Image processing system, image processing method, and program

Abstract

A video processing system (2) is provided with: a first input interface (21); a second input interface (22); and a CPU (231). The first input interface (21) acquires a video signal to be outputted to a display panel (10) of a display (1). The second input interface (22) acquires color temperature information indicating the color temperature of environment light emitted toward the display panel (10). The CPU (231) calculates a correction amount of the color temperature of the video signal so as to conform to the color temperature of the environment light. The CPU (231) subtracts the absolute value of the correction amount of the color temperature of the video signal so as to cancel the color temperature of the environment light when the pixel luminance of the video signal is less than a luminance threshold value. The CPU (231) outputs the video signal having the color temperature of the video signal corrected in accordance with the correction amount.

Description

Technical Field

[0001] The present disclosure relates to a video processing system for processing video displayed on a display panel of a display, etc.

Background Art

[0002] For example, Patent Document 1 discloses a television device. This television device includes an external light detection unit that detects the illuminance and color tone of ambient light, and an image quality control unit that adjusts the image quality of the video displayed on the display panel. The image quality control unit adjusts the color temperature of the video to be displayed according to the illuminance value and color tone value detected by the external light detection unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a video processing system or the like that can easily and accurately correct the color temperature of video displayed on a display panel.

Means for Solving the Problems

[0005] A video processing system according to an aspect of the present disclosure includes a first input interface, a second input interface, and a processor. The first input interface acquires a video signal output to a display panel of a display. The second input interface acquires color temperature information indicating the color temperature of ambient light irradiated onto the display panel. The processor calculates a correction amount for the color temperature of the video signal so as to follow the color temperature of the ambient light. The processor In the calculation of the aforementioned correction amount, when the pixel luminance of the video signal is below a luminance threshold ,before cancels the color temperature of the ambient light A sub-correction amount is calculated, and the sub-correction amount is usedAbsolute value of the aforementioned correction amount The correction amount is adjusted so that it becomes smaller. The processor outputs the video signal with its color temperature corrected according to the correction amount.

[0006] In one aspect of the present disclosure, a video signal output to a display panel of a display is acquired, color temperature information indicating the color temperature of ambient light irradiated onto the display panel is acquired, and a color temperature correction amount for the video signal is calculated to follow the color temperature of the ambient light. In the calculation of the aforementioned correction amount, When the pixel brightness of the aforementioned video signal falls below the brightness threshold ,before The color temperature of the ambient light is canceled out. A sub-correction amount is calculated, and the sub-correction amount is used Absolute value of the aforementioned correction amount The correction amount is corrected so that it becomes smaller. The system outputs the video signal with its color temperature corrected according to the correction amount.

[0007] A program according to one aspect of this disclosure causes one or more processors to execute the video processing method. [Effects of the Invention]

[0008] The image processing system described in this disclosure has the advantage of being able to accurately correct the color temperature of the image displayed on the display panel of a display. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 illustrates the challenges of correcting the color temperature of video signals based on the color temperature of ambient light. [Figure 2] Figure 2 is a block diagram showing the overall configuration including the video processing system according to the embodiment. [Figure 3] Figure 3 is a flowchart showing an example of the operation of the video processing system according to the embodiment. [Figure 4] Figure 4 is a flowchart showing an example of the operation for calculating the sub-correction amount for the color temperature of a video signal. [Figure 5] Figure 5 is an explanatory diagram illustrating the operation of calculating the sub-correction amount for the color temperature of the video signal. [Figure 6]Figure 6 shows an example of color temperature correction for a video signal. [Figure 7] Figure 7 shows another example of color temperature correction for a video signal. [Figure 8] Figure 8 shows the correlation between the amount of color temperature correction in the video signal and the pixel brightness. [Figure 9] Figure 9 is an explanatory diagram illustrating the advantages of the image processing system according to the embodiment. [Modes for carrying out the invention]

[0010] [1. Knowledge forming the basis of this disclosure] First, the inventor's perspective is explained below.

[0011] Conventionally, a technique has been known for correcting white balance by detecting ambient light illuminating a display with an RGB sensor and using the information about the ambient light detected by the RGB sensor to correct the color temperature of the video signal to match the color temperature of the ambient light. Here, "ambient light" refers to light that is irradiated onto the display from the surroundings, such as sunlight or light emitted from lighting fixtures. In this technique, for example, if the color temperature of the ambient light is higher than the reference color temperature, the color temperature of the video signal is corrected to be higher, and if the color temperature of the ambient light is lower than the reference color temperature, the color temperature of the video signal is corrected to be lower. By correcting the color temperature of the video signal in this way, it becomes easier to display images on the display at an appropriate color temperature that takes into account the color adaptation of human vision.

[0012] However, the above technology has the following problems. FIG. 1 is an explanatory diagram of the problems of the color temperature correction process of the video signal based on the color temperature of the ambient light. In each of FIGS. 1(a) and 1(c), arrow A1 represents the ambient light irradiated on display 1, and arrow A2 represents the ambient light reflected by display panel 10 of display 1. Also, in each of FIGS. 1(a) and 1(c), arrow A3 represents the light output from display panel 10 of display 1 based on the video signal. And the size of arrow A3 represents the magnitude of the luminous flux output from display panel 10 of display 1, in other words, the level of the luminance of the video signal.

