A polarization image edge enhancement calculation method and system

Abstract

The present invention belongs to the field of image processing technology, and in particular to a polarization image edge enhancement calculation method, comprising the following steps: Step 1: using a split-focus plane polarization camera to obtain polarization intensity images at 0°, 45°, 90°, and 135° directions, and calculating and obtaining a light intensity image I S0 , the first polarization parameter image I S1 , the second polarization parameter image I S2 , polarization image I DoLP And the polarization angle image I AoP ; Step 2: Calculate and obtain the edge feature image I using the polarization parameter images obtained in step S1 EF , polarization edge enhanced image I PES The method of this invention simultaneously and rationally combines the advantageous information of polarization images and intensity images to complement each other, making the contrast between the target and the background more distinct and highlighting the target's outline and details. The resulting polarization edge-enhanced image has more pronounced edge and outline information and can be applied to subsequent advanced computer vision tasks such as image fusion, target detection, and recognition.

Description

Technical Field

[0001] The present invention relates to the technical field of image processing, and in particular to a polarization image edge enhancement calculation method and system. Background Art

[0002] Polarization is a key characteristic of light. The asymmetry of light's vibration direction with respect to its propagation direction is called polarization. It's the most obvious distinction between transverse waves and longitudinal waves, and only transverse waves exhibit polarization. Polarization imaging offers significant advantages over traditional imaging techniques. It captures both the target's light intensity and its polarization, particularly for surfaces or subtle changes that are difficult for the human eye to detect. Therefore, polarization imaging technology is widely used in military and civilian applications, including target detection, camouflage identification, and remote sensing.

[0003] Edge information is one of the most important features of an object, representing the boundary between the object and the background. In images, edge information is also a crucial metric, used to describe the differences between different regions within the image. It is crucial for tasks such as object detection, segmentation, and classification. While traditional edge computing methods can enhance or highlight edge contours and details to a certain extent, they are not particularly effective for polarized images, and research on edge information in polarized images is relatively limited. Therefore, we propose a polarized image edge enhancement computation method and system to address this issue. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In view of the deficiencies in the prior art, the present invention provides a polarization image edge enhancement calculation method and system, which solves the problems raised in the above background technology.

[0006] (2) Technical solution

[0007] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0008] A polarization image edge enhancement calculation method includes the following steps:

[0009] Step 1: Use a focal plane polarization camera to obtain polarization intensity images at 0°, 45°, 90°, and 135°, and calculate the light intensity image I S0 , the first polarization parameter image I S1 , the second polarization parameter image I S2 , polarization image I DoLP And the polarization angle image I AoP ;

[0010] Step 2: Use the polarization parameter images obtained in step 1 to calculate and obtain the edge feature image I EF, polarization edge enhanced image I PES And the polarization edge information

[0011] Step 3: Based on the obtained image, design the polarization edge enhancement function F and add the gradient weight function ω g , while removing noise, further highlighting edge information;

[0012] Step 4: Obtain polarized edge-enhanced image I PES And the polarization edge enhancement function F is calculated and the final polarization edge enhanced image I is obtained PEA .

[0013] Furthermore, the formula for obtaining each polarization parameter image in step 1 is:

[0014]

[0015] Where ε represents AoP, δ represents the ellipticity angle, χ represents the radiation intensity, and DoLP can be expressed as cos2δ.

[0016] Furthermore, in step 2, edge feature image I is calculated and obtained. EF , polarization edge enhanced image I PES And the polarization edge information The calculation formula is as follows:

[0017]

[0018] R B (φ,I EF )=R B (φ,I EF )(1-I EF )

[0019]

[0020]

[0021] Where g x g y Represents the two kernels of the edge detection operator, I EF For edge feature images, the polarization distance model is referenced and improved, and the polarization images in four angular directions are used as input to calculate the linear polarization target sensitivity R(φ,I EF ), where the value of φ is Using edge feature image I EF To highlight the edge of the target source image, S pis the activation threshold; then the target area activation values ​​ET1, ET2, and ET3 are calculated using the formula, and the linear polarization background sensitivity R of light in different directions can also be calculated B (φ,I EF ) to obtain the background area activation values ​​EB1, EB2 and EB3, and finally calculate the polarization edge enhanced image I PES ; in and Represent the edge strength and direction orientation value at (i, j), ω X Represents the importance of each source image to the polarization edge enhanced image. The polarization edge information amount is calculated by the amount of information transferred from the source image to the polarization edge enhanced image. To reflect the edge difference between the source image and the polarization edge enhanced image, and highlight the structural complexity and edge complexity of the polarization edge enhanced image.

