A scanning multi-polarization state image acquisition system and method

Abstract

The application discloses a scanning type multi-polarization state image acquisition system and method, and belongs to the technical field of polarization imaging. A gradual polarization patch for generating multiple polarization states is attached to a surface array camera; each row of different columns on the gradual polarization patch is a polarization state; the surface array camera is connected with a motion controller, an imaging calculation module and a data processing module; the surface array camera is controlled by the motion controller to perform scanning; the surface array camera receives a camera exposure time calculated by the imaging calculation module, and performs imaging with the camera exposure time to acquire multiple gradually changing polarization state image data row by row, and transmits the data to the data processing module; the camera exposure time is matched with the motion speed of the surface array camera; and the data processing module processes the gradually changing polarization state image row by row into multiple polarization state images. The system and method of the application can acquire different polarization state image data of the same target scene, and have important application value in target polarization information acquisition and target clear imaging.

Description

Technical Field

[0001] This invention relates to the field of polarization imaging technology, and in particular to a scanning multi-polarization state image acquisition system and method. Background Technology

[0002] Polarization is one of the fundamental properties of light. Polarization imaging can simultaneously provide information on spatial light intensity distribution and polarization information of the target and background, and has important application value in military and civilian fields such as aviation, aerospace, oceanography, remote sensing, and industrial inspection.

[0003] Currently, typical polarization imaging mainly acquires polarization image information in the form of amplitude spectrophotometry, aperture spectrophotometry, and focal plane spectrophotometry, generally obtaining three or four polarization images, that is, obtaining three or four polarization state information.

[0004] However, in practical applications, the polarization characteristics of the target and the background are numerous. When the physical properties of the target and the background change slightly, it can cause slight changes in the polarization state. At this time, the four common polarization state imaging methods may not be able to detect such minute information, requiring high-sensitivity polarization detection, that is, richer and more precise polarization state information acquisition. The richer the polarization state information that the system can acquire, the more beneficial it will be for target imaging, detection, and identification. Summary of the Invention

[0005] To acquire more polarization state image information of a target, this invention proposes a scanning multi-polarization state image acquisition system and method. By attaching a gradient polarizer with multiple polarization states to the focal plane of a camera sensor, and controlling the relative motion speed between the target and the camera to match the camera exposure time, multiple progressively gradient polarization state image data are acquired. Data stitching processing is then used to obtain the multi-polarization state image. This system and method overcome the limitation of limited polarization state information in traditional polarization imaging and can be widely applied to the acquisition of polarization information of moving or stationary targets, which has significant value and importance in the field of polarization imaging.

[0006] Therefore, the present invention provides the following technical solution:

[0007] This invention provides a scanning multi-polarization state image acquisition system, comprising: a gradient polarizer for generating multiple polarization states, an area array camera for imaging, a motion controller, an imaging calculation module, and a data processing module; each row and column on the gradient polarizer represents a polarization state.

[0008] The gradient polarizer is attached to the area array camera; the area array camera is connected to the motion controller, the imaging calculation module and the data processing module respectively;

[0009] The area scan camera performs scanning under the control of the motion controller; the area scan camera receives the camera exposure time calculated by the imaging solution module, and performs imaging with the camera exposure time to acquire multiple progressively polarized image data, and transmits the data to the data processing module; the camera exposure time is matched with the movement speed of the area scan camera.

[0010] The data processing module processes the line-by-line gradually changing polarization image into multiple polarization images.

[0011] Furthermore, the gradient polarizer is implemented using metamaterials.

[0012] Furthermore, the graded polarizer is attached to the area array camera, comprising:

[0013] Measure the dimensions of the graded polarizer and the dimensions of the graded polarizer element to determine the number of polarization states;

[0014] Determine the camera pixel size and sensor size, and determine the position of the area array window that is the same size as the graduated polarizer.

[0015] The gradient polarizer is attached above the window of the area array camera sensor.

[0016] Furthermore, the imaging calculation module calculates the camera exposure time based on the input target's ground motion velocity vt, the camera's ground motion velocity vb, the imaging distance h, the camera's focal length f, and the sensor pixel size d.

[0017] Furthermore, the area scan camera performs scanning under the control of the motion controller, including:

[0018] The motion controller receives the input camera's ground motion speed and uses that speed to control the camera's scanning and imaging.

