WO2009125743A1 - 映像信号処理回路、表示装置、携帯端末及びプログラム - Google Patents
映像信号処理回路、表示装置、携帯端末及びプログラム Download PDFInfo
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- WO2009125743A1 WO2009125743A1 PCT/JP2009/057060 JP2009057060W WO2009125743A1 WO 2009125743 A1 WO2009125743 A1 WO 2009125743A1 JP 2009057060 W JP2009057060 W JP 2009057060W WO 2009125743 A1 WO2009125743 A1 WO 2009125743A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/46—Colour picture communication systems
- H04N1/56—Processing of colour picture signals
- H04N1/60—Colour correction or control
- H04N1/6027—Correction or control of colour gradation or colour contrast
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/46—Colour picture communication systems
- H04N1/56—Processing of colour picture signals
- H04N1/60—Colour correction or control
- H04N1/6002—Corrections within particular colour systems
- H04N1/6005—Corrections within particular colour systems with luminance or chrominance signals, e.g. LC1C2, HSL or YUV
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/64—Circuits for processing colour signals
- H04N9/73—Colour balance circuits, e.g. white balance circuits or colour temperature control
Definitions
- the present invention relates to image processing, and more particularly, to an image processing technique that can easily perform good white display.
- color TV broadcasting such as NTSC / PAL (EBU)
- R, G, B chromaticity points and standard white points are defined for each broadcasting system.
- the TV video is broadcast with color adjustment based on the defined colors, and it is expected that a predetermined color (white) is displayed on the display device.
- a display device such as a liquid crystal display based on digital RGB video data
- the display device When displaying video on a display device such as a liquid crystal display based on digital RGB video data, the display device generally performs ⁇ correction on the display device side to perform white color adjustment and display a predetermined white color. I was letting.
- the display device described in Patent Document 1 below describes that image processing is performed on an RGB video signal before being input to the display device.
- the main components of this display device are an acquisition unit (illuminance sensor), a conversion unit (control unit), a correction unit (color correction circuit), an output unit (display device), and a storage unit (RAM).
- FIG. 16 is a diagram illustrating an example of input / output characteristics based on the technique disclosed in Patent Document 1 below.
- Chromaticity coordinates when white is displayed on the display device are acquired, correction coefficients corresponding to RGB are obtained so as to output predetermined white, and the intensity of each RGB video signal is corrected.
- the RGB correction coefficients are determined so that the largest value is 1.0 while maintaining the ratio of each coefficient so that a predetermined white color can be output, and the input / output characteristics are composed of only straight lines. The Therefore, the correction coefficient is a slope of a straight line.
- JP 2007-241120 A JP 2007-241120 A
- each line of GB has not been fully increased to the maximum value, so that the brightness of white is lowered.
- the input / output characteristics that simply hold the RGB ratio are used, so that a component with a correction coefficient of 1 or less appears (G, B). There is a problem that falls.
- An object of the present invention is to suppress a decrease in the maximum luminance due to correction processing while maintaining a white hue.
- the video signal processing circuit calculates the RGB correction coefficient so as to output a predetermined white color, and then adjusts the minimum correction coefficient of RGB so that the input luminance and the output luminance are approximately 1.
- the maximum luminance is maintained by adjusting the correction coefficient so as to match.
- an n (n> 1) degree curve such as a quadratic curve is used to adjust the input / output characteristics so as not to be saturated.
- components with a correction coefficient of less than 1 are lifted using a quadratic curve so that when the input is the maximum value in the input / output characteristics, the output reaches the maximum value.
- a video signal input / output conversion processing unit that converts an input value of an RGB video signal into an output value of an RGB video signal is provided, and the output value of the video signal input / output conversion processing unit is displayed on a display unit.
- the input / output characteristics are corrected by the respective RGB correction values, and the first input / output characteristics of the color having the correction value exceeding 1 are represented by an n (n> 1) degree curve in the high luminance region.
- n n> 1 degree curve in the high luminance region.
- a video signal processing circuit characterized by having a white corrector is provided that.
- the predetermined white color is a white color generated based on a standard white point defined on the video source side or a white point defined in a color space used for moving image / still image content.
- predetermined white means white that is expected to be displayed on the display device by performing color adjustment based on the RGB chromaticity point and standard white point defined for each broadcasting system.
- Point to the color space sRGB used for the standard white point defined in color TV broadcasting systems such as NTSC / PAL (EBU), moving image content distributed over the Internet, or still image content shot with a digital camera or the like This is a white color generated based on a white point defined by / sYCC / AdobeRGB.
- the saturation region appearing in the high luminance region can be suppressed and actual input / output characteristics can be obtained.
- the primary straight line is not necessarily a complete primary straight line, but the primary straight line is preferable for simplifying the processing. Further, to make the minimum value of the correction value substantially 1 is not necessarily “1” itself, and “1” is cited as a more ideal value.
- a relatively simple curve such as a quadratic curve or a cubic curve is preferable for the simplification of the n-order curve used for suppressing saturation.
