Polarization image edge enhancement calculation method and system

Abstract

The invention belongs to the technical field of image processing, and particularly relates to a polarization image edge enhancement calculation method, which comprises the following steps of: 1, acquiring polarization intensity images in 0-degree, 45-degree, 90-degree and 135-degree directions by using a focal plane polarization camera, resolving to obtain a light intensity image IS0, a first polarization parameter image IS1, a second polarization parameter image IS2, a polarization degree image IDoLP and a polarization angle image IAoP; and step 2, calculating and obtaining an edge feature image IEF, a polarization edge enhanced image IPES and polarization edge information amount # imgabs0 # by using each polarization parameter image obtained in the step S1. According to the method provided by the invention, the advantage information of the polarization image and the light intensity image can be simultaneously and reasonably combined for complementation, so that the difference comparison between the target and the background is more obvious; the contour and details of the target are highlighted. The finally obtained polarization edge enhanced image has more significant edge and contour information, and can be applied to subsequent image fusion, target detection and recognition and other advanced computer vision tasks.

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 one of the important characteristics of light. The asymmetry of the vibration direction of light with respect to the propagation direction is called polarization. It is the most obvious sign that distinguishes transverse waves from longitudinal waves. Only transverse waves have polarization. Polarization imaging has obvious advantages over traditional imaging technology. It can obtain the polarization information of the target object while obtaining the light intensity information of the target object, especially the surface or subtle changes that are not easily observed by the human eye. Therefore, polarization imaging technology is widely used in military and civilian fields such as target detection, camouflage recognition, and remote sensing detection.

[0003] Edge information is one of the most important features of the target object. It is the dividing line between the target and the background. In the image, edge information is also an extremely important indicator, which is used to describe the differences between different areas in the image. It is of great significance for tasks such as target detection, segmentation, and classification. Although traditional edge calculation methods can enhance or highlight edge contours and details to a certain extent, the effect on polarized images is not outstanding, and there is relatively little research on edge information of polarized images. Therefore, we propose a polarized image edge enhancement calculation method and system to solve the above problems. Summary of the invention

[0004] 1. Technical issues to be resolved

[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] (II) 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 comprises 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 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 amount of 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 to obtain the final polarization edge enhanced image I PEA .

[0013] Furthermore, the formula for solving and 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 amount of 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] In the formula, g x g y Represents the two kernels of the edge detection operator, I EF The edge feature image is used as input to calculate the four-channel polarization distance and the linear polarization 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 ET1, ET2, ET3, and EB1, EB2, and EB3 can also be obtained, and finally the polarization edge enhanced image I is obtained. PES ; in and Respectively 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 transferring the information 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 to highlight the structural complexity and edge complexity of the polarization edge enhanced image.

[0021] Furthermore, the calculation formula for designing the polarization edge enhancement function F in step 3 is as follows:

[0022]

[0023] 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 gray 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.

[0024] Furthermore, in step 4, a polarization edge enhanced image I is obtained. PEA The calculation formula is:

[0025] I PEA =F(I PES )

[0026] In the formula, I PES is the polarization edge enhanced image, F is the polarization edge enhancement function, I PEA Enhances images for polarized edges.

[0027] A system for implementing the polarization image edge enhancement calculation method according to any one of claims 1 to 5, the system comprising:

[0028] Polarization parameter calculation module: used to collect polarization images in four directions from the focal plane polarization camera and calculate the 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 ;

[0029] Edge feature image, polarization edge enhancement image, polarization edge information calculation module: used for calculating the edge feature image I from the polarization parameter images solved above EF , polarization edge enhanced image I PES And obtain the polarization edge information

[0030] Polarization edge enhancement function module: used to design a polarization edge enhancement function F based on the acquired image, to remove noise and further highlight edge information;

[0031] Polarization edge enhanced image acquisition module: used to enhance the polarization edge image I based on the calculated PES , polarization edge enhancement function F, calculate and obtain the polarization edge enhanced image I PEA .

[0032] (III) Beneficial effects

[0033] Compared with the prior art, the present invention provides a polarization image edge enhancement calculation method and system, which has the following beneficial effects:

[0034] 1. The present invention uses a focal plane polarization camera to obtain intensity images in four directions and calculates and obtains 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 amount of polarization edge information Then design the polarization edge enhancement function F and add the gradient weight function ω g , while removing noise, further highlighting the edge information; 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 outline and details of the polarized image, and significantly improve the image quality, and can be applied to subsequent military and civilian fields such as image fusion, image enhancement, target detection, and edge detection.

