CN105578166B - A kind of colour temperature determines method and device - Google Patents

Abstract

The present invention provides a method and device for determining color temperature, the method comprising: counting the white balance gains of any two primary colors of images of a target gray object collected under target light sources of at least three different color temperatures, and determining the The relationship curve between white balance gain and color temperature; wherein, the target light source is a light source satisfying black body radiation; the equicorrelated color temperature line in the CIE chromaticity diagram is mapped to the relationship curve between white balance gain and color temperature to calibrate each The iso-correlated color temperature line corresponding to the color temperature of the image of the target gray object collected under the target light source; according to the white balance gain of the image to be detected and the iso-correlated color temperature line, determine the color temperature corresponding to the image to be detected. The applicability and accuracy of color temperature determination can be improved by applying the embodiments of the present invention.

Description

Method and device for determining color temperature

technical field

The present invention relates to the technical field of image processing, in particular to a method and device for determining color temperature.

Background technique

Color temperature is an attribute representing the spectral composition of the light source. In the spectrum, the short-wave components have more high color temperature, the light is blue-green, and the long-wave components have more low color temperature, and the image is reddish-yellow.

The image acquisition device equipped with an image sensor realizes the acquisition of color images through the photoelectric signal conversion of the three channels R (Red, red), G (Green, green), and B (Blue, blue). The intensities of the R, G, and B color components are different, the transmission rates of the three color components of the R, G, and B color components are different, and the conversion ratios of different photoelectric conversion devices to different intensity color components are different, which may cause image acquisition equipment The electrical signal strength of the final color image is different from the color of the object itself. For example, a white object in the actual scene is yellowish in a low color temperature environment and blue in a high color temperature environment, while the output of a photoelectric conversion device with better green light sensitivity The image is greenish, that is, the color of the image captured by the image acquisition device is affected by the color temperature, and the color needs to be restored according to the color temperature. Therefore, color temperature estimation plays an important role in the image acquisition system.

Contents of the invention

The invention provides a method and device for determining color temperature to improve the applicability and accuracy of determining color temperature.

According to the first aspect of the embodiments of the present invention, a method for determining color temperature is provided, including:

Statistics of the white balance gains and corresponding color temperatures of any two of the three primary colors of images of the target gray object collected under target light sources of at least three different color temperatures, and determining the relationship curve between the white balance gain and the color temperature; wherein, The target light source is a light source satisfying blackbody radiation;

Map the isocorrelated color temperature line in the CIE chromaticity diagram of the International Commission on Illumination to the relationship curve between the white balance gain and the color temperature, so as to calibrate the isocorrelated color temperature line corresponding to the color temperature of the image of the target gray object collected under each target light source ;

The color temperature corresponding to the image to be detected is determined according to the white balance gain of the image to be detected and the iso-correlated color temperature line.

According to a second aspect of the embodiments of the present invention, there is provided a device for determining color temperature, including:

The statistical unit is used to count the white balance gain of any two primary colors in the three primary colors of the image of the target gray object collected under at least three target light sources with different color temperatures; wherein, the target light source is a light source that satisfies black body radiation;

a first determining unit, configured to determine the relationship curve between the white balance gain and the color temperature;

A calibration unit, configured to map the isocorrelated color temperature line in the CIE chromaticity diagram of the International Commission on Illumination to the relationship curve between the white balance gain and the color temperature, so as to calibrate the color temperature corresponding to the image of the target gray object collected under each target light source The isocorrelated color temperature line;

The second determination unit is configured to determine the color temperature corresponding to the image to be detected according to the white balance gain of the image to be detected and the iso-correlated color temperature lines.

Applying the embodiment of the present invention, by counting the white balance gains of any two of the three primary colors of the image of the target gray object collected under at least three target light sources with different color temperatures, the relationship curve between the white balance gain and the color temperature is determined, and Map the equicorrelated color temperature lines in the CIE chromaticity diagram to the relationship curve between the white balance gain and the color temperature to calibrate the equicorrelated color temperature lines corresponding to the color temperature of the image of the target gray object collected under each target light source, and then according to The white balance gain and equal correlation color temperature line of the image to be detected can determine the corresponding color temperature of the image to be detected. When the light source in the image acquisition scene does not meet the black body radiation, the color temperature can still be determined accurately, which improves the applicability and reliability of the color temperature determination. accuracy.

