Crosstalk removal method based on multi-channel linear coefficient inverse matrix

Abstract

The present invention relates to the technical field of spectral line array cameras, and in particular to a de-crosstalk method based on a multi-channel linear coefficient inverse matrix. The method comprises: S1: sequentially irradiating monochromatic light of different bands onto each line pixel array of a multi-channel spectral line array camera; S2: normalizing the spectral response value of the first line pixel array; S3: repeating step S2 to calculate the normalized spectral response value of each line pixel array; S4: obtaining a linear equation of the theoretical response value and the actual response value of each line pixel array according to the calculation result of step S3; S5: calculating a multi-channel linear coefficient inverse matrix; S6: multiplying the multi-channel linear coefficient inverse matrix with the actual response value of each line pixel array to obtain the theoretical response value of each line pixel array after de-crosstalk. The present invention can purify the spectral response of each line pixel array of a multi-channel spectral line array camera.

Description

Technical Field

[0001] The present invention relates to the technical field of spectral linear array cameras, and in particular to a crosstalk removal method based on a multi-channel linear coefficient inverse matrix. Background Art

[0002] Theoretically, when the incident light is incident vertically on the spectroscopic film, the spectroscopic films of each band correspond to the imaging pixels one by one. However, in actual use, the light from the lens to the spectroscopic film is incident at an angle. Due to the problem of the incident angle of the light, part of the light incident on the multi-channel spectral line array camera will not be irradiated vertically to the imaging pixel corresponding to the spectroscopic film of the band, but will be irradiated to the imaging pixels of several adjacent bands, so that the imaging pixel not only produces a spectral response to the light of a single band, but also partially responds to the light of other bands, thereby causing the response spectrum of each line pixel array of the multi-channel spectral line array camera to have crosstalk and aliasing problems. Summary of the invention

[0003] In order to solve the problem that the response spectra of each line pixel array of a multi-channel spectral line array camera are prone to crosstalk aliasing, the present invention provides a de-crosstalk method based on a multi-channel linear coefficient inverse matrix, which can purify the spectral response of each line pixel array of the multi-channel spectral line array camera.

[0004] The de-crosstalk method based on the inverse matrix of multi-channel linear coefficients proposed in the present invention is used to purify the spectral response of each line pixel array of a multi-channel spectral linear array camera, and specifically includes the following steps:

[0005] S1: sequentially irradiate monochromatic lights of different wavelength bands onto each line pixel array of the multi-channel spectral line array camera, and each line pixel array performs spectral response to the monochromatic lights of different wavelength bands;

[0006] S2: Normalize the spectral response value of the first line pixel array by the following formula:

[0007] (1);

[0008] in, is the normalized value of the spectral response of the first band of monochromatic light in the first line of pixel array, is the spectral response value of the monochromatic light of the i-th band in the j-th line pixel array;

[0009] S3: repeat step S2 to calculate the normalized value of the spectral response of each line pixel array;

[0010] S4: According to the calculation result of step S3, the linear equation of the theoretical response value and the actual response value of each line pixel array is obtained by the following formula:

[0011] (2);

[0012] in, is the normalized value of the spectral response of the monochromatic light in the i-th band at the j-th line pixel array, is the theoretical response value of the nth line pixel array, is the actual response value of the nth line pixel array;

[0013] S5: Convert equation (2) into matrix form and calculate the inverse matrix of multi-channel linear coefficients:

[0014] × = (3);

[0015] =C(4);

[0016] Where C is the multi-channel linear coefficient matrix;

[0017] S6: multiplying the multi-channel linear coefficient inverse matrix by the actual response value of each line pixel array to obtain the theoretical response value of each line pixel array after crosstalk removal, thereby achieving purification of the spectral response of each line pixel array of the multi-channel spectral line array camera.

[0018] Preferably, the value of n is 2-8.

[0019] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0020] The present invention restores the spectral response of each channel of a multi-channel spectral camera by establishing linear equations of primary and secondary peaks. Compared with the method of realizing industrial sorting by using only the primary peak response for reflectance calculation, the present invention linearly restores the spectral energy scattered in other line pixel arrays, so that the measured value of the reflectance of the object is closer to the true value, thereby improving the accuracy of industrial sorting. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flow chart of a crosstalk removal method based on a multi-channel linear coefficient inverse matrix provided according to an embodiment of the present invention;

[0022] Figure 2 is a spectral response diagram of monochromatic lights of four different central wavelengths incident on a multi-channel short-wave infrared spectrum linear array camera provided by an embodiment of the present invention;

[0023] FIG3 (a) is a spectral response diagram of monochromatic light before crosstalk removal according to an embodiment of the present invention;

[0024] FIG3( b ) is a spectral response diagram of monochromatic light after crosstalk removal according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are represented by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, the detailed description thereof will not be repeated.

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0027] Aiming at the crosstalk aliasing problem of the response spectrum of each line pixel array of a multi-channel spectral line array camera, the present invention proposes a crosstalk removal method based on the inverse matrix of multi-channel linear coefficients, which can purify the spectral response of each line pixel array of the multi-channel spectral line array camera.