- the correction value is 1 or more for all RGB colors, so that bright white can be displayed. If the minimum value of the correction value exceeds 1, it is possible to suppress a decrease in the maximum luminance due to the correction process while maintaining a white hue in a practical luminance range (0 to 70%) of a TV image or the like. Furthermore, the closer the minimum correction value is to 1, the higher the gradation in the high luminance region.
- the luminance range of the images is approximately 0 to 70% of the input luminance. Therefore, practically, it is only necessary to output a predetermined white color within a range of about 0 to 70% of the input luminance.
- the first input / output characteristic and the second input / output characteristic have an intersection within an input luminance range, and the first input / output characteristic to the second input / output characteristic with the intersection as a boundary. It is preferable to switch to.
- the first input / output characteristic covers a practical luminance range of about 0 to 70%, and the second input / output characteristic covers a practical luminance range of 70% or more. preferable.
- a video signal input / output conversion processing unit for converting an input value of the RGB video signal into an output value of the RGB video signal, and a video signal processing circuit for outputting the output value of the video signal input / output conversion processing unit to the display unit;
- the first input / output characteristics are set to RGB so that the RGB ratio of the initial correction values (initial correction coefficients) for other colors is substantially maintained.
- the first input / output characteristic for a color with the correction value exceeding 1 is expressed by an n-th (n> 1) -order curve in the high luminance region.
- the first input / output characteristic is replaced with a downwardly convex third input / output characteristic represented by an n (n> 1) degree curve in the high luminance region.
- a video signal processing circuit is provided.
- the first input / output characteristic is replaced by a second convex input / output characteristic represented by an n (n> 1) degree curve in the high luminance region.
- the correction value exceeds 1
- the saturation region appearing in the high luminance region is suppressed to obtain the actual input / output characteristics.
- the first input / output characteristic is replaced with a downwardly convex third input / output characteristic represented by an n (n> 1) degree curve in the high luminance region.
- the first input / output characteristic and the second and third input / output characteristics have an intersection within an input luminance range, and the second input / output characteristic is changed from the first input / output characteristic to the second with the intersection as a boundary. It is preferable to switch to the third input / output characteristic.
- the first input / output characteristic covers a practical luminance range of about 0 to 70%, and the second and third input / output characteristics cover a practical luminance range of 70% or more. It is preferable to do.
- the ⁇ correction processing of the display device may be stopped.
- the present invention may be a display device including the video signal processing circuit and a display unit that displays video based on the video signal processed by the video signal processing circuit. Furthermore, it is preferable to have an operation unit for performing an operation of changing the parameter (at least one of the correction value or the curvature of the n (n> 1) degree curve).
- a portable communication terminal including the display device described above and a communication unit that performs communication may be used.
- the present invention may be a method for realizing the above functions, a program for causing a computer to execute the method, and a computer-readable recording medium for recording the program.
- the program may be acquired by a transmission medium.
- the present invention it is possible to suppress a decrease in the maximum luminance due to the correction process while maintaining a white hue in a practical luminance range (0 to 70%) of a TV image or the like.
- the brightness of the display image can be maintained.
- FIG. 1 is a diagram showing an overview of an image processing system according to an embodiment of the present invention. It is a figure which shows the input / output characteristic for the color adjustment by the 1st Embodiment of this invention. It is a figure which shows the example in the case where the line connected to a primary straight line is a primary straight line (a), the case of a quadratic curve (b), and the case of a cubic curve (c). It is a figure which shows the input / output characteristic for the color adjustment in the image processing system by the 2nd Embodiment of this invention.
- Respect X linear, X lcurve a diagram showing a state determining one is whether it is appropriate for the X ucurve.
- FIG. 7 is a diagram showing the flow of processing when the functions of the hardware configuration (circuit) according to the first embodiment shown in FIG. 6 in the image processing technique according to the embodiment of the present invention are directly processed by software.
- predetermined white color is defined as follows. That is, in color TV broadcasting such as NTSC / PAL (EBU), R, G, B chromaticity points and standard white points are defined for each broadcasting system. The TV video is broadcast with color adjustment based on the defined colors, and it is expected that a predetermined color (white) is displayed on the display device. Such an expected color relating to white is referred to as “predetermined white”. In other words, “predetermined white” is white that is expected to be displayed on the display device by performing color adjustment based on the RGB chromaticity point and the standard white point defined for each broadcasting system. is there.
- the “predetermined white” is a white point defined by a color space sRGB / sYCC / AdobeRGB used for moving image content distributed over the Internet, still image content shot with a digital camera, etc. in addition to color TV broadcasting. It may be used.
- the “initial correction value (initial correction coefficient)” means that the display color is measured with a measuring instrument such as a chromaticity meter in a state where white is displayed on the display device, and the chromaticity of the display color is determined to be a predetermined white. This correction value when the correction value is obtained by adjusting the RGB level to be the same.
- the maximum correction coefficient is adjusted to be 1.
- brightness cannot be maintained by such a method.
