1 only receives white light excited by the opposite light source. Figure 3 There are 15 cameras 1 and 15 backlights 2, which form a 15-source imaging system. Each adjacent camera 1 and backlight 2 are spaced 12 degrees apart. The spacing between adjacent cameras 1 and the spacing between adjacent backlights 2 are both 24 degrees. The 15 cameras 1 receive white light excited by the 15 opposite backlights 2 to obtain 15 projection images. The projection images obtained by every two adjacent cameras 1 are spaced 24 degrees apart. The 15 cameras 1 and the 15 backlights 2 are arranged in an alternating manner,

[0051] Alternatively, the white backlight can be replaced by different waveband backlights such as red light, blue light and green light according to the different sensitivity of the imaging sample to different wavebands.

[0052] Alternatively, the 15-source imaging system can be replaced by any number of sources. The more sources, the more projection images obtained, and the better the final imaging quality. As shown in Figure 5As shown, taking the 45-source imaging system as an example, it is further illustrated that the system can be replaced by any number of sources. The system is composed of 45 cameras 1 and 45 backlight sources 2, which are arranged alternately and form a ring structure as in the 15-source imaging system. Meanwhile, each camera 1 of the system can only receive light excited by the opposite backlight source 2, and a total of 45 projection images can be obtained. In the system, each adjacent camera 1 and backlight source 2 are spaced by 4 degrees, the interval between adjacent cameras 1 and the interval between adjacent backlight sources 2 are both 8 degrees, and the projection images obtained by each two adjacent cameras are spaced by 8 degrees.

[0053] As shown in FIG. 1, the 15-source imaging system is taken as an example to further illustrate that the system can be replaced by any number of sources. The system is composed of 15 cameras 1 and 15 backlight sources 2, which are arranged alternately and form a ring structure. Meanwhile, each camera 1 of the system can only receive light excited by the opposite backlight source 2, and a total of 15 projection images can be obtained. In the system, each adjacent camera 1 and backlight source 2 are spaced by 4 degrees, the interval between adjacent cameras 1 and the interval between adjacent backlight sources 2 are both 8 degrees, and the projection images obtained by each two adjacent cameras are spaced by 8 degrees. Figure 6 As shown in FIG. 2, the water tank 4 structure corresponding to the 15-source imaging system is shown. The water tank 4 is composed of transparent acrylic or glass material. In order to ensure that the water tank 4 does not deform after containing water and maintains good reliability, the wall thickness of the water tank 4 is 7 mm. The water tank 4 is not capped, and is composed of a water tank bottom and a water tank side wall. The 15-source imaging system has a total of 15 cameras and 15 light sources. The width of the camera is 40 mm, and the width of the light source is 100 mm. The water tank side wall has a total of 30 faces, including 15 long faces and 15 short faces. The long faces correspond to the light sources, and the short faces correspond to the cameras. The radius of the water tank 4 is 366.15 mm, the long side of the side wall corresponds to a central angle of 16.815 degrees, and the short side of the side wall corresponds to a central angle of 7.185 degrees, which satisfies the requirement that the sum of the two angles is 24 degrees. The outer wall length of the long side of the side wall is 107.07 mm, which satisfies the requirement of being greater than 100 mm; the outer wall length of the short side of the side wall is 45.879 mm, which satisfies the requirement of being greater than 40 mm. The included angle between two side walls is fixed at 168 degrees. The height of the water tank 4 is 150 mm, and the long side of the water tank 4 and the opposite short side should be parallel to each other (the short side and the opposite long side should also be parallel to each other).

[0054] The water tank 4 is placed inside the ring structure composed of the camera 1 and the backlight source 2. The inscribed circle of the water tank 4 and the inscribed circle of the camera 1 and the backlight source 2 structure should be on the same plane and have the same center. The lens of the camera 1 and the backlight source 2 should be as close to the side wall of the water tank as possible. Without using the water tank 4 structure, if the projection data is collected directly, due to the small imaging container, the curvature of the circular shape in the container cylinder is large, and the transmitted light through the sample will be severely refracted at the container wall of the imaging container cylinder, so the imaging light field will become small, and the sample will appear to be distorted laterally. The water tank 4 designed by this method can greatly reduce the influence of refraction and obtain projection images with less distortion.

[0055] Optionally, the structure of the water tank 4 corresponds to the number of system sources. When the number of system sources changes, the structure of the water tank 4 should also be adjusted. Taking a 45-source imaging system as an example, the side wall of the water tank should be designed as 90 faces, including 45 long faces and 45 short faces, and the length of the outer wall of the long and short faces should be determined according to the width of the camera 1 and the width of the backlight source 2. The height of the water tank 4 should be higher than the height of the backlight source 2. When arranging, as in the 15-source imaging system, it should be ensured that the water tank 4 is placed in the middle of the camera 1 backlight source 2 ring structure, the inscribed circle of the water tank 4 and the inscribed circle of the camera 1 backlight source 2 structure should be on the same plane and have the same center, and the lens of the camera 1 and the backlight source 2 should be as close to the side wall of the water tank as possible.

