WO2020232812A1

WO2020232812A1 - Scene illuminant color temperature control method

Info

Publication number: WO2020232812A1
Application number: PCT/CN2019/095927
Authority: WO
Inventors: 饶洋
Original assignee: 深圳市华星光电半导体显示技术有限公司
Priority date: 2019-05-20
Filing date: 2019-07-15
Publication date: 2020-11-26
Also published as: CN110211062A

Abstract

Provided is a scene illuminant color temperature control method. The scene illuminant color temperature control method is used to correct an RGB value of an intelligent lamp so as to realize scene presentation of a color temperature between 1000K and 15000K. Moreover, the embodiments of the present invention provide a look-up table, obtained through calculation, of RGB values corresponding to various color temperatures so as to control an RGB digital input of an intelligent lamp, such that the efficiency requirement of a scene illuminant color temperature control system can be reduced, so as to quickly reproduce a required color temperature environment.

Description

Method for controlling color temperature of scene light source

Technical field

The present disclosure relates to the technical field of scene light source color temperature control, and more particularly to a method for controlling the color temperature of a scene light source corresponding to an image by using a smart lamp.

Background technique

The color temperature measurement unit is Kelvin Scale (K). The color temperature measurement standard is that the standard black body starts to be heated from physical absolute zero (minus 273°C), when it is 0°C, it is 273K. When the standard black body is heated to 800°C, the color temperature of the standard black body is about 1000K, which is red, and when heated to 5727°C, the color temperature is about 6000K. At this time, the color temperature of the standard black body is similar to the white light of the sun. If the standard black body is heated to more than 10000°C, the color temperature of the standard black body is about 10000K, which is blue-violet. It can be seen from this that the scene becomes blue when the color temperature is high, and the scene becomes red when the color temperature is low.

When the color temperature is less than 3300K, the light is mainly red, and the human eye generally feels warm and healthy. The color temperature is a neutral color temperature at 3300K-6000K, and the content of red, green, and blue light accounts for a certain proportion. At this time, the human eye usually feels comfortable, refreshing, and soft. When the color temperature is greater than 6000K, blue light accounts for a larger proportion, and the human eye usually feels cold and deep.

For scene lighting equipment, different light source color temperatures in the space will bring different feelings and atmospheres to the human eye. Therefore, if the scene lighting equipment can provide the light source color temperature corresponding to the current environmental requirements according to the suitable environment or atmosphere, Give users a sense of visual satisfaction.

technical problem

In order to solve the above-mentioned problems in the prior art, the purpose of the present disclosure is to provide a method for controlling the color temperature of a scene light source, which can meet the demand of the scene light source device to provide a light source color temperature corresponding to the current environmental requirements.

Technical solutions

In order to achieve the foregoing objective, the embodiments of the present disclosure provide a method for controlling the color temperature of a scene light source, and the method for controlling the color temperature of a scene light source includes:

Step 1: Calculate the RGB (Red, Green, Blue) values of the pixels of the currently displayed image frame;

Step 2: Convert the RGB value of the pixel into the corresponding xy value of the CIE 1931 color space;

Step 3: Determine where the xy value is located in the CIE 1931 color space. If the xy value is in the effective color temperature area, set it as the first color point, and perform step 4; Set as the second color point outside the effective area of the color temperature, and perform step 6;

Step 4: Calculate the color temperature value of the first color point, and execute step 5;

Step five, accumulate the color temperature value of the first color point into the color temperature statistical table, and execute step seven;

Step 6, calculate the color temperature value of the second color point, and execute step 7; and

Step 7: Calculate the image color temperature value according to the weight value of the color temperature value of the first color point and the weight value of the color temperature value of the second color point.

In the embodiment of the present disclosure, the boundary between the color temperature effective area and the non-color temperature effective area is the connection between the equal energy point (Equal Energy point) of the CIE 1931 color space and the standard blackbody radiation curve 15000K color temperature point and equal energy The connection between the point and the 1000K color temperature point of the standard blackbody radiation curve, the connection between the Equal Energy point of the CIE 1931 color space and the 15000K color temperature point of the standard blackbody radiation curve and the equal energy point and the Above the line connecting the 1000K color temperature point of the standard blackbody radiation curve is the effective area of the color temperature. In the CIE 1931 color space, the line connecting the middle energy point and the 15000K color temperature point of the standard blackbody radiation curve and the iso-energy point and the Below the line connecting the 1000K color temperature points of the standard blackbody radiation curve is the non-color temperature effective area, and the non-color temperature effective area is divided into a left area and a right area by a downward vertical line passing through the isoenergy point as a dividing line.