[0035] 2. The present invention calculates a polarization edge enhancement image based on each polarization parameter image, which can make the edge features of the polarization image more obvious and better utilize the polarization information of the image. The present invention calculates a polarization edge enhancement image based on a polarization image and a polarization edge enhancement function, which makes the edge information of the image more significant. Compared with the traditional edge calculation method, it is more suitable for polarization images. The image generated by this calculation method is more in line with the human eye's perception of vision, and it can be intuitively seen that the edge information has a more significant visual effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A flow chart of the polarization edge enhancement calculation method provided by the present invention;

[0037] Figure 2 A schematic diagram of the polarization edge enhancement calculation method provided by the present invention;

[0038] Figure 3 The S0 light intensity image provided by the example of the present invention;

[0039] Figure 4 The first polarization parameter image S1 provided by the example of the present invention;

[0040] Figure 5 The S2 second polarization parameter image provided by the example of the present invention;

[0041] Figure 6 The DoLP linear polarization degree image provided by the example of the present invention;

[0042] Figure 7 AoP linear polarization angle image provided by the example of the present invention;

[0043] Figure 8 The edge feature image IEF provided by the example of the present invention;

[0044] Fig. 9 A polarized edge enhanced image IPES provided by an example of the present invention;

[0045] Fig.10 A polarization edge enhanced image IPEA is provided for an example of the present invention. DETAILED DESCRIPTION

[0046] 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.

[0047] Example 1

[0048] like Figure 1 As shown, a polarization image edge enhancement calculation method provided by Embodiment 1 of the present invention includes the following steps:

[0049] Step 1: Use a focal plane polarization camera to obtain polarization intensity images at 0°, 45°, 90°, and 135°, and calculate the 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 ;

[0050] The formula for calculating and obtaining each polarization parameter image is:

[0051]

[0052] Where ε represents AoP, δ represents the ellipticity angle, χ represents the radiation intensity, and DoLP can be expressed as cos2δ.

[0053] 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 amount of polarization edge information Obtain edge feature image I through each polarization parameter image EF , polarization edge enhanced image I PES The calculation formula is:

[0054]

[0055]

[0056] R B (φ,I EF )=R B (φ,I EF )(1-I EF )

[0057]

[0058] In the formula, 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). EF is the edge feature image. Use the polarization images at 0°, 45°, 90°, and 135° as input to calculate the four-channel polarization distance and the linear polarization 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 ET1, ET2, and ET3, and you can also get EB1, EB2, and EB3. Finally, you can get the polarization edge enhanced image I PES .

[0059] 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 the polarization image I DoLP , polarization angle image I AoP , edge feature image I EF And the polarization edge enhanced image I PES ,like Figure 3-Figure 9 The calculated polarization edge enhanced image can make the edge information of the target more obvious and contain rich polarization information.

[0060] Calculate and obtain polarization edge information The calculation formula is as follows:

[0061]

[0062] In the formula, in and Respectively 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.

[0063] The present invention innovatively proposes the above calculation formula, and the technical function is: to enhance the image I by polarization edge PES Calculate the polarization edge information Polarization edge information The amount of information transferred from the source image to the polarization edge enhanced image is calculated by To reflect the edge difference between the source image and the polarization edge enhanced image, and to highlight the structural complexity and edge complexity of the polarization edge enhanced image.

[0064] 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; the calculation formula is as follows:

[0065]

[0066] 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 gray 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.

[0067] Step 4: Obtain polarized edge-enhanced image I PES And the polarization enhancement function F is calculated to obtain the final polarization edge enhanced image I PEA ; The calculation formula is as follows:

[0068] I PEA =F(I PES )

[0069] In the formula, I PES is the polarization edge enhanced image, F is the polarization edge enhancement function, I PEA Enhances images for polarized edges.

[0070] The present invention innovatively proposes to calculate the polarization edge enhancement function F, and finally obtains the polarization edge enhanced image I PEA ,like Fig.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.

[0071] Example 2

[0072] As another implementation manner of the present invention, a polarization image edge enhancement calculation method provided in Example 2 of the present invention includes the following steps:

[0073] Step 1: Use a focal plane polarization camera to obtain polarization intensity images at 0°, 45°, 90°, and 135°, and obtain the corresponding polarization intensity images I0°, I45°, I90°, and I135°; and solve the polarization intensity images I0°, I45°, I90°, and I135°, and use the following calculation formula to obtain polarization parameter images S0, S1, S2, DoLP, and AoP;

[0074]

[0075] Where ε represents AoP, δ represents the ellipticity angle, χ represents the radiation intensity, and DoLP can be expressed as cos2δ.