[0013] FIGS. 1(b) and 1(d) represent the grayscale displayed on display panel 10 of display 1, respectively. Note that in FIGS. 1(b) and 1(d), it is shown that the larger the dot density, the darker, and the smaller the dot density, the brighter. FIG. 1(b) represents the grayscale when the luminance of the video signal is relatively high as shown in FIG. 1(a). As shown in FIG. 1(b), when the luminance of the video signal is relatively high, since the intensity of the ambient light is relatively low with respect to the light output from display panel 10 of display 1, the influence of the ambient light does not appear or hardly appears in the grayscale.

[0014] On the other hand, FIG. 1(d) represents the grayscale when the luminance of the video signal is relatively low as shown in FIG. 1(c). As shown in FIG. 1(d), when the luminance of the video signal is relatively low, since the intensity of the ambient light is relatively high with respect to the light output from display panel 10 of display 1, the influence of the ambient light appears in the grayscale. Specifically, in region G1 showing a relatively bright gradation, the influence of the ambient light does not appear or hardly appears, but in region G2 showing a relatively dark gradation, as indicated by the slanted hatching, the influence of the ambient light appears. For example, when the ambient light is bluish light and the luminance of the video signal is relatively low, a bluish color appears in region G2 showing a relatively dark gradation.

[0015] As described above, when correcting the color temperature of a video signal based on the color temperature of ambient light, there is a problem that it is difficult to accurately correct the color temperature of the video displayed on the display panel 10 of the display 1 depending on the luminance of the video signal.

[0016] In view of the above, the inventor has created the present disclosure.

[0017] Hereinafter, embodiments will be specifically described with reference to the drawings. Note that each of the embodiments described below shows comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps, order of steps, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. In addition, among the components in the following embodiments, the components not described in the independent claims are described as optional components.

[0018] Each figure is a schematic diagram and is not necessarily drawn precisely. Also, in each figure, the same reference numerals are given to substantially the same configurations, and duplicate explanations may be omitted or simplified.

[0019] (Embodiment) [2. Configuration] [2-1. Overall Configuration] First, the overall configuration including the video processing system according to the embodiment will be described using FIG. 2. FIG. 2 is a block diagram showing the overall configuration including the video processing system 2 according to the embodiment. The video processing system 2 is a system that executes a process of correcting a video signal output to the display panel 10 of the display 1 and outputs the corrected video signal. In the embodiment, the video processing system 2 is built in the display 1. Note that the video processing system 2 may be provided outside the display 1.

[0020] The display panel 10 is composed of, for example, a liquid crystal panel or an organic EL (Electro-Luminescence) panel. The display panel 10 displays video, including moving images or still images, as shown by the acquired video data. This video data is included in the corrected video signal output from the video processing system 2.

[0021] The video signal includes, for example, video data for terrestrial broadcasting obtained by converting an analog signal received by an antenna into a digital signal and decoding the converted digital signal. The video signal may also include, for example, video data transmitted via a network such as the Internet from a server providing a video distribution service. Furthermore, the video signal may also include, for example, video data stored in a recording device connected to display 1.

[0022] An RGB sensor 3 is provided around the display 1. The RGB sensor 3 is a sensor for detecting ambient light illuminating the display panel 10 of the display 1. Specifically, the RGB sensor 3 has three photodiodes corresponding to R (red), G (green), and B (blue), respectively, and detects the constituent intensity of the ambient light illuminating each photodiode. The RGB sensor 3 then outputs RGB information corresponding to the detected constituent intensity of the ambient light. Here, the constituent intensity of the ambient light includes the light intensity of the R component of the ambient light, the light intensity of the G component of the ambient light, and the light intensity of the B component of the ambient light. The RGB information output by the RGB sensor 3 is input to the video processing system 2.

[0023] [2-2. Video Processing System] Next, the configuration of the video processing system 2 will be described in detail. As shown in Figure 2, the video processing system 2 includes a first input interface (hereinafter referred to as "first input I / F (Interface)") 21, a second input interface (hereinafter referred to as "second input I / F") 22, and an SoC (System on a Chip) 23. The SoC 23 includes a CPU (Central Processing Unit) 231, memory 232, and video processing circuit 233.

[0024] The first input interface 21 is, for example, a wired communication interface that acquires the video signal output to the display panel 10 of the display 1. The first input interface 21 may also be a wireless communication interface. Furthermore, a tuner that receives broadcast waves and outputs a video signal may be connected to the first input interface 21.

[0025] The second input interface 22 is, for example, a wired communication interface, and acquires color temperature information indicating the color temperature of the ambient light illuminating the display panel 10. In this embodiment, the second input interface 22 acquires RGB information (color temperature information) from the RGB sensor 3 by performing wired communication with the RGB sensor 3. The second input interface 22 may also be a wireless communication interface.

[0026] The CPU 231 performs information processing on the video signal acquired by the first input I / F 21, correcting it based on the color temperature information acquired by the second input I / F 22, and outputting the corrected video signal to the video processing circuit 233. The above information processing is realized by the CPU 231 executing a computer program stored in memory 232. The CPU 231 is an example of a processor in the video processing system 2.

