WO2020107661A1 - Image color temperature acquisition method - Google Patents

Abstract

Provided is an image color temperature acquisition method. The image color temperature acquisition method of the present invention involves: dividing a color gamut space into a first area, a second area and a third area; calculating a color difference value between pixels, at the same position, in two adjacent frames of images, and taking same as a weighting parameter of a pixel in a next frame of image; determining the position of color coordinates of the pixel in the next frame of image, when the color coordinates are located in the first area, using a pixel color temperature formula to calculate a color temperature value of the pixel and adding the corresponding weighting parameter to a weight of the color temperature value in a statistical table, when the color coordinates are located in the second area, using a position relationship between the color coordinates of the pixel and a reference point and the weighting parameter to calculate a weight value of the pixel and adding the weight value to a weight of the maximum reference color temperature in the statistical table, and when the color coordinates are located in the third area, using a position relationship between the color coordinates of the pixel and the reference point and the weighting parameter to calculate a weight value of the pixel and adding the weight value to a weight of the minimum reference color temperature in the statistical table; and calculating a color temperature of the next frame of image in conjunction with the weight. By means of the method, an image color temperature can more accurately be acquired.

Description

Image color temperature acquisition method Technical field

The present invention relates to the field of display technology, and in particular, to a method for acquiring image color temperature.

Background technique

With the development of display technology, liquid crystal display devices (Liquid Crystal Display, LCD) and organic light emitting diode display devices (Organic Light Emitting Display, OLED) and other flat display devices have high image quality, power saving, thin body and application range It has been widely used in various consumer electronic products such as mobile phones, televisions, personal digital assistants, digital cameras, notebook computers, desktop computers, etc., and has become the mainstream in display devices.

Most of the existing liquid crystal display devices generally include: a liquid crystal display panel and a backlight module. The working principle of the liquid crystal display panel is to place liquid crystal molecules in two parallel glass substrates. There are many vertical and horizontal small wires between the two glass substrates. The liquid crystal molecules can be controlled to change the direction by turning on or off, and the backlight module light Refracted to produce a picture.

The existing OLED display device usually includes a substrate, an anode provided on the substrate, an organic light emitting layer provided on the anode, an electron transport layer provided on the organic light emitting layer, and a cathode provided on the electron transport layer. During operation, the hole from the anode and the electron from the cathode are emitted to the organic light-emitting layer, and these electrons and holes are combined to generate an excited electron-hole pair, and the excited electron-hole pair is output from the excited state to the ground state Achieve glow.

In the display industry, color temperature is an important parameter used to characterize the color characteristics of light. The lower the color temperature, the more reddish the light color, and conversely, the lighter the color. The overall color temperature of the image can characterize the overall feeling of the image to the viewer. In the existing methods for obtaining the color temperature of an image, the color temperature of a single frame of image is calculated, and in actual use, the image displayed by the display device is constantly changing, and the human eye will change the pixels in the adjacent frame of the image that change greatly The area is more sensitive, and the existing image color temperature acquisition method cannot combine the human eye attention to locally adjust the pixel area in the adjacent frame image that changes greatly, so that the final obtained image color temperature is different from the actual human eye perception.

Summary of the invention

The object of the present invention is to provide an image color temperature acquisition method, which can more accurately acquire the color temperature of an image.

To achieve the above object, the present invention provides a method for acquiring image color temperature, including the following steps:

Step S1. Establish a statistical table; the statistical table includes a plurality of preset reference color temperatures and a plurality of weights corresponding to the plurality of reference color temperatures, respectively, the plurality of reference color temperatures increase sequentially, and the weights corresponding to the plurality of reference color temperatures are all equal Is 0;

Step S2. Provide a chromatogram, divide the color gamut space in the chromatogram into the first zone, the second zone and the third zone connected in pairs; the boundary between the first zone and the second zone, the second zone and the third zone The boundary line of the zone and the boundary line of the third zone and the first zone converge at a reference point. The boundary line of the first zone and the second zone coincides with the iso-color temperature line corresponding to the largest reference color temperature among the multiple reference color temperatures. The first The boundary between the zone and the third zone coincides with the isochromatic line of the smallest reference color temperature among the multiple reference color temperatures, and the boundary between the second zone and the third zone is parallel to the y-axis of the chromatogram;

Step S3, providing display data of two adjacent frames of images; each frame of images includes a plurality of pixels arranged in an array, and the display data of each frame of images includes a plurality of RGB digital values respectively corresponding to the plurality of pixels;

Step S4: Use the display data of the two adjacent frames to calculate the weight parameters corresponding to the pixels of the next frame of image respectively. The weight parameters corresponding to the pixels in the i-th row and j-th column of the next frame of image are equal to the latter The color difference between the pixel in the i-th row and j-th column in the frame image and the pixel in the i-th row and j-th column in the previous frame image, i and j are both positive integers;

Step S5: Select one of the pixels in the next frame of image as the processing pixel; convert the rgb digital value of the processing pixel into the color coordinate of the processing pixel in the chromatogram;