[0056] The acquisition control unit includes a pulse trigger and a light source controller. The pulse trigger is based on a field programmable logic gate array (FPGA). In the control process, the control mode of the light source controller is set in advance to an external trigger mode, the lighting time is equal to the duration of the high level of the external trigger, and the light intensity of each channel is set. The light intensity should meet the requirements of better transmission of the sample and the camera 1 can obtain transmission light with high contrast, and the light intensity of each channel should be consistent. According to the timing diagram drawn according to the acquisition scheme, the exposure time of all cameras 1 is set. The camera 1 is set to a rising edge external trigger mode, that is, the camera 1 is exposed once according to the exposure time set in advance when receiving the rising edge level. During data acquisition, the pulse trigger sends a control signal to the pulse trigger through the control host, and the pulse trigger further sends a pulse to realize the control of the exposure of the camera 1, and at the same time, the pulse trigger also sends a pulse to the light source controller to realize the control of the lighting of the light source through the light source controller.

[0057] Specifically, the acquisition control flow is as follows Figure 7As shown, first, according to the needs of collection and the performance of the supporting hardware, the logic timing is designed, and then the logic timing program is written in the hardware description language according to the designed logic timing diagram in the control host end, and then the timing program is exported to the FPGA, and the FPGA realizes power supply through the USB interface. In order to realize the matching of the output pulse level of the FPGA and the input trigger level of the camera light source, the pulse output port of the FPGA is connected to the level driving conversion circuit, and the circuit can smoothly output the given voltage pulse. The hard trigger voltage of the camera 1 and the backlight source 2 is usually 5V, and in the circuit, the DC power module generates 5V and 3.3V DC voltage to power the level conversion driving circuit, and further realizes the function of converting the 3.3V pulse signal output by the FPGA into a 5V pulse signal, and realizes the demand of outputting multiple 5V pulse hard trigger control through the level conversion driving circuit. For a 15-source imaging system, the pulse trigger needs to control 15 cameras and 15 light sources. In the level conversion driving circuit, there are 30 output paths in total, of which 15 output paths are directly connected to the camera 1 to realize the hard trigger exposure control of the camera 1; and the other 15 output paths are connected to the light source controller to further realize the lighting control of the light source through the light source controller.

[0058] Optionally, the control method can be applied to an imaging system with any number of sources. For an x-source imaging system, only the number of FPGA output ports and the number of level conversion driving circuit output ports need to be increased or decreased. Figure 7 In the example, the number of FPGA output ports and the number of level conversion driving circuit output ports are increased or decreased.

[0059] The control timing diagram shows that all cameras 1 are exposed once and all backlights 2 are lit once in a cycle. The time when all cameras 1 are exposed once and all backlights 2 are lit once becomes a frame period, that is, the same number of projection images as the number of sources can be obtained in the cycle, and a three-dimensional sample reconstruction data of a frame can be obtained according to the projection images. When all backlights 2 are lit at the same time and all cameras 1 are exposed at the same time, the frame period time is the shortest, the frame rate after reconstruction is the highest, and at the same time, for samples with relatively fast motion speed, each projection image is basically obtained at the same time, and there is no case that the projection data deviates too much, that is, each projection data describes different motion postures of the sample. However, when all backlights 2 are lit at the same time, the camera 1 will receive stray light from non-corresponding light sources, the quality of the projection image is reduced, and the reconstruction result will be affected. When all backlights 2 are lit in turn and all cameras 1 are exposed in turn according to the lighting of the backlights 2, the frame period time is the longest, the frame rate after reconstruction is lower, and at the same time, for samples with relatively fast motion speed, each projection image is obtained at a relatively close but not exactly the same time, and there may be a case that each projection data describes different motion postures of the sample. However, since the backlights 2 and the cameras 1 use the lighting method in turn, that is, only one backlight 2 is lit at the same time and only the camera 1 corresponding to the backlight 2 is exposed at the same time, therefore, all the transmitted light received by the camera 1 comes from the light source on the opposite side, the quality of the projection image is higher, and the reconstruction result is also improved accordingly.

