Simple lens point spread function generation method

Abstract

The application discloses a simple lens point spread function generation method, comprising the following steps: parameterized modeling and generation are performed on a single lens point spread function; a star polygon is generated, star polygon vertex coordinates are calculated according to parameters, a point set inside the star polygon is screened out, and point energy is modeled; the point energy should satisfy the constraint that the total energy is 1; after the undetermined constant is determined, the point spread function energy distribution in the star polygon is calculated, and the generated point spread function is obtained. The application performs accurate parameterized modeling and generation on a single lens point spread function, so that the generated point spread function is more in line with the single lens characteristics, a series of image processing technical features are provided, and a more accurate point spread function can be quickly obtained.

Description

Technical Field

[0001] This invention relates to the field of digital image processing, specifically to a point spread function (PSF) estimation method applied to simple lens imaging. Background Technology

[0002] In recent years, with the continuous development of computational photography technology and optical design, simple lens computational imaging technology has gradually become a new research direction. Simple lens imaging refers to the phenomenon that light forms a real image on the focal plane through a single lens. Compared with traditional complex lens imaging, simple lens imaging can significantly reduce the economic cost of the imaging system, but the imaging effect is affected by the fact that the light path of the simple lens cannot converge to a single point on the focal plane, resulting in a blurry image. The point spread function is a function representing the image formed on the focal plane by light emitted from a point source through a lens. Estimating the point spread function of the simple lens at different imaging block positions based on the blurred image obtained by the lens is one of the preliminary steps for image restoration of the blurred image.

[0003] With the continuous development of single-lens computational imaging technology and the increasing demands for image quality, existing methods, while capable of estimating the PSF (Power Sequence Fault) of a single lens, can no longer meet the practical needs of single-lens computational imaging in terms of speed and accuracy. Simple lens imaging generally exhibits characteristics of small distortion in the central region and large distortion in the peripheral region. Due to manufacturing precision issues, the actual measured results of the point spread function of a simple lens exhibit an irregular "quadrilateral star" shape. Therefore, a single-point spread function cannot be used to model the entire simple lens image; instead, the image must be divided into blocks and modeled individually based on the distance from the imaging region to the image center. Summary of the Invention

[0004] To overcome the problems in the prior art, this invention aims to provide a simple method for generating lens point spread functions, thereby solving the problem that existing PSF estimation methods are not accurate enough.

[0005] The objective of this invention is achieved through the following technical solution: a method for optimizing the attacker's strategy in complex network games based on intuitionistic fuzzy logic, the method comprising:

[0006] A point spread function estimation method includes the following steps:

[0007] Parametric modeling and generation of the point spread function of a single lens;

[0008] Let n be the number of angles of the generated star-shaped polygon, and D be the outer diameter. o ∈R n The inner diameter is D i ∈R n The deviation angle is A r∈R n Let the k-th dimensions of the outer diameter and inner diameter be respectively... and Initialize the outer diameter using a uniformly distributed random distribution: The formula for initializing the inner diameter is: k = 1, ..., n. Where r ~ U(0.1, 0.3) is randomly generated. This represents the (k-1)th dimension of the outer diameter, and the deviation angle is initialized using a uniform distribution.

[0009] Calculate the vertex coordinates {P} of the star-shaped polygon based on the parameters. k =(x k y k x |k = 1, ..., 2n} k Let y represent the x-coordinate of the k-th vertex. k Let A0 ∈ R be the ordinate of the k-th vertex, and let A0 ∈ R be the polar coordinate angle of the vertex of the star-shaped polygon. 2n+1 ,and k = 1, ..., 2n+1, Let A ∈ R be the polar coordinate angle of the 0th vertex, also known as the initial polar coordinate angle. 2n+1 ,and k = 1, ..., 2n+1, A k This represents the k-th dimension of the polar coordinate angle A. This represents the difference between the k-th dimension of the polar coordinate angle A and the initial polar coordinate angle, and is obtained through random generation. When k is even, the formula for calculating the vertex coordinates of the generated star-shaped polygon is as follows:

