A structured light ghost imaging method and device suitable for full-depth multi-target

Abstract

The present invention discloses a structured light ghost imaging method and device applicable to multiple targets at full depth, comprising the following steps: step S1, obtaining multiple beams of structured light; step S2, the multiple beams of structured light expand the depth search range of the target area through a flexible fast zoom device; step S3, sampling the multiple beams of structured light in the target area to obtain a light intensity value; step S4, reconstructing the light intensity value and the corresponding speckle information. The technical solution of the present invention can be used to detect and ghost image multiple targets at different depths, thereby improving the GI solution of image quality.

Description

Technical Field

[0001] The present invention belongs to the field of optical imaging technology, and in particular relates to a structured light ghost imaging device and method suitable for full-depth multi-target. Background Art

[0002] Ghost imaging (GI) technology is a new imaging technology. Its main principle is the correlation measurement technology based on the fluctuation of light field intensity. Therefore, compared with traditional optical imaging technology, ghost imaging has the advantages of ultra-high resolution, strong anti-noise ability, and no need to use lens imaging. However, due to its statistical correlation properties, the imaging signal-to-noise ratio (SNR) is usually not as good as traditional imaging technology. For high-quality imaging systems, they should have higher resolution and signal-to-noise ratio. Three-dimensional ghost imaging has the characteristics of acquiring images of targets at different depths. It is generally combined with time-of-flight method or triangulation method to achieve three-dimensional imaging, and is widely used in many fields. Three-dimensional ghost imaging is essentially a combination of two-dimensional ghost imaging. Therefore, improving the quality of two-dimensional ghost imaging has become a breakthrough in obtaining high-performance three-dimensional ghost imaging technology.

[0003] Structured laser beams (SLB) generally refer to beams with spatial structure of amplitude, phase or polarization. The light field is customized in space by amplitude, phase and polarization, or controlled in time and spectrum. By solving the paraxial scalar Helmholtz equation in rectangular coordinates or cylindrical coordinates, the Hermite-Gaussian (HG n,m ) and Laguerre-Gaussian (LG p,l These characteristic modes, except for the lowest-order TEM00 mode, represent structured light themselves and can be used to synthesize other more complex structured light through coherent or incoherent superposition.

[0004] The generation of spatial structured light can be divided into two categories: direct excitation of structured light in the cavity and structured light generated by regulation outside the cavity. However, since the excitation of structured light in the cavity is limited by the resonant cavity, the output mode is limited. Therefore, compared with the method of directly exciting structured light in the cavity, the method of directly inserting a spatial light modulation device in the optical path outside the cavity is more flexible. In recent years, the use of digital micromirror devices (DMDs) to construct structured light using amplitude control methods has become a research hotspot.

[0005] From the perspective of practical application, there are usually multiple targets in the field of view. The light intensity at different depths of traditional ghost imaging is difficult to obtain a clear image due to the depth of field problem. Although it can be compensated by the subsequent defocus coefficient, it requires prior knowledge. Especially under multi-target conditions, it is necessary to use optical zoom devices to achieve switching of different depths. The typical working method is: in addition to using mechanical axial movement of several lenses at a specific distance along the optical axis to achieve the zoom function, variable focal length devices such as liquid lenses can also be used. However, these not only increase system cost and power consumption, but also lead to reduced efficiency, making it difficult to apply to imaging and detection fields such as moving targets, biomedicine, unmanned driving, and robot perception. Therefore, how to balance efficiency and imaging quality at different depths has become an issue that needs to be studied urgently. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a structured light ghost imaging device and method suitable for full-depth multi-targets, which can detect and perform ghost imaging on multiple targets at different depths, thereby improving the GI solution of image quality.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] A structured light ghost imaging method applicable to full-depth multi-targets comprises the following steps:

[0009] Step S1, obtaining multiple beams of structured light;

[0010] Step S2, the multiple beams of structured light are used to expand the depth search range of the target area through a flexible fast zoom device;

[0011] Step S3, sampling multiple beams of structured light in the target area to obtain light intensity values;

[0012] Step S4: reconstructing the light intensity value and the corresponding speckle information.

[0013] Preferably, in step S1, the laser is modulated by DMD to generate multiple beams of structured light.