[0027] The correction process described above includes a first correction calculation process and a second correction calculation process. The first correction calculation process calculates the amount of color temperature correction for the video signal to follow the color temperature of the ambient light, taking into account the color adaptation of human vision. The second correction calculation process reduces the absolute value of the correction amount calculated in the first correction calculation process to cancel out the color temperature of the ambient light, according to the pixel brightness of the video signal. In other words, the second correction calculation process adjusts the amount of color temperature correction for the video signal in the first correction calculation process, which may be excessive depending on the pixel brightness of the video signal, to an appropriate correction amount by reducing its absolute value. The first and second correction calculation processes will be explained in detail later in [3. Operation].

[0028] Memory 232 is a storage device that stores computer programs executed by the CPU 231, as well as information necessary for realizing various functions. Memory 232 is implemented, for example, by semiconductor memory. Note that memory 232 may be implemented as an internal memory of the CPU 231, rather than as an external memory of the CPU 231.

[0029] The video processing circuit 233 outputs a corrected video signal, whose color temperature has been corrected by the CPU 231, to the display panel 10. The video processing circuit 233 may also perform correction processes other than color temperature correction on the corrected video signal, such as contour correction or noise reduction. Furthermore, if the video signal input from the first input I / F 21 is encoded or encrypted, the video processing circuit 233 decodes it and performs various video processing, including correction, on the decoded video signal. In this embodiment, the CPU 231 is configured separately from the video processing circuit 233, but this is not limited to the CPU 231; it may be part of the video processing circuit 233.

[0030] [3. Operation] The operation of the video processing system 2 according to this embodiment, that is, an example of a video processing method, will be described below.

[0031] [3-1. Color temperature correction processing of video signals] First, the main operation of the video processing system 2 according to this embodiment, which is the color temperature correction process of the video signal, will be explained using Figure 3. Figure 3 is a flowchart showing an example of the operation of the video processing system 2 according to this embodiment.

[0032] First, the first input I / F 21 of the video processing system 2 acquires a video signal (S101). In this embodiment, the video signal acquired by the first input I / F 21 is an RGB signal converted from a YUV signal or a YCbCr signal. The second input I / F 22 of the video processing system 2 acquires RGB information output from the RGB sensor 3 (S102). Steps S101 and S102 are not limited to this order; they may be executed in reverse order or in parallel.

[0033] Next, the CPU 231 of the video processing system 2 calculates and obtains illuminance information indicating the illuminance of ambient light and color temperature information indicating the color temperature of ambient light based on the acquired RGB information (S103). Specifically, the CPU 231 obtains illuminance information by performing calculations to convert the light intensity of the R component, the light intensity of the G component, and the light intensity of the B component of ambient light contained in the acquired RGB information into the illuminance of ambient light using an appropriate conversion formula. The CPU 231 also obtains color temperature information by performing calculations to convert the light intensity of the R component, the light intensity of the G component, and the light intensity of the B component of ambient light contained in the acquired RGB information into the color temperature of ambient light using an appropriate conversion formula different from the above conversion formula.

[0034] Next, the CPU 231 calculates the color temperature correction amount A for the video signal (S104). Step S104 corresponds to the first correction calculation process described above. Specifically, the CPU 231 calculates the color temperature correction amount A for the video signal to follow the color temperature of the ambient light, based on the color temperature of the ambient light calculated in step S103.

[0035] For example, if the ambient light is bluish, meaning the color temperature of the ambient light is higher than the reference color temperature (for example, approximately 5000K, which represents daylight white), the CPU 231 calculates a correction amount A based on the difference between the ambient light color temperature and the reference color temperature. In this case, the correction amount A will be a positive value because it corrects the color temperature of the video signal to be higher. Also, for example, if the ambient light is reddish, meaning the color temperature of the ambient light is lower than the reference color temperature, the CPU 231 calculates a correction amount A based on the difference between the ambient light color temperature and the reference color temperature. In this case, the correction amount A will be a negative value because it corrects the color temperature of the video signal to be lower.

[0036] Furthermore, the CPU 231 calculates the sub-correction amount for the color temperature of the video signal (S105). Here, the sub-correction amount is a value added to the color temperature correction amount A of the video signal calculated in step S104. The calculation process for the sub-correction amount will be explained in detail later in [3-2. Calculation process for sub-correction amount]. Steps S104 and S105 are not limited to this order; they may be executed in reverse order or in parallel.

[0037] Next, the CPU 231 compares the pixel brightness with the brightness threshold Th3 (see Figure 8) for each pixel of the video signal (S106). The brightness threshold Th3 is the brightness corresponding to the boundary between the region G1, which shows relatively bright gradations, and the region G2, which shows relatively dark gradations, as explained in [1. Knowledge on which this disclosure is based]. The brightness threshold Th3 is set in advance by, for example, the designer of the video processing system 2 and stored in the memory 232.

[0038] If the pixel brightness is greater than or equal to the brightness threshold Th3 (S106: No), the CPU 231 does not perform correction using the sub-correction amount (S107). In other words, in this case, the CPU 231 does not add the sub-correction amount for the color temperature of the video signal calculated in step S105 to the correction amount A for the color temperature of the video signal calculated in step S104. On the other hand, if the pixel brightness is less than the brightness threshold Th3 (S106: Yes), the CPU 231 performs correction using the sub-correction amount (S108). In other words, in this case, the CPU 231 adds the sub-correction amount for the color temperature of the video signal calculated in step S105 to the correction amount A for the color temperature of the video signal calculated in step S104.

