Static OPT imaging system and acquisition control method thereof

Abstract

The invention discloses a static OPT imaging system, and relates to the technical field of optical projection tomography, the static OPT imaging 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 for acquiring projection images, and comprises N cameras, N backlights, an imaging container and a water tank; the image acquisition processing unit is used for acquiring, storing and processing the projection image and sending a control signal to the acquisition control unit according to a logic sequence diagram; the acquisition control unit controls the camera and the backlight source according to the control signal; the acquisition control unit comprises a pulse trigger and a light source controller; and the display unit comprises data acquisition real-time display, three-dimensional reconstruction result dynamic display and sectional image dynamic display. According to the invention, a multi-source static OPT imaging system is adopted, a plurality of projection images can be obtained at the same time on the premise of not rotating a sample, and real-time imaging of a moving sample and a growth change sample is realized.

Description

Technical Field

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

[0002] Optical Projection Tomography (OPT), as a mesoscopic imaging technology, has made outstanding contributions in the imaging of translucent objects (such as biological embryos, in vitro organs, living small animals, gels, etc.). The principle of OPT imaging technology is to use the different attenuation degrees of light of different translucent materials to reconstruct the optical attenuation image of the material and realize three-dimensional tomographic imaging of translucent objects.

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

[0004] Compared with other semi-transparent object imaging systems, the OPT imaging system is low-priced, fast, and has no ionizing radiation, and provides a new means of imaging semi-transparent objects.

[0005] Most of the existing OPT imaging systems are used for biological tissues that have been chemically cleaned and made transparent, or for in vitro imaging of genetically modified biological embryos. As far as we know, single-source OPT imaging devices are usually used on the market to achieve the above imaging requirements, but the imaging samples need to remain relatively still during the imaging process. To achieve this goal, the existing technology requires anesthetizing the imaging samples or inactivating the samples through chemical means. However, anesthetizing the samples will cause stress responses in the samples, causing irreversible damage, especially to embryonic samples; chemical treatment of the samples will directly kill the samples, resulting in the inability to observe the dynamic information of the samples and the inability to record the continuous growth changes of the same sample. In addition, the traditional OPT equipment is a single-source device that uses a square water tank, which is not suitable for multi-source scenarios.

[0006] Therefore, technicians in this field are committed to developing a static OPT imaging system and an imaging method thereof, which can image moving living organisms without damaging living samples. Summary of the invention

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

[0008] To achieve the above-mentioned object, the present invention 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 a projection image and send the acquired projection image to the image acquisition processing unit, and 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 them to the display unit; the image acquisition processing unit includes multi-channel data acquisition, high-speed data transmission, control and calculation host; the control and calculation host sends a control signal to the acquisition control unit according to the logic timing diagram, and the logic timing diagram is designed according to the acquisition requirements;

[0010] The acquisition control unit controls the camera and the backlight source according to the 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 FPGA;

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

[0012] Furthermore, 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.

[0013] Furthermore, the imaging container is placed at the center of the annular structure formed by the N cameras and the N backlight sources; the imaging container is used to place imaging samples; and the imaging container is a cylindrical transparent container.

[0014] Furthermore, the water tank includes a water tank bottom and a water tank side wall; the water tank side wall includes N long faces and N short faces, the long faces correspond to the backlight source, and the short faces correspond to the camera; the water tank is placed inside the annular structure formed by the N cameras and the 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.

[0015] Furthermore, the multi-channel data acquisition is used to acquire the projection image obtained by each camera, and send the projection image 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.

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

[0017] Furthermore, the image reconstruction comprises:

[0018] After the position of the camera, the position of the water tank and the position of the imaging container are fixed, determining the position of each camera in the world coordinate system;

[0019] Obtain the three-dimensional projection angle of each projection view;

[0020] Three-dimensional image reconstruction under sparse angles is achieved by using analytical algorithms, iterative algorithms and deep learning.

[0021] Furthermore, the data acquisition real-time display unit is used to display multiple frames of data acquired by each camera in real time, thereby realizing real-time observation of the projected image;

[0022] 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 angle and then display them in the form of video;

[0023] 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 during the movement.

[0024] A method for controlling the acquisition of a static OPT imaging system, the method comprising the following steps:

[0025] Step 1, setting 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 setting the light intensity of each channel; setting the camera to the rising edge external trigger mode and the camera exposure time;

[0026] Step 2: Design the logic timing diagram according to the acquisition requirements and supporting hardware performance;

[0027] 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;

[0028] 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;

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

[0030] Furthermore, the time it takes for all the cameras to be exposed once and for all the backlight sources to be lit once is a frame period, and the same number of projection images as the number of sources are obtained within a 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 the cameras are selected to be lit and exposed at the same time.

