CN117147106A - Bayer type color CCD chip calibration system and method - Google Patents

Abstract

The invention discloses a Bayer type color CCD chip calibration system and a Bayer type color CCD chip calibration method, which aim to solve the problem that a Bayer type color CCD chip changes color information by loss of space information in a scene, so that the scene is color cast. The device specifically comprises a red light optical fiber laser component, a green light optical fiber laser component, a blue light optical fiber laser component, an integrating sphere and an optical fiber spectrometer; the integrating sphere is provided with a red light entrance port, a green light entrance port, a blue light entrance port, a detection port and a mounting port; the red light fiber laser component is used for incidence of red light into the integrating sphere through the red light incidence port; the green light fiber laser component is used for entering green light into the integrating sphere through the green light entrance port; the blue light optical fiber laser component is used for incidence of blue light into the integrating sphere through the blue light incidence port; the probe of the optical fiber spectrometer is arranged at the detection port and is used for detecting the energy of the emergent light of the integrating sphere and monitoring the proportion of the red, green and blue three-primary-color light; the mounting port is used for mounting a Bayer type color CCD chip to receive emergent light of the integrating sphere.

Description

Bayer type color CCD chip calibration system and method

Technical Field

The invention relates to CCD chip calibration and method, in particular to a Bayer color CCD chip calibration system and method.

Background

The Bayer-type color CCD is widely used in various optical cameras, and can be used to acquire true color images of a target scene. To obtain the color information of the scene, a color filter array of three primary colors, typically RGB, i.e., red, green, and blue, is added in front of adjacent CCD pixels, as shown in fig. 1 and 2, due to the sensitivity of the human eye to light. Because each pixel records one color of three primary colors respectively, the other two colors of the pixel are obtained through neighborhood interpolation, so that the three primary colors of the pixel are obtained. The gray information of the pixel is obtained by weighted accumulation. Therefore, the loss of space information is caused to a certain extent, and the resolution is reduced; namely, the loss of space information in the scene is used for exchanging color information, so that the purpose of acquiring a color image is achieved, and the scene is color cast.

Disclosure of Invention

The invention aims to provide a Bayer type color CCD chip calibration system and a Bayer type color CCD chip calibration method, which are used for solving the technical problem that a Bayer type color CCD chip changes color information by loss of space information in a scene, so that the scene is color cast.

In order to achieve the above object, the present invention provides a Bayer color CCD chip calibration system, where the Bayer color CCD chip is connected with a power supply control system; the Bayer type color CCD chip is used for receiving light rays; the power supply control system supplies power to the Bayer type color CCD chip, sets optical system parameters in the Bayer type color CCD chip and controls the Bayer type color CCD chip to image;

the special feature is that: the device comprises a red light optical fiber laser component, a green light optical fiber laser component, a blue light optical fiber laser component, an integrating sphere and an optical fiber spectrometer;

the integrating sphere is provided with a red light incidence port, a green light incidence port, a blue light incidence port, a detection port and a mounting port;

the red light fiber laser component is used for entering red light into the integrating sphere through a red light entrance port;

the green light fiber laser component is used for entering green light into the integrating sphere through the green light entrance port;

the blue light fiber laser component is used for entering blue light into the integrating sphere through a blue light entrance port;

the probe of the optical fiber spectrometer is arranged at the detection port and is used for detecting the energy of the emergent light of the integrating sphere and monitoring the proportion among the red, green and blue three-primary-color lights;

the mounting port is used for mounting a Bayer type color CCD chip so as to receive emergent light of the integrating sphere.

Further, the red optical fiber laser component comprises a red optical laser, a first adjustable attenuator and a red optical beam shaper which are sequentially connected through a first optical fiber;

the exit end of the red light beam shaper is opposite to the red light entrance of the integrating sphere, and a first light homogenizer is arranged between the exit end of the red light beam shaper and the red light entrance.

Further, the green light fiber laser assembly comprises a green light laser, a second adjustable attenuator and a green light beam shaper which are sequentially connected through a second optical fiber;

the emergent end of the green light beam shaper is opposite to the green light entrance of the integrating sphere, and a second light homogenizer is arranged between the emergent end of the green light beam shaper and the green light entrance.

Further, the blue light fiber laser component comprises a blue light laser, a third adjustable attenuator and a blue light beam shaper which are sequentially connected through a third optical fiber;

the exit end of the blue light beam shaper is opposite to the blue light entrance of the integrating sphere, and a third light homogenizer is arranged between the exit end of the blue light beam shaper and the blue light entrance.