Step S6: Determine the position of the color coordinate of the processing pixel in the color gamut space; if the color coordinate of the processing pixel is located in the first area, calculate the color temperature value of the processing pixel according to the color coordinate of the processing pixel and the preset pixel color temperature calculation formula, Determine whether the color temperature value of the processing pixel is one of multiple reference color temperatures, if it is, increase the weight corresponding to the color temperature value of the processing pixel in the statistical table by the weight parameter corresponding to the processing pixel, otherwise the color temperature value of the processing pixel and the processing The weight parameters corresponding to the pixels are added to the statistical table as the reference color temperature and their corresponding weights; if the color coordinates of the processed pixel are located in the second zone, the connection between the point corresponding to the color coordinate of the processed pixel and the reference point and the The angle between the boundary between the first zone and the second zone, the weight parameter corresponding to the processed pixel and the preset first weight value calculation formula calculate the weight value of the processed pixel, and add the weight value to the statistical table and the reference color temperature The largest one corresponds to the weight; if the color coordinate of the processing pixel is located in the third area, the angle between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary between the first area and the third area 1. The weight parameter corresponding to the processing pixel and the preset second weight value calculation formula calculate the weight value of the processing pixel, and add the weight value to the weight corresponding to the smallest one of the reference color temperatures in the statistical table;

Step S7. Repeat steps S5 and S6 until multiple pixels of the next frame of the image all execute steps S5 and S6;

Step S8. Multiply each reference color temperature in the statistical table by the corresponding weight, and divide the sum of the products of multiple reference color temperatures and corresponding weights by the sum of the weights corresponding to multiple reference color temperatures to obtain the image of the next frame. Color temperature value.

The specific process of converting the rgb digital value of the processing pixel to the color coordinate of the processing pixel in the chromatogram in the step S5 is as follows: calculating the rgb optical value of the processing pixel according to the rgb digital value of the processing pixel and the preset rgb optical value calculation formula , Calculate the tristimulus value of the processing pixel according to the optical rgb value of the processing pixel and the preset tristimulus value calculation formula, and calculate the color coordinate of the processing pixel in the chromatogram according to the tristimulus value of the processing pixel and the preset color coordinate calculation formula.

The preset calculation formula of rgb optical value is:

Where R is the red optical value in the rgb optical value, G is the green optical value in the rgb optical value, B is the blue optical value in the rgb optical value, r is the red digital value in the rgb digital value, and g is rgb The green digital value in the digital value, b is the blue digital value in the rgb digital value,

Represents the value obtained by performing gamma transformation on r,

Represents the value obtained by performing gamma transformation on b,

Represents the value obtained by performing gamma transformation on g.

The preset formula for calculating the tristimulus value is:

Wherein, X is the red stimulus value in the tristimulus value, Y is the green stimulus value in the tristimulus value, Z is the blue stimulus value in the tristimulus value, and M is the preset conversion matrix.

The preset color coordinate formula is:

Where u is the abscissa of the color coordinate in the chromatogram, and v is the ordinate of the color coordinate in the chromatogram.

The coordinates of the reference points where the boundary between the first zone and the second zone, the boundary between the second zone and the third zone, and the boundary between the third zone and the first zone in the chromatogram are (0.332, 0.1858).

The preset calculation formula of pixel color temperature is: CT=-437×n ³ +3601×n ² -6861×n+5514.31;

Among them, CT is the pixel color temperature value,

The preset formula for calculating the first weight value is: γ1=(1-α1/β1)×k;

Among them, γ1 is the weight value of the processing pixel when the color coordinate of the processing pixel is in the second area, and α1 is the line between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary line between the first area and the second area Angle, β1 is the angle between the boundary between the first zone and the second zone and the boundary between the second zone and the third zone, and k is the weight parameter corresponding to the processed pixels;

The preset second weight value calculation formula is: γ2=(1-α2/β2)×k;

Where γ2 is the weight value of the processing pixel when the color coordinate of the processing pixel is in the third zone, and α2 is the line between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary between the first zone and the third zone The angle, β2, is the angle between the boundary between the first and third regions and the boundary between the second and third regions.

The chromatogram is CIE1931 chromatogram;

The smallest one of the reference color temperatures is 1000K; the largest one of the reference color temperatures is 15000K.

The step S4 is specifically as follows:

Step S41: Set one of the pixels in the next frame image as the first weight extraction pixel, and set the pixel number of the row and column in the previous frame image as the first weight extraction pixel in the next frame image. To extract pixels for the second weight, calculate the rgb optical value of the first weight extraction pixel according to the rgb digital value of the first weight extraction pixel and the preset rgb optical value calculation formula, and extract the rgb optical value and preset of the pixel according to the first weight The tristimulus value calculation formula calculates the tristimulus value of the first weight extraction pixel, and calculates the brightness component, the first color component and the first weight extraction pixel according to the tristimulus value of the first weight extraction pixel and the preset Lab space conversion formula The second color component, the rgb digital value of the extracted pixel according to the second weight and the preset rgb optical value calculation formula to calculate the rgb optical value of the second weight extracted pixel, according to the rgb optical value of the second weight and the preset tristimulus value The calculation formula calculates the tristimulus value of the second weight extraction pixel, and calculates the brightness component, the first color component and the second color component of the second weight extraction pixel according to the tristimulus value of the second weight extraction pixel and the preset Lab space conversion formula ;

The preset Lab space conversion formula is:

Where L is the luminance component, a is the first color component, b'is the second color component, X1 is the preset first parameter, Y1 is the preset second parameter, and Z1 is the preset third parameter,

t is a real number;

Step S42: Extract the luminance component, the first color component and the second color component of the pixel according to the first weight, extract the luminance component, the first color component and the second color component of the pixel according to the second weight and the preset color difference calculation formula Calculating the color difference value of the first weight extraction pixel and the second weight extraction pixel as the weight parameter corresponding to the first weight extraction pixel;

The preset formula for calculating the color difference value is:

Among them, L ₁ is the luminance component of the first weight extraction pixel, a ₁ is the first color component of the first weight extraction pixel, b′ ₁ is the second color component of the first weight extraction pixel, and L ₂ is the second weight extraction the luminance component of a pixel, a ₂ of the second weight extraction first color component pixel, b _'2 to the second weight extraction of the second color component pixel, ΔE is the first weight and the second weight extraction pixel extracting color pixels value;

Step S43. Repeat the above steps S41 and S42 until the acquisition of the weight parameters corresponding to all pixels in the next frame of image is completed.