[0039] Next, the CPU 231 corrects the color temperature of the video signal (in this case, the pixels to be processed) (S109). Specifically, if step S107 is completed, the CPU 231 corrects the color temperature of the video signal based on the color temperature correction amount A calculated in step S104. On the other hand, if step S108 is completed, the CPU 231 corrects the color temperature of the video signal based on a correction amount obtained by adding the sub-correction amount calculated in step S105 to the color temperature correction amount A calculated in step S104. In other words, if the correction amount referenced in step S109 is "correction amount B", then if step S107 is completed, "correction amount B = correction amount A", and if step S108 is completed, "correction amount B = correction amount A + sub-correction amount". Steps S105 to S108 correspond to the second correction calculation process described above.

[0040] Subsequently, the CPU 231 executes steps S106 to S109 described above for each pixel until processing is completed for all pixels of the video signal (while S110 is No). When processing is completed for all pixels of the video signal (S110: Yes), the CPU 231 outputs the corrected video signal to the video processing circuit 233 (S111). As a result, the display panel 10 of the display 1 displays an image with a color temperature corrected based on the color temperature of the ambient light.

[0041] [3-2. Calculation process for sub-correction amount of color temperature of video signal] Next, the calculation process for the sub-correction amount of the color temperature of the video signal by the video processing system 2 according to the embodiment will be explained with reference to Figures 4 and 5. Figure 4 is a flowchart showing an example of the operation for calculating the sub-correction amount of the color temperature of the video signal. Figure 5 is an explanatory diagram of the operation for calculating the sub-correction amount of the color temperature of the video signal.

[0042] Figure 5(a) shows correlation data between ambient light illuminance and the correction coefficient, with the vertical axis representing the correction coefficient and the horizontal axis representing ambient light illuminance. Note that the "correction coefficient" may also be referred to as the "correction ratio". As shown in Figure 5(a), the correction coefficient is zero when the ambient light illuminance is below the illuminance threshold Th1, and increases proportionally to the ambient light illuminance when the ambient light illuminance exceeds the illuminance threshold Th1. The correction coefficient then becomes a constant value when the ambient light illuminance is above a predetermined illuminance value Th10.

[0043] Figure 5(b) is a diagram showing the relationship between ambient light color temperature and correction amount C, where the vertical axis represents correction amount C and the horizontal axis represents ambient light color temperature. As shown in Figure 5(b), the correction amount C is zero when the ambient light color temperature is within a predetermined range R1. Here, the predetermined range R1 is the range in which the ambient light color temperature is above the first color threshold Th21 and below the second color threshold Th22. The correction amount C becomes a positive value when the ambient light color temperature falls below the first color threshold Th21, and its absolute value increases proportionally to the ambient light color temperature. Then, the correction amount C becomes a constant value when the ambient light color temperature is below the predetermined color value Th210. On the other hand, the correction amount C becomes a negative value when the ambient light color temperature exceeds the second color threshold Th22, and its absolute value increases proportionally to the ambient light color temperature. Then, the correction amount C becomes a constant value when the ambient light color temperature is above the predetermined color value Th220.

[0044] The relationship data shown in Figures 5(a) and 5(b) is set by, for example, the designer of the video processing system 2 and is stored in memory 232 in advance.

[0045] As shown in Figure 4, first, the CPU 231 compares the ambient light illuminance acquired in step S103 with the illuminance threshold Th1 (step S201). If the ambient light illuminance is less than or equal to the illuminance threshold Th1 (S201: No), the CPU 231 determines the correction coefficient to be zero (S202). In other words, in this case, the CPU 231 does not perform the process of reducing the absolute value of the color temperature correction amount of the video signal according to the ambient light illuminance.

[0046] On the other hand, if the ambient light illuminance exceeds the illuminance threshold Th1 (S201: Yes), the CPU 231 refers to the relationship data shown in Figure 5(a) and determines a correction coefficient corresponding to the ambient light illuminance (S203). In other words, in this case, the CPU 231 performs a process to reduce the absolute value of the color temperature correction amount of the video signal according to the ambient light illuminance.

[0047] Furthermore, the CPU 231 compares the ambient light color temperature acquired in step S103 with a predetermined range R1 (S204). If the ambient light color temperature is within the predetermined range R1, that is, within the range where the first color threshold Th21 is greater than or equal to the second color threshold Th22 (S204: Yes), the CPU 231 determines the correction amount C to be zero (S205). In other words, in this case, the CPU 231 does not perform the process of reducing the absolute value of the color temperature correction amount of the video signal according to the ambient light color temperature.

[0048] On the other hand, if the color temperature of the ambient light deviates from a predetermined range R1 (S204: No), the CPU 231 refers to the relationship data shown in Figure 5(b) and determines a correction amount C corresponding to the color temperature of the ambient light (S206). In other words, in this case, the CPU 231 performs a process to reduce the absolute value of the color temperature correction amount of the video signal according to the color temperature of the ambient light.

[0049] In this embodiment, the CPU 231 executes the processes in steps S201 to S203 and steps S204 to S206 in parallel, but is not limited to this. For example, the CPU 231 may execute the processes in steps S201 to S203 first, and then the processes in steps S204 to S206, or it may execute them in the reverse order.

[0050] Then, CPU 231 calculates a sub-correction amount by multiplying the correction coefficient calculated in steps S201 to S203 by the correction amount C calculated in steps S204 to S206 (S207).

