CN112866529B - Unit detector optical tomography scanning time division modulation imaging system - Google Patents

Unit detector optical tomography scanning time division modulation imaging system Download PDF

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CN112866529B
CN112866529B CN202110033103.8A CN202110033103A CN112866529B CN 112866529 B CN112866529 B CN 112866529B CN 202110033103 A CN202110033103 A CN 202110033103A CN 112866529 B CN112866529 B CN 112866529B
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CN112866529A (en
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李保生
韩宝坤
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Hefei University of Technology
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/50Constructional details
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/50Constructional details
    • H04N23/54Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/50Constructional details
    • H04N23/55Optical parts specially adapted for electronic image sensors; Mounting thereof
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/60Control of cameras or camera modules
    • H04N23/695Control of camera direction for changing a field of view, e.g. pan, tilt or based on tracking of objects
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/80Camera processing pipelines; Components thereof
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00Cameras or camera modules comprising electronic image sensors; Control thereof
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    • H04N23/81Camera processing pipelines; Components thereof for suppressing or minimising disturbance in the image signal generation

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Abstract

A unit detector optical tomography scanning time division modulation imaging system comprises an image rotating device, a cylindrical mirror and an imaging detector which are sequentially arranged along the front direction of an imaging surface of an object to be imaged; the image rotating device is used for rotating the incident object image to generate a rotating image; the cylindrical mirror is used for carrying out one-dimensional integral amplification on the incident rotating image; the imaging detector is used for collecting a rotating image subjected to one-dimensional integral amplification by the cylindrical mirror. The invention realizes the signal enhancement of the optical signal by performing one-dimensional integration on the optical signal through the cylindrical mirror, namely, the pixel value of the rotating image passing through the cylindrical mirror is improved in the integration direction. Through the cooperation of the cylindrical mirror and the imaging detector, the reflected light of the object to be imaged is equivalently subjected to secondary integration, so that pixels of a rotating image obtained by the imaging detector are easier to distinguish, and a finally obtained reconstructed two-dimensional image of the object to be imaged is clearer.

Description

Unit detector optical tomography scanning time division modulation imaging system
Technical Field
The invention relates to the field of imaging, in particular to a time division modulation imaging system for optical tomography scanning of a unit detector.
Background
Target detection and tracking are scientific topics that have been of great interest to people all the time. In pursuit of better target detection effect, attention is always paid to detection of target imaging technology. The existing imaging detection device is mostly used in a parallel light environment, and the resolution ratio in a natural light environment is not ideal.
Disclosure of Invention
In order to solve the defect that the resolution of the imaging detection device in the prior art is not ideal in a natural light environment, the invention provides a unit detector optical tomography time-division modulation imaging system.
The purpose of the invention adopts the following technical scheme:
a unit detector optical tomography scanning time division modulation imaging system comprises an image rotating device, a cylindrical mirror and an imaging detector which are sequentially arranged along the front direction of an imaging surface of an object to be imaged;
the image rotating device is used for rotating the incident object image to generate a rotating image;
the cylindrical mirror is used for carrying out one-dimensional integral amplification on the incident rotating image;
the imaging detector is used for collecting a rotating image subjected to one-dimensional integral amplification by the cylindrical mirror.
Preferably, the imaging detector is a dot matrix detector, and the dot matrix detector is further connected with a first driving device for driving the dot matrix detector to reciprocate in a linear direction perpendicular to the one-dimensional integral direction of the cylindrical mirror and parallel to the plane direction of the cylindrical mirror.
Preferably, the system also comprises an upper computer; the image rotating device adopts a Pechan prism connected with a second driving device, and the second driving device is used for driving the Pechan prism to rotate around the optical axis of the Pechan prism; the upper computer controls the imaging detector to reciprocate through the first driving device, and controls the Pechan prism to rotate around the optical axis through the second driving device; when the Pechan prism rotates by an angle theta, the imaging detector reciprocates once to acquire a rotating image amplified by one-dimensional integration.
Preferably, the upper computer is further configured to reconstruct a two-dimensional image of the object to be imaged according to the N images acquired by the imaging detector; and N is 180/theta.
Preferably, a time division modulation panel is arranged on the light incident surface of the imaging detector, and a preamplifier circuit, a phase-locked amplifier circuit and an analog signal acquisition card are sequentially connected in series between the imaging detector and the upper computer; the chopping frequency of the time division modulation disk is equal to the reference signal frequency of the phase-locked amplifier.