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

[0032] 1. The present invention adopts a multi-source static OPT imaging system, thereby achieving the simultaneous acquisition of multiple projection images without rotating the sample, and realizing real-time imaging of moving samples and growing and changing samples;

[0033] 2. The present invention designs a polygonal water tank according to the number of system sources, so that the light is refracted and deflected slightly after being projected through the imaging sample, and the projection image is distorted slightly, while at the same time, no additional space is added to the system;

[0034] 3. The present invention builds a pulse trigger circuit based on FPGA to achieve accurate lighting and exposure of multiple light sources and multiple cameras, and obtain multi-angle projection data of the sample within 1 frame.

[0035] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

[0040] Figure 5 It is a structural schematic diagram of an arrangement of any number of backlight cameras in a preferred embodiment of the present invention;

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

[0042] Figure 7It is a schematic diagram of the structure of a collection control unit of a preferred embodiment of the present invention;

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

[0044] The following describes several preferred embodiments of the present invention with reference to the drawings in the specification, so that the technical content is clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0045] In the drawings, components with the same structure are indicated by the same numerical reference numerals, and components with similar structures or functions are indicated by similar numerical reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. In order to make the illustration clearer, the thickness of the components is appropriately exaggerated in some places in the drawings.

[0046] This embodiment provides a static OPT imaging system, such as Figure 1 As shown, it includes 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 main body of data acquisition, such as Figure 2 As shown, it includes N cameras 1, N backlight sources 2, an imaging container 3, and a water tank 4.

[0048] In order to ensure the consistency of projection data at various projection angles, 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 very thin thickness, and the container wall should ensure uniform thickness and flatness without protrusions. In the actual placement process, the container can be optionally fixed by the upper or lower end of the imaging container 3, and the fixing device should not block the side of the container wall. During the data acquisition process, pure water or salt water suitable for the survival of marine organisms needs to be added to the container, and the imaging sample also needs to be placed in the imaging container 3.

[0049] The core parts of the projection data acquisition unit are camera 1 and backlight source 2. Camera 1 uses an industrial camera. The front end of each camera 1 is equipped 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 are kept with similar aperture size and focus to ensure that each camera 1 can clearly image the imaging area. Each camera 1 has two external wiring connections. One wire is used to ensure the power supply to camera 1 and the transmission of data after camera exposure; the other wire is used to realize the hard trigger control of camera 1 by the acquisition control unit. Backlight source 2 uses white light. Backlight source 2 is composed of evenly distributed multiple rows of LED white lights and diffuse reflection plates. The diffuse reflection plate can ensure the uniformity of light intensity distribution. The size of backlight source 2 is determined by two factors: the distance from backlight source 2 to the opposite camera 1 and the size of the imaging field of view. During the imaging process, the background of the imaging field of view should be completely covered by the light field, that is, the area of ​​backlight source 2 in camera 1 should be larger than the imaging field of view, and there should be no black shadow border part around the imaging field of view that is not illuminated by the backlight source.

[0050] like Figure 3 , Figure 4 As shown, N cameras 1 and N backlight sources are arranged alternately, and the outermost lens of the camera 1 lens and the diffuse reflection plate of the backlight source 2 form a ring structure. A camera 1 and its opposite backlight source 2 are called a group of imaging sources. During the data acquisition process, each camera 1 only receives white light stimulated by the opposite light source. Figure 3 15 cameras 1 and 15 backlight sources 2 form a 15-source imaging system. The interval between each adjacent camera 1 and backlight source 2 is 12 degrees, and the interval between adjacent cameras 1 and adjacent backlight sources 2 is 24 degrees. The 15 cameras 1 receive white light stimulated by 15 opposite backlight sources 2 to obtain 15 projection images, and the interval between the projection images obtained by every two adjacent cameras 1 is 24 degrees. The 15 cameras 1 and the 15 backlight sources 2 are arranged alternately.

[0051] Optionally, the white backlight source may be replaced with a backlight source of a different wavelength band as an excitation, such as red light, blue light, green light, etc., according to the characteristic that the imaging sample has different sensitivities to different wavelength bands.