Further, the first optical fiber, the second optical fiber and the third optical fiber are all single mode optical fibers.

Further, the center wavelength of the red light laser is 700nm;

the central wavelength of the green light laser is 546.1nm;

the center wavelength of the blue light laser is 435.8nm.

The invention also provides a Bayer type color CCD chip calibration method based on the Bayer type color CCD chip calibration system, which is characterized by comprising the following steps:

step 1, calibrating inconsistent response of a single-color pixel;

1.1, starting a red light optical fiber laser component and an optical fiber spectrometer;

1.2, opening a Bayer type color CCD chip and a power supply control system, wherein the Bayer type color CCD chip receives emergent light of an integrating sphere;

1.3, changing the energy of the red light emitted by the red optical fiber laser component, and detecting the energy change of the emitted light at the detection port of the integrating sphere by the optical fiber spectrometer through the probe;

1.4, continuously changing optical system parameters of a Bayer color CCD chip by a power supply control system, obtaining response curves under different red laser energies according to energy changes detected by an optical fiber spectrometer, and completing radiation calibration of red pixels;

1.5, closing the red optical fiber laser component, opening the green optical fiber laser component, and correspondingly repeating the steps 1.2-1.4 to obtain response curves under different green laser energies, thereby completing the radiation calibration of the green pixels;

1.6, closing the green optical fiber laser component, opening the blue optical fiber laser component, and correspondingly repeating the steps 1.2 to 1.4 to obtain response curves under different blue optical laser energies, thereby completing the radiation calibration of the blue pixels;

step 2, correcting the response inconsistency of the monochromatic pixels;

2.1, according to response curves under different red laser energies, obtaining a red pixel response matrix by using a corresponding fitting algorithm;

2.2, obtaining the most probable response coefficient from the red pixel response matrix to obtain a correction coefficient matrix;

2.3, bringing the correction coefficient matrix into the red pixel response matrix to obtain a correction response matrix with consistent red pixel response;

and 2.4, correspondingly repeating the steps 2.1-2.3 to respectively obtain a correction response matrix with consistent green pixel response and a correction response matrix with consistent blue pixel response, and correcting the inconsistent single-color pixel response to finish the calibration of the Bayer color CCD chip.

Further, in step 1.4, the optical system parameters include exposure time and gain.

The invention has the beneficial effects that:

1. according to the invention, the lasers with three colors of red light, green light and blue light are coupled into the integrating sphere, the uniform area light source is formed after homogenization by the integrating sphere, meanwhile, the proportion of each monochromatic light is regulated by each monochromatic light attenuator, and light sources with different colors are formed, so that the calibration and correction of the response rate of each pixel of the Bayer color CCD chip are realized, the acquisition of gray information in a scene without losing space information is realized, and the problem of scene color cast caused by inconsistent response of each same-color pixel is solved.

2. The invention realizes the Bayer type color CCD gray information acquisition method without sacrificing the spatial resolution.

3. The invention corrects the non-uniformity response of each same-color pixel, and eliminates the problem of scene color cast caused by inconsistent response of the same-color pixels.

4. Through simulation and calibration of colors in scene expectation, the scene color cast problem introduced by an optical system is reduced and corrected.

Drawings

FIG. 1 is a schematic diagram of a Bayer color CCD pixel arrangement;

FIG. 2 is a three primary color pixel, where a is a red pixel; b is a green pixel; c is a blue pixel;

FIG. 3 is a schematic diagram of a Bayer color CCD chip calibration system in accordance with an embodiment of the present invention.

In the figure:

1A is a red optical fiber laser;

1B is a first adjustable attenuator for realizing energy adjustment of red light;

1C is a red light beam shaper;

1D is a first light homogenizer which is used for driving the frosted glass plate to shake at a high speed so as to reduce laser speckles;

2A is a green light fiber laser;

2B is a second adjustable attenuator to realize energy adjustment of green light;

2C is a green beam shaper;

2D is a second light homogenizer for driving the frosted glass plate to shake at high speed so as to reduce laser speckles;

3A is a blue light fiber laser;

3B is a third adjustable attenuator to realize energy adjustment of blue light;

3C is a blue light beam shaper;

the 3D is a third light homogenizer and is used for driving the frosted glass plate to shake at a high speed so as to reduce laser speckles;

4 is an integrating sphere, which can realize the homogenization of laser and generate a uniform area light source;

5A is a probe;

5B is an optical fiber spectrometer, and the optical fiber spectrometer and a probe thereof are cascaded by an optical fiber;

6A is a Bayer color CCD chip;

and 6B is a power supply control system, and the power supply control system and the Bayer color CCD chip are connected in cascade through a circuit.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to fall within the scope of the invention.