[0019] Furthermore, the data processing module processes the line-by-line gradually changing polarization state image into multiple polarization state images, including:

[0020] Extract the same polarization state data from multiple progressively changing polarization state images, and arrange and stitch the same polarization state image information sequentially according to the imaging order to form multiple polarization images.

[0021] This invention also provides a scanning multi-polarization state image acquisition method, which involves attaching a graded polarizer to an area array camera; the method includes the following steps:

[0022] The area scan camera performs scanning under the control of the motion controller;

[0023] The area array camera receives the camera exposure time calculated by the imaging solution module, and performs imaging using the camera exposure time to acquire multiple progressively polarized image data. The data is then transmitted to the data processing module, which processes the progressively polarized images into multiple polarization images. The camera exposure time is matched with the movement speed of the area array camera.

[0024] Furthermore, the graded polarizer is attached to the area array camera, comprising:

[0025] Measure the dimensions of the graded polarizer and the dimensions of the graded polarizer element to determine the number of polarization states;

[0026] Determine the camera pixel size and sensor size, and determine the position of the area array window that is the same size as the graduated polarizer.

[0027] The gradient polarizer is attached above the window of the area array camera sensor.

[0028] Furthermore, the camera exposure time is calculated, including:

[0029] The camera exposure time is calculated based on the input target's ground motion velocity vt, the camera's ground motion velocity vb, the imaging distance h, the camera's focal length f, and the sensor pixel size d.

[0030] Furthermore, the progressively changing polarization state image is processed into multiple polarization state images, including:

[0031] Extract the same polarization state data from multiple progressively changing polarization state images, and arrange and stitch the same polarization state image information sequentially according to the imaging order to form multiple polarization images.

[0032] Advantages and positive effects of the present invention: The present invention proposes a scanning multi-polarization state image acquisition system and method, filling the gap in the current domestic lack of corresponding scanning multi-polarization state imaging systems. By combining a gradient polarizer with an area array camera, imaging is performed in the form of motion scanning. The polarization signals of the target area are stitched together to form multi-polarization state image information. The present invention overcomes the limitation of limited polarization state information in traditional polarization imaging and can be widely applied to the acquisition of polarization information of moving or stationary targets. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1This is a schematic diagram of the structure of a scanning multi-polarization state image acquisition system according to an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of a gradient polarizer in an embodiment of the present invention;

[0036] Figure 3 This is a schematic flowchart of a scanning multi-polarization state image acquisition method according to an embodiment of the present invention. Detailed Implementation

[0037] The purpose of this invention is to provide a scanning multi-polarization state image acquisition system and method for acquiring multi-polarization state image data in a polarization imaging system.

[0038] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0039] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0040] Example 1

[0041] like Figure 1 As shown in the figure, an embodiment of the present invention proposes a scanning multi-polarization state image acquisition system, which includes: a gradient polarizer, an area array camera, a motion controller, an imaging calculation module, and a data processing module. Wherein:

[0042] A gradient polarizer is attached to the focal plane of the camera sensor; the area array camera is also connected to the motion controller, the imaging calculation module, and the data processing module.

[0043] Gradient polarizers are used to generate multiple polarization states, such as... Figure 2As shown, each row and column on the plate represents a different polarization state, and different rows have different polarization states, which can be achieved through metamaterials and other technologies. The size of the gradient polarizer is 1mm*2mm, the size of the gradient polarizer element is 5μm*5μm, and the number of polarization states k = 1mm / 5μm = 200. The gradient polarizer is then attached above the window position of the area array camera sensor.

[0044] Gradient polarizers can be fabricated using the following method: micro / nano structures such as plasmon structures, gap surface plasmon structures, and all-dielectric structures are fabricated on a semiconductor substrate using micro / nano fabrication processes to achieve control over the polarization characteristics of the light field. More specifically, the polarization state at each pixel position can be obtained by filling a microcavity between a planar anisotropic chiral metamaterial and a metallic reflective layer with materials of different refractive indices. External excitations (such as electrical, optical, thermal, or humidity-induced) are applied to the refractive index-controlled materials, dynamically adjusting the refractive index of the materials and changing the interference effect of the microcavity. This allows for continuous control over linearly polarized, elliptically polarized, and circularly polarized light. The same polarization state obtained using the same control method for each row forms a gradient polarizer. In specific implementations, there are many methods for fabricating the gradient polarizers of this invention; regardless of the method used, the gradient polarizer is within the scope of protection of this invention.