[0010] When k is even

[0011] When k is odd, the calculation formula is as follows:

[0012] When k is odd

[0013] Filter out the star-shaped polygon S P The set of points inside G = {(i, j) | (i, j) ∈ S} p}, where i represents the x-coordinate of a point inside the star-shaped polygon, and j represents the y-coordinate of a point inside the star-shaped polygon;

[0014] Model the energy at the point: E(i,j)=αexp(-β||i 2 +j 2 ||), where α and β are undetermined constants, ||·|| represents the calculation of the absolute value, and the point energy should satisfy the constraint that the total energy is 1, i.e., ∏ (i，j)∈G E(i,j) = 1;

[0015] Therefore, we have: α=1 / (∏) (i，j)∈G exp(-β||i 2 +j 2 ||)), the undetermined constant β characterizes the degree of energy dispersion of the point diffusion function;

[0016] After the undetermined constants are determined, the energy distribution of the point spread function within the star-shaped polygon is calculated, and the generated point spread function {E(i,j)|i,j=1,…,m} is obtained, where m∈N + Let be the size of the point spread function.

[0017] Furthermore, the generated point spread function is the convolution of the point spread function energy distribution E and the smooth convolution kernel κ: PSF = E * κ.

[0018] Specifically, smooth convolution kernel

[0019] Among them, β~U(0.004, 0.008). Attached Figure Description

[0020] Figure 1 A single-lens structure diagram according to an embodiment of the present invention is shown;

[0021] Figure 2 A block division diagram of single-lens imaging according to an embodiment of the present invention is shown;

[0022] Figure 3 A flowchart illustrating an embodiment of the present invention is shown;

[0023] Figure 4 The diagram shows the effect of partial point diffusion function generation in an embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0025] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0026] like Figure 1As shown, simple lens imaging can significantly reduce the economic cost of imaging systems, but the imaging effect is affected by the fact that the light paths of a simple lens cannot converge to a single point on the focal plane, resulting in a blurry image. Estimating the point spread function of the simple lens at different imaging block positions based on the blurred image obtained through the lens is one of the preliminary steps for image restoration of the blurred image.

[0027] The image segmentation method in this embodiment is as follows: Figure 2 As shown, the 4:3 scale single-lens imaging is first divided into 12×9 blocks, and then blur kernel estimation is performed block by block.

[0028] like Figure 3 As shown, a simple method for generating lens point spread functions includes the following steps:

[0029] Randomly initialize the required parameters. Let n be the number of angles of the generated star-shaped polygon, and D be the outer diameter. o ∈R n The inner diameter is D i ∈R n The deviation angle is A r ∈R n Let the k-th dimensions of the outer diameter and inner diameter be respectively... and The outer diameter is initialized randomly using a uniform distribution.

[0030]

[0031] The initial calculation of the inner diameter is as shown in formula (2).

[0032]

[0033] Where r ~ U(0.1, 0.3) is randomly generated. The deviation angle A i Similar to the outer diameter, the uniform distribution initialization is adopted using formula (1).

[0034] Calculate the vertex coordinates {P} of the star-shaped polygon based on the parameters. k =(x k y k Let A0 ∈ R be the polar coordinate angle of the vertex of the star-shaped polygon, where k = 1, ..., 2n. 2n+1 ,and

[0035]

[0036] Let the polar coordinate angles of the vertices of the generated star-shaped polygon be A∈R. 2n+1 and

[0037]

[0038] The vertex coordinates of the generated star-shaped polygon are calculated using formula (5) when k is even.

[0039]

[0040] When k is odd, use formula (6) to calculate.

[0041]

[0042] Generate a point spread function {E(i,j)|i,j=1,...,m.} based on the vertex coordinates of the star-shaped polygon, where m∈N. + Let be the size of the point spread function. First, select points within the star-shaped polygon S. P The set of points inside G = {(i, j) | (i, j) ∈ S} p Secondly, model the energy at the points.

[0043] E(i,j)=αexp(-β||i 2 +j 2 ||). (7)

[0044] Where α and β are undetermined constants. The potential energy should satisfy the constraint that the total energy sum is 1, i.e.