The invention provides a pixel non-uniformity calibration and expected scene color simulation device based on a Bayer color CCD, which considers each pixel of the Bayer color CCD as a non-uniform pixel with inconsistent response rate,

the calibration is carried out, the correction coefficient is given, the acquisition method of gray information in the scene without losing space information is realized, the non-uniformity response of each same-color pixel is corrected, and the scene color cast problem caused by inconsistent pixel response is eliminated, and the method is concretely as follows:

first, as shown in fig. 3, the Bayer-type color CCD includes a Bayer-type color CCD chip 6A and a power supply control system 6B connected to each other; the Bayer-type color CCD chip 6A is configured to receive light; the power supply control system 6B supplies power to the Bayer type color CCD chip 6A, sets optical system parameters in the Bayer type color CCD chip 6A and controls imaging of the Bayer type color CCD chip 6A.

Next, as shown in fig. 3, the Bayer-type color CCD calibration system provided in the present embodiment includes a red light fiber laser assembly, a green light fiber laser assembly, a blue light fiber laser assembly, an integrating sphere 4, and a fiber spectrometer 5B;

the integrating sphere 4 is provided with a red light incidence port, a green light incidence port, a blue light incidence port, a detection port and a mounting port;

the red optical fiber laser component comprises a red optical laser 1A, a first adjustable attenuator 1B and a red optical beam shaper 1C which are sequentially connected through a first optical fiber; the red light laser 1A is a red light fiber laser with the center wavelength of 700nm and is used for emitting red light into the integrating sphere 4; the first adjustable attenuator 1B is used for adjusting the energy of red light; the emergent end of the red light beam shaper 1C is opposite to the red light entrance of the integrating sphere 4, and a first light homogenizer 1D is arranged between the emergent end of the red light beam shaper 1C and the red light entrance; the first homogenizer 1D is used to reduce laser speckle. The first optical fiber is a single mode optical fiber.

The green light fiber laser assembly comprises a green light laser 2A, a second adjustable attenuator 2B and a green light beam shaper 2C which are sequentially connected through a second optical fiber; the green light laser 2A is a green light fiber laser with a central wavelength of 546.1nm and is used for emitting green light into the integrating sphere 4; the emitting end of the green light beam shaper 2C is opposite to the green light entrance of the integrating sphere 4, and a second light homogenizer 2D is arranged between the emitting end of the green light beam shaper 2C and the green light entrance for reducing laser speckle. The second optical fiber is also a single mode optical fiber.

The blue light fiber laser component comprises a blue light laser 3A, a third adjustable attenuator 3B and a blue light beam shaper 3C which are sequentially connected through a third optical fiber; the blue light laser 3A is a blue light fiber laser with a center wavelength of 435.8nm and is used for entering blue light into the integrating sphere 4; the exit end of the blue light beam shaper 3C is opposite to the blue light entrance of the integrating sphere 4, and a third light homogenizer 3D is arranged between the exit end of the blue light beam shaper 3C and the blue light entrance for reducing laser speckle. The third optical fiber is also a single mode optical fiber.

The probe 5A of the optical fiber spectrometer 5B is disposed at the detection port of the integrating sphere 4, and is used for detecting the energy of the emergent light emitted after passing through the integrating sphere 4 and monitoring the proportion of the red, green and blue three primary colors.

The mounting port of the integrating sphere 4 is used for mounting a Bayer-type color CCD chip 6A, and the Bayer-type color CCD chip 6A is used for receiving the outgoing light of the integrating sphere 4.

The Bayer type color CCD chip calibration system is adopted to calibrate the Bayer type color CCD chip, and the specific steps are as follows:

(1) Starting a red light laser 1A, a first light homogenizer 1D and an optical fiber spectrometer 5B;

(2) The Bayer color CCD chip 6A and the power supply control system 6B thereof are opened, so that the Bayer color CCD chip 6A can normally receive the image homogenized by the integrating sphere 4;

(3) The energy of the red light laser 1A is changed through the first adjustable attenuator 1B, and the optical fiber spectrometer 5B monitors and measures the change of the energy through the probe 5A;

(4) The Bayer color CCD chip 6A is controlled to complete the response under different red laser energies under certain optical system parameters (such as exposure time and gain), obtain response curves under different red laser energies, implement radiometric calibration of red pixels, and then obtain a red pixel response matrix by using a corresponding fitting algorithm, for example:

when the response model of the red picture element is considered to be a linear model, i.e

I _i (x,y)＝k(x,y)×E _i +b(x,y)

Wherein: i _i (x, y) is energy E _i The gray response of the red pixel at image coordinates (x, y);

k (x, y) is the response coefficient to be optimized;

E _i the energy of the ith sampling point in the linear interval;

b (x, y) is the dark background response to be optimized for the red pixel in this linear interval.