Description of drawings

Fig. 1 is a schematic flowchart of a color temperature determination method provided by an embodiment of the present invention;

2A is a schematic diagram of a relationship curve between white balance gain and color temperature provided by an embodiment of the present invention;

2B is a schematic diagram of a relationship curve between white balance gain and color temperature in a three-dimensional coordinate space provided by an embodiment of the present invention;

Fig. 2C is a schematic diagram of equicorrelated color temperature lines in a CIE chromaticity diagram;

FIG. 2D is a schematic diagram of interpolation of the relationship curve between white balance gain and color temperature provided by an embodiment of the present invention;

Fig. 2E is a schematic diagram of a calibrated iso-correlated color temperature line provided by an embodiment of the present invention;

Fig. 3 is a schematic flowchart of another method for determining color temperature provided by an embodiment of the present invention;

Fig. 4 is a schematic structural diagram of a color temperature determination device provided by an embodiment of the present invention;

Fig. 5 is a schematic structural diagram of another color temperature determination device provided by an embodiment of the present invention;

Fig. 6 is a schematic structural diagram of another color temperature determination device provided by an embodiment of the present invention;

Fig. 7 is a schematic structural diagram of another device for determining color temperature provided by an embodiment of the present invention.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, and to make the above-mentioned purposes, features and advantages of the embodiments of the present invention more obvious and understandable, the following describes the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings For further detailed explanation.

Please refer to FIG. 1. FIG. 1 is a schematic flowchart of a color temperature determination method provided by an embodiment of the present invention. As shown in FIG. 1, the color temperature determination method may include the following steps:

Step 101. Count the white balance gains of any two of the three primary colors of the image of the target gray object collected under at least three target light sources with different color temperatures, and determine the relationship curve between the white balance gain and the color temperature, wherein the target The light source is a light source satisfying black body radiation.

In the embodiment of the present invention, the above method may be applied to an image acquisition device (such as a camera, a video camera, etc.) configured with an image sensor (such as a digital image sensor). For ease of description, an image acquisition device is used as an example for the execution of the above method.

In the embodiment of the present invention, the target gray object does not specifically refer to a certain fixed gray object, but may refer to any gray object used to establish an isocorrelated color temperature line model; wherein, gray refers to a color with a saturation of 0 .

Preferably, the target gray object can be a standard gray card.

In the embodiment of the present invention, the image acquisition device can acquire the image data of the target gray object under at least three light sources with different color temperatures satisfying black body radiation (hereinafter referred to as the target light source), and calculate the acquired image data of the target light source with different color temperatures. The white balance gain of any two of the three primary colors of the image data of the target gray object.

Wherein, the white balance gain of the image data includes the gains of the R, G, and B components required for white balance correction of the image: RGain (R gain), GGain (G gain), and BGain (B gain), which can be used as a In the selected embodiment, the gains of the three components can be calculated by the following formulas:

Among them, avgR(i), avgG(i), and avgB(i) are the average values of the R, G, and B components of each pixel in the image data of the target gray object collected under the target light source of each color temperature, i Represents target light sources of different color temperatures.

Wherein, since in this embodiment, the G gain is a constant value, therefore, the corresponding white balance gain and Color temperature curve.

However, it is worth noting that, in the embodiment of the present invention, the calculation method of the white balance gains of the above three primary colors is only a specific example of the technical solution provided by the embodiment of the present invention, rather than limiting the protection scope of the present invention. For example, in the embodiment of the present invention, the gains of the three components can also be calculated by the following formulas:

Correspondingly, in this case, since the R gain is a constant value, it is possible to determine the corresponding white balance gain and Color temperature curve.

Similarly, in the embodiment of the present invention, the corresponding white balance gain and color temperature relationship curve can also be determined according to the white balance gain of the G component and the R component in the three primary colors of the image of the target gray object collected, which is specifically implemented in This will not be repeated here.

For the convenience of description, the following takes the white balance gain of the R component and the B component in the three primary colors of the collected image of the target gray object as an example to determine the relationship curve between the corresponding white balance gain and color temperature.

In the embodiment of the present invention, the color temperature of the target light source can be measured by a color temperature measuring device (such as a color temperature meter).

In the embodiment of the present invention, the image acquisition device counts any two of the three primary colors of the image of the target gray object collected under the target light sources of different color temperatures (in the embodiment of the present invention, the R component and the B component are taken as an example) After specifying the white balance gain, the relationship curve between the white balance gain and the color temperature can be determined.

As an optional implementation manner, determining the relationship curve between white balance gain and color temperature may include the following steps:

11), according to the white balance gain (ie RGain, BGain) of the above-mentioned two primary colors of the image collected under the target light source of each different color temperature and the corresponding color temperature, the white balance gain (ie RGain and BGain) of the two primary colors is used respectively BGain) determines the corresponding calibration point in the coordinate system of horizontal and vertical coordinates;

12) Perform curve fitting on the calibration points to determine the relationship curve between the white balance gain and the color temperature.