In the embodiment of the present disclosure, the step four of the method for controlling the color temperature of the scene light source further includes:

Substituting the corresponding xy value of the first color point in the CIE 1931 color space into a correlated color temperature formula to calculate the color temperature value (CT) of the first color point,

n=(x-0.332)/(y-0.1858),

CT=(-437×n ³ )+(3601×n ² )-(6861×n)+5514.31,

The color temperature value is accumulated to calculate the weight value of the first color point.

In the embodiment of the present disclosure, the sixth step of the method for controlling the color temperature of the scene light source further includes:

Calculate the connection between the second color point located in the left area of the non-color temperature effective area and the intermediate energy point of the CIE 1931 color space and the connection between the equal energy point and the 15000K color temperature point of the standard blackbody radiation curve The included angle α, the included angle β is the angle between the line connecting the iso-energy point and the 15000K color temperature point of the standard blackbody radiation curve and the downward vertical line passing through the iso-energy point;

Calculating the second color point weight value γ=1-(α/β) of the left area of the non-color temperature effective area;

The second color point weight value γ of the left region of the non-color temperature effective area is accumulated to be a weight value of 15000K color temperature.

Calculate the connection between the second color point in the right area of the non-color temperature effective area and the intermediate energy point of the CIE1931 color space and the connection between the equal energy point and the 1000K color temperature point of the standard blackbody radiation curve The included angle α, the included angle β is the angle between the line connecting the iso-energy point and the 1000K color temperature point of the standard blackbody radiation curve and the downward vertical line passing through the iso-energy point;

Calculating the second color point weight value γ=1-(α/β) in the right area of the non-color temperature effective area;

The second color point weight value γ of the right area of the non-color temperature effective area is accumulated to be a weight value of 1000K color temperature.

In the embodiment of the present disclosure, the method for controlling the color temperature of the scene light source further includes:

Step 8: Provide a look-up table (LUT) corresponding to RGB values of various color temperatures;

Step 9: Perform the steps 1 to 7 to calculate the corresponding color temperature values of a plurality of images;

Step 10: Based on the corresponding color temperature values of the plurality of images calculated in step 9, and query the corresponding color temperature values of the plurality of images based on the corresponding quick reference table of the RGB values corresponding to the various color temperatures in step 8 to obtain the corresponding RGB value;

Step eleven, output the RGB values corresponding to the plurality of images to the scene light source device to present the corresponding color temperature.

In the embodiment of the present disclosure, the color temperature range presented by the scene light source color temperature control method is between 1000K and 15000K.

In the embodiment of the present disclosure, the scene light source device is a smart lamp or a color display.

In the embodiment of the present disclosure, the number of the plurality of images is determined according to the needs of the user or the performance of the color temperature control system.

In the embodiment of the present disclosure, the method for controlling the color temperature of the scene light source is implemented using Qt programming.

In the embodiment of the present disclosure, the method for controlling the color temperature of the scene light source can cooperate with a dynamic movie to present the corresponding color temperature.

Beneficial effect

The beneficial effects brought by the embodiments of the present disclosure are: the embodiments of the present disclosure use the color temperature control method of the scene light source to correct the RGB value of the smart lamp, and realize the presentation of the scene with the color temperature between 1000K and 15000K. In addition, the embodiment of the present invention provides a quick reference table based on the calculated RGB values of various color temperatures to control the RGB digital input of the smart light, thereby reducing the performance requirements of the scene light source color temperature control system, and quickly reproducing the desired color temperature environment .

Description of the drawings

In order to explain the embodiments or the technical solutions in the prior art more clearly, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are merely inventions For some embodiments, those of ordinary skill in the art can obtain other drawings based on these drawings without creative work.

FIG. 1 is a flowchart of the steps of a method for controlling the color temperature of a scene light source provided by an embodiment of the disclosure.

FIG. 2 is a schematic diagram of color temperature division provided by an embodiment of the disclosure.

Figure 3 is a color temperature statistical table provided by an embodiment of the disclosure.

FIG. 4 is a corresponding table of RGB values corresponding to various color temperatures provided by the embodiments of the disclosure.

FIG. 5 is a schematic diagram of a scene color temperature control interface provided by an embodiment of the disclosure.

FIG. 6 is a schematic diagram of a scene color temperature presentation method provided by an embodiment of the disclosure.

