A multi-channel rotational coding imaging system

Abstract

This invention discloses a multi-channel rotating coded imaging system, which solves the technical problem in the prior art where the imaging rate of coded aperture imaging technology based on digital micromirror devices is still difficult to reach the MHz level because the switching speed of the digital micromirror device itself depends on the discrete control of the tiny rotating mirror. The system includes an imaging lens, a beam splitter, a rotating coded plate, a driving device, a data processing unit, and multiple image sensors. By setting up a beam splitter, a single beam of light signal is split into multiple identical light signals in multiple channels, which are projected onto different coding positions on the coding area of ​​the rotating coded plate and imaged on multiple image sensors that are set one-to-one with the multiple identical light signals in multiple channels. The driving device drives the rotating coded plate to rotate, and the light signals of ultrafast processes at different times are encoded and recorded to achieve ultrafast continuous two-dimensional imaging at the microsecond to nanosecond level.

Description

Technical Field

[0001] This invention relates to coded imaging systems, and more specifically to a multi-channel rotational coded imaging system. Background Technology

[0002] With the deepening research into ultrafast physics, chemical reactions, and high-energy dynamics, extremely high demands are being placed on time-resolved imaging of transient phenomena. Many typical processes, such as laser-matter interactions, plasma discharges, shock wave propagation, and material phase transitions, occur on timescales ranging from microseconds (μs) to nanoseconds (ns) or even picoseconds (ps), requiring imaging systems to possess dynamic capture capabilities of millions to billions of frames per second. Traditional CCD and CMOS imaging systems, limited by charge transfer speed, readout bandwidth, and data storage rate, struggle to exceed a frame rate of 10^ ... 6 At the fps level, direct observation of ultrafast transient events is impossible.

[0003] The emergence of coded imaging technology based on Compressive Sensing (CS) theory has made it possible to overcome the imaging rate bottleneck of traditional detectors. Compressive sensing theory utilizes the sparsity of signals, allowing complete information to be reconstructed with only a small amount of projection, thus achieving high-dimensional data acquisition at a measurement rate far lower than the Nyquist sampling rate. Guided by this theory, coded aperture imaging technology based on Digital Micromirror Devices (DMDs) has gradually become a research hotspot.

[0004] Encoded aperture imaging technology based on digital micromirror devices (DVMs) is an advanced method for achieving high spatiotemporal resolution imaging through spatial light modulation. A DVM consists of a large number of tiny, independently flippable mirror units (i.e., micro-rotating mirrors). Each mirror can rapidly switch between different reflection directions, thereby precisely encoding the incident light. Using DVMs as the coded aperture, the two-dimensional light signals of the target scene can be encoded in real time. These encoded light signals are then acquired via CMOS / CCD overlay, and finally, the original image is reconstructed using compressed sensing algorithms or other reconstruction algorithms, achieving high-speed two-dimensional imaging.

[0005] This imaging technology utilizes a rapidly switching binary emission array of digital micromirror devices (DMMs) to dynamically modulate the incident light field in the optical system, enabling multi-time-sequence spatially encoded sampling. By inverting the integrated signal from the detector in each encoded state, time-series images or high-dimensional information data can be reconstructed. Compared to traditional high-speed cameras, DMM-based encoded aperture imaging eliminates the need for frame-by-frame electronic readout, instead achieving compressed light domain acquisition through optical modulation, thus significantly improving temporal resolution and signal-to-noise ratio. However, the switching speed of the DMMs themselves depends on the discrete control of tiny rotating mirrors, and this control speed determines the final temporal resolution of the optical system, making it difficult to reach the MHz level. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problem that in the prior art, the imaging rate of the coded aperture imaging technology based on digital micromirror devices is still difficult to reach the MHz level because the switching speed of the digital micromirror device itself depends on the discrete control of the micro rotating mirror. Therefore, this invention provides a multi-channel rotation coded imaging system.

[0007] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0008] A multi-channel rotating coded imaging system is characterized by comprising an imaging lens, a beam splitter, a rotating coded plate, a driving device, a data processing unit, and multiple image sensors.

[0009] The imaging lens is used to receive the light signal from the external ultrafast light field, and then project it onto the beam splitter after focusing.

[0010] The beam splitter is located at the rear end of the imaging lens and is used to split the light signal converged by the imaging lens into multiple identical light signals.

[0011] The rotating encoder is located at the rear end of the beam splitter, so that the same optical signals from multiple channels are projected onto different encoding positions in its encoding area to encode the same optical signals from multiple channels.