[0045] An area array camera is used for imaging. The camera sensor size o*q = 2mm*2mm is not less than the size of the graded polarizer m*n = 1mm*2mm. The pixel size d = 5μm is divisible by the graded polarizer element size a*b = 5μm*5μm. The window position must be the same size as the graded polarizer size m*n = 1mm*2mm. A graded polarizer is attached above the window position. The camera is connected to a motion controller and scans under the control of the motion controller. It receives the camera exposure time T = 2.5ms calculated by the imaging solution module and performs imaging based on this exposure time. The camera acquires n = 200 progressively graded polarized image data and transmits the data to the data processing module.

[0046] The motion controller is used to control the scanning motion of the area scan camera. When the camera's ground motion speed vb = 2m / s is input to the motion controller, the motion controller will use this speed to control the camera to scan and form images.

[0047] The imaging calculation module is used to solve the imaging exposure time T of the area array camera. Based on the input target ground motion velocity vt = 1m / s, camera ground motion velocity vb = 2m / s, imaging distance h = 2m, camera focal length f = 2cm and sensor pixel size d = 5μm, the camera exposure time T = 2.5ms is calculated and transmitted to the area array camera.

[0048] The data processing module is used to process the progressively changing polarization state image into multiple polarization state images, extract the same polarization state data pj (j = 1, 2, ..., 200) from 200 progressively changing polarization state images I1, I2, ..., I200, and arrange and stitch the same polarization state image information in the order of imaging to form 200 polarization images [I1(pj), I2(pj), ..., I200(pj)] (j = 1, 2, ..., 200).

[0049] In practice, the data processing module can operate on the image data on a computer or in the imaging module using a digital field, and either method is acceptable.

[0050] The scanning multi-polarization state image acquisition system in the above embodiments acquires multiple progressively polarized state image data by attaching a gradient polarizer with multiple polarization states to the focal plane of the camera sensor, controlling the relative motion speed between the target and the camera to match the camera exposure time, and then using data stitching processing to obtain multi-polarization state images. This overcomes the limitation of traditional polarization imaging having limited polarization state information and can be widely used to acquire polarization information of moving or stationary targets, which has important value and significance in the field of polarization imaging.

[0051] The method described in the above embodiments is to obtain multiple polarization states. The more polarization states the polarizer can produce, the more polarization states can be obtained. If a graded polarizer can produce 10 polarization states, 100 polarization states can be obtained; if a graded polarizer can produce 100 polarization states, 100 polarization states can be obtained. With current metamaterials and other technologies, the polarization states that can theoretically be obtained from graded polarizers can be continuous. As long as the cost is willing to be invested, theoretically, any number of polarization states can be achieved; there is no limit to the quantity.

[0052] Example 2

[0053] like Figure 3 As shown in the figure, an embodiment of the present invention provides a scanning multi-polarization state image acquisition method, which includes the following steps:

[0054] Step 1: Measure the size of the graded polarizer m*n = 1mm*2mm, measure the size of the graded polarizer element a*b = 5μm*5μm, and determine the number of polarization states k = m / a = 1mm / 5μm = 200;

[0055] Step 2: Determine the camera pixel size as d = 5μm and the sensor size as o*q = 2mm*2mm. Determine the window position (x, x+m; y, y+n) = (0.1mm; 0.2mm) of the area array with the same size as the graduated polarizer size m*n = 1mm*2mm.

[0056] Step 3: Place the gradient polarizer above the window position of the area array camera sensor;

[0057] Step 4: Input the target's ground motion velocity vt = 1 m / s, the camera's ground motion velocity vb = 1.2 m / s, the imaging distance h = 2 m, the camera's focal length f = 2 cm, and the sensor pixel size d = 5 μm into the imaging calculation module, and calculate the camera exposure time T:

[0058] 2.5ms;

[0059] Step 5: Input the camera's ground motion speed vb = 2m / s into the motion controller, and use this speed to control the movement of the area array camera;

[0060] Step 6: The area array camera performs imaging with an exposure time of T = 2.5 ms, obtaining 200 progressively changing polarization state image data I1, I2, ..., I200. Among them, the Ii-th image (i = 1, 2, ..., 200) has m / d = 1 mm / 5 μm = 200 rows, n / d = 2 mm / 5 μm = 400 columns, and each a / d = 1 row is a polarization state data pj (j = 1, 2, ..., 200). The entire image contains a total of 200 polarization states.