The invention also provides a method for acquiring image color temperature, including the following steps:

Step S1. Establish a statistical table; the statistical table includes a plurality of preset reference color temperatures and a plurality of weights corresponding to the plurality of reference color temperatures, respectively, the plurality of reference color temperatures increase sequentially, and the weights corresponding to the plurality of reference color temperatures are all equal Is 0;

Step S2. Provide a chromatogram, divide the color gamut space in the chromatogram into the first zone, the second zone and the third zone connected in pairs; the boundary between the first zone and the second zone, the second zone and the third zone The boundary line of the zone and the boundary line of the third zone and the first zone converge at a reference point. The boundary line of the first zone and the second zone coincides with the iso-color temperature line corresponding to the largest reference color temperature among the multiple reference color temperatures. The first The boundary between the zone and the third zone coincides with the isochromatic line of the smallest reference color temperature among the multiple reference color temperatures, and the boundary between the second zone and the third zone is parallel to the y-axis of the chromatogram;

Step S3, providing display data of two adjacent frames of images; each frame of images includes a plurality of pixels arranged in an array, and the display data of each frame of images includes a plurality of RGB digital values respectively corresponding to the plurality of pixels;

Step S4: Use the display data of the two adjacent frames to calculate the weight parameters corresponding to the pixels of the next frame of image respectively. The weight parameters corresponding to the pixels in the i-th row and j-th column of the next frame of image are equal to the latter The color difference between the pixel in the i-th row and j-th column in the frame image and the pixel in the i-th row and j-th column in the previous frame image, i and j are both positive integers;

Step S5: Select one of the pixels in the next frame of image as the processing pixel; convert the rgb digital value of the processing pixel into the color coordinate of the processing pixel in the chromatogram;

Step S6: Determine the position of the color coordinate of the processing pixel in the color gamut space; if the color coordinate of the processing pixel is located in the first area, calculate the color temperature value of the processing pixel according to the color coordinate of the processing pixel and the preset pixel color temperature calculation formula, Determine whether the color temperature value of the processing pixel is one of multiple reference color temperatures, if it is, increase the weight corresponding to the color temperature value of the processing pixel in the statistical table by the weight parameter corresponding to the processing pixel, otherwise the color temperature value of the processing pixel and the processing The weight parameters corresponding to the pixels are added to the statistical table as the reference color temperature and their corresponding weights; if the color coordinates of the processed pixel are located in the second zone, the connection between the point corresponding to the color coordinate of the processed pixel and the reference point and the The angle between the boundary between the first zone and the second zone, the weight parameter corresponding to the processed pixel and the preset first weight value calculation formula calculate the weight value of the processed pixel, and add the weight value to the statistical table and the reference color temperature The largest one corresponds to the weight; if the color coordinate of the processing pixel is located in the third area, the angle between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary between the first area and the third area 1. The weight parameter corresponding to the processing pixel and the preset second weight value calculation formula calculate the weight value of the processing pixel, and add the weight value to the weight corresponding to the smallest one of the reference color temperatures in the statistical table;

Step S7. Repeat steps S5 and S6 until multiple pixels of the next frame of the image all execute steps S5 and S6;

Step S8. Multiply each reference color temperature in the statistical table by the corresponding weight, and divide the sum of the products of multiple reference color temperatures and corresponding weights by the sum of the weights corresponding to multiple reference color temperatures to obtain the image of the next frame. Color temperature value

The specific process of converting the rgb digital value of the processing pixel to the color coordinate of the processing pixel in the chromatogram in the step S5 is as follows: calculating the rgb optical value of the processing pixel according to the rgb digital value of the processing pixel and the preset rgb optical value calculation formula , Calculate the tristimulus value of the processing pixel according to the optical rgb value of the processing pixel and the preset tristimulus value calculation formula, and calculate the color coordinate of the processing pixel in the chromatogram according to the tristimulus value of the processing pixel and the preset color coordinate calculation formula;

The preset formula for calculating the first weight value is: γ1=(1-α1/β1)×k;

Among them, γ1 is the weight value of the processing pixel when the color coordinate of the processing pixel is in the second area, and α1 is the line between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary line between the first area and the second area Angle, β1 is the angle between the boundary between the first zone and the second zone and the boundary between the second zone and the third zone, and k is the weight parameter corresponding to the processed pixels;

The preset second weight value calculation formula is: γ2=(1-α2/β2)×k;

Where γ2 is the weight value of the processing pixel when the color coordinate of the processing pixel is in the third zone, and α2 is the line between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary between the first zone and the third zone The angle, β2, is the angle between the boundary between the first and third regions and the boundary between the second and third regions.