[0012] Each of the aforementioned image sensors is configured to correspond one-to-one with the same optical signal from multiple channels, and all are located at the rear end of the rotating encoder plate, with identical imaging parameters;

[0013] The power output end of the drive device is connected to the power input end of the rotary encoder plate through a rotating shaft, which is used to drive the rotary encoder plate to rotate around the rotating shaft, so that the encoding area of ​​the rotary encoder plate is relatively displaced with each image sensor, so as to generate different encoded images at the same imaging position of each image sensor.

[0014] The data processing unit is electrically connected to each image sensor and is used to receive the coded image acquired by each image sensor and perform two-dimensional imaging on the coded image according to the compressed sensing reconstruction algorithm.

[0015] Furthermore, the compression ratio of each of the image sensors All ;

[0016] Where r is the coding rate, ;

[0017] R is the distance between the center of the coded image of the image sensor and the axis of rotation;

[0018] The rotational speed of the rotary encoder plate;

[0019] The symbol diameter of the rotating encoder plate;

[0020] This represents the exposure time of the image sensor.

[0021] Furthermore, the beam splitting device includes a conical reflector and a plurality of plane reflectors arranged sequentially along the direction of optical signal propagation;

[0022] The conical reflector is used to split the light signal converged by the imaging lens into multiple identical light signals;

[0023] The number of the planar reflectors is the same as the number of multiple identical light signals;

[0024] The light signal converged by the imaging lens is projected onto the conical mirror, which splits the single light signal into multiple identical light signals. These multiple identical light signals are simultaneously projected onto their corresponding plane mirrors, and after reflection, they form multi-channel identical light signals.

[0025] Furthermore, the reflectivity of the conical mirror and the plane mirror is greater than 95%.

[0026] Furthermore, the encoding area of ​​the rotating encoding plate is annular.

[0027] Furthermore, the rotating encoder plate includes a glass body;

[0028] A light-shielding coating is provided on one side of the glass body, and a ring mask is photolithographically engraved on the light-shielding coating to form a coding area;

[0029] The drive device is connected to the axis of the glass body via a rotating shaft to drive the glass body to rotate.

[0030] Furthermore, the light-shielding coating is a chromium coating.

[0031] Furthermore, the image sensor is either a CMOS or a CCD.

[0032] Furthermore, the imaging parameters include exposure duration and exposure time.

[0033] Furthermore, the driving device is a motor.

[0034] Compared with the prior art, the present invention has the following beneficial technical effects:

[0035] 1. This invention discloses a multi-channel rotating coded imaging system. By setting up a beam splitting device, a single beam of light is divided into multiple identical light signals, which are projected onto different encoding positions on the encoding area of ​​a rotating encoding plate. Imaging is then performed on multiple image sensors, each corresponding to one of the multiple identical light signals. A driving device drives the rotating encoding plate to rotate, encoding and recording the light signals at different ultrafast timescales, achieving microsecond-nanosecond level ultrafast continuous two-dimensional imaging and solving the current technical challenges of continuous two-dimensional imaging at the microsecond-nanosecond timescale. Furthermore, the multiple image sensors separately acquire the coded images formed by the multiple identical light signals from each channel, avoiding the data loss problem caused by single-channel coded image acquisition. Simultaneously, a data processing unit uses a compressed sensing reconstruction algorithm to fuse the multi-channel coded image data for two-dimensional imaging, improving the image algorithm reconstruction and spatial resolution capabilities of the multi-channel rotating coded imaging system.

[0036] 2. The present invention provides a multi-channel rotating encoding imaging system, which uses a motor to drive a rotating encoding plate and achieves high-frequency encoding changes through the natural cycle of mask rotation. This overcomes the limitations of electronic drive and micromirror switching rate of digital micromirror devices, thereby achieving equivalent time-resolved imaging at the microsecond or even nanosecond level in a single exposure.

[0037] 3. The present invention provides a multi-channel rotational coding imaging system in which the same optical signals from multiple channels are acquired and superimposed by each image sensor through continuous low-frequency acquisition or single exposure. The compression ratio is determined by the coding rate and the single exposure duration. Furthermore, by adjusting the compression ratio, the quality and imaging rate of the two-dimensional imaging can be adjusted. When the two-dimensional imaging process is important, the compression ratio is increased; when the two-dimensional imaging rate is important, the compression ratio is decreased. The adjustment is convenient and quick, and can meet more two-dimensional imaging needs. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of an embodiment of a multi-channel rotational coding imaging system according to the present invention;

[0039] Figure 2 This is a schematic diagram of the encoding area of ​​the rotating encoding plate in an embodiment of a multi-channel rotating encoding imaging system of the present invention.