[0052] Optionally, the 15-source imaging system can be replaced with any number of sources. The more sources there are, the more projection images can be obtained, and the better the final imaging quality. Figure 5As shown, a 45-source imaging system is taken as an example to further illustrate that the system can be replaced with any number of sources. The system is composed of 45 cameras 1 and 45 backlight sources 2. The cameras 1 and backlight sources 2 are arranged alternately with the 15-source imaging system and form a ring structure. At the same time, each camera 1 of the system can only receive light stimulated by the backlight source 2 on the opposite side, and a total of 45 projection images can be obtained. In this system, the interval between each adjacent camera 1 and the backlight source 2 is 4 degrees, the interval between adjacent cameras 1 and the interval between adjacent backlight sources 2 are both 8 degrees, and the interval between the projection images obtained by every two adjacent cameras is 8 degrees.

[0053] like Figure 6 As shown, the structure of the water tank 4 corresponding to the 15-source imaging system is shown. The water tank 4 is made of transparent acrylic or glass. In order to ensure that the water tank 4 does not deform after being filled with water and maintain good reliability, the wall thickness of the water tank 4 is 7mm. The water tank 4 is not capped on the top 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 40mm, and the width of the light source is 100mm. The side wall of the water tank has a total of 30 faces, including 15 long faces and 15 short faces, of which the long faces correspond to the light source and the short faces correspond to the camera. The radius of the water tank 4 is 366.15mm, the central angle corresponding to the long side of the side wall is 16.815 degrees, and the central angle corresponding to the short side of the side wall is 7.185 degrees, which meets 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 107.07mm, which meets the requirement of being greater than 100mm; the outer wall length of the short side of the side wall is 45.879mm, which meets the requirement of being greater than 40mm. The angle between the two side walls is fixed at 168 degrees. The height of the water tank 4 is 150mm, and the long side of the water tank 4 should be parallel to the short side on the opposite side (the short side should also be parallel to the long side on the opposite side).

[0054] The water tank 4 is placed inside the annular structure formed by the camera 1 and the backlight source 2. 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. 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 directly collected, due to the small imaging container and the large curvature of the circle in the container cylinder, the transmitted light passing through the sample will be severely refracted at the container wall of the imaging container cylinder, so the imaging light field will become smaller and the sample will be lateral distorted. The water tank 4 designed by this method can greatly reduce the impact of refraction and obtain a projection image with less distortion.

[0055] Optionally, the structure of the water tank 4 corresponds to the number of sources of the system. When the number of system sources changes, the structure of the water tank 4 should also be adjusted. Taking the 45-source imaging system as an example, the side wall of the water tank should be designed to have 90 faces, including 45 long faces and 45 short faces. The length of the outer wall of the long faces and the 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 with the 15-source imaging system, it should be ensured that the water tank 4 is placed in the middle of the annular structure of the camera 1 backlight source 2, 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. Among them, the pulse trigger is based on a field programmable gate array (FPGA). During the control process, the control mode of the light source controller is set to an external trigger mode in advance, and the lighting time is equal to the duration of the external trigger high level. At the same time, the light intensity of each channel is set. The light intensity should be able to transmit the sample well, and the camera 1 can obtain the transmitted light with a high contrast, and the light intensity of each channel should be consistent. According to the timing diagram drawn according to the acquisition plan, the exposure time of all cameras 1 is set, and camera 1 is set to a rising edge external trigger mode, that is, when the camera 1 receives the rising edge level, it is exposed once according to the exposure time set in advance. During data acquisition, the control host sends a control signal to the pulse trigger, and the pulse trigger further sends a pulse to realize the exposure control of camera 1. At the same time, the pulse trigger also sends a pulse to the light source controller, and the light source lighting control is realized through the light source controller.

[0057] Specifically, the acquisition control process is as follows: Figure 7As shown, firstly, the logic timing is designed according to the needs of acquisition and the performance of supporting hardware. The logic timing program is written in hardware description language according to the designed logic timing diagram on the control host side, and then the timing program is exported to the FPGA, and the FPGA is powered through the USB interface. In order to match the output pulse level of the FPGA with the input trigger level of the camera light source, the pulse output port of the FPGA is connected to the level drive conversion circuit, which can smoothly output pulses of a given voltage. Usually, the hard trigger voltage for camera 1 and backlight source 2 is 5V. In this circuit, a DC power supply module generates 5V and 3.3V DC voltages to power the level conversion drive circuit, and further realizes the function of converting the FPGA output 3.3V pulse signal into a 5V pulse signal, realizing the need for outputting multiple 5V pulse hard trigger control through the level conversion drive circuit. For a 15-source imaging system, the pulse trigger needs to control 15 cameras and 15 light sources. There are 30 outputs in the level conversion drive circuit, of which 15 outputs are directly connected to camera 1 to realize the hard trigger exposure control of camera 1; the other 15 outputs are connected to the light source controller, and the light source controller is used to further realize the lighting control of the light source.

