CN207516234U - A kind of device of optical projection tomography - Google Patents

Abstract

The utility model discloses an optical projection tomography device, comprising: a parallel light source, a camera, a telecentric imaging system, a stepping motor, a rotating sample stage, and a computer, the computer is electrically connected to the camera, and the The parallel light source, rotating sample stage, telecentric imaging system, and camera are sequentially connected through the optical path. The device uses the camera, telecentric imaging system, stepping motor, and rotating platform to collect photos of different focal points for each focal plane, and then pass The Laplacian Pyramid Algorithm of the computer is used to obtain a long depth of field photo, and then the filtered back projection algorithm is used for reconstruction to obtain an image with sufficient information and high resolution. Can be widely used in biological imaging.

Description

A device for optical projection tomography

technical field

The invention relates to the technical field of biological imaging, in particular to an optical projection tomography device.

Background technique

Optical projection tomography (Optical Projection Tomography, OPT) technology is a new three-dimensional optical imaging technology, which can realize three-dimensional imaging of small animals with a detection depth of 10mm.

Optical projection tomography is based on microscope camera imaging. In the process of microscopic imaging, due to the small depth of field of the microscopic system, when imaging an object with a certain thickness, only part of the details in the obtained image are in good focus, and other parts are in focus. is blurred, which makes it impossible to clearly study the internal structure of the sample with optical projection tomography. For the imaging system, a large depth of field means that there are more clear scenes in the same picture, which means more objects that can be measured, controlled and monitored. Therefore, increasing the depth of field of an optical system has always been an urgent problem to be solved in the field of optics.

At present, the methods for increasing the depth of field in the optical system mainly include the amplitude cutting method, image fusion of two-dimensional imaging sequence, special design lens combined with image processing, common lens with phase template combined with image processing (wavefront encoding), 3D digital holography, etc. The amplitude cutting method will greatly reduce the imaging light energy and imaging resolution; both the image fusion method and the digital holography method require complex calculations that take a long time.

Utility model content

The purpose of the utility model is to provide a device for enlarging the field depth of optical projection tomography.

The solution of the utility model to solve the technical problem is: a device for optical projection tomography, including: a parallel light source device, a camera, a telecentric imaging system, a stepping motor, a rotating sample stage, and a computer. The camera is electrically connected, the parallel light source device, the rotating sample stage, the telecentric imaging system, and the camera are sequentially connected through an optical path, the stepping motor is used to drive the camera to move linearly towards the biological sample, and the rotating sample stage is used to Drive the biological sample to rotate, the camera is used to take several images of the biological sample at different angles and different focal planes under the drive of the stepping motor and the rotation of the rotating sample stage, and the computer is used to obtain the images taken by the camera, And use the Laplacian pyramid algorithm to fuse images of different focal planes at the same angle into a long depth-of-field image, and use the filtered back-projection algorithm to form a three-dimensional image from long-depth images of biological samples at different angles.

Further, a glass pool filled with water is provided on the rotating sample stage.

Further, the telecentric imaging system includes: front and rear lenses, and an aperture, and the aperture is located between the front and rear lenses and on the rear focal plane of the front lens.

Further, the camera is a COMS camera.

The beneficial effects of the utility model are: the device utilizes a camera, a telecentric imaging system, a stepping motor, and a rotating platform to collect photos of different focal points for each focal plane, and then through the Laplace pyramid algorithm of a computer to obtain Take a long depth of field photo, and then use the filtered back projection algorithm to reconstruct it to obtain an image with sufficient information and high resolution.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following will briefly describe the accompanying drawings that are used in the description of the embodiments. Apparently, the drawings described are only some embodiments of the utility model, not all embodiments, and those skilled in the art can also obtain other designs and drawings according to these drawings without creative work.

Fig. 1 is the structural representation of creation device of the present invention;

FIG. 2 is a flow chart of the optical projection layer imaging method in Embodiment 1. FIG.

Detailed ways

The idea, specific structure and technical effects of the present utility model will be clearly and completely described below in conjunction with the embodiments and accompanying drawings, so as to fully understand the purpose, characteristics and effects of the present utility model. Apparently, the described embodiments are only some of the embodiments of the present utility model, rather than all embodiments. Based on the embodiments of the present utility model, other embodiments obtained by those skilled in the art without paying creative efforts, All belong to the protection scope of the utility model. In addition, all the connection/connection relationships mentioned in this article do not refer to the direct connection of components, but mean that a better connection structure can be formed by adding or reducing connection accessories according to specific implementation conditions. The various technical features in the invention can be combined interactively on the premise of not conflicting with each other.

Embodiment 1, with reference to Fig. 1 and Fig. 2, a device for optical projection tomography, comprising: a parallel light source device, a camera 5, a telecentric imaging system 4, a stepping motor 5, a rotating sample stage 10, and a computer 9, the The parallel light source device is composed of a white light source device 1 and a diffusion sheet 2, the computer 9 is electrically connected to the camera 5, and the parallel light source device, the rotating sample stage 10, the telecentric imaging system 4, and the camera 5 are sequentially connected through an optical path. , the telecentric imaging system 4 includes: front and rear lenses, a diaphragm, the diaphragm is located between the front and rear lenses, and is located on the rear focal plane of the front lens; the rotating sample stage 10 A glass pool 3 full of water is provided on the top. The camera 5 is a CMOS camera.

