CN-121995398-A - Non-vision-area associated imaging method based on chaotic optical comb

CN121995398ACN 121995398 ACN121995398 ACN 121995398ACN-121995398-A

Abstract

The invention discloses a non-vision-area-related imaging method based on a chaotic light comb, and relates to the technical field of computational imaging. The associated imaging system provided by the method comprises a chaotic light comb source, a two-dimensional dispersion projection module, a single-pixel detector, a time-distance association module and a second-order association reconstruction module, wherein a silicon nitride micro-ring is utilized to generate a random light frequency comb, multiple points of random illumination are formed through a VIPA and a grating, echo time sequences are recorded through single pixels, virtual voxels are constructed by combining with flight time, and a three-dimensional image of a hidden target is reconstructed at one time through second-order association operation. The invention can realize high-speed and high-efficiency non-visual field three-dimensional imaging without mechanical scanning or a spatial light modulator, and is suitable for complex environment detection, post-disaster searching, corner sensing in unmanned driving and other scenes.

Inventors

SHI YAOYAO
WANG KAIXIN
CHENG FENG
DONG DAXING
HU CHUANJIE
FEI YUE
LIU YOUWEN
FU YANGYANG

Assignees

南京航空航天大学

Dates

Publication Date: 20260508
Application Date: 20260122

Claims (10)

1. The non-vision-area associated imaging method based on the chaotic optical comb is characterized by comprising the following steps of: acquiring a chaotic optical comb and taking the chaotic optical comb as an illumination source; dividing the chaotic light comb into N multiplied by M chaotic sub-beams through a two-dimensional dispersion device, and forming N multiplied by M random illumination points on the surface of a relay wall of a non-visual scene; The chaotic sub-beams emitted by each illumination point are diffused and reflected by the relay wall and then are transmitted to a target non-vision scene area, and echo time sequence signals are obtained through the single-pixel detector; Mapping the echo time into the space depth of the chaotic sub-beam according to the constant light speed principle, and constructing a virtual voxel for the space by using a picosecond time slice; And obtaining a three-dimensional image of the hidden target in the non-view scene area based on the second-order correlation value of the three-dimensional time-varying mask and the echo signal.
2. The non-vision-related imaging method based on a chaotic light comb of claim 1, wherein the chaotic light comb is generated by a silicon nitride micro-ring under continuous wave pumping through a Kerr nonlinear effect; Wherein, the time domain fluctuation of the chaotic optical comb generated by Kerr nonlinear effect is less than 10 ps, the frequency domain broadening is more than or equal to 20 nm, and the repetition frequency is more than or equal to 1 GHz.
3. The method of claim 1, wherein the two-dimensional dispersive device is formed by orthogonal cascading of a VIPA etalon and a reflective grating, and wherein the free spectral range of the VIPA etalon is perpendicular to the dispersion direction of the reflective grating.
4. The non-vision-area-related imaging method based on the chaotic light comb according to claim 1, wherein the illumination point is equivalent to an independent spherical wave source point which uniformly emits light to the direction of the hidden object, and the intensity of the illumination point changes along with time according to a random sequence of the chaotic light comb and meets a lambertian scattering model on the surface of the hidden object.
5. The chaotic light comb-based non-visual field correlation imaging method of claim 1, wherein the obtaining a three-dimensional image of a hidden target in a non-visual field scene area based on the three-dimensional time-varying mask and the second-order correlation value of the echo signal comprises: And adopting a differential ghost imaging algorithm to carry out three-dimensional reconstruction, wherein the reconstruction formula is as follows: ; Wherein, the A reconstructed value for the voxel; The number of time slices; mask values of corresponding voxels at the moment i; Is an echo intensity sequence; representing a time average.
6. The non-visual field correlation imaging method based on the chaotic light comb of claim 1, wherein the bandwidth of the single pixel detector is more than or equal to 1 GHz, the sampling rate is more than or equal to 128 GSa/s, and the acquisition point number T is more than or equal to 5000.
7. The chaotic light comb-based non-view correlation imaging method of claim 1, wherein the reconstruction signal to noise ratio is improved by performing background noise subtraction on the echo timing signal before calculating the second-order correlation value of the three-dimensional time-varying mask and the echo signal.
8. The chaotic light comb-based non-view-dependent imaging method of claim 1, wherein the obtaining the echo timing signal by the single pixel detector comprises: in a target non-visual field scene area, obtaining a three-dimensional space formed by a plurality of voxels through voxel discretization; Part of the rays of the chaotic sub-beams interact with the target in the voxel and scatter; the scattered light returns to the relay wall according to the coordinates of each voxel Obtaining the distance from the voxel to the illumination point; obtaining an echo time sequence signal by calculating the diffusion time of the spherical wave diffused after the chaotic light signal is reflected by the relay wall to each voxel; The distance from the voxel to the illumination point is calculated by the following formula: ; The time t of the scattered spherical wave after the chaotic light signal is reflected by the relay wall to be diffused to each voxel is calculated by the following formula: ; wherein d represents the distance from the voxel to the illumination point and c represents the propagation speed of light in air.
9. The chaotic light comb based non-visual field association imaging method of claim 8, wherein the obtaining a three-dimensional space formed by a plurality of voxels through voxel discretization processing comprises: dispersing the non-view scene into a three-dimensional grid with the number of transverse pixels P multiplied by Q and the number of depth direction pixels K; wherein the lateral resolution 、 Depth resolution of less than or equal to 5 mm Time slice width of 1 ps =0.15 mm.
10. A chaotic light comb-based non-vision-related imaging system, comprising: the chaotic optical comb source module is used for acquiring a chaotic optical comb and taking the chaotic optical comb as an illumination source; the two-dimensional dispersion projection module is used for dividing the chaotic light comb into N multiplied by M chaotic sub-beams through a two-dimensional dispersion device and forming N multiplied by M random illumination points on the surface of a relay wall of a non-visual field scene; the single-pixel detector module is used for transmitting the chaotic sub-beam emitted by each illumination point to a target non-visual field scene area after diffuse reflection of the relay wall, obtaining an echo time sequence signal through the single-pixel detector, determining the echo time of the chaotic sub-beam emitted by the illumination point to the target area, and recording the original intensity time sequence signal of the chaotic sub-beam as a reference light signal; The time-distance correlation module is used for mapping the echo time into the space depth of the chaotic sub-beam according to the constant light speed principle and constructing a virtual voxel for the space by using a picosecond time slice; And the second-order correlation reconstruction module is used for obtaining a three-dimensional image of the hidden target in the non-visual scene area based on the second-order correlation value of the three-dimensional time-varying mask and the echo signal.