[0040] The annotations in the attached figures are explained as follows:

[0041] 1. Ultrafast light field; 2. Imaging lens; 3. Plane mirror; 4. Conical mirror; 5. Rotary encoder; 6. Image sensor; 7. Drive unit; 8. Data processing unit. Detailed Implementation

[0042] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0043] like Figure 1-2 As shown, this embodiment provides a multi-channel rotating coded imaging system, including an imaging lens 2, a beam splitter, a rotating coded plate 5, a driving device 7, a data processing unit 8, and multiple image sensors 6.

[0044] Imaging lens 2 is used to receive the light signal from the external ultrafast light field 1, and project it onto the beam splitter after focusing. The beam splitter is located at the rear end of imaging lens 2 and is used to split the light signal focused by imaging lens 2 into multiple identical light signals. Rotating encoder 5 is located at the rear end of beam splitter, so that the multiple identical light signals are projected onto different encoding positions in their encoding areas to encode the multiple identical light signals. Multiple image sensors 6 are respectively set one-to-one with the multiple identical light signals and are all located at the rear end of rotating encoder 5, with the same imaging parameters.

[0045] The power output end of the drive device 7 is connected to the power input end of the rotary encoder 5 through a rotating shaft, which is used to drive the rotary encoder 5 to rotate around the rotating shaft, so that the encoding area of ​​the rotary encoder 5 is relatively displaced with each image sensor 6, so as to generate different encoded images at the same imaging position of each image sensor 6; in this embodiment, the drive device 7 is a motor.

[0046] The data processing unit 8 is electrically connected to each image sensor 6 and is used to receive the coded image acquired by each image sensor 6 and perform two-dimensional imaging on the coded image according to the compressed sensing reconstruction algorithm.

[0047] Compression ratio of each image sensor 6 All ;

[0048] Where r is the coding rate, ;

[0049] R is the distance between the center region of the encoded image from image sensor 6 and the rotation axis;

[0050] The rotational speed of the rotary encoder 5;

[0051] The symbol diameter of the rotating encoder plate 5;

[0052] This is the exposure time for image sensor 6.

[0053] The same light signals from multiple channels are collected and superimposed by each image sensor 6 through continuous low frequency or single exposure. The compression ratio is determined by the encoding rate and the single exposure time. By adjusting the compression ratio, the quality and imaging rate of the two-dimensional imaging can be adjusted. When the two-dimensional imaging process is important, the compression ratio is increased, and when the two-dimensional imaging rate is important, the compression ratio is decreased. The adjustment is convenient and quick, and can meet more two-dimensional imaging needs.

[0054] The beam splitting device includes a conical reflector 4 and multiple planar reflectors 3 arranged sequentially along the direction of light signal propagation. Each planar reflector 3 corresponds to an image sensor 6. The light signal converged by the imaging lens 2 is projected onto the conical reflector 4, which splits the single beam into multiple identical beams. These beams are simultaneously projected onto their corresponding planar reflectors 3, where they are reflected to form multi-channel identical light signals. These multi-channel identical light signals are then simultaneously projected onto different coding positions within the coding area of ​​the rotating coding plate 5, forming their respective codes. These multiple codes simultaneously form a coded image on the corresponding image sensor 6, which is then acquired and transmitted to the data processing unit. In this embodiment, the reflectivity of the conical reflector 4 and the planar reflectors 3 is greater than 95%.

[0055] Beam splitters can also use beam splitters.

[0056] The encoding area of ​​the rotating encoder 5 is annular. The rotating encoder 5 includes a glass body; one side of the glass body is provided with a light-shielding coating, on which an annular mask is photo-etched to form the encoding area; the driving device 7 is connected to the axis of the glass body via a rotating shaft to drive the glass body to rotate. The light-shielding coating is a chromium plating.

[0057] The image sensor 6 is either CMOS or CCD. Its imaging parameters include exposure time and exposure duration.