[0022] Furthermore, the calculation formula for the polarization edge enhancement function F designed in step 3 is as follows:

[0023]

[0024] Where Ω represents the number of pixels in the Ω area, p and q are the pixel points in the Ω area, and W p represents the normalized weight, I represents the input image, μ r and μ s Represent the grayscale value domain and spatial domain Gaussian function respectively, and Represent their standard deviations, ω g represents the gradient weight function, which calculates the weight by the ratio between the gradient magnitudes, Represents the gradient information of the image, and C is a constant that controls the impact of gradient differences on weights.

[0025] Furthermore, in step 4, a polarization edge enhanced image I is obtained. PEA The calculation formula is:

[0026] I PEA =F(I PES )

[0027] Where, I PES is the polarization edge enhanced image, F is the polarization edge enhancement function, I PEA Enhances images for polarization edges.

[0028] A system for calculating a polarization image edge enhancement method, the system comprising:

[0029] Polarization parameter calculation module: used to collect polarization images in four directions from the focal plane polarization camera and calculate the light intensity image I S0 , the first polarization parameter image I S1 , the second polarization parameter image I S2 , polarization image I DoLP And the polarization angle image I AoP ;

[0030] Edge feature image, polarization edge enhancement image, polarization edge information calculation module: used for the polarization parameter images solved above to calculate the edge feature image I EF , polarization edge enhanced image I PES And obtain the polarization edge information

[0031] Polarization edge enhancement function module: used to design a polarization edge enhancement function F based on the acquired image to remove noise while further highlighting edge information;

[0032] Polarization edge enhanced image acquisition module: used to obtain polarization edge enhanced image I based on the calculated PES , polarization edge enhancement function F, calculate and obtain polarization edge enhanced image I PEA .

[0033] (3) Beneficial effects

[0034] Compared with the prior art, the present invention provides a polarization image edge enhancement calculation method and system, which has the following beneficial effects:

[0035] 1. The present invention uses a focal plane polarization camera to obtain intensity images in four directions and calculates the light intensity image I S0 , the first polarization parameter image I S1 , the second polarization parameter image I S2 , polarization image I DoLP And the polarization angle image I AoP ; Then the edge feature image I is obtained by calculating each polarization parameter image EF , polarization edge enhanced image I PES And the polarization edge information Then design the polarization edge enhancement function F and add the gradient weight function ω g , further highlighting the edge information while removing noise; finally, the polarization edge enhanced image I is obtained PEA The present invention can make the edge information of the polarized image more prominent, highlight the contours and details of the polarized image, and significantly improve the image quality. It can be applied to subsequent military and civilian fields such as image fusion, image enhancement, target detection, and edge detection.

[0036] 2. The present invention calculates a polarization edge enhancement image based on each polarization parameter image, making the edge features of the polarization image more distinct and better utilizing the polarization information of the image. The polarization edge enhancement image calculated by the present invention based on the polarization image and the polarization edge enhancement function makes the edge information of the image more prominent and is more suitable for polarization images compared to traditional edge calculation methods. The image generated by this calculation method is more consistent with the human eye's visual perception and understanding, and it can be intuitively seen that the edge information has a more significant visual effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Flowchart of the polarization edge enhancement calculation method provided by the present invention;

[0038] Figure 2 Schematic diagram of the polarization edge enhancement calculation method provided by the present invention;

[0039] Figure 3 The S0 light intensity image provided by the example of the present invention;

[0040] Figure 4 The first polarization parameter image S1 provided by the example of the present invention;

[0041] Figure 5 The second polarization parameter image S2 provided by the example of the present invention;

[0042] Figure 6 The DoLP linear polarization degree image provided by the example of the present invention;

[0043] Figure 7 The AoP linear polarization angle image provided by the example of the present invention;

[0044] Figure 8 The edge feature image IEF provided by the example of the present invention;

[0045] Figure 9 Polarized edge enhanced image IPES provided by an example of the present invention;

[0046] Figure 10 This is a polarization edge enhanced image IPEA provided by an example of the present invention. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0048] Example 1

[0049] like Figure 1 As shown, a polarization image edge enhancement calculation method provided by embodiment 1 of the present invention includes the following steps:

[0050] Step 1: Use a focal plane polarization camera to obtain polarization intensity images at 0°, 45°, 90°, and 135°, and calculate the light intensity image I S0 , the first polarization parameter image I S1 , the second polarization parameter image I S2 , polarization image I DoLP And the polarization angle image I AoP ;

[0051] The formula for calculating each polarization parameter image is:

[0052]

[0053]

[0054] Where ε represents AoP, δ represents the ellipticity angle, χ represents the radiation intensity, and DoLP can be expressed as cos2δ.