In this embodiment, after the image acquisition device counts the white balance gains of the images collected under the target light sources with different color temperatures, the image acquisition device can calculate the RGain and BGain of the images collected under the target light sources with different color temperatures. Determine the corresponding calibration point (or white balance correction position) in the coordinate system with RGain as the abscissa and BGain as the ordinate, and perform curve fitting on each calibration point to determine the relationship between white balance gain and color temperature. Its schematic diagram can be as shown in Figure 2A (wherein Tc is color temperature); Wherein, the schematic diagram of the relationship curve between white balance gain and color temperature in the three-dimensional coordinate system with RGain, BGain and color temperature as coordinate axes can be as shown in Figure 2B, The relationship curve between white balance gain and color temperature shown in Figure 2A is the projection of the relationship curve shown in Figure 2B in a coordinate system with RGain and BGain as the horizontal and vertical coordinates respectively, and this paper is based on the relationship curve shown in Figure 2A Correlated color temperature line model.

Step 102: Map the isocorrelated color temperature lines in the CIE chromaticity diagram to the relationship curve between white balance gain and color temperature, so as to calibrate the isocorrelated color temperature lines corresponding to the color temperature of the image of the target gray object collected under each target light source.

In the embodiment of the present invention, after the image acquisition device determines the relationship curve between the white balance gain and the corresponding color temperature of the image of the target gray object collected under the target light sources of different color temperatures, it can further calibrate the target gray objects collected under the target light sources. Equicorrelated color temperature lines corresponding to the color temperature of the image of the object, so as to establish a corresponding equicorrelated color temperature line model.

Specifically, each target can be calibrated according to the slope of the equal-correlated color temperature line at each color temperature in the CIE (International Commission on illumination, International Commission on Illumination) 1960UCS chromaticity diagram (a standard chromaticity diagram, hereinafter referred to as the CIE chromaticity diagram). The slope of the equal-correlated color temperature line corresponding to the color temperature of the image of the target gray object collected under the light source. Among them, the equicorrelated color temperature lines in the CIE chromaticity diagram can be shown in Figure 2C, and the horizontal and vertical coordinates of the CIE chromaticity diagram correspond to and

Among them, for the color temperature existing in the CIE chromaticity diagram, the slope of the iso-correlated color temperature line of the color temperature in the CIE chromaticity diagram is determined as the equi-correlated color temperature line of the color temperature in the above-mentioned relationship curve between white balance gain and color temperature The slope of;

For a color temperature that does not exist in the CIE chromaticity diagram, determine the equicorrelated color temperature line of the color temperature according to the slope of the equicorrelated color temperature lines of two adjacent color temperatures existing in the CIE chromaticity diagram in the CIE chromaticity diagram The slope in the relationship curve between the above-mentioned white balance gain and color temperature; among them, one of the two color temperatures adjacent to the color temperature is higher than the color temperature, and the other is lower than the color temperature; the slope of the equal-correlated color temperature line and the size of the color temperature satisfy monotonicity (ie monotonically increasing or monotonically decreasing as the color temperature increases).

For example, assuming that the CIE chromaticity diagram includes color temperatures of 10000K, 6000K and 4000K, and the corresponding color temperatures of the images of the target gray object collected under each target light source are 10000K, 7500K and 6000K respectively, then the target gray object collected under the target light source The slopes of the equi-correlated color temperature lines corresponding to the color temperature of 10000K and 6000K corresponding to the image of the object can be determined directly from the slopes of the equi-correlated color temperature lines of the color temperature 10000K and 6000K in the above chromaticity diagram, while the slope of the equi-correlated color temperature line of the color temperature of 7500K is It can be determined according to the slope of the two color temperatures (10000K and 6000K) adjacent to the color temperature (7500K) in the CIE chromaticity diagram. For example, assuming that the angle corresponding to the slope of the equi-correlated color temperature line with a color temperature of 10000K in the CIE chromaticity diagram is A1, and the angle corresponding to the slope of the equi-correlated color temperature line with a color temperature of 6000K in the CIE chromaticity diagram is A2, then the color temperature of a color temperature of 7500K is The angle corresponding to the slope of the correlated color temperature line in the CIE chromaticity diagram can be: A2+(A2-A1)*(7500K-6000K)/(10000K-6000K), and then, according to this angle, the color temperature 6000K can be determined at the above white balance gain The slope in a curve versus color temperature. Among them, the isocorrelated color temperature lines of 6000K, 7500K, and 10000K color temperatures increase sequentially in the CIE chromaticity diagram and the above-mentioned relationship curve between white balance gain and color temperature.

Step 103: Determine the color temperature corresponding to the image to be detected according to the white balance gain and the iso-correlated color temperature line of the image to be detected.

In the embodiment of the present invention, the image to be detected may be any frame of image collected by the image collection device.

When the image acquisition device needs to determine the color temperature corresponding to the image to be detected, the image acquisition device can calculate the white balance gain of the image to be detected, and determine the image to be detected according to the white balance gain of the image to be detected and the above-mentioned correlated color temperature line corresponding color temperature. Wherein, the color temperature corresponding to the image to be detected is the color temperature of the light source of the scene where the image acquisition device collects the image to be detected.