Embodiments of the invention

The reference to "embodiment" in the specific implementation means that a specific feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present disclosure. The same terms appearing in different positions in the specification are not necessarily limited to the same implementation manner, but should be understood as implementation manners independent or alternative to other embodiments. Under the enlightenment of the technical solutions disclosed in the embodiments provided in this disclosure, those of ordinary skill in the art should understand that the embodiments described in this disclosure may have other technical solution combinations or variations that conform to the concept of the disclosure.

The description of the following embodiments refers to the attached drawings to illustrate specific embodiments that the present disclosure can be implemented. Directional terms mentioned in this disclosure, such as [up], [down], [front], [rear], [left], [right], [inside], [outside], [side], [vertical] , [Horizontal], etc., are only for reference to the direction of the attached drawings. Therefore, the directional terms used are used to illustrate and understand the present disclosure, rather than to limit the present invention.

First, the embodiment of the present invention will be described with the content illustrated in Figures 1 and 2. Figure 1 is a flow chart of the steps of a method for controlling the color temperature of a scene light source provided by an embodiment of the present invention, and Figure 2 is an embodiment of the present invention according to the CIE 1931 color space. (CIE 1931 color spaces) provides a schematic diagram of color temperature zones. The correlation chromaticity coordinate xy calculation method of CIE1931 color space is:

Step 1: Calculate the optical red (Red, R), green (Green, G), blue (Blue, B) parameter values according to the following formula (γ value can be determined according to the specific display characteristics):

Step 2: Calculate the tristimulus value XYZ according to the following formula (M is the conversion matrix of the corresponding display):

Step 3: Calculate the chromaticity coordinate xy according to the following formula:

The different color points or colors on the color temperature division diagram in FIG. 2 represent different color temperature values, and the color points or colors on the Correlated Color Temperature (CCT) curve have the same color temperature characteristics. In area A in Figure 2, the color temperature is calculated according to the correlated color temperature formula:

n=(x-0.332)/(y-0.1858);

CT=(-437×n ³ )+(3601×n ² )-(6861×n)+5514.31; (CT represents Color Temperature)

In the color temperature zoning diagram, there are some areas B and C where the color temperature cannot be calculated by the correlated color temperature formula. Area B is the transition area of cool and neutral colors, and area C is the transition area of warm and neutral colors. Area B and area C cannot be calculated. The color temperature has an effect on the tone of the image color temperature. The dividing line between area A and area B is roughly the line between point O (Equal Energy point) in Figure 2 and the 15000K color temperature point of the standard blackbody radiation curve. The dividing line between area A and area C is roughly the line between point O and the standard The line connecting the 1000K color temperature point of the black body radiation curve, the area B and the area C are divided by the downward vertical line passing through the O point.

The following describes the flow of steps of the method for controlling the color temperature of a scene light source according to an embodiment of the present invention in conjunction with FIG. 1.

Step 102: Calculate the pixel RGB value of the currently displayed image frame.

Step 104: Convert the pixel RGB values into RGB optical values through Gamma conversion, convert the RGB optical values into XYZ tristimulus values through the TM matrix of the display, and then convert the XYZ tristimulus values into CIE 1931 color space xy value.

Step 106: determining the pixel values xy color point which partitions, if the A region xy-values, color temperature compared with the effective area, the color point P _A is set, step 108 is performed; if xy-values in the B region or C region, was If the color temperature is outside the effective area, set the color point P _B or P _C , and go to step 112.

Step 108: color point P _A color temperature based on the correlation color temperature value calculation formula as follows,

n=(xP _A -0.332)/(yP _A -0.1858)

CT=(-437×n ³ )+(3601×n ² )-(6861×n)+5514.31

.

Step 110: Accumulate the color temperature value to calculate the weight value to the CT value in the color temperature statistical table as shown in FIG. 3, that is, VCT=VCT+1.

Step 112: If the value of xy in the B region, set the color point P _B, P _B is calculated based on the color point CCT CCT value following formula,

Calculate the angle α between the line connecting the color point P _B to the point O and the 15000K color temperature line in Figure 2, and the angle β is the angle between the 15000K color temperature line and the vertical line passing through the O point;

Calculate the weight value γ=1-(α/β);

The cumulative weight value γ reaches the 15000K color temperature in the color temperature statistics table, that is, V15000=V15000+γ.

If the value of xy region located in the C, P _C is set to the color point, the color point PC is calculated based on the following CCT CCT value formula,

Calculating the angle α color point O to the point P _C 1000K color temperature in connection with the line of FIG. 2, the color temperature of 1000K angle β is the angle from a vertical line through the point O;

Calculate the weight value γ=1-(α/β);

The cumulative weight value γ reaches the 1000K color temperature in the color temperature statistics table, that is, V1000=V1000+γ.