When the device of the present utility model works, at first, the white light emitted by the white light source device 1 passes through the diffuser 2 to become a parallel beam of white light with uniform illuminance, which is irradiated on the biological sample 8. Because the biological sample generally adopts agar with a concentration of 1% to fix , so in order to reduce the refractive index when light passes through the agar, the biological sample 8 is placed into the glass tank 3 filled with water, and then placed on the rotating platform 10 to perform refractive index matching. The front and rear lenses of the telecentric imaging system 4 Both are 10× microscope eyepieces, and the diaphragm is located on the rear focal plane of the front lens, wherein the function of the diaphragm of the telecentric imaging system 4 is to increase the diaphragm to reduce the cone angle of the light cone and the distance between the light cone and the main lens. The included angle of the optical axis increases the imaging depth and reduces the system error, and the effect of adding two lenses on both sides of the diaphragm at the same time is that the distance between the front lens and the sample is relatively long, and the image of the sample passing through the front lens is a reduced real image. The rear lens can magnify the reduced real image passed through the front lens to a certain extent.

The camera 5 is used to collect a series of projected digital images and transmit them to the computer 9 . The model of camera 5 is Basler acA2000-340k (Base), the depth of field of the lens is 2mm, the magnification is 0.16, and the exposure time is 0.09.

The stepping motor 6 drives the camera 5 to move, so that the distance between the biological sample 8 and the telecentric imaging system 4 changes, thereby changing the initial position of the depth of field. Every time it is driven, it waits until it is relatively stationary, and then takes a picture, finally obtaining the same angle. A plurality of photos with different focal planes, 5 in this embodiment, and using the Laplacian pyramid algorithm to fuse images of different focal planes at the same angle to form a depth-of-field picture.

The servo motor 7 will drive the rotating platform 10 on which the biological sample 8 is placed. Every time the rotating platform 10 rotates 1.8 degrees, the above steps are performed to collect images at the same angle. The rotating platform 10 rotates 200 times, 360 degrees, and then the camera 5 Collect images and transmit the projected digital images to the computer 9 to fuse 200 long depth-of-field pictures. These pictures will be reconstructed by the computer 9 using the filtered back-projection algorithm, where the filter function of the filtered back-projection algorithm is the SL function. After obtaining the projection volume of each analysis layer under different rotation angles, each tomographic image of the sample can be obtained by computer 9 reconstruction according to the algorithm, and the reconstruction results can be observed from different angles and virtual slices along different directions can be obtained, and then can be obtained The three-dimensional light absorption tomography structure of the whole sample is obtained. Then use amira software to synthesize three-dimensional images.

The method and device collect photos with different focal points for each focal plane, and then use the Laplacian pyramid algorithm to obtain a long depth of field photo, and then use the filter back projection algorithm to reconstruct, so that the information extracted from the image Full, high-resolution images.

Wherein, the principle steps of the Laplacian Pyramid Algorithm are:

Step 1: Perform gradient pyramid analysis on each source image to establish a gradient pyramid of the image.

Step 2: Fusion processing is performed on each decomposition layer of the image gradient pyramid; different decomposition layers and different direction detail images are fused with different fusion operators, and finally the gradient pyramid of the fused image is obtained.

Step 3: Perform inverse pyramid transformation (that is, perform image reconstruction) on the gradient pyramid obtained after fusion.

The preferred embodiments of the present utility model have been specifically described above, but the present invention is not limited to the described embodiments, and those skilled in the art can also make various equivalent modifications without violating the spirit of the present utility model Or replacement, these equivalent modifications or replacements are all included in the scope defined by the claims of the present application.

Claims (4)

1. A device for optical projection tomography, comprising: a parallel light source device, a camera, and a telecentric imaging system, characterized in that, it also includes a stepping motor, a rotating sample stage, and a computer, and the computer is electrically connected to the camera , the parallel light source device, rotating sample stage, telecentric imaging system, and camera are sequentially connected through an optical path, the stepping motor is used to drive the camera to move linearly towards the biological sample, and the rotating sample stage is used to drive the biological sample The sample is rotated, and the camera is used to take several images of the biological sample at different angles and different focal planes under the drive of the stepping motor and the rotation of the rotating sample stage. The computer is used to obtain the images taken by the camera, and use The Las Pyramid algorithm fuses images of different focal planes at the same angle into a long depth-of-field image, and uses the filtered back-projection algorithm to form a three-dimensional image from long depth-of-field images of biological samples at different angles. 2 . The optical projection tomography device according to claim 1 , wherein a glass pool filled with water is provided on the rotating sample stage. 3 . 3. A device for optical projection tomography according to claim 2, wherein the telecentric imaging system comprises: front and rear lenses, and a diaphragm, and the diaphragm is located at the front and rear lenses between and on the back focal plane of the front lens. 4. The optical projection tomography device according to any one of claims 1-3, wherein the camera is a CMOS camera.