As an optional implementation, in the above step 103, determining the color temperature corresponding to the image to be detected according to the white balance gain and the isocorrelated color temperature line of the image to be detected may include the following steps:

21) According to the white balance gains (i.e. RGain and BGain) of the above two primary colors of the image to be detected, the corresponding determination in the coordinate system with the white balance gains (RGain and BGain) of the two primary colors as the horizontal and vertical coordinates respectively target position;

22), according to the distance from the target position to two adjacent equi-correlated color temperature lines, and the color temperature corresponding to the adjacent two equi-correlated color temperature lines, determine the corresponding color temperature of the image to be detected; wherein, the adjacent two equi-correlated color temperature lines Correlated color temperature lines are located on either side of the target location.

In this embodiment, for any captured image, the image acquisition device can perform white balance processing on the image to obtain the RGain and BGain of the image, and then in the coordinates with RGain as the abscissa and BGain as the ordinate In the system, determine the corresponding target position.

Further, the image acquisition device can traverse the above equi-correlated color temperature lines to obtain two adjacent equi-correlated color temperature lines corresponding to the target position, that is, the two equi-correlated color temperature lines located on both sides of the target position and closest to the target position . The image acquisition device can calculate the distance from the target position to the two adjacent equi-correlated color temperature lines, and then according to the distance from the target position to the two adjacent equi-correlated color temperature lines, and the corresponding Color temperature, determine the color temperature corresponding to the image to be detected.

As an optional implementation, in the embodiment of the present invention, the image to be detected is determined according to the distance from the target position to two adjacent equi-correlated color temperature lines, and the color temperature corresponding to the two adjacent equi-correlated color temperature lines The corresponding color temperature can be realized by the following formula:

Among them, TcCur is the color temperature corresponding to the image to be detected, TcLf and TcRt are the color temperatures corresponding to the two adjacent equi-correlated color temperature lines, TcRt>TcLf, distLf and distRt are the distance from the target position to the adjacent two equi-correlated color temperature lines distance.

In the embodiment of the present invention, after the image acquisition device determines the color temperature corresponding to the captured image, it can perform color restoration and correction according to the color temperature, and the specific implementation of the embodiment of the present invention will not be repeated.

It is worth noting that, in the embodiment of the present invention, the calibration of the iso-correlated color temperature lines described in steps 101 to 102 can be performed only once in the whole process, and based on the parameters of the iso-correlated color temperature lines, the image acquisition device can perform any Step 103 is performed multiple times, that is, the image acquisition device can always use the parameters of the correlated color temperature line to determine the color temperature of subsequent acquired images. It is not necessary to re-determine the equi-correlated color temperature line every time the color temperature is determined.

Further, considering that the image acquisition equipment uses different hardware devices such as filters, the color temperature of the captured images may also be different. Therefore, for any type of image acquisition equipment, it is necessary to target different hardware used by the image acquisition equipment. Devices (such as filters and other hardware devices that affect the color temperature of the collected images) calibrate different equi-correlated color temperature lines, and the specific implementation thereof will not be repeated here.

It can be seen that in the method flow shown in Figure 1, the relationship curves between the white balance gain and the corresponding color temperature of the image of the target gray object collected under at least three target light sources with different color temperatures are counted, and the CIE chromaticity diagram The iso-correlated color temperature line is mapped to the relationship curve between white balance gain and color temperature to calibrate the iso-correlated color temperature line corresponding to the color temperature of the image of the target gray object collected under each target light source, and then determine the color temperature of the image to be detected When , the color temperature of the image to be detected can be determined according to the white balance gain of the image to be detected and the isocorrelated color temperature line. When the light source in the image acquisition scene does not meet the black body radiation, the color temperature can still be determined accurately, which improves the color temperature determination. applicability and accuracy.

Please refer to FIG. 3. FIG. 3 is a schematic flowchart of another color temperature determination method provided by an embodiment of the present invention. As shown in FIG. 3, the color temperature determination method may include the following steps:

Step 301 , counting the white balance gains of the R component and the B component of the image of the target gray object collected under at least three target light sources with different color temperatures.

Step 302: According to the RGain, BGain and the corresponding color temperature of the image of the target gray object collected under the target light sources with different color temperatures, determine the corresponding calibration points in the coordinate system with RGain and BGain as the horizontal and vertical coordinates respectively.

Step 303 , performing curve fitting on the calibration points to determine a relationship curve between white balance gain and color temperature.

In the embodiment of the present invention, for the specific implementation of steps 301 to 303, reference may be made to the relevant description in the method flow shown in FIG.

Step 304 , interpolating the calibration points in the relationship curve between white balance gain and color temperature, so as to increase the number of calibration points on the relationship curve between white balance gain and color temperature.