Preferably, the device also comprises a front focusing lens and a front reflector which are positioned between the object to be imaged and the image rotating device, wherein the front focusing lens adopts a convex lens; the optical axis of the image rotating device is positioned in the vertical direction, the front focusing lens is used for focusing an object to be imaged, and the front reflector is used for reflecting emergent light of the front focusing lens to the incident surface of the image rotating device.
Preferably, the device further comprises a rear reflector and a rear focusing lens which are positioned between the image rotating device and the cylindrical mirror, wherein the rear focusing lens is a convex lens; the rear reflector is used for reflecting the rotating image emitted by the rotating imaging device to the light incident surface of the rear focusing lens, and the rotating image is focused by the rear focusing lens and then transmitted to the light incident surface of the cylindrical mirror; the optical axis of the rear focusing lens is located in the horizontal direction, and the distance between the cylindrical lens and the rear focusing lens is 1.5-2 times of the focal length of the rear focusing lens.
Preferably, a front focusing lens andthe focal lengths of the rear focusing lenses are all 100mm, and the optical path between the front focusing lens and the rear focusing lens is 250 mm; the front reflector and the rear reflector are reflectors which take K9 glass as a substrate, have the reflectivity of 95 percent and are in visible light wave bands; the focal length of the cylindrical lens is 50 mm; the working wave band of the imaging detector is 380nm-1100nm, and the photosensitive area is 0.15mm2(ii) a The time division modulation disc is circular, the diameter of the time division modulation disc is 10cm, and the time division modulation disc is divided into 10 frames.
Preferably, the system is used for imaging, and specifically comprises the following steps: s1, setting a light path: arranging an object to be imaged and the unit detector optical tomography scanning time division modulation imaging system in a completely black environment, enabling the imaging detector to be positioned at the image rotation center of the imaging rotating device, and polishing the object to be imaged; the imaging detector adopts a dot matrix detector, and the imaging detector is vertically translated to the outside of an image space view field in the one-dimensional integral direction of the cylindrical mirror and in the plane direction parallel to the cylindrical mirror;
s2, acquiring a one-dimensional integral image: driving the image rotating device to rotate by an angle theta, and then driving the imaging detector to translate in a direction perpendicular to the one-dimensional integral direction of the cylindrical mirror and in a direction parallel to the plane of the cylindrical mirror so as to acquire a one-dimensional integral image, wherein the one-dimensional integral image is a rotating image amplified by one-dimensional integral of the cylindrical mirror; the translation path of the imaging detector spans the image space field of view;
s3, reconstructing a two-dimensional image: repeating the step S2, and collecting N one-dimensional integral images, wherein N is 180/theta; and reconstructing a two-dimensional image of the object to be imaged by combining the N one-dimensional integral images.
Preferably, in step S2, the imaging detector is reset after acquiring the one-dimensional integral image; in step S3, reconstructing a two-dimensional image of the object to be imaged based on the filtered back projection image reconstruction theory;
the method for acquiring the image rotation center of the imaging rotation device in step S1 is as follows:
setting an imaging rotating device and an area array detector for collecting emergent images of the imaging rotating device, and setting checkerboard pictures as imaging targets; after the imaging rotating device is driven to rotate by an angle alpha, a target two-dimensional image is collected through the area array detector; obtaining M target two-dimensional images, wherein M is 180/alpha; and obtaining checkerboard areas with the same pixel value in the N target two-dimensional images as image rotation centers.
The invention has the advantages that:
(1) the invention realizes the signal enhancement of the optical signal by performing one-dimensional integration on the optical signal through the cylindrical mirror, namely, the pixel value of the rotating image passing through the cylindrical mirror is improved in the integration direction. Through the cooperation of the cylindrical mirror and the imaging detector, the reflected light of the object to be imaged is equivalently subjected to secondary integration, so that pixels of a rotating image obtained by the imaging detector are easier to distinguish, and a finally obtained reconstructed two-dimensional image of the object to be imaged is clearer.
(2) The invention combines the advantage that the lattice detector is suitable for working in low-illumination environment, can greatly improve the signal-to-noise ratio of the system and realize higher resolution.
(3) In the invention, the time division modulation disk is matched with the phase-locked amplifier to modulate and demodulate the image signal subjected to the one-dimensional integration of the cylindrical mirror, so that the extraction of weak signals in noise can be realized, and the signals collected by the imaging detector are filtered to realize high-efficiency denoising.