Then the least square linear fitting algorithm is correspondingly adopted, k (x, y) and b (x, y) are obtained by the following formulas, and the following matrixes are constructed:

A＝[k(x,y),b(x,y)]

Q＝I _i (x,y)

A＝(M ^T M) ^-1 M ^T Q

the response coefficient and dark background response of the point are obtained.

(5) And analyzing the response coefficient of the red pixel response matrix to obtain the response coefficient with the highest probability, namely the most probable response coefficient, thereby giving a correction coefficient matrix and eliminating the inconsistency of the red pixel response.

(6) And carrying out correction by taking the correction coefficient matrix into a red pixel response matrix to obtain a correction response matrix with consistent pixel response.

(7) Turning off the red light laser 1A and the first light homogenizer 1D, turning on the green light laser 2A and the second light homogenizer 2D, and repeating the steps (2) to (6) correspondingly, wherein in the steps, the energy of the green light laser 2A is changed correspondingly through the second adjustable attenuator 2B; and correspondingly correcting the response matrix of the green pixels to obtain a corrected response matrix with consistent pixel response.

(8) Turning off the green light laser 2A and the second light homogenizer 2D, turning on the blue light laser 3A and the third light homogenizer 3D, and repeating the steps (2) - (6) correspondingly, wherein in the steps, the energy of the blue light laser 3A is changed correspondingly through the third adjustable attenuator 3B; and correspondingly correcting the response matrix of the blue pixels to obtain a corrected response matrix with consistent pixel response.

And (5) completing the calibration of the Bayer color CCD chip.

Application one: the calibrated Bayer color CCD chip is adopted to acquire gray information:

and integrating the Bayer color CCD chip 6A with an optical system, repeating the steps (1) - (8), and completing calibration and correction of inconsistent pixel responses of single-color pixels by the whole machine to obtain a correction response matrix with consistent pixel responses of red light, green light and blue light, thereby correcting corresponding pixel points of a scene image shot by the whole machine to obtain gray information of the scene image.

And (2) application II: color information recovery using calibrated Bayer color CCD chip

(1) Starting a red optical fiber laser 1A, a green optical fiber laser 2A, a blue optical fiber laser 3A and an optical fiber spectrometer 5B;

(2) The first adjustable attenuator 1B, the second adjustable attenuator 2B and the third adjustable attenuator 3B are adjusted, and the proportion of red light, green light and blue light, namely the proportion of trichromatic light, is monitored through the optical fiber spectrometer 5B so as to reach the color proportion in the expected scene;

(3) The response non-uniformity among the single-color pixels is corrected by using a correction coefficient matrix of the response non-uniformity of the single-color pixels of each of the three primary colors; correcting the response coefficient of the three primary colors after the single-color responses are consistent, corresponding to the color proportion in the expected scene, so that the response rate of the final three primary colors corresponds to the color proportion in the expected scene;

(4) And correcting the response coefficients of the three primary colors corresponding to the color proportions in the expected scene respectively on the whole machine integrated by the Bayer type color CCD chip and the optical system so as to solve the problem of color cast of the actual scene caused by inconsistent spectral passing rate and pixel response of the optical system.

The foregoing is merely illustrative of specific embodiments of the present invention, and the scope of the present invention is not limited thereto, but any changes or substitutions within the technical scope of the present invention should be covered by the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (8)

1. A Bayer-type color CCD chip scaling system, the Bayer-type color CCD chip (6A) being connected to a power supply control system (6B); the Bayer type color CCD chip (6A) is used for receiving light rays; the power supply control system (6B) supplies power to the Bayer type color CCD chip (6A), sets optical system parameters in the Bayer type color CCD chip (6A) and controls the Bayer type color CCD chip (6A) to image;

the method is characterized in that: the device comprises a red light optical fiber laser component, a green light optical fiber laser component, a blue light optical fiber laser component, an integrating sphere (4) and an optical fiber spectrometer (5B);

the integrating sphere (4) is provided with a red light incidence port, a green light incidence port, a blue light incidence port, a detection port and a mounting port;

the red light fiber laser component is used for incidence of red light into the integrating sphere (4) through a red light incidence port;

the green light fiber laser component is used for entering green light into the integrating sphere (4) through a green light entrance port;

the blue light fiber laser component is used for incidence of blue light into the integrating sphere (4) through a blue light incidence port;

the probe (5A) of the optical fiber spectrometer (5B) is arranged at the detection port and is used for detecting the energy of the emergent light of the integrating sphere (4) and monitoring the proportion of the red, green and blue three-primary-color light;

the mounting opening is used for mounting a Bayer type color CCD chip (6A) so as to receive emergent light of the integrating sphere (4).