[0051] Here, we will explain the significance of calculating the sub-correction amount. First, when the color temperature of the video signal is corrected using the correction amount A calculated in step S104, the color temperature of the video signal is corrected to follow the color temperature of the ambient light. For example, if the color temperature of the ambient light is high, correcting it using correction amount A will increase the color temperature of the video signal.

[0052] However, when the brightness of the video signal is relatively low (i.e., the pixel brightness of the video signal is below the brightness threshold Th3), correcting the color temperature of the video signal using correction amount A tends to result in excessive correction. For example, if the color temperature of the ambient light is high and the brightness of the video signal is relatively low, correcting using correction amount A will cause the color temperature of the image seen by the user to become too high due to the influence of the ambient light, making the image appear bluish.

[0053] Therefore, in this embodiment, when the brightness of the video signal is relatively low, the sub-correction amount is added to the correction amount A, thereby reducing the absolute value of the correction amount A. This makes it possible to suppress the excessive correction of the color temperature of the image seen by the user due to the color temperature correction of the video signal.

[0054] However, if the ambient light intensity is relatively low (i.e., the ambient light intensity is below the illuminance threshold Th1), the effect of ambient light is small, and therefore, the process of reducing the absolute value of correction amount A is unnecessary. In this case, the sub-correction amount is set to zero by setting the correction coefficient to zero.

[0055] [3-3. Examples of color temperature correction for video signals] In this embodiment, the CPU 231 corrects the color temperature of the video signal by correcting the correction amounts of the R, G, and B components in the video signal, that is, by correcting the RGB values ​​in the video signal. Examples of color temperature correction of the video signal will be explained below with reference to Figures 6 and 7.

[0056] Figure 6 shows an example of color temperature correction of a video signal. Figure 7 shows another example of color temperature correction of a video signal. Figures 6(a), (b), and (c) show the relationship between the correction amount of the R component of the video signal and pixel brightness, the relationship between the correction amount of the G component of the video signal and pixel brightness, and the relationship between the B component of the video signal and pixel brightness, respectively. Figures 7(a), (b), and (c) are similar.

[0057] First, we will explain how to correct the color temperature of a video signal by adjusting the correction amounts for each of the R, G, and B components of the video signal. For example, by correcting the R component to be relatively smaller than the G and B components, it is possible to increase the color temperature of the video signal. Conversely, for example, by correcting the B component to be relatively smaller than the R and G components, it is possible to decrease the color temperature of the video signal.

[0058] Figures 6 and 7 both show the relationships that are referenced when correcting the color temperature of the video signal to cancel out the color temperature of the ambient light, that is, when determining the sub-correction amount.

[0059] Specifically, Figure 6 shows the case where the ambient light is reddish, that is, the R component of the ambient light is relatively large. As shown in Figure 6, when the R component of the ambient light is relatively large, that is, when the color temperature of the ambient light is lower than the reference color temperature, the CPU 231 determines a sub-correction amount that cancels out the color temperature of the ambient light by increasing the correction amounts of the G component and B component, respectively.

[0060] Figure 7 shows the case where the ambient light is bluish, meaning the B component of the ambient light is relatively large. As shown in Figure 7, when the B component of the ambient light is relatively large, that is, when the color temperature of the ambient light is higher than the reference color temperature, the CPU 231 determines sub-correction amounts that cancel out the color temperature of the ambient light by increasing the correction amounts of the R and G components, respectively.

[0061] In this embodiment, the magnitude of the correction amounts for the R, G, and B components changes according to the magnitude of the correction coefficient, that is, the illuminance of the ambient light. Specifically, when the illuminance of the ambient light is high, i.e., the correction coefficient is high, the CPU 231 increases the correction amounts for the R, G, and B components. On the other hand, when the illuminance of the ambient light is low, i.e., the correction coefficient is low, the CPU 231 decreases the correction amounts for the R, G, and B components.

[0062] Figure 8 shows the correlation between the color temperature correction amount of the video signal and the pixel brightness. Note that Figure 8 represents the case where the ambient light illuminance is relatively high and above the illuminance threshold Th1. Figure 8(a) shows the correlation between the color temperature correction amount A of the video signal calculated in step S104 and the pixel brightness, with the vertical axis representing the correction amount A and the horizontal axis representing the pixel brightness. As shown in Figure 8(a), the correction amount A calculated in step S104 is constant regardless of the pixel brightness. Furthermore, when the color temperature of the ambient light is higher than the reference color temperature, the correction amount A calculated in step S104 is a positive value, as indicated by the white arrow, in order to correct the color temperature of the video signal to follow the color temperature of the ambient light. On the other hand, when the color temperature of the ambient light is lower than the reference color temperature, the correction amount A calculated in step S104 is a negative value, as indicated by the black arrow, in order to correct the color temperature of the video signal to follow the color temperature of the ambient light.

[0063] Figure 8(b) shows the correlation between the sub-correction amount calculated in step S105 and the pixel brightness, with the vertical axis representing the sub-correction amount and the horizontal axis representing the pixel brightness. As shown in Figure 8(b), the sub-correction amount is constant at zero when the pixel brightness is equal to or greater than the brightness threshold Th3. On the other hand, when the pixel brightness is below the brightness threshold Th3, the sub-correction amount becomes a value corresponding to the ambient light color temperature and the pixel brightness. Specifically, when the ambient light color temperature is higher than the reference color temperature, the sub-correction amount becomes a negative value, as indicated by the black arrow, in order to correct the color temperature of the video signal to cancel out the ambient light color temperature. On the other hand, when the ambient light color temperature is lower than the reference color temperature, the sub-correction amount becomes a positive value, as indicated by the white arrow, in order to correct the color temperature of the video signal to cancel out the ambient light color temperature.