(4) The optical axis of the image rotating device is positioned in the vertical direction so as to facilitate the image rotating device to be horizontally placed and rotate in the horizontal direction, thereby reducing the rotation eccentricity introduced by gravity.
Drawings
FIG. 1 is a light path diagram of a time-division modulation imaging system for optical tomography scanning of a unit detector;
FIG. 2 is a light path diagram of another time-division modulation imaging system for optical tomography scanning of a unit detector;
FIG. 3 is an optical path diagram of another time-division modulation imaging system with unit detector optical tomography;
the figure is as follows: 1. a front focusing lens; 2. a front mirror; 3. an image rotating device; 4. a rear mirror; 5. a rear focusing lens; 6. a cylindrical mirror; 7. a time division modulation disc; 8. an imaging detector;
FIG. 4 is a block diagram of a circuit of a single-detector optical tomography time-division modulation imaging system;
FIG. 5 is a flow chart of a single pixel tomographic imaging method;
fig. 6(a) is a reconstructed two-dimensional image corresponding to N-360 in the embodiment;
fig. 6(b) is a reconstructed two-dimensional image corresponding to N-225 in the embodiment;
fig. 6(c) shows a reconstructed two-dimensional image corresponding to N-75 in the example.
Detailed Description
Name interpretation: the field angle of the diameter of the entrance window to the center of the entrance pupil is called an object space field angle, which is called an object space field for short; the field angle of the exit window diameter to the exit pupil center is called an image space field angle, which is called an image space field for short;
mm: millimeter; cm: centimeters.
The unit detector optical tomography time-division modulation imaging system provided by the embodiment comprises an image rotating device 3, a cylindrical mirror 6 and an imaging detector 8 which are sequentially arranged along the front direction of an imaging surface of an object to be imaged, namely, the object to be imaged, the image rotating device 3, the cylindrical mirror 6 and the imaging detector 8 are sequentially arranged along the light propagation direction, and in the light propagation direction, the imaging surface of the object to be imaged faces the image rotating device 3.
The image rotating device 3 is used for rotating the incident object image to generate a rotating image.
The cylindrical mirror 6 is used for one-dimensional integral amplification of the incident rotation image.
The imaging detector 8 is used for collecting the rotation image after one-dimensional integral amplification by the cylindrical mirror 6.
In the present embodiment, the light signal is one-dimensionally integrated by the cylindrical mirror 6, so that the signal enhancement of the light signal is realized, that is, the pixel value of the rotation image passing through the cylindrical mirror 6 is increased in the integration direction. Through the cooperation of the cylindrical mirror 6 and the imaging detector 8, the reflected light of the object to be imaged is equivalently subjected to secondary integration, so that the pixels of the rotating image obtained by the imaging detector 8 are easier to distinguish, and the finally obtained reconstructed two-dimensional image of the object to be imaged is clearer.
In this embodiment, the imaging detector 8 is a dot matrix detector, and the dot matrix detector is further connected with a first driving device for driving the dot matrix detector to reciprocate in a linear direction perpendicular to the one-dimensional integration direction of the cylindrical mirror 6 and parallel to the plane direction of the cylindrical mirror 6. In this way, in the present embodiment, when the image rotation device 3 is stationary, the dot-matrix detector performs translational motion and spans the image space field of view, so as to ensure the acquisition of the rotation image one-dimensionally integrated and amplified by the cylindrical mirror 6. In the embodiment, the accuracy of pixel acquisition is ensured by the application of the dot matrix detector; the completeness of pixel acquisition is ensured through the translational motion of the dot matrix detector.
The system also comprises an upper computer. The image rotating device 3 adopts a Pechan prism connected with a second driving device, and the second driving device is used for driving the Pechan prism to rotate around the optical axis of the Pechan prism. The upper computer controls the imaging detector 8 to reciprocate through the first driving device, and the upper computer also controls the Pechan prism to rotate around the optical axis through the second driving device. When the Pechan prism rotates by an angle theta, the imaging detector 8 performs reciprocating motion once to acquire a rotating image amplified by one-dimensional integration. Specifically, each reciprocation of the imaging detector 8 spans the image-side field of view. In the embodiment, the first driving device and the second driving device are controlled by the upper computer, so that the intelligent control over the Pechan prism and the imaging detector 8 is realized, the Pechan prism and the imaging detector are matched with each other, and the effective collection of the rotation image is ensured. Specifically, the upper computer is configured to reconstruct a two-dimensional image of the object to be imaged according to the N images acquired by the imaging detector 8. And N is 180/theta. The image rotating device 3 rotates by an angle theta by taking the optical axis as an axis, and the image output by the image rotating device 3 in the static state of the object to be imaged rotates by an angle 2 theta, so that N images are acquired in specific implementation, and acquisition of 360-degree rotating images of the object to be imaged can be realized.