Beneficial effect of the present invention: The image color temperature acquisition method of the present invention divides the color gamut space into the first area, the second area, and the third area, and calculates the color difference value between pixels at the same position in two adjacent frames of images as The weight parameter of the pixels in the next frame of image, to determine the color coordinate position of the pixel in the next frame of image, when it is in the first zone, use the pixel color temperature formula to calculate the color temperature value of the pixel and weight the color temperature value in the statistical table Add the corresponding weight parameter, when it is in the second area, use the pixel's color coordinate and reference point positional relationship and the weight parameter to calculate the pixel's weight value and add it to the weight of the maximum reference color temperature in the statistical table. In the third zone, the pixel's color coordinate and the reference point's positional relationship and weight parameters are used to calculate the pixel's weight value and add it to the weight of the smallest reference color temperature in the statistical table. Combined with the weight to calculate the color temperature of the next frame image, it can be more Obtain the color temperature of the image accurately.

BRIEF DESCRIPTION

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings are provided for reference and explanation only, and are not intended to limit the present invention.

In the drawings,

1 is a flowchart of a method for acquiring image color temperature of the present invention;

2 is a schematic diagram of a chromatogram in the method for acquiring image color temperature of the present invention.

detailed description

In order to further elaborate on the technical means adopted by the present invention and its effects, the following will be described in detail with reference to the preferred embodiments of the present invention and the accompanying drawings.

Please refer to FIG. 1, the present invention provides a method for acquiring image color temperature, including the following steps:

Step S1, create a statistical table. The statistical table includes a plurality of preset reference color temperatures and a plurality of weights respectively corresponding to the plurality of reference color temperatures, the plurality of reference color temperatures increase in sequence, and the weights corresponding to the plurality of reference color temperatures are all 0.

Specifically, the smallest one of the reference color temperatures is 1000K. The largest one of the reference color temperatures is 15000K.

Preferably, the difference between adjacent reference color temperatures may be 500K, and the statistical table may be the statistical table of Table 1 below.

Table 1. Statistics

Reference color temperature	1000K	1500K	...	15000K
Weights	0	0	...	0

Step S2. Please refer to FIG. 2 to provide a chromatogram to divide the color gamut space in the chromatogram into the first area A, the second area B, and the third area C connected in pairs; the first area A and the second area B , The boundary between the second area B and the third area C, and the boundary between the third area C and the first area A converge at a reference point O. The boundary between the first area A and the second area B is more than The reference color temperature corresponding to the largest reference color temperature coincides with the isochromatic temperature line, the boundary between the first area A and the third area C coincides with the isochromatic temperature line with the smallest reference color temperature among the multiple reference color temperatures, and the second area B coincides with the third The boundary of zone C is parallel to the y-axis of the chromatogram.

Specifically, the chromatogram is a CIE1931 chromatogram.

Specifically, all the isochromatic temperature lines in the chromatogram converge on this reference point O.

Specifically, the coordinates of the reference point O are (0.332, 0.1858).

Step S3: Provide display data of two adjacent frames of images. Each frame of image includes multiple pixels arranged in an array, and the display data of each frame of image includes multiple RGB digital values corresponding to the multiple pixels, respectively.

Specifically, the rgb digital value includes a red digital value, a green digital value, and a blue digital value.

Step S4: Use the display data of the two adjacent frames to calculate the weight parameters corresponding to the pixels of the next frame of image respectively. The weight parameters corresponding to the pixels in the i-th row and j-th column of the next frame of image are equal to the latter The color difference between the pixel in the i-th row and j-th column in the frame image and the pixel in the i-th row and j-th column in the previous frame image, i and j are both positive integers.

Specifically, the step S4 is specifically:

Step S41: Set one of the pixels in the next frame image as the first weight extraction pixel, and set the pixel number of the row and column in the previous frame image as the first weight extraction pixel in the next frame image. To extract pixels for the second weight, calculate the rgb optical value of the first weight extraction pixel according to the rgb digital value of the first weight extraction pixel and the preset rgb optical value calculation formula, and extract the rgb optical value and preset of the pixel according to the first weight The tristimulus value calculation formula calculates the tristimulus value of the first weight extraction pixel, and calculates the brightness component, the first color component and the first weight extraction pixel according to the tristimulus value of the first weight extraction pixel and the preset Lab space conversion formula The second color component, the rgb digital value of the extracted pixel according to the second weight and the preset rgb optical value calculation formula to calculate the rgb optical value of the second weight extracted pixel, according to the rgb optical value of the second weight and the preset tristimulus value The calculation formula calculates the tristimulus value of the second weight extraction pixel, and calculates the brightness component, the first color component and the second color component of the second weight extraction pixel according to the tristimulus value of the second weight extraction pixel and the preset Lab space conversion formula .

Specifically, the preset calculation formula of the rgb optical value is:

Where R is the red optical value in the rgb optical value, G is the green optical value in the rgb optical value, B is the blue optical value in the rgb optical value, r is the red digital value in the rgb digital value, and g is rgb The green digital value in the digital value, b is the blue digital value in the rgb digital value,

Represents the value obtained by performing gamma transformation on r,

Represents the value obtained by performing gamma transformation on b,

Represents the value obtained by performing gamma transformation on g.

Specifically, the preset tristimulus calculation formula is:

Wherein, X is the red stimulus value in the tristimulus value, Y is the green stimulus value in the tristimulus value, Z is the blue stimulus value in the tristimulus value, and M is the preset conversion matrix.

Specifically, the preset Lab space conversion formula is:

Where L is the luminance component, a is the first color component, b'is the second color component, X1 is the preset first parameter, Y1 is the preset second parameter, and Z1 is the preset third parameter,

t is a real number.

Step S42: Extract the luminance component, the first color component and the second color component of the pixel according to the first weight, extract the luminance component, the first color component and the second color component of the pixel according to the second weight and the preset color difference calculation formula The color difference value of the first weight extraction pixel and the second weight extraction pixel is calculated as a weight parameter corresponding to the first weight extraction pixel.