[0064] Figure 8(c) shows the correlation between the correction amount B, which is obtained by adding the sub-correction amount calculated in step S105 to the color temperature correction amount A of the video signal calculated in step S104, and the pixel brightness. The vertical axis represents the correction amount B, and the horizontal axis represents the pixel brightness. As shown in Figure 8(c), when the pixel brightness is greater than or equal to the brightness threshold Th3, the correction amount B remains constant. On the other hand, when the pixel brightness falls below the brightness threshold Th3, the absolute value of the correction amount B is reduced according to the sub-correction amount added.

[0065] Specifically, when the ambient light color temperature is higher than the reference color temperature, the correction amount B will be a positive value (see the white arrow on the right), but when the pixel brightness falls below the brightness threshold Th3, its absolute value will be reduced according to the sub-correction amount (see the black arrow on the left). Also, when the ambient light color temperature is lower than the reference color temperature, the correction amount B will be a negative value (see the black arrow on the right), but when the pixel brightness falls below the brightness threshold Th3, its absolute value will be reduced according to the sub-correction amount (see the white arrow on the left).

[0066] [4. Effects, etc.] The advantages of the video processing system 2 according to this embodiment will be explained below with reference to Figure 9. Figure 9 is an explanatory diagram of the advantages of the video processing system 2 according to this embodiment. Figure 9 is a diagram showing the correlation between the color temperature and pixel brightness of the image viewed by the user, displayed on the display panel 10, with the vertical axis representing color temperature and the horizontal axis representing pixel brightness. The color temperature of the image is affected by the color temperature of the ambient light. In the region in Figure 9 where the pixel brightness is less than or equal to the brightness threshold Th3, the two dotted lines represent the case where the color temperature of the video signal is corrected based only on the color temperature correction amount A of the video signal calculated in step S104. On the other hand, in the same region, the solid line represents the case where the color temperature of the video signal is corrected with a correction amount B, which is obtained by adding the sub-correction amount calculated in step S105 to the color temperature correction amount A of the video signal calculated in step S104.

[0067] As shown in Figure 9, if the color temperature of the video signal is corrected based solely on the color temperature correction amount A calculated in step S104, the color temperature will be overcorrected in areas where the pixel brightness is below the brightness threshold Th3, i.e., in areas showing relatively dark gradations. In the example shown in Figure 9, if the ambient light is bluish, that is, if the color temperature of the ambient light is relatively high, the color temperature will be high in areas showing relatively dark gradations, as shown by the upper dotted line, and a bluish color will appear on the display panel 10. This is because areas with low pixel brightness are more strongly affected by the color temperature of the ambient light, so if the color temperature of the ambient light is high, the color temperature of that area will appear high. If correction according to the ambient light (correction to increase the color temperature when the color temperature of the ambient light is high) is applied to that area in the same way as in areas with high pixel brightness, the color temperature will become too high. Furthermore, if the ambient light is reddish, that is, if the color temperature of the ambient light is lower than the reference color temperature, the color temperature will be lower in the areas showing relatively dark gradations, as shown by the dotted line at the bottom, and a reddish color will appear on the display panel 10. This is because, as mentioned above, areas with low pixel brightness are more strongly affected by the color temperature of the ambient light, so if the color temperature of the ambient light is low, the color temperature of that area will appear low. If a correction corresponding to the ambient light (a correction to lower the color temperature when the color temperature of the ambient light is low) is applied to that area in the same way as in areas with high pixel brightness, the color temperature will become too low.

[0068] In contrast, the video processing system 2 according to the embodiment not only performs a first correction calculation process that calculates the amount of color temperature correction for the video signal to follow the color temperature of the ambient light, as described above, but also performs a second correction calculation process that reduces the absolute value of the correction amount to cancel out the color temperature of the ambient light, according to the pixel brightness of the video signal. In the example shown in Figure 9, when the ambient light is bluish light, that is, when the color temperature of the ambient light is relatively high, the absolute value of the color temperature correction amount for the video signal is reduced in the region showing relatively dark gradations, as indicated by the black arrows. As a result, the color temperature of the image displayed on the display panel 10 becomes generally constant regardless of the pixel brightness, and bluish colors are less likely to appear on the display panel 10. Also, when the ambient light is reddish light, that is, when the color temperature of the ambient light is relatively low, the absolute value of the color temperature correction amount for the video signal is reduced in the region showing relatively dark gradations, as indicated by the white arrows. As a result, the color temperature of the image displayed on the display panel 10 becomes generally constant regardless of the pixel brightness, and reddish colors are less likely to appear on the display panel 10.

[0069] Thus, in the video processing system 2 according to this embodiment, the color temperature of the video signal is corrected to follow the color temperature of the ambient light, and the absolute value of the correction amount is reduced in accordance with the pixel brightness of the video signal to cancel out the color temperature of the ambient light. For this reason, the video processing system 2 according to this embodiment has the advantage that the color temperature of the video signal is less likely to be overcorrected in areas showing relatively dark gradations, making it easier to accurately correct the color temperature of the image displayed on the display panel 10 of the display 1.