In this embodiment, a time division modulator panel 7 is disposed on the light incident surface of the imaging detector 8, and a preamplifier circuit, a phase-locked amplifier circuit, and an analog signal acquisition card are sequentially connected in series between the imaging detector 8 and the upper computer. The chopping frequency of the time division modulation disk 7 is equal to the reference signal frequency of the phase-locked amplifier, and the time division modulation disk 7 is matched with the phase-locked amplifier to modulate and demodulate the image signal subjected to one-dimensional integration of the cylindrical mirror 6, so that extraction of weak signals in noise can be realized, the signals collected by the imaging detector 8 are filtered, and efficient denoising is realized.
The analog signal acquisition card is used for capturing the analog signals output by the phase-locked amplifier and converting the analog signals into digital signals, so that the upper computer can reconstruct two-dimensional images according to the digital signals output by the analog signal acquisition card
The system further comprises a front focusing lens 1 and a front mirror 2 between the object to be imaged and the image rotating means 3. The optical axis of the image rotating device 3 is located in the vertical direction to facilitate the horizontal placement and rotation of the image rotating device 3, i.e., the Pechan prism, in the horizontal direction, thereby reducing the rotational eccentricity introduced by the gravity factor. The front focusing lens 1 is used for focusing an object to be imaged, and the front reflector 2 is used for reflecting emergent light of the front focusing lens 1 to an incident surface of the image rotating device 3.
The system also comprises a rear reflector 4 and a rear focusing lens 5 which are positioned between the image rotating device 3 and the cylindrical lens 6, wherein the rear reflector 4 is used for reflecting a rotating image emitted by the rotating imaging device to the light incident surface of the rear focusing lens 5, and the rotating image is focused by the rear focusing lens 5 and then is transmitted to the light incident surface of the cylindrical lens 6. The optical axis of the rear focusing lens 5 is located in the horizontal direction, and the distance between the cylindrical lens 6 and the rear focusing lens 5 is 1.5-2 times of the focal length of the rear focusing lens 5.
Thus, the front focusing lens 1 and the rear focusing lens 5 are combined for use, so that the image space view field is enlarged, and focusing is facilitated. Specifically, the front focusing lens 1 and the rear focusing lens 5 each use a convex lens. Meanwhile, the arrangement of the front reflector 2 and the rear reflector 4 is combined in the embodiment, so that the arrangement of light paths at the front end and the rear end of the Pechan prism is facilitated. For example, in the present embodiment, the front mirror 2 makes an angle of 45 ° with the main optical axis of the front focus lens 1. The light inlet of the image rotating device 3 is opposite to the light outlet of the front reflector 2. The light inlet of the rear reflector 4 is right opposite to the light outlet of the image rotating device 3, and meanwhile, the rear reflector 4 and the main optical axis of the image rotating device 3 form an angle of 45 degrees. And a rear focusing lens 5 and a cylindrical lens are coaxially arranged in sequence at a light outlet of the rear reflector 4. So, in the whole light signal propagation process, the main light path is horizontal flat vertical, and the spare part of being convenient for arranges for the center of image space visual field is convenient for align formation of image detector 8, thereby reduces the operation degree of difficulty, improves operating efficiency.
The system is used for imaging and specifically comprises the following steps.
S1, setting a light path: the optical tomography scanning time division modulation imaging system of the unit detector provided by the implementation of the object to be imaged is arranged in a completely black environment, so that the imaging detector 8 is positioned at the image rotation center of the imaging rotating device 3 and the object to be imaged is polished; the imaging detector 8 adopts a dot matrix detector, and the imaging detector 8 is vertically arranged in the one-dimensional integral direction of the cylindrical mirror 6 and is horizontally moved to the outside of the image space view field in the direction parallel to the plane of the cylindrical mirror 6.