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

[0059] The control timing diagram shows that in one cycle, all cameras 1 are exposed once and all backlight sources 2 are lit once. The time when all cameras 1 are exposed once and all backlight sources 2 are lit once becomes a frame cycle, that is, the same number of projection images as the number of sources can be obtained in this cycle, and one frame of three-dimensional sample reconstruction data can be obtained based on these projection images. When all backlight sources 2 are lit at the same time and all cameras 1 are exposed at the same time, the frame cycle time is the shortest, and the frame rate after reconstruction is higher. At the same time, for samples with faster movement speeds, each projection image is obtained at basically the same time, and there will be no excessive deviation in the projection data, that is, each projection data describes different motion postures of the sample. However, when all backlight sources 2 are lit at the same time, camera 1 will receive stray light from non-corresponding light sources, the quality of the projection image will be reduced, and it will affect the subsequent reconstruction results. When all backlight sources 2 are lit in sequence and all cameras 1 are exposed in sequence according to the lighting of backlight sources 2, the frame cycle time is the longest, and the frame rate after reconstruction is lower. At the same time, for samples with faster movement speeds, each projection image is obtained at a relatively close but not completely the same time, and each projection data may describe different motion postures of the sample. However, since the backlight source 2 and the camera 1 are lit in sequence, that is, only one backlight source 2 is lit at the same time and only the camera 1 corresponding to the backlight source 2 is exposed, all the transmitted light received by the camera 1 comes from the opposite light source, the quality of the projected image is higher, and the reconstruction result will be improved accordingly.

[0060] Figure 8 The timing control diagram for a frame cycle of a 15-source imaging system is shown. All cameras 1 are numbered from 1 to 15, and backlight sources 2 are numbered from 1 to 15. Cameras 1 and backlight sources 2 with the same number are grouped together and arranged symmetrically around the imaging container 3. This timing diagram adopts a control method in which 15 cameras 1 and backlight sources 2 are sequentially lit for exposure. The frame period is 35ms, and the imaging frame rate is about 28.6fps. The transmission time of the electrical signal and the reaction time of the camera 1 backlight source 2 are both less than 10ns, which can be ignored in this timing. In order to ensure that the backlight source 2 is always lit during the exposure process of 1 camera, the backlight source 2 is lit 0.2ms before each exposure of camera 1. The exposure time of camera 1 and the intensity of backlight source 2 need to cooperate with each other to obtain a projection image with high contrast and clear details. In this example, the exposure time of camera 1 is 2ms, the effective lighting time of backlight source 2 is also 2ms, and the total lighting time of backlight source 2 is 2.2ms. Backlight source 2 receives a high level that lasts for 2.2ms and lights up for 2.2ms. Camera 1 exposes for 2ms after receiving a rising edge level. Figure 8As shown, backlight source 1 2 is lit during 0ms to 2.2ms, camera 1 is exposed during 0.2ms to 2.2ms, backlight source 2 is lit during 2.2ms to 4.4ms after backlight source 1 2 and camera 1 are lit, and camera 1 is exposed during 2.4ms to 4.4ms, ensuring that backlight source 1 2 is completely extinguished when camera 2 is exposed. Similarly, 33ms after backlight source 15 and camera 15 are lit, the next cycle of lighting and exposure begins after an interval of 2ms.

[0061] Optionally, this timing diagram is a control method for lighting and exposing light source cameras in sequence, that is, only one light source camera is lit and exposed at the same time. Similarly, according to the movement speed of different imaging samples, 2 to all light source cameras can be chosen to be lit and exposed at the same time to shorten the frame period and increase the imaging frame rate.

[0062] Optionally, this timing diagram is a timing control method for a 15-source imaging system, and a similar timing control method can be designed for any number of sources.