Specifically, the preset formula for calculating the color difference value is:

Among them, L ₁ is the luminance component of the pixel extracted by the first weight, a ₁ is the first color component of the pixel extracted by the first weight, b′ ₁ is the second color component of the pixel extracted by the first weight, and L ₂ is the second weight extracted the luminance component of a pixel, a ₂ of the second weight extraction first color component pixel, b _'2 to the second weight extraction of the second color component pixel, ΔE is the first weight and the second weight extraction pixel extracting color pixels value.

Step S43. Repeat the above steps S41 and S42 until the acquisition of the weight parameters corresponding to all pixels in the next frame of image is completed.

Step S5: Select one of the pixels in the next frame of the image as the processing pixel. Convert the rgb digital value of the processed pixel to the color coordinate of the processed pixel in the chromatogram.

Specifically, the specific process of converting the rgb digital value of the processing pixel into the color coordinate of the processing pixel in the chromatogram in the step S5 is as follows: calculating the processing pixel's value based on the processing pixel's rgb digital value and a preset rgb optical value calculation formula rgb optical value, calculate the tristimulus value of the processing pixel according to the processing pixel's optical rgb value and the preset tristimulus value calculation formula, calculate the tristimulus value of the processing pixel according to the processing pixel's tristimulus value and the preset color coordinate calculation formula Color coordinates.

Specifically, the preset rgb optical value calculation formula and the preset tristimulus calculation formula used in step S5 are the same as the preset rgb optical value calculation formula and the preset tristimulus value calculation formula used in step S41.

Specifically, the preset color coordinate formula is:

Where u is the abscissa of the color coordinate in the chromatogram, and v is the ordinate of the color coordinate in the chromatogram.

Step S6: Determine the position of the color coordinate of the processing pixel in the color gamut space. If the color coordinate of the processing pixel is located in the first area A, for example, at point P(A) in FIG. 2, the color temperature value of the processing pixel is calculated according to the color coordinate of the processing pixel and the preset pixel color temperature calculation formula to determine the processing pixel Whether the color temperature value is one of multiple reference color temperatures, if so, the weight corresponding to the color temperature value of the processing pixel in the statistical table is increased by the weight parameter corresponding to the processing pixel, otherwise the color temperature value of the processing pixel and the weight corresponding to the processing pixel are increased The parameters are added to the statistical table as reference color temperatures and their corresponding weights. If the color coordinate of the processing pixel is located in the second area B, for example, at the point P(B) in FIG. 2, the line between this point and the reference point O and the boundary line between the first area A and the second area B The angle is α1, and the angle between the boundary between the first area A and the second area B and the boundary between the second area B and the third area C is β1, according to the point and reference corresponding to the color coordinates of the processed pixel The angle between the connection point O and the boundary between the first area A and the second area B is also α1, the weight parameter corresponding to the processing pixel and the preset first weight value calculation formula to calculate the weight value of the processing pixel, and The weight value is added to the weight corresponding to the largest one in the reference color temperature, namely 15000K, in the statistical table. If the color coordinate of the processing pixel is located in the third area C, for example, at the point P(C) in FIG. 3, the line between this point and the reference point O and the boundary line between the first area A and the third area C The angle is α2, and the angle between the boundary between the first area A and the third area C and the boundary between the second area B and the third area C is β2. At this time, the point and reference corresponding to the color coordinates of the processed pixel The angle between the line connecting point O and the boundary between the first area A and the third area C is α2, the weight parameter corresponding to the processing pixel and the preset second weight value calculation formula to calculate the weight value of the processing pixel, and The weight value is added to the weight corresponding to the smallest one of the reference color temperatures in the statistical table, that is, 1000K.

Specifically, the preset calculation formula of the pixel color temperature is: CT=-437×n ³ +3601×n ² -6861×n+5514.31. Among them, CT is the pixel color temperature value,

Specifically, the preset formula for calculating the first weight value is: γ1=(1-α1/β1)×k.

Among them, γ1 is the weight value of the processing pixel when the color coordinate of the processing pixel is in the second area, and α1 is the line between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary line between the first area and the second area Angle, β1 is the angle between the boundary between the first area and the second area and the boundary between the second area and the third area, and k is the weight parameter corresponding to the processed pixels.

Specifically, the preset formula for calculating the second weight value is: γ2=(1-α2/β2)×k.

Where γ2 is the weight value of the processing pixel when the color coordinate of the processing pixel is in the third zone, and α2 is the line between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary between the first zone and the third zone The angle, β2, is the angle between the boundary between the first and third regions and the boundary between the second and third regions.

Step S7. Repeat steps S5 and S6 until multiple pixels of the next frame of the image all execute steps S5 and S6.

Step S8. Multiply each reference color temperature in the statistical table by the corresponding weight, and divide the sum of the products of multiple reference color temperatures and corresponding weights by the sum of the weights corresponding to multiple reference color temperatures to obtain the image of the next frame. Color temperature value.