[0060] Figure 8 The timing control diagram for a frame period of a 15-source imaging system is shown. All cameras 1 are numbered 1-15, and backlights 2 are numbered 1-15. The camera 1 and the backlight 2 with the same number are a group and are arranged symmetrically around the imaging container 3. The timing diagram uses a control mode in which 15 cameras 1 and backlights 2 are lit and exposed in turn, the frame period is 35 ms, and the imaging frame rate is about 28.6 fps. The transmission time of the electrical signal and the reaction time of the camera 1 and the backlight 2 are both less than 10 ns, which can be ignored in this timing. In order to ensure that the backlight 2 is always lit during the exposure of the camera 1, the backlight 2 is lit 0.2 ms before each camera 1 exposure. The exposure time of the camera 1 and the intensity of the backlight 2 need to be coordinated to obtain a projection image with high contrast and clear details. In this example, the exposure time of the camera 1 is 2 ms, the effective lighting time of the backlight 2 is also 2 ms, and the total lighting time of the backlight 2 is 2.2 ms. The backlight 2 receives a high-level lighting of 2.2 ms for 2.2 ms, and the camera 1 is exposed for 2 ms after receiving the rising edge level. As shown in the timing diagram, the camera 1 is exposed for 2 ms after the rising edge level is received, and the backlight 2 is lit for 2.2 ms after the falling edge level is received. Figure 8The 1st backlight 2 is lit during 0ms to 2.2ms, the 1st camera 1 is exposed during 0.2ms to 2.2ms, the 2nd backlight 2 is lit after the 1st backlight 2 and the 1st camera 1 are lit and exposed during 2.2ms to 4.4ms, the 2nd camera 1 is exposed during 2.4ms to 4.4ms, which ensures that the 1st backlight 2 has been completely turned off when the 2nd camera 1 is exposed. By analogy, after the 15th backlight 2 and the 15th camera 1 are lit and exposed for 33ms, the next cycle of lighting and exposure work starts after 2ms.

[0061] Alternatively, the timing diagram is a control mode for the light source camera to be lit and exposed in turn, that is, only one light source camera is lit and exposed at the same time. Similarly, 2 to all light source cameras can be selected to be lit and exposed at the same time according to the motion speed of different imaging samples to reduce the frame period and improve the imaging frame rate.

[0062] Alternatively, the timing diagram is a timing control mode for a 15-source imaging system. Similar timing control modes can also be designed for any number of sources.

[0063] The image acquisition and processing unit is used for acquiring, saving and processing the projection images obtained by the projection data acquisition host, and sending to the display unit, including multi-channel data acquisition, high-speed data transmission and control, and a computing host. In the multi-channel data acquisition process, each camera 1 transmits the real-time exposed data in binary form to the switch through a separate gigabit network cable. The switch includes multiple gigabit network ports and multiple terabit network ports, wherein the gigabit network ports are connected with the cameras, and the terabit network ports are connected with the control and computing host through optical fiber jumpers. After the data is read into the host, it is first stored in the memory, and then written to the hard disk. The control and computing host is mainly responsible for camera image acquisition, image preprocessing, and image reconstruction according to the previous calibration results. In the image acquisition process, all channels of the camera need to be saved according to the camera serial number. In the image preprocessing process, gray scale correction and other operations need to be performed on the images collected by each camera 1 to obtain high-resolution and clear outline projection images. In order to improve the reconstruction speed, the non-motion area of the sample needs to be cropped. After the positions of the camera 1, the water tank 4 and the imaging container 3 are fixed, the camera calibration technology is used to determine the positions of each camera 1 in the world coordinate system, so as to further obtain the three-dimensional projection angles of each projection view, thereby assisting the image reconstruction. After obtaining the projection angles of each camera 1 projection image, methods such as analytical algorithm-based method, iterative algorithm-based method, and deep learning-based method can be used to realize three-dimensional image reconstruction under sparse angles.

[0064] The display unit comprises real-time data acquisition display, three-dimensional reconstruction result dynamic display and tomographic image dynamic display. The real-time data acquisition display unit can display the multi-frame data acquired by each camera according to the camera serial number, so that the projection data can be observed in real time. The dynamic display of the three-dimensional reconstruction result can observe the three-dimensional reconstruction result of a single frame from multiple angles, and can project the three-dimensional reconstruction result of multiple frames into a two-dimensional image according to the observation angle selected by the user or the observation angle determined by the motion track, and then display the three-dimensional reconstruction result in the form of a video. The dynamic display of the tomographic image can randomly select a cross section in an arbitrary direction in the sample motion space, and display the two-dimensional tomographic image of the sample in real time.

[0065] The application adopts a plurality of light source cameras and a polygonal water tank combination to form the core part of the system projection data acquisition host, and then forms the static OPT imaging system through the control and processing display mode of the acquisition control unit, the image acquisition processing unit and the display unit. Compared with the traditional OPT imaging system, the system can realize real-time imaging of a moving object, and expands the application range of the OPT technology.