[0045] Π (i，j)∈G E(i,j)=1 (8)

[0046] Substituting formula (7) into (8) yields...

[0047] α=1 / (Π (i，j)∈G exp(-β||i 2 +j 2 ||)) (9)

[0048] The undetermined constant β characterizes the degree of dispersion of the point spread function energy, and is usually taken as β ~ U (0.004, 0.008). When the constant β is determined, the constant α can be calculated according to formula (8), and then the point spread function energy distribution within the star-shaped polygon can be calculated according to formula (7).

[0049] We utilize a smooth point spread function (PSF) generated by convolution. The PSF generated in the previous steps may have discontinuous edges; therefore, we construct a smooth convolution kernel κ. The final PSF is the convolution of the energy distribution E and the smooth convolution kernel κ.

[0050] PSF=E*κ (10)

[0051] Where the convolution kernel is taken

[0052]

[0053] Figure 4This diagram illustrates the effect of the diffusion function at a single lens point generated by the method described in this patent. Brightness enhancement was applied to improve the display.

[0054] It can be seen that the generated effect retains the "quadrilateral star" shape of the point spread function of single-lens imaging, while the shape and angle of the corners are diverse, providing support for simulating point spread functions under different processing errors.

[0055] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

Claims

1. A simple method for generating lens point spread function, characterized in that, Includes the following steps: Parametric modeling and generation of the point spread function of a single lens; Let n be the number of angles of the generated star-shaped polygon, and D be the outer diameter. o ∈R n The inner diameter is D i ∈R n The deviation angle is A r ∈R n Let the k-th dimensions of the outer diameter and inner diameter be respectively... and Initialize the outer diameter using a uniformly distributed random distribution: The formula for initializing the inner diameter is: Where r ~ U(0.1,0.3) is randomly generated. This represents the (k-1)th dimension of the outer diameter, and the deviation angle is initialized using a uniform distribution. Calculate the vertex coordinates {P} of the star-shaped polygon based on the parameters. k =(x k ,y k x |k=1,…,2n},x k Let y represent the x-coordinate of the k-th vertex. k Let A0 ∈ R be the ordinate of the k-th vertex, and let A0 ∈ R be the polar coordinate angle of the vertex of the star-shaped polygon. 2n+1 ,and Let A ∈ R be the polar coordinate angle of the 0th vertex, also known as the initial polar coordinate angle. 2n+1 ,and A k This represents the k-th dimension of the polar coordinate angle A. This represents the difference between the k-th dimension of the polar coordinate angle A and the initial polar coordinate angle, and is obtained through random generation. When k is even, the formula for calculating the vertex coordinates of the generated star-shaped polygon is as follows: When k is even When k is odd, the calculation formula is as follows: When k is odd Filter out the star-shaped polygon S P The set of points inside G = {(i,j)|(i,j)∈S} p }, where i represents the x-coordinate of a point inside the star-shaped polygon, and j represents the y-coordinate of a point inside the star-shaped polygon; Model the energy at the point: E(i,j)=αexp(-β||i 2 +j 2 ||), where α and β are undetermined constants, ||·|| represents calculating the absolute value, and the point energy should satisfy the constraint that the total energy sum is 1, i.e., ∏ (i,j)∈G E(i,j) = 1; Therefore, we have: α=1 / (∏) (i,j)∈G exp(-β||i 2 +j 2 ||)), the undetermined constant β characterizes the degree of energy dispersion of the point diffusion function; Once the undetermined constants are determined, the energy distribution of the point spread function within the star-shaped polygon is calculated, and the generated point spread function is obtained.

2. The simple lens point diffusion function generation method according to claim 1, characterized in that, The generated point spread function is the convolution of the point spread function energy distribution E and the smooth convolution kernel κ: PSF = E * κ.

3. The simple lens point diffusion function generation method according to claim 2, characterized in that, Smooth convolution kernel 4. The simple lens point diffusion function generation method according to claim 1, characterized in that, The undetermined coefficients β ~ U (0.004, 0.008).

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