[0014] Preferably, in step S3, the light intensity value S n (x,y) is obtained by formula (1):

[0015]

[0016] Among them, P n (x, y) is the speckle information obtained by light beams of different modes, I n (x, y) is the information of the detected target, x, y are two-dimensional information, and n is the nth modulation process.

[0017] Preferably, in step S4, the light intensity value Sn (x,y) and different projected speckle patterns P n (x, y) to perform second-order cross-correlation operation to achieve high-definition image reconstruction of multiple targets, that is,

[0018]

[0019] Where N is the total number of projected speckles, and Represents the average value of light intensity detection and speckle pattern, I n To finally reconstruct the image information.

[0020] The present invention also provides a structured light ghost imaging device suitable for full-depth multi-target, comprising:

[0021] An acquisition module, used for acquiring multiple beams of structured light;

[0022] A processing module, used for the multiple beams of structured light to expand the depth search range of the target area through a flexible fast zoom device;

[0023] A sampling module, used for sampling multiple beams of structured light in the target area to obtain a light intensity value;

[0024] The reconstruction module is used to reconstruct the image of the light intensity value and the corresponding speckle information.

[0025] Preferably, the acquisition module generates multiple beams of structured light by modulating laser through DMD.

[0026] Preferably, the light intensity value S n (x,y) is obtained by formula (1):

[0027]

[0028] Among them, P n (x, y) is the speckle information obtained by light beams of different modes, I n (x, y) is the information of the detected target, x, y are two-dimensional information, and n is the nth modulation process.

[0029] Preferably, the reconstruction module converts the light intensity value S n (x,y) and different projected speckle patterns P n (x, y) to perform second-order cross-correlation operation to achieve high-definition image reconstruction of multiple targets.

[0030] The present invention generates a structured beam by adding a DMD into the extracavity optical path, thereby replacing the traditional pulsed beam. The laser mode in the structured beam is changed to detect and perform ghost imaging on multiple targets at different depths, thereby improving the GI solution of image quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of a scene of a structured light ghost imaging method applicable to multiple targets at full depth according to an embodiment of the present invention;

[0032] Figure 2 The present invention is a flowchart of a structured light ghost imaging method applicable to multiple targets at full depth according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Embodiment 1:

[0036] The embodiment of the present invention provides a structured light ghost imaging method applicable to multiple targets at full depth, which realizes efficient and accurate detection of multiple targets by combining structured light beam with ghost imaging technology. The design purpose is to ensure accurate detection of targets while improving detection efficiency and imaging clarity as much as possible, while taking into account the future development and practicality of the technology. Figure 1 As shown, the embodiment of the present invention includes three parts: emission, detection and reception: Emission: Using a laser light source as a structured light beam can ensure that the light field of the structured light beam remains unchanged during long-distance transmission, and by developing Alvarez flexible optical fast zoom optical devices, the problem of poor stability caused by traditional mechanical zoom is fundamentally solved, and efficient imaging of targets at different depths is achieved. Detection: The structured light with different modes generated by the DMD is used to detect different targets, which can improve detection accuracy, clarity and detection efficiency. Reception: Different detectors are used for different types of detection objects, such as Figure 1 Detectors A, B, and C are shown.

[0037] like Figure 2 As shown, an embodiment of the present invention provides a structured light ghost imaging method applicable to multiple targets in full depth, comprising the following steps:

[0038] Step S1, the laser is modulated by the DMD to generate multiple beams of structured light in different modes;

[0039] Step S2, the multiple beams of structured light are used to expand the depth search range of the target area through a flexible fast zoom device;

[0040] Step S3, sampling multiple beams of structured light in the target area to obtain light intensity values;

[0041] Step S4: reconstructing the light intensity value and the corresponding speckle information.

[0042] As an implementation method of the present invention, in step S1, each beam of structured light includes different patterns for different targets, thereby improving spatial resolution and detection efficiency.

[0043] As an implementation of an embodiment of the present invention, in step S3, multiple beams of structured light are sampled and received by single-point detectors A, B, and C. The single-point detectors receive light beams with different light intensities generated by different modes. The light intensity value S received by the detectors n (x,y) can be obtained by formula (1):

[0044]

[0045] Among them, P n (x, y) is the speckle information obtained by beams of different modes, I n (x, y) is the information of the detected target, x, y are two-dimensional information, and n is the nth modulation process.