[0055] Step 2: Use the polarization parameter images obtained in step 1 to calculate and obtain the edge feature image I EF , polarization edge enhanced image I PES And the polarization edge information Obtain edge feature image I through each polarization parameter image EF , polarization edge enhanced image I PES The calculation formula is:

[0056]

[0057] R B (φ,I EF )=R B (φ,I EF )(1-I EF )

[0058]

[0059]

[0060] Where g x g y Represents the two kernels of the Prewitt edge detection operator. The size of the two kernels is 3×3. The small area of ​​each kernel is represented by zi (i∈1~9). EFThe polarization distance model is referenced and improved, and the polarization images at 0°, 45°, 90°, and 135° are used as input to calculate the linear polarization target sensitivity R(φ,I EF ), where the value of φ is Using edge feature image I EF To highlight the edge of the target source image, S p Is the activation threshold. Then use the formula to calculate the target area activation value ET1, ET2, ET3, and the linear polarization background sensitivity R of light in different directions can also be calculated. B (φ,I EF ) to obtain the background area activation values ​​EB1, EB2 and EB3, and finally calculate the polarization edge enhanced image I PES .

[0061] The present invention innovatively proposes the above calculation formula, and the technical function is: light intensity image I S0 , the first polarization parameter image I S1 , the second polarization parameter image I S2 And polarization image I DoLP , polarization angle image I AoP , edge feature image I EF And polarization edge enhanced image I PES ,like Figure 3-Figure 9 The calculated polarization edge enhancement image can make the edge information of the target more obvious and contain rich polarization information.

[0062] Calculate and obtain polarization edge information The calculation formula is as follows:

[0063]

[0064] Where, in and Represent the edge strength and direction orientation value at (i, j), ω X Represents the importance of each source image to the polarization edge-enhanced image.

[0065] The present invention innovatively proposes the above calculation formula, and the technical function is to enhance the image I by polarization edge PES Calculate its polarization edge information Polarization edge information The amount of information transferred from the source image to the polarization edge enhanced image is calculated by the polarization edge information amount. To reflect the edge difference between the source image and the polarization edge enhanced image, and highlight the structural complexity and edge complexity of the polarization edge enhanced image.

[0066] Step 3: Based on the obtained image, design the polarization edge enhancement function F and add the gradient weight function ω g , while removing noise and further highlighting edge information; the calculation formula is as follows:

[0067]

[0068] Where Ω represents the number of pixels in the Ω area, p and q are the pixel points in the Ω area, and W p represents the normalized weight, I represents the input image, μ r and μ s Represent the grayscale value domain and spatial domain Gaussian function respectively, and Represent their standard deviations, ω g represents the gradient weight function, which calculates the weight by the ratio between the gradient magnitudes, Represents the gradient information of the image, and C is a constant that controls the impact of gradient differences on weights.

[0069] Step 4: Obtain polarized edge-enhanced image I PES And the polarization enhancement function F is calculated and the final polarization edge enhanced image I is obtained PEA The calculation formula is as follows:

[0070] I PEA =F(I PES )

[0071] Where, I PES is the polarization edge enhanced image, F is the polarization edge enhancement function, I PEA Enhances images for polarization edges.

[0072] The present invention proposes a novel calculation method for the polarization edge enhancement function F, and finally obtains the polarization edge enhanced image I PEA ,like Figure 10 As shown in the figure, the effect of the technology is: the polarization edge enhancement function F better retains the edge information of the image in the gray value domain, spatial domain, and gradient, while removing the noise in the image, achieving the effect of image smoothing, making the edge information of the image more prominent, and facilitating further analysis and understanding of the image.