2. The Bayer color CCD chip scale system according to claim 1, wherein: the red optical fiber laser component comprises a red optical laser (1A), a first adjustable attenuator (1B) and a red optical beam shaper (1C) which are sequentially connected through a first optical fiber;

the emitting end of the red light beam shaper (1C) is opposite to the red light incidence port of the integrating sphere (4), and a first light homogenizer (1D) is arranged between the emitting end of the red light beam shaper (1C) and the red light incidence port.

3. The Bayer color CCD chip scale system according to claim 2, wherein: the green light optical fiber laser component comprises a green light laser (2A), a second adjustable attenuator (2B) and a green light beam shaper (2C) which are sequentially connected through a second optical fiber;

the emergent end of the green light beam shaper (2C) is opposite to the green light incidence port of the integrating sphere (4), and a second light homogenizer (2D) is arranged between the emergent end of the green light beam shaper (2C) and the green light incidence port.

4. A Bayer color CCD chip scale system according to claim 3, wherein: the blue light optical fiber laser component comprises a blue light laser (3A), a third adjustable attenuator (3B) and a blue light beam shaper (3C) which are sequentially connected through a third optical fiber;

the exit end of the blue light beam shaper (3C) is opposite to the blue light entrance of the integrating sphere (4), and a third light homogenizer (3D) is arranged between the exit end of the blue light beam shaper (3C) and the blue light entrance.

5. The Bayer color CCD chip scale system according to claim 4, wherein: the first optical fiber, the second optical fiber and the third optical fiber are all single-mode optical fibers.

6. The Bayer color CCD chip scale system according to claim 5, wherein: the center wavelength of the red light laser (1A) is 700nm;

the central wavelength of the green light laser (2A) is 546.1nm;

the center wavelength of the blue light laser (3A) is 435.8nm.

7. A Bayer-type color CCD chip calibrating method based on the Bayer-type color CCD chip calibrating system according to any one of claims 1 to 6, comprising the steps of:

step 1, calibrating inconsistent response of a single-color pixel;

1.1, starting a red light optical fiber laser component and an optical fiber spectrometer (5B);

1.2, opening a Bayer color CCD chip (6A) and a power supply control system (6B), wherein the Bayer color CCD chip (6A) receives emergent light of an integrating sphere (4);

1.3, changing the energy of red light emitted by a red optical fiber laser component, and detecting the energy change of light emitted by an integrating sphere (4) at a detection port by an optical fiber spectrometer (5B) through a probe (5A) of the optical fiber spectrometer;

1.4, a power supply control system (6B) continuously changes the parameters of an optical system of a Bayer color CCD chip (6A), and obtains response curves under different red laser energies according to the energy changes detected by an optical fiber spectrometer (5B), so as to complete the radiation calibration of red pixels;

1.5, closing the red optical fiber laser component, opening the green optical fiber laser component, and correspondingly repeating the steps 1.2-1.4 to obtain response curves under different green laser energies, thereby completing the radiation calibration of the green pixels;

1.6, closing the green optical fiber laser component, opening the blue optical fiber laser component, and correspondingly repeating the steps 1.2 to 1.4 to obtain response curves under different blue optical laser energies, thereby completing the radiation calibration of the blue pixels;

step 2, correcting the response inconsistency of the monochromatic pixels;

2.1, according to response curves under different red laser energies, obtaining a red pixel response matrix by using a corresponding fitting algorithm;

2.2, obtaining the most probable response coefficient from the red pixel response matrix to obtain a correction coefficient matrix;

2.3, bringing the correction coefficient matrix into the red pixel response matrix to obtain a correction response matrix with consistent red pixel response;

and 2.4, correspondingly repeating the steps 2.1-2.3 to respectively obtain a correction response matrix with consistent green pixel response and a correction response matrix with consistent blue pixel response, and correcting the inconsistent single-color pixel response to finish the calibration of the Bayer color CCD chip.

8. The Bayer color CCD chip calibrating method according to claim 7, wherein:

in step 1.4, the optical system parameters include exposure time and gain.