[0070] [5. Other Embodiments] Although embodiments have been described above, this disclosure is not limited to the embodiments described above.

[0071] In the above embodiment, the image processing system 2 acquires illuminance information and color temperature information by calculating them based on the RGB information output by the RGB sensor 3, but it is not limited to this. For example, the image processing system 2 may acquire illuminance information by acquiring illuminance information output by an image sensor installed around the display 1. The image sensor is composed of, for example, a CMOS (Complementary Metal-Oxide Semiconductor) sensor. Thus, the device that detects the illuminance of ambient light and the device that detects the color temperature of ambient light may be separate.

[0072] In the above embodiment, the video processing system 2 adjusts the sub-correction amount by referring to illuminance information indicating the illuminance of ambient light, but it is not limited to this. For example, the video processing system 2 may adjust the sub-correction amount by referring only to color temperature information indicating the color temperature of ambient light. In this case, steps S201 to S203 in the flowchart shown in Figure 4 become unnecessary. Also, in this case, in step S207, the sub-correction amount becomes equal to the correction amount C.

[0073] In the above embodiment, the video processing system 2 corrects the color temperature of the video signal by correcting the RGB values ​​in the video signal, but is not limited to this. For example, if the video signal is a YCbCr signal, the video processing system 2 may correct the color temperature of the video signal by correcting the YCbCr values ​​in the video signal.

[0074] In the above embodiment, the video processing system 2 is equipped with a video processing circuit 233, but is not limited to this. In other words, the video processing system 2 only needs to be equipped with a first input I / F 21, a second input I / F 22, and a CPU 231 (processor).

[0075] Furthermore, although the video processing system 2 was implemented by a single device in the above embodiment, it may be implemented by multiple devices. When the video processing system 2 is implemented by multiple devices, the functional components of the video processing system 2 may be distributed among the multiple devices in any way.

[0076] Furthermore, the method of communication between devices in the above embodiment is not particularly limited. When two devices communicate in the above embodiment, a relay device (not shown) may be interposed between the two devices.

[0077] Furthermore, the processing order described in the above embodiment is merely an example. The order of multiple processing steps may be changed, and multiple processing steps may be executed in parallel. Also, processing performed by one processing unit may be performed by another processing unit. In addition, some of the digital signal processing described in the above embodiment may be implemented by analog signal processing.

[0078] Furthermore, in the above embodiment, each component may be realized by executing a software program suitable for each component. Each component may also be realized by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0079] Furthermore, each component may be implemented by hardware. For example, each component may be a circuit (or integrated circuit). These circuits may form a single circuit as a whole, or they may be separate circuits. Also, each of these circuits may be a general-purpose circuit or a dedicated circuit.

[0080] Furthermore, the general or specific embodiments of this disclosure may be implemented as a system, apparatus, method, integrated circuit, computer program, or recording medium such as a computer-readable CD-ROM. They may also be implemented in any combination of systems, apparatus, methods, integrated circuits, computer programs, and recording media. For example, this disclosure may be implemented as a video processing method executed by a computer, or as a program to cause a computer to execute such a video processing method. Furthermore, this disclosure may be implemented as a computer-readable non-temporary recording medium on which such a program is recorded. The program as used herein includes an application program to cause a general-purpose information terminal to function as the video processing system of the above embodiment.

[0081] Furthermore, this disclosure also includes forms obtained by applying various modifications to each embodiment that a person skilled in the art could conceive, or forms realized by arbitrarily combining the components and functions of each embodiment without departing from the spirit of this disclosure.

[0082] (summary) As described above, the video processing system 2 according to the first embodiment includes a first input I / F 21, a second input I / F 22, and a CPU 231. The CPU 231 is an example of a processor. The first input I / F 21 acquires the video signal output to the display panel 10 of the display 1. The second input I / F 22 acquires color temperature information indicating the color temperature of the ambient light illuminating the display panel 10. The CPU 231 calculates the amount of color temperature correction for the video signal to follow the color temperature of the ambient light. If the pixel brightness of the video signal falls below a brightness threshold, the CPU 231 reduces the absolute value of the color temperature correction amount for the video signal to cancel out the color temperature of the ambient light. The CPU 231 outputs a video signal with the color temperature of the video signal corrected according to the correction amount.

[0083] According to this, the color temperature of the video signal is less likely to be overcorrected in areas exhibiting relatively dark gradations, which has the advantage of making it easier to accurately correct the color temperature of the video displayed on the display panel 10 of display 1.

[0084] Furthermore, in the video processing system 2 according to the second embodiment, the CPU 231 further acquires illuminance information indicating the illuminance of ambient light, as in the first embodiment. If the pixel brightness of the video signal falls below the brightness threshold Th3, the CPU 231 further adjusts the correction amount based on the illuminance of ambient light.

[0085] This method has the advantage of making it easier to correct the color temperature of the image with greater accuracy compared to not referencing ambient light illuminance.

[0086] Furthermore, in the image processing system 2 according to the third embodiment, in the second embodiment, the CPU 231 increases the absolute value of the correction amount as the illuminance of the ambient light exceeds the illuminance threshold Th1 until the illuminance of the ambient light reaches a predetermined illuminance value Th10, and once the illuminance of the ambient light reaches the predetermined illuminance value Th10, it does not increase the absolute value of the correction amount thereafter.