[0073] Example 2

[0074] As another embodiment of the present invention, a polarization image edge enhancement calculation method provided in Example 2 of the present invention includes the following steps:

[0075] Step 1: Use a focal plane polarization camera to acquire polarization intensity images at 0°, 45°, 90°, and 135°, and obtain the corresponding polarization intensity images I0°, I45°, I90°, and I135°. Then, perform calculations on the polarization intensity images I0°, I45°, I90°, and I135° to obtain the polarization parameter images S0, S1, S2, DoLP, and AoP using the following formulas.

[0076]

[0077] Where ε represents AoP, δ represents the ellipticity angle, and χ represents the radiation intensity. DoLP can be expressed as cos2δ.

[0078] Step 2: Use the polarization parameter images obtained in step 1 to calculate and obtain the edge feature image I EF , polarization edge enhanced image I PES And the polarization edge information The calculation formula is as follows:

[0079]

[0080] R B (φ,I EF )=R B (φ,I EF )(1-I EF )

[0081]

[0082]

[0083] Where g x g y Represents the two kernels of the Sobel edge detection operator, I EF For edge feature images, the polarization distance model is referenced and improved, and polarization images at 0°, 45°, 90°, and 135° directions are used as input to calculate the linear polarization target sensitivity R(φ,I EF ), where the value of φ is Using edge feature image I EF To highlight the edge of the target source image, S p Is the activation threshold. Then use the formula to calculate the target area activation value ET1, ET2, ET3, and the linear polarization background sensitivity R of light in different directions can also be calculated. B (φ,I EF ) to obtain the background area activation values ​​EB1, EB2 and EB3, and finally calculate the polarization edge enhanced image I PES , in and Represent the edge strength and direction orientation value at (i, j), ω X Represents the importance of each source image to the polarization edge enhanced image. Polarization edge information The amount of information transferred from the source image to the polarization edge enhanced image is calculated by the polarization edge information amount. To reflect the edge difference between the source image and the polarization edge enhanced image, and highlight the structural complexity and edge complexity of the polarization edge enhanced image.

[0084] Step 3: Based on the obtained image, design the polarization edge enhancement function F and add the gradient weight function ω g , while removing noise and further highlighting edge information, the calculation formula is as follows:

[0085]

[0086]

[0087] Where Ω represents the number of pixels in the Ω area, p and q are the pixel points in the Ω area, and W p represents the normalized weight, I represents the input image, μ r and μ s Represent the grayscale value domain and spatial domain Gaussian function respectively, and Represent their standard deviations, ω g Represents the gradient weight function ω g , which calculates the weight by the ratio between the gradient magnitudes, Represents the gradient information of the image, and C is a constant that controls the impact of gradient differences on weights.

[0088] Step 4: Obtain polarized edge-enhanced image I PES And the polarization edge enhancement function F is calculated and the final polarization edge enhanced image I is obtained PEA , the calculation formula is as follows:

[0089] I PEA =F(I PES )

[0090] Where, I PES is the polarization edge enhanced image, F is the polarization edge enhancement function, I PEA Enhances images for polarization edges.

[0091] Example 3

[0092] Embodiment 3 of the present invention provides a polarization image edge enhancement calculation system, including:

[0093] Polarization parameter calculation module, used to collect polarization images in four directions from the focal plane polarization camera and calculate the light intensity image I S0 , the first polarization parameter image I S1 , the second polarization parameter image I S2 , polarization image I DoLP And the polarization angle image I AoP ;

[0094] Edge feature image, polarization edge enhancement image, polarization edge information calculation module, used for the above-mentioned calculated polarization parameter images, calculate the edge feature image I EF , polarization edge enhanced image I PES And obtain the polarization edge information

[0095] Polarization edge enhancement function module, used to design polarization edge information enhancement function F based on the obtained image, and add gradient weight function ω g , while removing noise, further highlighting edge information;

[0096] Polarization edge enhanced image acquisition module, used for polarization edge enhanced image I PES , polarization edge enhancement function F, calculate and obtain polarization edge saliency image I PEA .

[0097] In the above embodiments, the description of each embodiment has different emphases. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0098] As auxiliary evidence for the inventiveness of the claims of the present invention, it is also reflected in the following important aspects:

[0099] 1. Polarization image edge enhancement is a novel method for calculating polarization images. Compared to traditional edge calculation methods, this method can complement the superior information between different source images, making image edges more prominent while filtering out surrounding noise. This enhanced edge information has important application prospects in target detection and recognition, classification and segmentation, biotechnology, medical imaging, remote sensing imagery, and military fields.