[0063] The image acquisition and processing unit is used to acquire, save, and process the projection images acquired by the projection data acquisition host, and send them to the display unit, including multi-channel data acquisition, high-speed data transmission, and control and computing hosts. In the multi-channel data acquisition process, each camera 1 transmits the real-time exposure data in binary form to the switch through a separate Gigabit network cable. The switch includes multiple Gigabit network ports and multiple 10 Gigabit network ports, wherein the Gigabit network port is connected to the camera, and the 10 Gigabit network port is connected to the control and computing host through an optical fiber jumper. After the data is read into the host, it is first stored in the memory and then synchronously written to the hard disk. The control and computing host is mainly responsible for camera image acquisition, image preprocessing, and image reconstruction based on previous calibration results. During the image acquisition process, all cameras need to be saved according to the camera serial number. In the image preprocessing process, it is necessary to perform grayscale correction and other operations on the image acquired by each camera 1 to obtain a high-resolution and clear-outline projection image. At the same time, in order to increase the reconstruction speed, the non-moving 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 position of each camera 1 in the world coordinate system needs to be determined through camera calibration technology, so as to further obtain the three-dimensional projection angle of each projection view to assist in image reconstruction. After obtaining the projection angle of each camera 1 projection image, the three-dimensional image reconstruction under sparse angles can be achieved by using methods such as analytical algorithms, iterative algorithms, and deep learning.

[0064] The display unit includes real-time display of data acquisition, dynamic display of 3D reconstruction results and dynamic display of tomographic images. The real-time display unit of data acquisition can display the multiple frames of data collected by each camera in real time according to the camera sequence number based on the images collected by the control and computing host, so as to realize real-time observation of the projection data. The dynamic display of 3D reconstruction results can observe the 3D reconstruction results of the selected single frame from multiple angles on the one hand, and on the other hand, the 3D reconstruction results of multiple frames can be projected into 2D images according to the observation angle selected by the user or the observation angle of the determined motion trajectory, and then displayed in the form of video. The dynamic display of tomographic images allows the user to randomly select a section in any direction in the sample motion space, and display the changes of the 2D tomographic image of the section as the sample moves during the movement in real time.

[0065] The present invention adopts a combination of multiple light source cameras and polygonal water tanks to form the core part of the system projection data acquisition host, and then forms a static OPT imaging system through the control processing display mode of the acquisition control unit, image acquisition processing unit and display unit. Compared with the traditional OPT imaging system, this system can realize real-time imaging of moving objects and expand the application scope of OPT technology.

[0066] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A static OPT imaging system, characterized in that: It includes 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 a projection image and send the acquired projection image to the image acquisition processing unit, and the projection data acquisition host includes N cameras, N backlight sources, an imaging container, and a water tank; The image acquisition processing unit is used to acquire, save, and process the projection images acquired by the projection data acquisition host, and send them to the display unit; the image acquisition processing unit includes multi-channel data acquisition, high-speed data transmission, control and calculation host; the control and calculation host sends a control signal to the acquisition control unit according to the logic timing diagram, and the logic timing diagram is designed according to the acquisition requirements; The acquisition control unit controls the camera and the backlight source according to the 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 FPGA; The display unit includes real-time display of data acquisition, dynamic display of three-dimensional reconstruction results and dynamic display of tomographic images.

2. The static OPT imaging system according to claim 1, characterized in that: 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 form a group of imaging sources.

3. The static OPT imaging system according to claim 1, characterized in that: The imaging container is placed at the center of the annular structure formed by the N cameras and the N backlight sources; the imaging container is used to place imaging samples; and the imaging container is a cylindrical transparent container.

4. The static OPT imaging system according to claim 1, characterized in that: The water tank includes a water tank bottom and a water tank side wall; the water tank side wall includes N long faces and N short faces, the long faces correspond to the backlight source, and the short faces correspond to the camera; the water tank is placed inside a ring 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.

5. The static OPT imaging system according to claim 1, characterized in that: The multi-channel data acquisition is used to acquire the projection image obtained by each camera, and send the projection image 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.

6. The static OPT imaging system according to claim 5, characterized in that: 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.

7. The static OPT imaging system according to claim 5, characterized in that: The image reconstruction comprises: After the position of the camera, the position of the water tank and the position of the imaging container are fixed, determining the position of each camera in the world coordinate system; Obtain the three-dimensional projection angle of each projection view; Three-dimensional image reconstruction under sparse angles is achieved by using analytical algorithms, iterative algorithms and deep learning.

8. The static OPT imaging system according to claim 1, characterized in that: The data acquisition real-time display unit is used to display multiple frames of data acquired 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 angle and then display them in the form of 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 during the movement.

9. The acquisition control method of a static OPT imaging system according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: Step 1, setting 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 setting the light intensity of each channel; setting the camera to the rising edge external trigger mode, and setting the camera exposure time; Step 2: Design the logic timing diagram according to 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.

10. The acquisition control method of the static OPT imaging system according to claim 9, characterized in that: The time it takes for all the cameras to be exposed once and for all the backlight sources to be lit up once is a frame period, and the same number of projection images as the number of sources are obtained within a 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 the cameras are selected to be lit up and exposed at the same time.

Images