In the embodiment of the present invention, it is considered that when there are too few calibration points in the relationship curve between white balance gain and color temperature, the accuracy rate of determining the color temperature of the image to be detected according to the iso-correlated color temperature line corresponding to each calibration point in the subsequent process will be relatively low. Therefore, After the relationship curve between white balance gain and color temperature is determined, calibration points on the relationship curve can be interpolated to increase the number of calibration points on the relationship curve, and a schematic diagram thereof can be shown in FIG. 2D .

It should be recognized that when the number of calibration points corresponding to the white balance gain of the image collected under each target light source in the relationship curve between white balance gain and color temperature is sufficient, that is, the type of target light source is sufficient (such as the type of target light source exceeds the preset When the threshold value is set), the interpolation of the calibration points may not be performed, but the processing of the subsequent steps may be directly performed.

Step 305: Map the isocorrelated color temperature lines in the CIE chromaticity diagram to the white balance gain-color temperature relationship curve to calibrate the isocorrelated color temperature line corresponding to each calibration point on the white balance gain-color temperature relationship curve.

In the embodiment of the present invention, after interpolating the calibration points in the relationship curve between white balance gain and color temperature, the image acquisition device can calculate each calibration point on the relationship curve between white balance gain and color temperature (including those collected under each target light source). The calibration points corresponding to the white balance gain of the image, and the calibration points newly added by interpolation) are used for calibration of the equi-correlated color temperature line, and the schematic diagram thereof can be shown in FIG. 2E .

Wherein, for the corresponding color temperature exists in the calibration point of the CIE chromaticity diagram, the slope of the iso-correlated color temperature line of the color temperature corresponding to the calibration point in the CIE chromaticity diagram is determined as the equi-correlated color temperature line corresponding to the calibration point. The slope in the white balance gain versus color temperature curve;

For a calibration point whose corresponding color temperature does not exist in the CIE chromaticity diagram, the slope of the equicorrelated color temperature lines of two color temperatures adjacent to the color temperature corresponding to the calibration point existing in the CIE chromaticity diagram in the CIE chromaticity diagram , determine the slope of the isocorrelated color temperature line corresponding to the calibration point in the relationship curve between white balance gain and color temperature; wherein, one of the two color temperatures adjacent to the color temperature corresponding to the calibration point is higher than the color temperature corresponding to the calibration point, The other is smaller than the color temperature corresponding to the calibration point; the slope of the equal-correlated color temperature line and the color temperature satisfy monotonicity.

Step 306: Determine the color temperature corresponding to the image to be detected according to the white balance gain and the iso-correlated color temperature line of the image to be detected.

In the embodiment of the present invention, for the specific implementation of step 306, reference may be made to the relevant description in the foregoing step 103, and details are not repeated in this embodiment of the present invention.

It should be noted that, in the embodiment of the present invention, if the target position is at the outermost side of the equi-correlated color temperature line, that is, there are no adjacent two equi-correlated color temperature lines located on both sides of the target position, the closest to the target position can be The color temperature corresponding to the iso-correlated color temperature line is determined as the color temperature corresponding to the image to be detected, or the color temperature corresponding to the image to be detected is further determined by other strategies, which is not limited in this embodiment of the present invention.

It can be seen from the above description that in the technical solutions provided by the embodiments of the present invention, by counting the white balance gains of any two of the three primary colors of the image of the target gray object collected under at least three target light sources with different color temperatures, Determine the relationship curve between the white balance gain and color temperature, and map the isocorrelated color temperature line in the CIE chromaticity diagram to the relationship curve between the white balance gain and color temperature, so as to calibrate the target gray objects collected under each target light source The equal-correlation color temperature line of the color temperature corresponding to the image, and then determine the corresponding color temperature of the image to be detected according to the white balance gain and the iso-correlation color temperature line of the image to be detected. When the light source in the image acquisition scene does not meet the black body radiation, it can still be accurately The determination of the color temperature improves the applicability and accuracy of the determination of the color temperature.

Please refer to FIG. 4 , which is a schematic structural diagram of a color temperature determination device provided by an embodiment of the present invention, wherein the color temperature determination device can be applied to the image acquisition device in the above method embodiment, as shown in FIG. 4 , the color temperature determination device Can include:

The statistical unit 410 is used to count the white balance gain of any two primary colors in the three primary colors of the image of the target gray object collected under at least three target light sources with different color temperatures; wherein, the target light source is a light source that satisfies black body radiation;

The first determining unit 420 is configured to determine the relationship curve between the white balance gain and the color temperature;

The calibration unit 430 is configured to map the isocorrelated color temperature line in the CIE chromaticity diagram to the relationship curve between the white balance gain and the color temperature, so as to calibrate the isocorrelation of the color temperature corresponding to the image of the target gray object collected under each target light source. Correlated color temperature line;

The second determination unit 440 is configured to determine the color temperature corresponding to the image to be detected according to the white balance gain of the image to be detected and the iso-correlated color temperature lines.