[0100] 2. Traditional image edge calculation methods are mainly used for light intensity images. The polarization image edge enhancement calculation method of the present invention comprehensively utilizes the polarization characteristic information of each polarization parameter image S1, S2, DoLP and AoP and the light intensity information of the S0 image, and rationally utilizes the edge information and contour details of different images.

[0101] 3. The polarization image edge enhancement calculation method of the present invention can be applied in the field of polarization image processing. It is more effective than traditional edge image calculation methods and can make the edge information and details of the polarization image more prominent, providing a basis for subsequent advanced computer vision task analysis and processing.

[0102] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A polarization image edge enhancement calculation method, characterized by: The steps include: Step 1: Use a focal plane polarization camera to obtain polarization intensity images at 0°, 45°, 90°, and 135°, and calculate the light intensity image I S0 , the first polarization parameter image I S1 , the second polarization parameter image I S2 , polarization image I DoLP And the polarization angle image I AoP ; Step 2: Use the polarization parameter images obtained in step 1 to calculate and obtain the edge feature image I EF , polarization edge enhanced image I PES And the polarization edge information Step 3: Based on the obtained image, design the polarization edge enhancement function F and add the gradient weight function ω g , while removing noise, further highlighting edge information; Step 4: Obtain polarized edge-enhanced image I PES And the polarization edge enhancement function F is calculated and the final polarization edge enhanced image I is obtained PEA ; In step 2, edge feature image I is calculated and obtained. EF , polarization edge enhanced image I PES And the polarization edge information The calculation formula is as follows: R B (φ,I EF )=R B (φ,I EF )(1-I EF ) Where g x g y Represents the two kernels of the edge detection operator, I EF For edge feature images, the polarization distance model is referenced and improved, and the polarization images in four angular directions are used as input to calculate the linear polarization target sensitivity R(φ,I EF ), where the value of φ is Using edge feature image I EF To highlight the edge of the target source image, S p is the activation threshold; Then use the formula to calculate the target area activation values ​​ET1, ET2, and ET3, and also calculate the linear polarization background sensitivity R of light in different directions. B (φ,I EF ) to obtain the background area activation values ​​EB1, EB2 and EB3, and finally calculate the polarization edge enhanced image I PES ; in and Represent the edge strength and direction orientation value at (i, j), ω X Represents the importance of each source image to the polarization edge-enhanced image; The calculation formula of the polarization edge enhancement function F designed in step 3 is as follows: Where Ω represents the number of pixels in the Ω area, p and q are the pixel points in the Ω area, and W p represents the normalized weight, I represents the input image, μ r and μ s Represent the grayscale value domain and spatial domain Gaussian function respectively, and Represent their standard deviations, ω g represents the gradient weight function, Represents the gradient information of the image, and C is a constant.

2. The polarization image edge enhancement calculation method according to claim 1, characterized in that: The formula for obtaining each polarization parameter image in step 1 is: Where ε represents AoP, δ represents the ellipticity angle, χ represents the radiation intensity, and DoLP is expressed as cos2δ.

3. The method for calculating polarization image edge enhancement according to claim 1, wherein: In step 4, the polarization edge enhanced image I is obtained. PEA The calculation formula is: I PEA =F(I PES ) Where, I PES is the polarization edge enhanced image, F is the polarization edge enhancement function, I PEA Enhances images for polarization edges.

4. A system for implementing the polarization image edge enhancement calculation method according to any one of claims 1 to 3, characterized in that: The system includes: Polarization parameter calculation module: used to collect polarization images in four directions from the focal plane polarization camera and calculate the light intensity image I S0 , the first polarization parameter image I S1 , the second polarization parameter image I S2 , polarization image I DoLP And the polarization angle image I AoP ; Edge feature image, polarization edge enhancement image, polarization edge information calculation module: used for the polarization parameter images solved above to calculate the edge feature image I EF , polarization edge enhanced image I PES And obtain the polarization edge information Polarization edge enhancement function module: used to design a polarization edge enhancement function F based on the acquired image to remove noise while further highlighting edge information; Polarization edge enhanced image acquisition module: used to obtain polarization edge enhanced image I based on the calculated PES , polarization edge enhancement function F, calculate and obtain polarization edge enhanced image I PEA .

Images