Description

Non-vision-area associated imaging method based on chaotic optical comb Technical Field The application relates to the technical field of computational imaging, in particular to a non-vision-domain associated imaging method based on a chaotic optical comb. Background Conventional imaging techniques mostly rely on the target being in direct view, with the image information being acquired by direct reflection of light rays to the imaging device. However, in many practical application scenarios, such as detection of hidden targets in complex environments, searching of trapped people or objects in ruins after disaster, etc., the targets are often in a non-viewing range, and conventional imaging means cannot function. Non-field-of-view imaging, also known as corner imaging, is an emerging imaging modality that is directed to acquiring target information beyond the limits of the field of view. Most of the existing non-vision imaging methods need to carry out dense laser raster scanning on the relay wall, have the problems of low imaging speed, severe requirements on the type of the relay wall surface and the like, and greatly limit the wide application of the method in actual scenes. Disclosure of Invention Based on the above, it is necessary to provide a non-visual field correlation imaging method based on a chaotic optical comb. The technical scheme adopted in the specification is as follows: the specification provides a non-vision-area-related imaging method based on a chaotic light comb, which comprises the following steps: acquiring a chaotic optical comb and taking the chaotic optical comb as an illumination source; dividing the chaotic light comb into N multiplied by M chaotic sub-beams through a two-dimensional dispersion device, and forming N multiplied by M random illumination points on the surface of a relay wall of a non-visual scene; The chaotic sub-beams emitted by each illumination point are diffused and reflected by the relay wall and then are transmitted to a target non-vision scene area, and echo time sequence signals are obtained through the single-pixel detector; Mapping the echo time into the space depth of the chaotic sub-beam according to the constant light speed principle, and constructing a virtual voxel for the space by using a picosecond time slice; And obtaining a three-dimensional image of the hidden target in the non-view scene area based on the second-order correlation value of the three-dimensional time-varying mask and the echo signal. Further, the chaotic optical comb is generated by a silicon nitride micro-ring through a Kerr nonlinear effect under continuous wave pumping; Wherein, the time domain fluctuation of the chaotic optical comb generated by Kerr nonlinear effect is less than 10 ps, the frequency domain broadening is more than or equal to 20 nm, and the repetition frequency is more than or equal to 1 GHz. Further, the two-dimensional dispersion device is formed by orthogonal cascading of the VIPA etalon and the reflection grating, wherein the free spectral range of the VIPA etalon is perpendicular to the dispersion direction of the reflection grating. Further, the illumination point is equivalent to an independent spherical wave source point which uniformly emits light to the direction of the hidden target, the intensity of the illumination point changes along with time according to the random sequence of the chaotic optical comb, and the lambertian scattering model is met on the surface of the hidden target. Further, the obtaining a three-dimensional image of the hidden target in the non-view scene area based on the second-order correlation value of the three-dimensional time-varying mask and the echo signal includes: And adopting a differential ghost imaging algorithm to carry out three-dimensional reconstruction, wherein the reconstruction formula is as follows: ; Wherein, the A reconstructed value for the voxel; The number of time slices; mask values of corresponding voxels at the moment i; Is an echo intensity sequence; representing a time average. Further, the bandwidth of the single-pixel detector is more than or equal to 1 GHz, the sampling rate is more than or equal to 128 GSa/s, and the acquisition point number T is more than or equal to 5000. Further, before calculating the second-order correlation value of the three-dimensional time-varying mask and the echo signal, background noise is subtracted from the echo time sequence signal to improve the reconstruction signal-to-noise ratio. Further, the obtaining the echo time sequence signal by the single pixel detector includes: in a target non-visual field scene area, obtaining a three-dimensional space formed by a plurality of voxels through voxel discretization; Part of the rays of the chaotic sub-beams interact with the target in the voxel and scatter; the scattered light returns to the relay wall according to the coordinates of each voxel Obtaining the distance from the voxel to the illumination point; obt