Please also refer to FIG. 5. FIG. 5 is a schematic structural diagram of another color temperature determination device provided by an embodiment of the present invention. On the basis of the embodiment shown in FIG. 4, in the color temperature determination device shown in FIG. 5, the first determination Unit 420 may include:

The first determining subunit 421 is configured to, according to the white balance gains of the two primary colors and the corresponding color temperatures of the images of the target gray object collected under the target light sources of different color temperatures, respectively use the white balance of the two primary colors Determine the corresponding calibration point in the coordinate system where the gain is the horizontal and vertical coordinates;

The fitting unit 422 is configured to perform curve fitting on the calibration points to determine the relationship curve between the white balance gain and the color temperature.

Please also refer to FIG. 6. FIG. 6 is a schematic structural diagram of another color temperature determination device provided by an embodiment of the present invention. On the basis of the embodiment shown in FIG. 5, the color temperature determination device shown in FIG. 6 may also include:

An interpolation unit 450, configured to interpolate calibration points in the relationship curve between white balance gain and color temperature, so as to increase the number of calibration points on the relationship curve between white balance gain and color temperature;

Correspondingly, the calibration unit 430 can be specifically configured to, for a calibration point existing in the CIE chromaticity diagram for the corresponding color temperature, put the equicorrelated color temperature line of the color temperature corresponding to the calibration point in the CIE chromaticity diagram The slope is determined as the slope of the iso-correlated color temperature line corresponding to the calibration point in the relationship curve between the white balance gain and the color temperature; for the calibration point whose corresponding color temperature does not exist in the CIE chromaticity diagram, according to the The slope of the equicorrelated color temperature lines of two color temperatures adjacent to the color temperature corresponding to the calibration point in the CIE chromaticity diagram in the CIE chromaticity diagram determines that the equicorrelated color temperature lines corresponding to the calibration point are in the white The slope of the relationship curve between balance gain and color temperature; among them, one of the two color temperatures adjacent to the color temperature corresponding to the calibration point is higher than the color temperature corresponding to the calibration point, and the other is lower than the color temperature corresponding to the calibration point; equal correlation color temperature The slope of the line and the color temperature satisfy monotonicity.

Please also refer to FIG. 7. FIG. 7 is a schematic structural diagram of another color temperature determination device provided by an embodiment of the present invention. On the basis of the embodiment shown in FIG. 4, in the color temperature determination device shown in FIG. 7, the second determination Unit 440 may include:

The second determining subunit 441 is configured to determine the corresponding target location;

The third determining subunit 442 is configured to determine the color temperature corresponding to the image to be detected according to the distance from the target position to two adjacent equi-correlated color temperature lines, and the color temperature corresponding to the two adjacent equi-correlated color temperature lines; , the two adjacent equicorrelated color temperature lines are located on both sides of the target position.

In an optional embodiment, the third determination subunit 442 can be specifically configured to realize the distance from the target position to two adjacent equi-correlated color temperature lines, and the equi-correlated color temperature lines of the two adjacent equi-correlated lines through the following formula: The color temperature corresponding to the color temperature line determines the color temperature corresponding to the image to be detected:

Wherein, TcCur is the color temperature corresponding to the image to be detected, TcLf and TcRt are the color temperatures corresponding to the two adjacent equi-correlated color temperature lines, TcRt>TcLf, distLf and distRt are respectively the distance between the target position and the two adjacent equi-correlated color temperature lines. The distance of the correlated color temperature line.

For the implementation process of the functions and effects of each unit in the above device, please refer to the implementation process of the corresponding steps in the above method for details, and will not be repeated here.

As for the device embodiment, since it basically corresponds to the method embodiment, for related parts, please refer to the part description of the method embodiment. The device embodiments described above are only illustrative, and the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in One place, or it can be distributed to multiple network elements. Part or all of the modules can be selected according to actual needs to achieve the purpose of the solution of the present invention. It can be understood and implemented by those skilled in the art without creative effort.

It can be seen from the above embodiments that by counting the white balance gains of any two of the three primary colors of the image of the target gray object collected under at least three target light sources with different color temperatures, the relationship curve between the white balance gain and the color temperature is determined, and Map the equicorrelated color temperature lines in the CIE chromaticity diagram to the relationship curve between the white balance gain and the color temperature to calibrate the equicorrelated color temperature lines corresponding to the color temperature of the image of the target gray object collected under each target light source, and then according to The white balance gain and equal correlation color temperature line of the image to be detected can determine the corresponding color temperature of the image to be detected. When the light source in the image acquisition scene does not meet the black body radiation, the color temperature can still be determined accurately, which improves the applicability and reliability of the color temperature determination. accuracy.