S2, acquiring a one-dimensional integral image: driving the image rotating device 3 to rotate by an angle theta, and then driving the imaging detector 8 to translate in a direction perpendicular to the one-dimensional integral direction of the cylindrical mirror 6 and in a direction parallel to the plane of the cylindrical mirror 6 so as to acquire a one-dimensional integral image, wherein the one-dimensional integral image is a rotating image subjected to one-dimensional integral amplification by the cylindrical mirror 6; the translation path of the imaging detector 8 spans the image-side field of view to ensure complete acquisition of the one-dimensional integral image by the imaging detector 8.
In step S2, the imaging detector 8 resets after acquiring the one-dimensional integral image, so as to ensure the next complete acquisition of the one-dimensional integral image. In the step, in each one-dimensional integral image acquisition process, the image rotating device 3 is stationary after rotating by an angle theta, and then the imaging detector 8 is driven to translate, so that the pixel values acquired by the imaging detector 8 at different positions are ensured to be relative to the rotating image emitted by the image rotating device 3 at the same rotation angle, and mutual interference between the rotating images at different rotation angles is avoided. In this embodiment, while the imaging detector 8 is moving horizontally, the analog signal acquisition card captures the analog signal output by the lock-in amplifier and converts the analog signal into a digital signal, so as to reconstruct a two-dimensional image.
Specifically, the imaging detector 8 traverses the one-dimensional integral image through reciprocating motion, and the starting point of the motion of the imaging detector 8 is outside the image space view field of the one-dimensional integral image, that is, pixels on the one-dimensional integral image cannot be acquired when the imaging detector 8 is stationary, so that interference and confusion of the pixels on the one-dimensional integral image corresponding to different rotation angles of the image rotating device 3 are avoided. Meanwhile, the translation path of the imaging detector 8 spans the image space view field, and the complete acquisition of the one-dimensional integral image corresponding to each rotation angle of the image rotating device 3 is ensured.
Specifically, table 1 below shows the pixel distribution of the rotated image a emitted from the image rotating device 3, and table 2 below shows the pixel distribution of the one-dimensional integral image a1 formed by passing the rotated image a through the cylindrical mirror 6.
Figure GDA0003454998340000081
Wherein xij is 0 or 1; i is more than or equal to 1 and less than or equal to m, and j is more than or equal to 1 and less than or equal to n;
Figure GDA0003454998340000082
p is more than or equal to 1 and less than or equal to k and less than or equal to m. In specific implementation, k/m is less than or equal to 0.5 by selecting the cylindrical mirror 6. Therefore, in the embodiment, the pixel distribution of each line of the image obtained by one-dimensional integration of the cylindrical mirror 6 is the same, so that the dot matrix detector is adopted in the embodiment, and the complete line of signals can be used for reconstruction of the two-dimensional image only by acquiring the complete line of signals through translation of the dot matrix detector, so that the signal processing workload is reduced, and the working efficiency is improved.
S3, reconstructing a two-dimensional image: and repeating the step S2, acquiring N one-dimensional integral images, wherein N is 180/theta, and reconstructing a two-dimensional image of the object to be imaged by combining the N one-dimensional integral images. In the step, the two-dimensional image of the object to be imaged is reconstructed based on the filtered back projection image reconstruction theory.
Specifically, in the present embodiment, a method of acquiring the image rotation center of the imaging rotation device 3 is also provided. The method comprises the following steps: setting an imaging rotating device 3 and an area array detector for acquiring an emergent image of the imaging rotating device 3, and setting a checkerboard picture as an imaging target; and after the imaging rotating device 3 is driven to rotate by an angle alpha, acquiring a target two-dimensional image through the area array detector. Obtaining M target two-dimensional images, wherein M is 180/alpha; and obtaining checkerboard areas with the same pixel value in the N target two-dimensional images as image rotation centers. Specifically, when image acquisition of an object to be imaged is performed, θ ═ α, that is, M ═ N may be set. And in the rotation center of the test image, the smaller the area of the unit cells in the checkerboard picture is, the more accurate the test result of the rotation center of the image is.
The invention is further explained below with reference to a specific embodiment.
The optical path portion of the present embodiment is provided with a front focusing lens 1, a front mirror 2, an image rotating device 3, a rear mirror 4, a rear focusing lens 5, and a cylindrical mirror 6. A time division modulation disk 7 is arranged between the cylindrical mirror 6 and the imaging detector 8, and the imaging detector 8 is connected with an upper computer through a preamplification circuit, a phase-locked amplifier and an analog signal acquisition card which are sequentially connected in series. The front focusing lens 1 and the rear focusing lens 5 both adopt biconvex lenses, and the cylindrical lens 6 adopts a plano-convex lens. In specific implementation, the front focusing lens 1 and the rear focusing lens 5 can also be plano-convex lenses, and the cylindrical lens 6 can also be plano-concave lenses.