[0066] The above describes the preferred embodiments of the application in detail. It should be understood that those skilled in the art can make many modifications and changes without creative labor according to the concept of the application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment on the basis of the prior art according to the concept of the application shall be within the protection scope defined by the claims.

Claims

1. A static OPT imaging system, characterized in that: The system comprises a projection data acquisition host, an image acquisition processing unit, an acquisition control unit, and a display unit. The projection data acquisition host is used to acquire projection images and send the acquired projection images to the image acquisition processing unit. The projection data acquisition host comprises N cameras, N backlight sources, an imaging container, and a water tank. The image acquisition and processing unit is used to acquire, store, and process the projection images obtained by the projection data acquisition host and send them to the display unit. The image acquisition and processing unit includes a multi-channel data acquisition, high-speed data transmission, and control and calculation host. The control and calculation host sends control signals to the acquisition control unit according to a logic timing diagram designed according to acquisition requirements. The acquisition control unit controls the camera and the backlight source according to a control signal; the acquisition control unit includes a pulse trigger and a light source controller; the pulse trigger controls the exposure of N cameras, and the pulse trigger controls the lighting of N backlight sources through the light source controller; the pulse trigger is based on an FPGA; The display unit includes real-time display of data acquisition, dynamic display of three-dimensional reconstruction results and dynamic display of tomographic images; The number of the cameras is equal to the number of the backlight sources, and N cameras and N backlight sources are alternately arranged to form a ring structure; one camera and the backlight source on the opposite side thereof form a group of imaging sources; The imaging container is placed at the center of a ring structure formed by N cameras and N backlight sources; the imaging container is used to place imaging samples; the imaging container is a cylindrical transparent container; The water tank includes a water tank bottom and a water tank side wall; the water tank side wall includes N long surfaces and N short surfaces, the long surfaces correspond to the backlight source, and the short surfaces correspond to the camera; the water tank is placed inside the annular structure formed by N cameras and N backlight sources, and the camera lens and the backlight source are close to the water tank; the water tank is made of transparent acrylic or glass.

2. The static OPT imaging system according to claim 1, wherein: The multi-channel data acquisition is used to collect the projection images obtained by each camera, and send the projection images to the control and computing host through the high-speed data transmission; the control and computing host includes camera image acquisition, image preprocessing, and image reconstruction.

3. The static OPT imaging system according to claim 2, wherein: The camera image acquisition is to save the projection images of all the cameras according to the sequence numbers of the cameras; the image preprocessing includes grayscale correction and non-motion area cropping.

4. The static OPT imaging system according to claim 2, wherein: The image reconstruction comprises: After the positions of the cameras, the water tank, and the imaging container are fixed, determining the positions of the cameras in the world coordinate system; Obtain the three-dimensional projection angle of each projection view; Analytical algorithms, iterative algorithms and deep learning-based algorithms are used to achieve three-dimensional image reconstruction under sparse angles.

5. The static OPT imaging system according to claim 1, wherein: The data acquisition and real-time display unit is used to display multiple frames of data collected by each camera in real time, thereby realizing real-time observation of the projected image; The three-dimensional reconstruction result dynamic display is used to observe the three-dimensional image reconstruction result of a selected single frame from multiple angles, and the three-dimensional reconstruction result dynamic display is used to project the three-dimensional image reconstruction results of multiple frames into two-dimensional images according to the observation angles and then display them in the form of a video; The dynamic display of the tomographic image is that the user randomly selects a section in any direction in the sample motion space, and displays in real time the changes of the two-dimensional tomographic image of the section as the sample moves.

6. The acquisition control method of a static OPT imaging system according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: Step 1: Set the control mode of the light source controller to the external trigger mode, the lighting time is equal to the duration of the external trigger high level, and set the light intensity of each channel; set the camera to the rising edge external trigger mode, and set the camera exposure time; Step 2: Design the logic timing diagram based on the acquisition requirements and supporting hardware performance; Step 3: The control and computing host uses a hardware description language to write a logic timing program according to the logic timing diagram, and exports the logic timing program to the pulse trigger; Step 4: the pulse trigger sends a pulse to the light source controller according to a logic timing program, and the light source controller controls the lighting of the backlight source; Step 5: The pulse trigger sends a pulse to the camera according to a logic timing program to control the exposure of the camera.

7. The acquisition control method of the static OPT imaging system according to claim 6, characterized in that: The time it takes for all the cameras to be exposed once and all the backlight sources to be lit once is one frame period. The same number of projection images as the number of sources are obtained in one frame period, and one frame of three-dimensional sample reconstruction data is obtained based on these projection images. According to the movement speed of different imaging samples, one to all the backlight sources and cameras are selected to be lit and exposed at the same time.

Images