Other embodiments of the invention will be readily apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present invention, these modifications, uses or adaptations follow the general principles of the present invention and include common knowledge or conventional technical means in the technical field not disclosed in the present invention . The specification and examples are to be considered exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It should be understood that the present invention is not limited to the precise constructions which have been described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims (8)

1. A method for determining color temperature, comprising: Count the white balance gains of any two of the three primary colors of the images of the target gray object collected under at least three target light sources with different color temperatures, and determine the relationship curve between the white balance gain and the color temperature; wherein, the target light source In order to satisfy the light source of black body radiation; Map the isocorrelated color temperature line in the CIE chromaticity diagram of the International Commission on Illumination to the relationship curve between the white balance gain and the color temperature, so as to calibrate the isocorrelated color temperature line corresponding to the color temperature of the image of the target gray object collected under each target light source ; Determine the color temperature corresponding to the image to be detected according to the white balance gain of the image to be detected and the iso-correlated color temperature line; Wherein, the determining the color temperature corresponding to the image to be detected according to the white balance gain of the image to be detected and the iso-correlated color temperature line includes: according to the white balance gains of the two primary colors of the image to be detected, respectively Determine the corresponding target position in the coordinate system with the white balance gains of the two primary colors as the horizontal and vertical coordinates; according to the distance from the target position to two adjacent equi-correlated color temperature lines, and the equi-correlated color temperature lines of the two adjacent The color temperature corresponding to the correlated color temperature line determines the color temperature corresponding to the image to be detected; wherein, the two adjacent equal correlated color temperature lines are located on both sides of the target position. 2. The method according to claim 1, wherein the determining the relationship curve between the white balance gain and the color temperature comprises: According to the white balance gain of the two primary colors and the corresponding color temperature of the image of the target gray object collected under the target light source with different color temperature, in the coordinate system with the white balance gain of the two primary colors as the horizontal and vertical coordinates respectively Determine the corresponding calibration point; Curve fitting is performed on the calibration points to determine the relationship curve between the white balance gain and the color temperature. 3. method according to claim 2, is characterized in that, after described calibration point is carried out curve fitting, also comprises: Interpolating the calibration points in the relationship curve between white balance gain and color temperature to increase the number of calibration points on the relationship curve between white balance gain and color temperature; Mapping the equicorrelated color temperature line in the CIE chromaticity diagram of the International Commission on Illumination to the relationship curve between the white balance gain and the color temperature to calibrate the equicorrelated color temperature of the color temperature corresponding to the image of the target gray object collected under each target light source lines, including: For the corresponding color temperature exists in the calibration point of the CIE chromaticity diagram, the slope of the equicorrelated color temperature line of the color temperature corresponding to the calibration point in the CIE chromaticity diagram is determined as the equicorrelated color temperature corresponding to the calibration point The slope of the line in the relational curve of white balance gain and color temperature; For a calibration point whose corresponding color temperature does not exist in the CIE chromaticity diagram, according to the equicorrelated color temperature lines of two color temperatures adjacent to the color temperature corresponding to the calibration point existing in the CIE chromaticity diagram in the CIE The slope in the chromaticity diagram determines the slope of the iso-correlated color temperature line corresponding to the calibration point in the relationship curve between the white balance gain and the color temperature; wherein, one of the two color temperatures adjacent to the color temperature corresponding to the calibration point is higher For the color temperature corresponding to the calibration point, the other is smaller than the color temperature corresponding to the calibration point; the slope of the equal correlation color temperature line and the color temperature satisfy monotonicity. 