In this embodiment, the focal lengths of the front focusing lens 1 and the rear focusing lens 5 are both 100mm, and the optical path between the front focusing lens 1 and the rear focusing lens 5 is 250 mm; the front reflector 2 and the rear reflector 4 are both reflectors which take K9 glass as a substrate, have the reflectivity of 95 percent and are in visible light wave bands; the Pechan prism as the image rotating means 3 is horizontally rotatably disposed with its optical axis in the vertical direction. The front reflector 2 and the rear reflector 4 are both at an angle of 45 degrees with the direction of the optical axis of the image rotating device 3, and are parallel to and opposite to the front reflector 2 and the rear reflector 4 so as to reduce the light intensity loss.
In this embodiment, the machined size of the Pechan prism is 28mm 30mm, and the Pechan prism works in a visible light wave band. The focal length of the cylindrical lens is 50mm, and the cylindrical lens is placed between 1.5 times of the focal length and 2 times of the focal length of the image space of the rear focusing lens 5. In this embodiment, the area of the area where the image is located is compressed to 1/2, and accordingly, the intensity of the optical signal received by the imaging detector 8 in a unit area is enhanced to 2 times that of the original area, that is, the pixel value of each pixel acquired by the imaging detector 8 is enhanced to 2 times that of the original area.
In this embodiment, the working band of the imaging detector 8 is 380nm-1100nm, and the photosensitive area is 0.15mm2(ii) a The time division modulation disk 7 is circular, the diameter of the time division modulation disk is 10cm, and the time division modulation disk is divided into 10 frames.
The imaging detector 8 is matched with the pre-amplification circuit to generate analog voltage output. The analog signal acquisition card is an analog signal acquisition card with 8 channels, 12kHz and a USB interface and can be connected with an upper computer. And performing A/D conversion on the analog signal output of the phase-locked amplifier to generate a txt file. And (5) waiting for the subsequent reconstructed image.
In this embodiment, the reflected light of the object to be imaged is integrated twice through the cylindrical mirror 6 and the imaging detector 8, and then a high-quality two-dimensional image is reconstructed through a reconstruction algorithm.
In this embodiment, a test is performed according to the single-pixel tomography method, matlab is used, and a two-dimensional image of an object to be imaged is reconstructed for the integrated data of each N value based on the filtered back projection image reconstruction theory, the test result is shown in fig. 6(a), 6(b), and 6(c), and the N values corresponding to fig. 6(a), 6(b), and 6(c) are 360, 225, and 75, respectively.
It can be seen that as the value of N increases, the image quality is significantly improved.
The invention is not to be considered as limited to the specific embodiments shown and described, but is to be understood to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

Claims (6)

1. A unit detector optical tomography scanning time division modulation imaging system is characterized by comprising an image rotating device (3), a cylindrical mirror (6) and an imaging detector (8) which are sequentially arranged along the front direction of an imaging surface of an object to be imaged;
the image rotating device (3) is used for rotating the incident object image to generate a rotating image;
the cylindrical mirror (6) is used for carrying out one-dimensional integral amplification on the incident rotating image;
the imaging detector (8) is used for collecting a rotating image subjected to one-dimensional integral amplification by the cylindrical mirror (6);
the imaging detector (8) adopts a dot matrix detector, and the dot matrix detector is also connected with a first driving device which is used for driving the dot matrix detector to reciprocate in a linear direction which is vertical to the one-dimensional integral direction of the cylindrical mirror (6) and parallel to the plane direction of the cylindrical mirror (6);
the unit detector optical tomography scanning time division modulation imaging system also comprises an upper computer; the image rotating device (3) adopts a Pechan prism connected with a second driving device; the upper computer controls the imaging detector (8) to reciprocate through the first driving device, and controls the Pechan prism to rotate around the optical axis through the second driving device; when the Pechan prism rotates by an angle theta, the imaging detector (8) performs reciprocating motion once to acquire a rotating image amplified by one-dimensional integration;
the upper computer is also used for reconstructing a two-dimensional image of the object to be imaged according to the N images acquired by the imaging detector (8); n is 180/theta;
a time division modulation disc (7) is arranged on the light incident surface of the imaging detector (8), and a preamplification circuit, a phase-locked amplification circuit and an analog signal acquisition card are sequentially connected in series between the imaging detector (8) and the upper computer; the chopping frequency of the time division modulation disk (7) is equal to the reference signal frequency of the phase-locked amplifier.