It should be noted that the image color temperature acquisition method of the present invention divides the color gamut space into the first area that can calculate the color temperature according to the pixel color temperature calculation formula, but cannot calculate the color temperature based on the pixel color temperature calculation formula, but has a second area of the image based on the image color temperature. And the third zone, where the second zone is the transition zone between cool and neutral colors, and the third zone is the transition zone between warm and neutral colors, and the color difference between the pixels at the same position in the two adjacent frames of image is calculated as The weight parameter of the pixels in a frame of image, to determine the position of the color coordinate of the pixel in the next frame of image, when it is in the first area, use the pixel color temperature formula to calculate the color temperature value of the pixel and add the weight of the color temperature value in the statistical table Corresponding weight parameter, when it is in the second area, use the positional relationship between the color coordinates of the pixel and the reference point and the weight parameter to calculate the weight value of the pixel and add it to the weight of the maximum reference color temperature in the statistical table. In the three zones, the pixel's color coordinate and the reference point's positional relationship and weight parameters are used to calculate the pixel's weight value and add it to the weight of the smallest reference color temperature in the statistical table. The change characteristic of the image of the adjacent frame obtains the color temperature of the image, so that the color temperature value of the obtained image is more accurate and matches the actual human eye perception.

In summary, the image color temperature acquisition method of the present invention divides the color gamut space into the first area, the second area, and the third area, and calculates the color difference value between pixels at the same position in the adjacent two frames of images as the post The weight parameter of the pixels in a frame of image, to determine the position of the color coordinate of the pixel in the next frame of image Corresponding weight parameter, when it is in the second area, use the positional relationship between the color coordinates of the pixel and the reference point and the weight parameter to calculate the weight value of the pixel and add it to the weight of the maximum reference color temperature in the statistical table. In the three zones, the pixel's color coordinates and the reference point's positional relationship and weight parameters are used to calculate the pixel's weight value and add it to the weight of the smallest reference color temperature in the statistical table. Combined with the weight to calculate the color temperature of the next frame image, it can be more accurate The color temperature of the acquired image.

As mentioned above, those of ordinary skill in the art can make various other corresponding changes and modifications according to the technical solutions and technical concepts of the present invention, and all such changes and modifications should fall within the protection scope of the claims of the present invention. .

Claims (15)

1. An image color temperature acquisition method includes the following steps:

   Step S1. Establish a statistical table; the statistical table includes a plurality of preset reference color temperatures and a plurality of weights corresponding to the plurality of reference color temperatures, respectively, the plurality of reference color temperatures increase sequentially, and the weights corresponding to the plurality of reference color temperatures are all equal Is 0;

   Step S2. Provide a chromatogram, divide the color gamut space in the chromatogram into the first zone, the second zone and the third zone connected in pairs; the boundary between the first zone and the second zone, the second zone and the third zone The boundary line of the zone and the boundary line of the third zone and the first zone converge at a reference point. The boundary line of the first zone and the second zone coincides with the iso-color temperature line corresponding to the largest reference color temperature among the multiple reference color temperatures. The first The boundary between the zone and the third zone coincides with the isochromatic line of the smallest reference color temperature among the multiple reference color temperatures, and the boundary between the second zone and the third zone is parallel to the y-axis of the chromatogram;

   Step S3, providing display data of two adjacent frames of images; each frame of images includes a plurality of pixels arranged in an array, and the display data of each frame of images includes a plurality of RGB digital values respectively corresponding to the plurality of pixels;

   Step S4: Use the display data of the two adjacent frames to calculate the weight parameters corresponding to the pixels of the next frame of image respectively. The weight parameters corresponding to the pixels in the i-th row and j-th column of the next frame of image are equal to the latter The color difference between the pixel in the i-th row and j-th column in the frame image and the pixel in the i-th row and j-th column in the previous frame image, i and j are both positive integers;

   Step S5: Select one of the pixels in the next frame of image as the processing pixel; convert the rgb digital value of the processing pixel into the color coordinate of the processing pixel in the chromatogram;

   Step S6: Determine the position of the color coordinate of the processing pixel in the color gamut space; if the color coordinate of the processing pixel is located in the first area, calculate the color temperature value of the processing pixel according to the color coordinate of the processing pixel and the preset pixel color temperature calculation formula, Determine whether the color temperature value of the processing pixel is one of multiple reference color temperatures, if it is, increase the weight corresponding to the color temperature value of the processing pixel in the statistical table by the weight parameter corresponding to the processing pixel, otherwise the color temperature value of the processing pixel and the processing The weight parameters corresponding to the pixels are added to the statistical table as the reference color temperature and their corresponding weights; if the color coordinates of the processed pixel are located in the second zone, the connection between the point corresponding to the color coordinate of the processed pixel and the reference point and the The angle between the boundary between the first zone and the second zone, the weight parameter corresponding to the processed pixel and the preset first weight value calculation formula calculate the weight value of the processed pixel, and add the weight value to the statistical table and the reference color temperature The largest one corresponds to the weight; if the color coordinate of the processing pixel is located in the third area, the angle between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary between the first area and the third area 1. The weight parameter corresponding to the processing pixel and the preset second weight value calculation formula calculate the weight value of the processing pixel, and add the weight value to the weight corresponding to the smallest one of the reference color temperatures in the statistical table;

   Step S7. Repeat steps S5 and S6 until multiple pixels of the next frame of the image all execute steps S5 and S6;

   Step S8. Multiply each reference color temperature in the statistical table by the corresponding weight, and divide the sum of the products of multiple reference color temperatures and corresponding weights by the sum of the weights corresponding to multiple reference color temperatures to obtain the image of the next frame. Color temperature value.
2. The method for acquiring the color temperature of an image according to claim 1, wherein the specific process of converting the rgb digital value of the processed pixel to the color coordinate of the processed pixel in the chromatogram in the step S5 is: according to the rgb digital value of the processed pixel and The preset rgb optical value calculation formula calculates the rgb optical value of the processing pixel, and calculates the tristimulus value of the processing pixel according to the processing pixel optical rgb value and the preset tristimulus value calculation formula, based on the tristimulus value and preset of the processing pixel The color coordinate calculation formula calculates the color coordinates of the pixels processed in the chromatogram.
3. The method for acquiring image color temperature according to claim 2, wherein the predetermined formula for calculating the rgb optical value is