[0046] As an implementation method of the present invention, in step S4, the light intensity value S obtained by the detector is n (x,y) and different projected speckle patterns P n (x, y) to perform second-order cross-correlation operation to achieve high-definition image reconstruction of multiple targets, that is,

[0047]

[0048] Where N is the total number of projected speckles, and Represents the average value of light intensity detection and speckle pattern, I n To finally reconstruct the image information.

[0049] The present invention has the following technical effects:

[0050] 1. The structured beam can improve the image quality by changing the laser mode, and the laser mode generated by the DMD method outside the cavity is richer and more flexible;

[0051] 2. For the parallel imaging system of multiple targets, since multiple targets will overlap laterally, this paper intends to use structured beams to detect multiple targets, using different mode beams for different targets, thereby generating images with better imaging quality that avoid overlap.

[0052] Embodiment 2:

[0053] The embodiment of the present invention further provides a structured light ghost imaging device applicable to full depth multi-targets, comprising:

[0054] An acquisition module, used for acquiring multiple beams of structured light;

[0055] A processing module, used for the multiple beams of structured light to expand the depth search range of the target area through a flexible fast zoom device;

[0056] A sampling module, used for sampling multiple beams of structured light in the target area to obtain a light intensity value;

[0057] The reconstruction module is used to reconstruct the image of the light intensity value and the corresponding speckle information.

[0058] As an implementation manner of the embodiment of the present invention, the acquisition module generates multiple beams of structured light by modulating laser through DMD.

[0059] As an implementation of the embodiment of the present invention, the light intensity value S n (x,y) is obtained by formula (1):

[0060]

[0061] Among them, P n (x, y) is the speckle information obtained by beams of different modes, I n (x, y) is the information of the detected target, x, y are two-dimensional information, and n is the nth modulation process.

[0062] As an implementation method of the embodiment of the present invention, the reconstruction module converts the light intensity value S n (x,y) and different projected speckle patterns P n (x, y) to perform second-order cross-correlation operation to achieve high-definition image reconstruction of multiple targets.

[0063] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope described in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A structured light ghost imaging method suitable for full depth multi-target, characterized in that: The following steps are involved: Step S1, obtaining multiple beams of structured light; Step S2, the multiple beams of structured light are used to expand the depth search range of the target area through a flexible fast zoom device; Step S3, sampling multiple beams of structured light in the target area to obtain light intensity values; Step S4, reconstructing the light intensity value and the corresponding speckle information; In step S1, laser is modulated by DMD to generate multiple beams of structured light; In step S3, the light intensity value S n (x,y) is obtained by formula (1): Among them, P n (x, y) is the speckle information obtained by light beams of different modes, I n (x, y) is the information of the detected target, x, y are two-dimensional information, and n is the nth modulation process; In step S4, the light intensity value S n (x,y) and different projected speckle patterns P n (x, y) to perform second-order cross-correlation operation to achieve high-definition image reconstruction of multiple targets, that is, Where N is the total number of projected speckles, and Represents the average value of light intensity detection and speckle pattern, I n To finally reconstruct the image information.

2. A structured light ghost imaging device suitable for full depth multi-target, characterized in that: include: An acquisition module, used for acquiring multiple beams of structured light; A processing module, used for the multiple beams of structured light to expand the depth search range of the target area through a flexible fast zoom device; A sampling module, used for sampling multiple beams of structured light in the target area to obtain a light intensity value; A reconstruction module, used for reconstructing the light intensity value and the corresponding speckle information; The acquisition module generates multiple beams of structured light by modulating the laser through DMD; The light intensity value S n (x,y) is obtained by formula (1): Among them, P n (x, y) is the speckle information obtained by light beams of different modes, I n (x, y) is the information of the detected target, x, y are two-dimensional information, and n is the nth modulation process; The reconstruction module converts the light intensity value S n (x,y) and different projected speckle patterns P n (x, y) to perform second-order cross-correlation operation to achieve high-definition image reconstruction of multiple targets.

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