Step 120: Calculate the image color temperature value CT _img based on the correlated color temperature weight formula combined with the weight:

The calculated image color temperature value CT _{img is} compared with the look-up table to obtain the corresponding RGB value, and the RGB value configuration corresponding to the look-up table is output to the smart light to achieve the scene color temperature reproduction effect.

4 to 6 illustrate an embodiment of the present invention using software programming to control the color temperature of a scene presented by a smart light to illustrate the steps of the method for controlling the color temperature of a scene light source using a smart lamp to present the color temperature of the scene.

Step 202: In the RGB mode of the smart light, adjust the RGB three-channel ratio, and use the color analyzer to measure the xy coordinates of the standard color temperature to achieve the required color temperature of each gear between 1000K-15000K, and record the corresponding color temperature The RGB value is made into a corresponding quick look-up table (Look-Up Table, LUT) corresponding to the RGB value of various color temperatures as shown in FIG. 4. The color analyzer can use the color analyzer model CA310 manufactured by Konica Minolta

Step 204: Calculate the corresponding color temperature values of the plurality of images based on the method of obtaining the image color temperature based on the Correlated Color Temperature (CCT) curve and the color temperature partition. The number of multiple images here can be determined according to user requirements or the design requirements or performance of the color temperature control system.

Step 206: As shown in Figure 5, the user interface is programmed based on software to control the display of multiple images, combined with the color temperature values calculated in step 204, and based on step 202, query the RGB corresponding to various color temperatures as shown in Figure 4 The corresponding quick lookup table of the value to obtain the corresponding RGB value. Software programming can use Qt programming or other programming. The user can select images corresponding to various color temperatures among the plurality of images, so that when the color temperature of the scene is presented, it can correspond to the image selected by the user.

Step 208: Output the final RGB value to the smart light, so that the smart light realizes the scene color temperature reproduction according to the corresponding RGB value.

Please refer to FIG. 6, which is a schematic diagram of a scene color temperature presentation method provided by an embodiment of the present invention. The method for controlling the color temperature of a scene light source provided by an embodiment of the present invention can control the smart lamp to present the required scene color temperature according to the corresponding RGB value. In addition, the color display can also be controlled to display images corresponding to the color temperature of the desired scene according to the corresponding RGB values, so as to correspond to the color temperature of the light source required by the current environment, so that the user is more immersive in the process of watching images or movies.

In the embodiment of the present invention, the color temperature control method of the scene light source is used to correct the RGB value of the smart lamp, so as to realize the scene presentation with the color temperature between 1000K and 15000K. In addition, the embodiment of the present invention provides a quick reference table based on the calculated RGB values of various color temperatures to control the RGB digital input of the smart light, thereby reducing the performance requirements of the scene light source color temperature control system, and quickly reproducing the desired color temperature environment .

To sum up, although the present disclosure has disclosed the above in preferred embodiments, the above preferred embodiments are not intended to limit the present invention. Those of ordinary skill in the art, without departing from the spirit and scope of the present disclosure, will derive each Such changes and changes are all covered by the protection scope of the present invention defined by the claims.

Claims

A method for controlling the color temperature of a scene light source, which includes:

Step 1: Calculate the RGB (Red, Green, Blue) values of the pixels of the currently displayed image frame;

Step 2: Convert the RGB value of the pixel into the corresponding xy value of the CIE 1931 color space;

Step 3: Determine where the xy value is located in the CIE 1931 color space. If the xy value is in the effective color temperature area, set it as the first color point, and perform step 4; Set as the second color point outside the effective area of the color temperature, and perform step 6;

Step 4: Calculate the color temperature value of the first color point, and execute step 5;

Step five, accumulate the color temperature value of the first color point into the color temperature statistical table, and execute step seven;

Step 6, calculate the color temperature value of the second color point, and execute step 7; and