[0058] During use, the imaging lens 2 acquires the light signal from the ultrafast light field 1. During transmission, the light signal is first split into multiple beams by the conical mirror 4, then reflected by multiple planar mirrors 3 to form multiple channels of identical light signals, which are finally imaged at different spatial positions within the encoding area of ​​the rotating encoder 5. At the rear end of the imaging position of the rotating encoder 5, a CMOS / CCD acquires the encoded image. The rotating encoder 5 has the following characteristics: Figure 2The annular encoding region shown has different codes in different local areas. When the rotating encoding plate 5 rotates, the encoding region and the CMOS / CCD undergo relative displacement, thus generating different coded images at the same imaging position on the CMOS / CCD. The rotating encoding plate 5 is driven by a motor and rotates at a controllable speed, thereby encoding the optical signal at different times at a controllable rate. When the optical signal passes through the rotating encoding plate 5, a coded image is formed. A displacement of one pixel in the encoding center region is considered as generating a new frame of code, and the optical signal passing through the rotating encoding plate 5 during this period is considered as a frame of coded image.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A multi-channel rotary encoding imaging system, characterized by: It includes an imaging lens (2), a beam splitter, a rotating encoder (5), a drive unit (7), a data processing unit (8), and multiple image sensors (6); The imaging lens (2) is used to receive the light signal of the external ultrafast light field (1), and project it onto the beam splitter after focusing. The beam splitting device is located at the rear end of the imaging lens (2) and is used to split the light signal converged by the imaging lens (2) into multiple channels of the same light signal. The rotating encoder (5) is located at the rear end of the beam splitter, so that the same optical signals from multiple channels are projected onto different encoding positions in its encoding area, in order to encode the same optical signals from multiple channels. Multiple image sensors (6) are respectively set to correspond one-to-one with the same optical signals in multiple channels, and are all located at the rear end of the rotating encoder plate (5) with the same imaging parameters; The power output end of the drive device (7) is connected to the power input end of the rotary encoder (5) through a rotating shaft, which is used to drive the rotary encoder (5) to rotate around the rotating shaft, so that the encoding area of ​​the rotary encoder (5) and each image sensor (6) are relatively displaced, so as to generate different encoded images at the same imaging position of each image sensor (6); The data processing unit (8) is electrically connected to each image sensor (6) to receive the coded image acquired by each image sensor (6) and to perform two-dimensional imaging of the coded image according to the compressed sensing reconstruction algorithm.

2. The multi-channel rotation-coded imaging system according to claim 1, characterized in that: Compression ratio of each of the image sensors (6) All ; Where r is the coding rate, ; R is the distance between the center of the encoded image of the image sensor (6) and the axis of rotation; The rotational speed of the rotary encoder plate (5); The symbol diameter of the rotating encoder plate (5); The exposure time of the image sensor (6) is .

3. The multi-channel rotational coded imaging system according to claim 1, characterized in that: The beam splitting device includes a conical reflector (4) and multiple plane reflectors (3) arranged sequentially along the direction of optical signal propagation. The conical reflector (4) is used to split the light signal converged by the imaging lens (2) into multiple identical light signals; The number of the plane mirrors (3) is the same as the number of multiple identical light signals; The light signal converged by the imaging lens (2) is projected onto the conical mirror (4). The conical mirror (4) splits the single light signal into multiple identical light signals. The multiple identical light signals are simultaneously projected onto the corresponding plane mirror (3), and after reflection, they form a multi-channel identical light signal.

4. The multi-channel rotation-coded imaging system according to claim 3, characterized in that: The reflectivity of the conical mirror (4) and the plane mirror (3) is greater than 95%.

5. The multi-channel rotation-coded imaging system according to claim 1, characterized in that: The encoding area of ​​the rotating encoder (5) is ring-shaped.

6. The multi-channel rotation-coded imaging system according to claim 5, characterized in that: The rotary encoder plate (5) includes a glass body; A light-shielding coating is provided on one side of the glass body, and a ring mask is photolithographically engraved on the light-shielding coating to form a coding area; The driving device (7) is connected to the axis of the glass body via a rotating shaft to drive the glass body to rotate.

7. The multi-channel rotation-coded imaging system according to claim 6, characterized in that: The light-shielding coating is a chromium coating.

8. The multi-channel rotation-coded imaging system according to claim 1, characterized in that: The image sensor (6) is either a CMOS or a CCD.

9. The multi-channel rotation-coded imaging system according to claim 1, characterized in that: The imaging parameters include exposure duration and exposure time.

10. The multi-channel rotation-coded imaging system according to claim 1, characterized in that: The driving device (7) is a motor.

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