   

   Where R is the red optical value in the rgb optical value, G is the green optical value in the rgb optical value, B is the blue optical value in the rgb optical value, r is the red digital value in the rgb digital value, and g is rgb The green digital value in the digital value, b is the blue digital value in the rgb digital value,

   

   Represents the value obtained by performing gamma transformation on r,

   

   Represents the value obtained by performing gamma transformation on b,

   

   Represents the value obtained by performing gamma transformation on g.
4. The method for acquiring image color temperature according to claim 3, wherein the preset formula for calculating the tristimulus value is

   

   Wherein, X is the red stimulus value in the tristimulus value, Y is the green stimulus value in the tristimulus value, Z is the blue stimulus value in the tristimulus value, and M is the preset conversion matrix.
5. The method for acquiring image color temperature according to claim 4, wherein the preset color coordinate formula is:

   

   Where u is the abscissa of the color coordinate in the chromatogram, and v is the ordinate of the color coordinate in the chromatogram.
6. The method for acquiring image color temperature according to claim 5, wherein the boundary between the first and second regions, the boundary between the second and third regions, and the boundary between the third and first regions in the chromatogram The coordinates of the reference points where the boundary lines converge are (0.332, 0.1858).
7. The method for acquiring the image color temperature according to claim 6, wherein the preset formula for calculating the pixel color temperature is: CT = -437×n ³ +3601×n ² -6861×n+5514.31;

   Among them, CT is the pixel color temperature value,

   
8. The method for acquiring image color temperature according to claim 1, wherein the preset formula for calculating the first weight value is: γ1=(1-α1/β1)×k;

   Among them, γ1 is the weight value of the processing pixel when the color coordinate of the processing pixel is in the second area, and α1 is the line between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary line between the first area and the second area Angle, β1 is the angle between the boundary between the first zone and the second zone and the boundary between the second zone and the third zone, and k is the weight parameter corresponding to the processed pixels;

   The preset second weight value calculation formula is: γ2=(1-α2/β2)×k;

   Where γ2 is the weight value of the processing pixel when the color coordinate of the processing pixel is in the third zone, and α2 is the line between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary between the first zone and the third zone The angle, β2, is the angle between the boundary between the first and third regions and the boundary between the second and third regions.
9. The method for acquiring image color temperature according to claim 1, wherein the chromatogram is a CIE1931 chromatogram;

   The smallest one of the reference color temperatures is 1000K; the largest one of the reference color temperatures is 15000K.
10. The method for acquiring image color temperature according to claim 4, wherein the step S4 is specifically:

    Step S41: Set one of the pixels in the next frame image as the first weight extraction pixel, and set the pixel number of the row and column in the previous frame image as the first weight extraction pixel in the next frame image. To extract pixels for the second weight, calculate the rgb optical value of the first weight extraction pixel according to the rgb digital value of the first weight extraction pixel and the preset rgb optical value calculation formula, and extract the rgb optical value and preset of the pixel according to the first weight The tristimulus value calculation formula calculates the tristimulus value of the first weight extraction pixel, and calculates the brightness component, the first color component and the first weight extraction pixel according to the tristimulus value of the first weight extraction pixel and the preset Lab space conversion formula The second color component, the rgb digital value of the extracted pixel according to the second weight and the preset rgb optical value calculation formula to calculate the rgb optical value of the second weight extracted pixel, according to the rgb optical value of the second weight and the preset tristimulus value The calculation formula calculates the tristimulus value of the second weight extraction pixel, and calculates the brightness component, the first color component and the second color component of the second weight extraction pixel according to the tristimulus value of the second weight extraction pixel and the preset Lab space conversion formula ;

    The preset Lab space conversion formula is:

    

    Where L is the luminance component, a is the first color component, b'is the second color component, X1 is the preset first parameter, Y1 is the preset second parameter, and Z1 is the preset third parameter,

    

    Step S42: Extract the luminance component, the first color component and the second color component of the pixel according to the first weight, extract the luminance component, the first color component and the second color component of the pixel according to the second weight and the preset color difference calculation formula Calculating the color difference value of the first weight extraction pixel and the second weight extraction pixel as the weight parameter corresponding to the first weight extraction pixel;

    The preset formula for calculating the color difference value is:

    

    Among them, L ₁ is the luminance component of the pixel extracted by the first weight, a ₁ is the first color component of the pixel extracted by the first weight, b′ ₁ is the second color component of the pixel extracted by the first weight, and L ₂ is the second weight extracted the luminance component of a pixel, a ₂ of the second weight extraction first color component pixel, b _'2 to the second weight extraction of the second color component pixel, ΔE is the first weight and the second weight extraction pixel extracting color pixels value;

    Step S43. Repeat the above steps S41 and S42 until the acquisition of the weight parameters corresponding to all pixels in the next frame of image is completed.
11. An image color temperature acquisition method includes the following steps:

    Step S1. Establish a statistical table; the statistical table includes a plurality of preset reference color temperatures and a plurality of weights corresponding to the plurality of reference color temperatures, respectively, the plurality of reference color temperatures increase sequentially, and the weights corresponding to the plurality of reference color temperatures are all equal Is 0;