4. The method according to claim 1, characterized in that, according to the distance from the target position to two adjacent equi-correlated color temperature lines, and the color temperature corresponding to the two adjacent equi-correlated color temperature lines, determine The color temperature corresponding to the image to be detected is specifically realized by the following formula: <mrow><mi>T</mi><mi>c</mi><mi>C</mi><mi>u</mi><mi>r</mi><mo>=</mo><mi>T</mi><mi>c</mi><mi>L</mi><mi>f</mi><mo>+</mo><mfrac><mrow><mi>d</mi><mi>i</mi><mi>s</mi><mi>t</mi><mi>L</mi><mi>f</mi></mrow><mrow><mi>d</mi><mi>i</mi><mi>s</mi><mi>t</mi><mi>L</mi><mi>f</mi><mo>+</mo><mi>d</mi><mi>i</mi><mi>s</mi><mi>t</mi><mi>R</mi><mi>t</mi></mrow></mfrac><mrow><mo>(</mo><mi>T</mi><mi>c</mi><mi>R</mi><mi>t</mi><mo>-</mo><mi>T</mi><mi>c</mi><mi>L</mi><mi>f</mi><mo>)</mo></mrow></mrow> Wherein, TcCur is the color temperature corresponding to the image to be detected, TcLf and TcRt are the color temperatures corresponding to the two adjacent equi-correlated color temperature lines, TcRt>TcLf, distLf and distRt are respectively the distance between the target position and the adjacent two equi-correlated color temperature lines. The distance of the correlated color temperature line. 5. A color temperature determining device, characterized in that it comprises: The statistical unit is used to count the white balance gain of any two primary colors in the three primary colors of the image of the target gray object collected under at least three target light sources with different color temperatures; wherein, the target light source is a light source that satisfies black body radiation; a first determining unit, configured to determine the relationship curve between the white balance gain and the color temperature; A calibration unit, configured to map the isocorrelated color temperature line in the CIE chromaticity diagram of the International Commission on Illumination to the relationship curve between the white balance gain and the color temperature, so as to calibrate the color temperature corresponding to the image of the target gray object collected under each target light source The isocorrelated color temperature line; The second determination unit is configured to determine the color temperature corresponding to the image to be detected according to the white balance gain of the image to be detected and the iso-correlated color temperature line Wherein, the second determination unit includes: The second determination subunit is used to determine the corresponding target in a coordinate system with the white balance gains of the two primary colors as the horizontal and vertical coordinates according to the white balance gains of the two primary colors of the image to be detected Location; The third determining subunit is used to determine the color temperature corresponding to the image to be detected according to the distance from the target position to two adjacent iso-correlated color temperature lines, and the color temperature corresponding to the two adjacent iso-correlated color temperature lines; wherein, The two adjacent equi-correlated color temperature lines are located on both sides of the target position. 6. The device according to claim 5, wherein the first determining unit comprises: The first determining subunit is used to, according to the white balance gain of the two primary colors and the corresponding color temperature of the image of the target gray object collected under the target light source with different color temperatures, respectively use the white balance gains of the two primary colors Determine the corresponding calibration point in the coordinate system of horizontal and vertical coordinates; A fitting unit is configured to perform curve fitting on the calibration points to determine a relationship curve between the white balance gain and the color temperature. 7. The device according to claim 6, further comprising: an interpolation unit, configured to interpolate calibration points in the relationship curve between white balance gain and color temperature, so as to increase the number of calibration points on the relationship curve between white balance gain and color temperature; The calibration unit is specifically used to calibrate a calibration point that exists in the CIE chromaticity diagram for the corresponding color temperature, and determine the slope of the equicorrelated color temperature line of the color temperature corresponding to the calibration point in the CIE chromaticity diagram. is the slope of the isocorrelated color temperature line corresponding to the calibration point in the relationship curve between the white balance gain and the color temperature; for a calibration point whose corresponding color temperature does not exist in the CIE chromaticity diagram, according to the CIE chromaticity diagram The slope of the iso-correlated color temperature lines of two color temperatures adjacent to the color temperature corresponding to the calibration point in the CIE chromaticity diagram, determine the equi-correlation color temperature line corresponding to the calibration point in the white balance gain and color temperature The slope in the relationship curve of the calibration point; wherein, one of the two color temperatures adjacent to the color temperature corresponding to the calibration point is higher than the color temperature corresponding to the calibration point, and the other is lower than the color temperature corresponding to the calibration point; the slope of the equal correlation color temperature line and The color temperature satisfies monotonicity. 8. The device according to claim 5, wherein the third determining subunit is specifically configured to realize the distance from the target position to two adjacent equi-correlated color temperature lines according to the following formula, and the phase Determine the color temperature corresponding to the image to be detected by the color temperature corresponding to the two adjacent equi-correlated color temperature lines: <mrow><mi>T</mi><mi>c</mi><mi>C</mi><mi>u</mi><mi>r</mi><mo>=</mo><mi>T</mi><mi>c</mi><mi>L</mi><mi>f</mi><mo>+</mo><mfrac><mrow><mi>d</mi><mi>i</mi><mi>s</mi><mi>t</mi><mi>L</mi><mi>f</mi></mrow><mrow><mi>d</mi><mi>i</mi><mi>s</mi><mi>t</mi><mi>L</mi><mi>f</mi><mo>+</mo><mi>d</mi><mi>i</mi><mi>s</mi><mi>t</mi><mi>R</mi><mi>t</mi></mrow></mfrac><mrow><mo>(</mo><mi>T</mi><mi>c</mi><mi>R</mi><mi>t</mi><mo>-</mo><mi>T</mi><mi>c</mi><mi>L</mi><mi>f</mi><mo>)</mo></mrow></mrow> Wherein, TcCur is the color temperature corresponding to the image to be detected, TcLf and TcRt are the color temperatures corresponding to the two adjacent equi-correlated color temperature lines, TcRt>TcLf, distLf and distRt are respectively the distance between the target position and the two adjacent equi-correlated color temperature lines. The distance of the correlated color temperature line.