[0087] According to this, the advantage is that it becomes easier to correct the color temperature of the image with greater accuracy by suppressing excessive color temperature correction in response to ambient light intensity.

[0088] Furthermore, in the video processing system 2 according to the fourth embodiment, in any one of the first to third embodiments, the CPU 231 increases the absolute value of the correction amount as the color temperature of the ambient light moves away from a predetermined range R1 until the color temperature of the ambient light reaches a predetermined color value Th210 (or Th220), and once the color temperature of the ambient light reaches the predetermined color value Th210 (or Th220), it does not increase the absolute value of the correction amount thereafter.

[0089] According to this, the advantage is that it becomes easier to correct the color temperature of the image with greater accuracy by suppressing excessive color temperature correction in response to the color temperature of the ambient light.

[0090] Furthermore, in the video processing system 2 according to the fifth embodiment, in any one of the first to fourth embodiments, the video signal is an RGB signal. The CPU 231 corrects the color temperature of the video signal by correcting the RGB values ​​in the video signal.

[0091] According to this method, the color temperature of the video signal is corrected using a simple technique of correcting RGB values, which has the advantage of making it easy to perform color temperature correction processing on the video signal.

[0092] Furthermore, in the video processing method according to the sixth embodiment, the video signal output to the display panel 10 of the display 1 is acquired (S101), color temperature information indicating the color temperature of the ambient light irradiated onto the display panel 10 is acquired (S103), the amount of color temperature correction of the video signal is calculated to follow the color temperature of the ambient light (S105), if the pixel brightness of the video signal falls below a brightness threshold (S106: Yes), the absolute value of the color temperature correction amount of the video signal is reduced to cancel out the color temperature of the ambient light (S108), and a video signal with the color temperature of the video signal corrected according to the correction amount is output (S111).

[0093] According to this, the color temperature of the video signal is less likely to be overcorrected in areas exhibiting relatively dark gradations, which has the advantage of making it easier to accurately correct the color temperature of the video displayed on the display panel 10 of display 1.

[0094] Furthermore, the program according to the seventh embodiment causes one or more processors to execute the video processing method according to the sixth embodiment.

[0095] According to this, the color temperature of the video signal is less likely to be overcorrected in areas exhibiting relatively dark gradations, which has the advantage of making it easier to accurately correct the color temperature of the video displayed on the display panel 10 of display 1. [Industrial applicability]

[0096] The video processing system, etc., disclosed herein is applicable to systems that process images displayed on a display panel of a display. [Explanation of Symbols]

[0097] 1 display 10 Display Panel 2. Video Processing System 21 1st input I / F 22 2nd input I / F 23 SoC 231 CPU 232 memory 233 Video Processing Circuit 3 RGB sensors A1, A2, A3 Arrows G1, G2 area R1 predetermined range Th1 Illuminance threshold Th10 Illuminance predetermined value Th210, Th220 color predetermined value Th21 First color threshold Th22 Second Color Threshold Th3 Brightness Threshold

Claims

1. A first input interface for acquiring the video signal output to the display panel of the display, A second input interface for acquiring color temperature information indicating the color temperature of ambient light irradiated onto the display panel, Equipped with a processor, The aforementioned processor, The amount of color temperature correction for the video signal is calculated to follow the color temperature of the ambient light. In the calculation of the correction amount, if the pixel brightness of the video signal falls below the brightness threshold, a sub-correction amount is calculated to cancel out the color temperature of the ambient light, and the correction amount is corrected so that the absolute value of the correction amount becomes smaller by the sub-correction amount. The system outputs the video signal with its color temperature corrected according to the correction amount. Video processing system.

2. The aforementioned processor, Further illuminance information indicating the illuminance of the ambient light is acquired, If the pixel brightness of the video signal falls below the brightness threshold, the correction amount is further adjusted based on the illuminance of the ambient light. The image processing system according to claim 1.

3. The processor increases the absolute value of the correction amount as the illuminance of the ambient light exceeds the illuminance threshold until the illuminance of the ambient light reaches a predetermined illuminance value, and once the illuminance of the ambient light reaches the predetermined illuminance value, it stops increasing the absolute value of the correction amount thereafter. The image processing system according to claim 2.

4. The processor increases the absolute value of the correction amount as the color temperature of the ambient light moves away from a predetermined range until the color temperature of the ambient light reaches a predetermined color value, and once the color temperature of the ambient light reaches the predetermined color value, it stops increasing the absolute value of the correction amount. The video processing system according to any one of claims 1 to 3.

5. The aforementioned video signal is an RGB signal, The processor corrects the color temperature of the video signal by correcting the RGB values ​​in the video signal. The video processing system according to any one of claims 1 to 3.

6. The video signal output to the display panel of the display is acquired. The color temperature information indicating the color temperature of the ambient light irradiated onto the display panel is acquired. The amount of color temperature correction for the video signal is calculated to follow the color temperature of the ambient light. In the calculation of the correction amount, if the pixel brightness of the video signal falls below the brightness threshold, a sub-correction amount is calculated to cancel out the color temperature of the ambient light, and the correction amount is corrected so that the absolute value of the correction amount becomes smaller by the sub-correction amount. The system outputs the video signal with its color temperature corrected according to the correction amount. Image processing methods.

7. One or more processors, The video processing method described in claim 6 is executed. program.

Images