    Step S2. Provide a chromatogram, divide the color gamut space in the chromatogram into the first zone, the second zone and the third zone connected in pairs; the boundary between the first zone and the second zone, the second zone and the third zone The boundary line of the zone and the boundary line of the third zone and the first zone converge at a reference point. The boundary line of the first zone and the second zone coincides with the iso-color temperature line corresponding to the largest reference color temperature among the multiple reference color temperatures. The first The boundary between the zone and the third zone coincides with the isochromatic line of the smallest reference color temperature among the multiple reference color temperatures, and the boundary between the second zone and the third zone is parallel to the y-axis of the chromatogram;

    Step S3, providing display data of two adjacent frames of images; each frame of images includes a plurality of pixels arranged in an array, and the display data of each frame of images includes a plurality of RGB digital values respectively corresponding to the plurality of pixels;

    Step S4: Use the display data of the two adjacent frames to calculate the weight parameters corresponding to the pixels of the next frame of image respectively. The weight parameters corresponding to the pixels in the i-th row and j-th column of the next frame of image are equal to the latter The color difference between the pixel in the i-th row and j-th column in the frame image and the pixel in the i-th row and j-th column in the previous frame image, i and j are both positive integers;

    Step S5: Select one of the pixels in the next frame of image as the processing pixel; convert the rgb digital value of the processing pixel into the color coordinate of the processing pixel in the chromatogram;

    Step S6: Determine the position of the color coordinate of the processing pixel in the color gamut space; if the color coordinate of the processing pixel is located in the first area, calculate the color temperature value of the processing pixel according to the color coordinate of the processing pixel and the preset pixel color temperature calculation formula, Determine whether the color temperature value of the processing pixel is one of multiple reference color temperatures, if it is, increase the weight corresponding to the color temperature value of the processing pixel in the statistical table by the weight parameter corresponding to the processing pixel, otherwise the color temperature value of the processing pixel and the processing The weight parameters corresponding to the pixels are added to the statistical table as the reference color temperature and their corresponding weights; if the color coordinates of the processed pixel are located in the second zone, the connection between the point corresponding to the color coordinate of the processed pixel and the reference point and the The angle between the boundary between the first zone and the second zone, the weight parameter corresponding to the processed pixel and the preset first weight value calculation formula calculate the weight value of the processed pixel, and add the weight value to the statistical table and the reference color temperature The largest one corresponds to the weight; if the color coordinate of the processing pixel is located in the third area, the angle between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary between the first area and the third area 1. The weight parameter corresponding to the processing pixel and the preset second weight value calculation formula calculate the weight value of the processing pixel, and add the weight value to the weight corresponding to the smallest one of the reference color temperatures in the statistical table;

    Step S7. Repeat steps S5 and S6 until multiple pixels of the next frame of the image all execute steps S5 and S6;

    Step S8. Multiply each reference color temperature in the statistical table by the corresponding weight, and divide the sum of the products of multiple reference color temperatures and corresponding weights by the sum of the weights corresponding to multiple reference color temperatures to obtain the image of the next frame. Color temperature value

    Wherein, the specific process of converting the rgb digital value of the processing pixel to the color coordinate of the processing pixel in the chromatogram in the step S5 is: calculating the rgb of the processing pixel according to the rgb digital value of the processing pixel and the preset rgb optical value calculation formula Optical value, calculate the tristimulus value of the processing pixel according to the optical rgb value of the processing pixel and the preset tristimulus value calculation formula, calculate the color of the processing pixel in the chromatogram according to the tristimulus value of the processing pixel and the preset color coordinate calculation formula coordinate;

    Wherein, the preset formula for calculating the first weight value is: γ1=(1-α1/β1)×k;

    Among them, γ1 is the weight value of the processing pixel when the color coordinate of the processing pixel is in the second area, and α1 is the line between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary line between the first area and the second area Angle, β1 is the angle between the boundary between the first zone and the second zone and the boundary between the second zone and the third zone, and k is the weight parameter corresponding to the processed pixels;

    The preset second weight value calculation formula is: γ2=(1-α2/β2)×k;

    Where γ2 is the weight value of the processing pixel when the color coordinate of the processing pixel is in the third zone, and α2 is the line between the point corresponding to the color coordinate of the processing pixel and the reference point and the boundary between the first zone and the third zone The angle, β2, is the angle between the boundary between the first and third regions and the boundary between the second and third regions.
12. The method for acquiring image color temperature according to claim 11, wherein the predetermined formula for calculating the RGB optical value is:

    

    Where R is the red optical value in the rgb optical value, G is the green optical value in the rgb optical value, B is the blue optical value in the rgb optical value, r is the red digital value in the rgb digital value, and g is rgb The green digital value in the digital value, b is the blue digital value in the rgb digital value,

    

    Represents the value obtained by performing gamma transformation on r,

    

    Represents the value obtained by performing gamma transformation on b,

    

    Represents the value obtained by performing gamma transformation on g.
13. The method for acquiring image color temperature according to claim 12, wherein the preset formula for calculating the tristimulus value is

    

    Wherein, X is the red stimulus value in the tristimulus value, Y is the green stimulus value in the tristimulus value, Z is the blue stimulus value in the tristimulus value, and M is the preset conversion matrix.
14. The image color temperature acquisition method according to claim 13, wherein the preset color coordinate formula is:

    

    Where u is the abscissa of the color coordinate in the chromatogram, and v is the ordinate of the color coordinate in the chromatogram.
15. The method for acquiring image color temperature according to claim 14, wherein the boundary between the first and second regions, the boundary between the second and third regions, and the boundary between the third and first regions in the chromatogram The coordinates of the reference points where the boundary lines converge are (0.332, 0.1858).

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