[0028] Figure 1 The flowchart of the crosstalk removal method based on the multi-channel linear coefficient inverse matrix provided according to an embodiment of the present invention is shown.

[0029] like Figure 1 As shown, the de-crosstalk method based on the multi-channel linear coefficient inverse matrix proposed in the present invention specifically includes the following steps:

[0030] S1: Monochromatic lights of different wavelengths are sequentially irradiated onto each line pixel array of the multi-channel spectral line array camera, and each line pixel array performs spectral response to the monochromatic lights of different wavelengths.

[0031] S2: Normalize the spectral response value of the first line pixel array by the following formula:

[0032] (1);

[0033] in, is the normalized value of the spectral response of the first band of monochromatic light in the first line of pixel array, is the spectral response value of the monochromatic light of the i-th band in the j-th line pixel array;

[0034] S3: Repeat step S2 to calculate the normalized spectral response value of each line pixel array.

[0035] S4: According to the calculation result of step S3, the linear equation of the theoretical response value and the actual response value of each line pixel array is obtained by the following formula:

[0036] (2);

[0037] in, is the normalized value of the spectral response of the monochromatic light in the i-th band at the j-th line pixel array, is the theoretical response value of the nth line pixel array, is the actual response value of the nth line pixel array.

[0038] The value of n is 2~8.

[0039] S5: Convert equation (2) into matrix form and calculate the inverse matrix of multi-channel linear coefficients:

[0040] × = (3);

[0041] =C(4);

[0042] Among them, C is the multi-channel linear coefficient matrix.

[0043] S6: multiplying the multi-channel linear coefficient inverse matrix by the actual response value of each line pixel array to obtain the theoretical response value of each line pixel array after crosstalk removal, thereby achieving purification of the spectral response of each line pixel array of the multi-channel spectral line array camera.

[0044] The following takes a multi-channel short-wave infrared spectrum linear array camera as an example to explain the de-crosstalk method based on the multi-channel linear coefficient inverse matrix proposed in the present invention. The multi-channel short-wave infrared spectrum linear array camera includes four linear pixel arrays, so n=4. When four monochromatic lights with different central wavelengths are sequentially incident on the multi-channel short-wave infrared spectrum linear array camera, a, b, c, and d are used to represent the four monochromatic lights with different central wavelengths, respectively. The spectral response of the four monochromatic lights with different central wavelengths incident on the multi-channel short-wave infrared spectrum linear array camera is as follows: Figure 2 As shown, from Figure 2 It can be seen that the monochromatic lights of four different central wavelengths have peaks at 630nm, 650nm, 750nm and 840nm, indicating that the monochromatic lights of four different central wavelengths have spectral responses in other bands. In addition, if five monochromatic lights of different central wavelengths are sequentially incident on a multi-channel short-wave infrared spectral linear array camera to achieve the purification of the spectral response of each line pixel array of the multi-channel spectral linear array camera, a, b, c, d and e are used to represent the monochromatic lights of five different central wavelengths respectively, and the number of monochromatic lights of different central wavelengths is set according to actual needs. After setting the parameters, the above formula is used to calculate the set parameters in turn. FIG3 (a)-FIG3 (b) respectively show the spectral response before and after the monochromatic light is de-crosstalked. It can be seen from FIG3 (a)-FIG3 (b) that the present invention can achieve the purification of the spectral response of each line pixel array of the multi-channel spectral linear array camera.

[0045] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0046] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A de-crosstalk method based on a multi-channel linear coefficient inverse matrix, used to purify the spectral response of each line pixel array of a multi-channel spectral linear array camera, characterized in that: The specific steps include: S1: sequentially irradiating monochromatic lights of different wavelength bands onto each line pixel array of the multi-channel spectral line array camera, and each line pixel array performs spectral response to the monochromatic lights of different wavelength bands; S2: Normalize the spectral response value of the first line pixel array by the following formula: （1）； in, is the normalized value of the spectral response of the first band of monochromatic light in the first line of pixel array, is the spectral response value of the monochromatic light of the i-th band in the j-th line pixel array; S3: repeating step S2 to calculate the normalized value of the spectral response of each line pixel array; S4: According to the calculation result of step S3, the linear equation of the theoretical response value and the actual response value of each line pixel array is obtained by the following formula: （2）； in, is the normalized value of the spectral response of the monochromatic light in the i-th band in the j-th line pixel array, is the theoretical response value of the nth line pixel array, is the actual response value of the nth line pixel array; S5: Convert equation (2) into a matrix form and calculate the multi-channel linear coefficient inverse matrix: × = （3）； =C（4）； Where C is the multi-channel linear coefficient matrix; S6: multiplying the multi-channel linear coefficient inverse matrix by the actual response value of each line pixel array to obtain the theoretical response value of each line pixel array after crosstalk removal, thereby purifying the spectral response of each line pixel array of the multi-channel spectral line array camera.

2. The crosstalk removal method based on the multi-channel linear coefficient inverse matrix according to claim 1, characterized in that: The value of n is 2~8.

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