[0076] 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 amount of polarization edge information The calculation formula is as follows:

[0077]

[0078] R B (φ,I EF )=R B (φ,I EF )(1-I EF )

[0079]

[0080] In the formula, g x g y Represents the two kernels of the Sobel edge detection operator, I EF The edge feature image is used as the input to calculate the polarization distance and the linear polarization 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 ET1, ET2, and ET3, and you can also get EB1, EB2, and EB3. Finally, you can get the polarization edge enhanced image I PES , in and Respectively 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.

[0081] 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, the calculation formula is as follows:

[0082]

[0083]

[0084] Where Ω represents the number of pixels in the Ω area, p and q are the pixel points in the Ω area, and Wp represents the normalized weight, I represents the input image, μ r and μ s Represent the gray 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 weights 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.

[0085] Step 4: Obtain polarized edge-enhanced image I PES And the polarization edge enhancement function F is calculated to obtain the final polarization edge enhanced image I PEA , the calculation formula is as follows:

[0086] I PEA =F(I PES )

[0087] In the formula, I PES is the polarization edge enhanced image, F is the polarization edge enhancement function, I PEA Enhances images for polarized edges.

[0088] Example 3

[0089] Embodiment 3 of the present invention provides a polarization image edge enhancement computing system, including:

[0090] Polarization parameter calculation module, used to collect polarization images in four directions from the focal plane polarization camera and calculate the 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 ;

[0091] The edge feature image, polarization edge enhancement image, and polarization edge information calculation module are used to calculate the edge feature image I from the polarization parameter images calculated above. EF , polarization edge enhanced image I PES And obtain the polarization edge information

[0092] Polarization edge enhancement function module, used to design polarization edge information enhancement function F based on the acquired image, and add gradient weight function ω g , while removing noise, further highlighting edge information;

[0093] The polarization edge enhanced image acquisition module is used to enhance the polarization edge image I based on the calculated polarization edge enhanced image I PES , polarization edge enhancement function F, calculate and obtain the polarization edge saliency image I PEA .

[0094] 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.

[0095] As auxiliary evidence of the inventiveness of the claims of the present invention, it is also reflected in the following important aspects:

[0096] 1. Polarization image edge enhancement calculation method is a new polarization image calculation method. Compared with the traditional image edge calculation method, this method can complement the superior information between different source images, making the edge information of the image more significant, while filtering out the noise around the edge. Significant edge information has important application prospects in target detection and recognition, classification and segmentation, biotechnology, medical imaging, remote sensing images and military fields.

[0097] 2. Traditional image edge calculation methods are mainly aimed at 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 reasonably utilizes the edge information and contour details of different images.

[0098] 3. The polarization image edge enhancement calculation method of the present invention can be applied in the field of polarization image processing. It has better effect 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.

[0099] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is 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 can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A polarization image edge enhancement calculation method, characterized in that: 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 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 amount of 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 to obtain the final polarization edge enhanced image I PEA .

2. The method for calculating edge enhancement of a polarization image according to claim 1, characterized in that: The formula for calculating and 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 can be expressed as cos2δ.

3. The method for calculating edge enhancement of a polarization image according to claim 2, characterized in that: In step 2, edge feature image I is calculated and obtained. EF , polarization edge enhanced image I PES And the amount of polarization edge information The calculation formula is as follows: R B (φ,I EF )=R B (φ,I EF )(1-I EF ) In the formula, g x g y Represents the two kernels of the edge detection operator, I EF The edge feature image is used as input to calculate the four-channel polarization distance and the linear polarization 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 ET1, ET2, and ET3, and you can also get EB1, EB2, and EB3. Finally, you can get the polarization edge enhanced image I. PES ; in and Respectively 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.

4. The method for calculating edge enhancement of a polarization image according to claim 1, characterized in that: The calculation formula for 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 gray value domain and spatial domain Gaussian function respectively, G σr and Represent their standard deviations, ω g represents the gradient weight function, Represents the gradient information of the image, and C is a constant.

5. The method for calculating edge enhancement of a polarization image according to claim 4, characterized in that: In step 4, a polarization edge enhanced image I is obtained. PEA The calculation formula is: I PEA =F(I PES ) In the formula, I PES is the polarization edge enhanced image, F is the polarization edge enhancement function, I PEA Enhances images for polarized edges.

6. A system for implementing the polarization image edge enhancement calculation method according to any one of claims 1 to 5, 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 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 calculating the edge feature image I from the polarization parameter images solved above 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 and further highlight edge information; Polarization edge enhanced image acquisition module: used to enhance the polarization edge image I based on the calculated PES , polarization edge enhancement function F, calculate and obtain the polarization edge enhanced image I PEA .

Images