[0061] Step 7: Extract the same polarization state data pj (j = 1, 2, ..., 200) from 200 progressively polarized polarization state images I1, I2, ..., I200. Arrange and stitch the same polarization state image information in the order of imaging to form 200 polarization images [I1(pj), I2(pj), ..., I200(pj)] (j = 1, 2, ..., 200), thus completing the acquisition of multiple polarization state images.

[0062] The scanning multi-polarization state image acquisition method in the above embodiments acquires multiple progressively polarized state image data by attaching a gradient polarizer with multiple polarization states to the focal plane of the camera sensor, controlling the relative motion speed between the target and the camera to match the camera exposure time, and then using data stitching processing to obtain multi-polarization state images. This overcomes the limitation of traditional polarization imaging having limited polarization state information and can be widely used to acquire polarization information of moving or stationary targets, which has important value and significance in the field of polarization imaging.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not 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; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A scanning multi-polarization state image acquisition system, characterized in that, include: Gradient polarizers for generating multiple polarization states, area array cameras for imaging, motion controllers, imaging calculation modules, and data processing modules; Each row and column of the gradient polarizer represents a different polarization state; the gradient polarizer is attached to the area array camera; The area scan camera is connected to the motion controller, the imaging resolution module, and the data processing module, respectively; the area scan camera performs scanning under the control of the motion controller; The area array camera receives the camera exposure time calculated by the imaging solution module, performs imaging with the camera exposure time, acquires multiple progressively polarized image data, and transmits the data to the data processing module. The camera exposure time is matched with the movement speed of the area array camera; The data processing module processes the line-by-line gradually changing polarization state image into multiple polarization state images, including: Extract the same polarization state data from multiple progressively changing polarization state images, and arrange and stitch the same polarization state image information sequentially according to the imaging order to form multiple polarization images.

2. The scanning multi-polarization state image acquisition system according to claim 1, characterized in that, The gradient polarizer is achieved using metamaterials.

3. The scanning multi-polarization state image acquisition system according to claim 1, characterized in that, The graded polarizer is attached to the area array camera, including: Measure the dimensions of the graded polarizer and the dimensions of the graded polarizer element to determine the number of polarization states; Determine the camera pixel size and sensor size, and determine the position of the area array window that is the same size as the graduated polarizer. The gradient polarizer is attached above the window of the area array camera sensor.

4. The scanning multi-polarization state image acquisition system according to claim 1, characterized in that, The imaging calculation module calculates the camera exposure time based on the input target's ground motion velocity vt, the camera's ground motion velocity vb, the imaging distance h, the camera's focal length f, and the sensor pixel size d.

5. The scanning multi-polarization state image acquisition system according to claim 1, characterized in that, The area scan camera performs scanning under the control of the motion controller, including: The motion controller receives the input camera's ground motion speed and uses that speed to control the camera's scanning and imaging.

6. A scanning multi-polarization state image acquisition method, characterized in that, A graded polarizer is attached to an area array camera, wherein each row and column of the graded polarizer represents a different polarization state; the process includes the following steps: The area scan camera performs scanning under the control of the motion controller; The area array camera receives the camera exposure time calculated by the imaging solution module, and performs imaging using the camera exposure time to acquire multiple progressively polarized image data. The data is then transmitted to the data processing module, which processes the progressively polarized images into multiple polarization images. The camera exposure time is matched with the movement speed of the area array camera. The process of processing a row-by-row gradually changing polarization state image into multiple polarization state images includes: extracting the same polarization state data from multiple row-by-row gradually changing polarization state images, arranging and stitching the same polarization state image information sequentially according to the imaging order to form multiple polarization images.

7. The scanning multi-polarization state image acquisition method according to claim 6, characterized in that, The graded polarizer is attached to the area array camera, including: Measure the dimensions of the graded polarizer and the dimensions of the graded polarizer element to determine the number of polarization states; Determine the camera pixel size and sensor size, and determine the position of the area array window that is the same size as the graduated polarizer. The gradient polarizer is attached above the window of the area array camera sensor.

8. The scanning multi-polarization state image acquisition method according to claim 7, characterized in that, Calculate the camera exposure time, including: based on the input target's ground motion velocity vt, the camera's ground motion velocity vb, the imaging distance h, the camera's focal length f, and the sensor pixel size d, calculate the camera exposure time.

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