2. The unit detector optical tomography time division modulation imaging system according to claim 1, further comprising a front focusing lens (1) and a front reflector (2) between the object to be imaged and the image rotating device (3), wherein the front focusing lens (1) adopts a convex lens; the optical axis of the image rotating device (3) is positioned in the vertical direction, the front focusing lens (1) is used for focusing an object to be imaged, and the front reflector (2) is used for reflecting emergent light of the front focusing lens (1) to the incident surface of the image rotating device (3).
3. The unit detector optical tomography time division modulation imaging system according to claim 2, further comprising a rear mirror (4) and a rear focusing lens (5) between the image rotating device (3) and the cylindrical mirror (6), wherein the rear focusing lens (5) is a convex lens; the rear reflector (4) is used for reflecting the rotating image emitted by the rotating imaging device to the light incident surface of the rear focusing lens (5), and the rotating image is focused by the rear focusing lens (5) and then transmitted to the light incident surface of the cylindrical mirror (6); the optical axis of the rear focusing lens (5) is located in the horizontal direction, and the distance between the cylindrical lens (6) and the rear focusing lens (5) is 1.5-2 times of the focal length of the rear focusing lens (5).
4. The unit detector optical tomography scanning time division modulation imaging system according to claim 3, wherein the focal lengths of the front focusing lens (1) and the rear focusing lens (5) are both 100mm, and the optical path length between the front focusing lens (1) and the rear focusing lens (5) is 250 mm; the front reflector (2) and the rear reflector (4) are reflectors which take K9 glass as a substrate, have the reflectivity of 95 percent and are in visible light wave bands; the focal length of the cylindrical lens is 50 mm; the working wave band of the imaging detector (8) is 380nm-1100nm, and the photosensitive area is 0.15mm2(ii) a The time division modulation dial (7) is circular, the diameter of the time division modulation dial is 10cm, and the time division modulation dial is divided into 10 frames.
5. The unit detector optical tomography time division modulation imaging system of any one of claims 1 to 4, wherein the system is used for imaging, and comprises the following steps:
s1, setting a light path: an object to be imaged and the system are arranged in a completely black environment, so that the imaging detector (8) is positioned at the image rotation center of the imaging rotating device (3) and the object to be imaged is polished; the imaging detector (8) adopts a dot matrix detector, and the imaging detector (8) is vertically arranged in the one-dimensional integral direction of the cylindrical mirror (6) and is horizontally moved to the outside of the image space view field in the direction parallel to the plane of the cylindrical mirror (6);
s2, acquiring a one-dimensional integral image: the image rotating device (3) is driven to rotate by an angle theta, then the imaging detector (8) is driven to translate in a direction perpendicular to the one-dimensional integral direction of the cylindrical mirror (6) and in a direction parallel to the plane of the cylindrical mirror (6) so as to acquire a one-dimensional integral image, and the one-dimensional integral image is a rotating image subjected to one-dimensional integral amplification by the cylindrical mirror (6); a translation path of the imaging detector (8) spans the image-wise field of view;
s3, reconstructing a two-dimensional image: repeating the step S2, and collecting N one-dimensional integral images, wherein N is 180/theta; and reconstructing a two-dimensional image of the object to be imaged by combining the N one-dimensional integral images.
6. The unit detector optical tomography time-division modulation imaging system as claimed in claim 5, wherein in step S2, the imaging detector (8) is reset after acquiring the one-dimensional integral image; in step S3, reconstructing a two-dimensional image of the object to be imaged based on the filtered back projection image reconstruction theory;
the method for acquiring the image rotation center of the imaging rotating device (3) in the step S1 is as follows:
arranging an imaging rotating device (3) and an area array detector for collecting emergent images of the imaging rotating device (3), and setting checkerboard pictures as imaging targets; after the imaging rotating device (3) is driven to rotate by an angle alpha, a target two-dimensional image is collected through the area array detector; obtaining M target two-dimensional images, wherein M is 180/alpha; and obtaining checkerboard areas with the same pixel value in the N target two-dimensional images as image rotation centers.
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