Step 7: Calculate the image color temperature value according to the weight value of the color temperature value of the first color point and the weight value of the color temperature value of the second color point.
The method for controlling the color temperature of a scene light source according to claim 1, wherein the boundary between the effective color temperature area and the non-color temperature effective area is the CIE 1931 color space equal energy point (Equal Energy point) and the standard black body radiation curve 15000K color temperature point The connection between the equal energy point and the 1000K color temperature point of the standard blackbody radiation curve, the connection between the Equal Energy point in the CIE 1931 color space and the 15000K color temperature point of the standard blackbody radiation curve and Above the line connecting the iso-energy point and the 1000K color temperature point of the standard blackbody radiation curve is the effective color temperature area. The connection line between the mid-energy point in the CIE 1931 color space and the 15000K color temperature point of the standard blackbody radiation curve and the Below the line connecting the iso-energy point and the 1000K color temperature point of the standard blackbody radiation curve is the non-color temperature effective area. The non-color temperature effective area is divided into a left area and a right area by a downward vertical line passing through the iso-energy point. area.
The method for controlling the color temperature of a scene light source according to claim 2, wherein the step four further comprises: substituting the corresponding xy value of the first color point in the CIE 1931 color space into a correlated color temperature formula to calculate the first color Point's color temperature (CT),

n=(x-0.332)/(y-0.1858),

CT=(-437×n 3 )+(3601×n 2 )-(6861×n)+5514.31,

The color temperature value is accumulated to calculate the weight value of the first color point.
The method for controlling the color temperature of a scene light source according to claim 2, wherein the step 6 further comprises: calculating the connection line from the second color point in the left area of the non-color temperature effective area to the middle energy point in the CIE1931 color space The angle α between the iso-energy point and the 15000K color temperature point of the standard blackbody radiation curve, and the angle β is the connecting line between the iso-energy point and the 15000K color temperature point of the standard blackbody radiation curve and passes through the The angle between the iso-energy point and the downward vertical line;

Calculating the second color point weight value γ=1-(α/β) in the left area of the non-color temperature effective area; and

The second color point weight value γ of the left area of the non-color temperature effective area is accumulated to be a weight value of 15000K color temperature.
The method for controlling the color temperature of a scene light source according to claim 2, wherein the step 6 further comprises: calculating a connection line from the second color point in the right area of the non-color temperature effective area to the medium energy point in the CIE1931 color space The angle α between the iso-energy point and the 1000K color temperature point of the standard blackbody radiation curve, and the angle β is the connecting line between the iso-energy point and the 1000K color temperature point of the standard blackbody radiation curve. The angle between the iso-energy point and the downward vertical line;

Calculating the second color point weight value γ=1-(α/β) in the right area of the non-color temperature effective area;

The second color point weight value γ of the right area of the non-color temperature effective area is accumulated to a weight value of 1000K color temperature.
8. The method for controlling the color temperature of a scene light source according to claim 1, wherein the color temperature range presented by the method for controlling the color temperature of the scene light source is between 1000K and 15000K.
The method for controlling the color temperature of a scene light source according to claim 1, wherein the method for controlling the color temperature of the scene light source is implemented by Qt programming.
The method for controlling the color temperature of a scene light source according to claim 1, wherein the method for controlling the color temperature of the scene light source can cooperate with a dynamic movie to present a corresponding color temperature.
The method for controlling the color temperature of a scene light source according to claim 1, wherein the method for controlling the color temperature of the scene light source further comprises:

Step 8: Provide a look-up table (LUT) corresponding to RGB values of various color temperatures;

Step 9: Perform the steps 1 to 7 to calculate the corresponding color temperature values of a plurality of images;

Step 10: Based on the corresponding color temperature values of the plurality of images calculated in step 9, and query the corresponding color temperature values of the plurality of images based on the corresponding quick reference table of the RGB values corresponding to the various color temperatures in step 8 to obtain the corresponding RGB Value; and

Step eleven, output the RGB values corresponding to the plurality of images to the scene light source device to present the corresponding color temperature.
9. The method for controlling the color temperature of a scene light source according to claim 9, wherein the color temperature range presented by the method for controlling the color temperature of the scene light source is between 1000K and 15000K.
The method for controlling the color temperature of a scene light source according to claim 9, wherein the scene light source device is a smart light.
9. The method for controlling the color temperature of a scene light source according to claim 9, wherein the scene light source device is a color display.
9. The method for controlling the color temperature of a scene light source according to claim 9, wherein the number of the plurality of images is determined according to the needs of the user.
9. The method for controlling the color temperature of a scene light source according to claim 9, wherein the number of the plurality of images is determined according to the performance of the color temperature control system.
9. The method for controlling the color temperature of a scene light source according to claim 9, wherein the method for controlling the color temperature of the scene light source is implemented using Qt programming.
9. The method for controlling the color temperature of a scene light source according to claim 9, wherein the method for controlling the color temperature of the scene light source can cooperate with a dynamic movie to present a corresponding color temperature.