- the inventor calculates RGB initial correction values (initial correction coefficients) A R , A G , and A B so as to output a predetermined white color, and then calculates the maximum of the correction coefficients A R , A G , and A B.
- the inventors have come up with the idea that the maximum brightness is maintained by adjusting the slope using a linear curve so that the minimum correction coefficient, which is the minimum correction coefficient, is 1 instead of the maximum correction coefficient, which is the correction coefficient.
- a reduction in the maximum luminance due to the correction process is suppressed while maintaining a white hue in a practical luminance range (0 to 70%) of a TV image or the like.
- FIG. 1 is a diagram showing an outline of an image processing system according to the present embodiment.
- digital RGB video data from a video signal output device 1 such as a personal computer (PC) or a graphic board also serves as white correction processing in an image processing unit 3 according to the present embodiment described below.
- Image processing is performed, and the output data is output as an output signal to the display device 5 such as a liquid crystal display device.
- the input digital RGB video data may be the display device 5 that does not already have the adjustment function 7 such as ⁇ correction, or the case where the adjustment function 7 is provided but not used.
- the digital RGB video data as it is is converted into an analog signal by the D / A converter 11 and the analog signal is supplied to a display panel such as the liquid crystal panel 15 so that white can be appropriately corrected.
- FIG. 2A is a diagram illustrating an example of input / output characteristics for performing video signal input / output conversion processing using the video signal processing circuit for color adjustment according to the first embodiment of the present invention.
- the horizontal axis is the value of the input signal
- the vertical axis is the value of the output signal.
- the minimum value of the correction coefficient is determined to be 1 so that the white brightness after white correction does not decrease.
- “1” here is not a strict value.
- the maximum value is corrected to about “1”
- the minimum value is set.
- the idea of setting it to “1” is the first point different from the conventional one. In this way, all correction coefficients become “1” or more. If the minimum value of the correction value exceeds 1, it is possible to suppress a decrease in the maximum luminance due to the correction process while maintaining a white hue in a practical luminance range (0 to 70%) of a TV image or the like. Furthermore, the closer the minimum correction value is to 1, the higher the gradation in the high luminance region.
- the correction coefficient is “1” or more
- the output is saturated when the input becomes large. Therefore, saturation suppression is performed using an nth-order curve ( Xcurve ), for example, a quadratic curve or a cubic curve so that saturation does not occur.
- Xcurve nth-order curve
- the maximum value obtained by the correction process is maintained while maintaining the hue of white in a practical luminance range (about 0 to 70%) of the image of the television receiver (TV). A decrease in luminance can be suppressed.
- the initial correction values (initial correction coefficients) of R, G, and B obtained by a conventional method so as to display a predetermined white color are A RI , A GI , and A BI .
- a quadratic curve (which is referred to as a first input / output characteristic) obtained by the first video signal input / output conversion process and a quadratic curve (this is referred to as a smooth curve) are connected to each other.
- the curvature (Cx) of the second input / output characteristic is determined.
- a case of a quadratic curve will be described as an example of the nth-order curve (n> 1).
- the correction formula will be described below.
- the video data is corrected by the following (Equation 1-4), where X in is the video input (input signal) and X out is the video output (output signal).
- X is replaced with R, G, and B, and the same processing is performed for each component of RGB.
- a x and C x in the following equations can be obtained by parameter fitting.
- X in is switched from X linear to X ucurve around 224. That is, the input / output characteristics are X1-X2 as shown by the solid line in FIG. 2A.
- X ucurve is preferably replaced with X linear at X in before X linear is saturated, and the second video signal input / output conversion processing is performed so that X out becomes about 255 when X in becomes 255.
- the connection is made as smooth as possible near the joint. Therefore, when the primary curves (straight lines) are connected, the smoothness is lost, and there is a high possibility that the display is jerky near the joint.
- n-order curve such as a cubic line
- the straight portion and the nth-order curve are smoothly connected to improve the image quality.
- the circuit scale can be reduced if the saturation suppression portion itself is a line having a small n such as a primary straight line.
- FIG. 2B shows an example of the case where the line connected to the primary straight line is a primary straight line (a), a quadratic curve (b), and a cubic curve (c) in the video signal input / output conversion process.
- FIG. 2B shows an example of the case where the line connected to the primary straight line is a primary straight line (a), a quadratic curve (b), and a cubic curve (c) in the video signal input / output conversion process.
- FIG. 2B shows an example of the case where the line connected to the primary straight line is a primary straight line (a), a quadratic curve (b), and a cubic curve (c) in the video signal input / output conversion process.
- the saturation suppression portion is a low-order line such as a primary straight line
- the circuit scale can be reduced.
- the number of n is basically determined at the time of product design, but the user may be able to switch while looking at the image quality, or the content provider side may provide it in the content. It may be possible to control from the provider side so as to match the content.
- the correction processing is performed while maintaining the white hue in the practical luminance range (0 to 70%) of the TV video or the like.
- luminance by can be suppressed is acquired.
- the image processing technique using the video signal processing circuit according to the present embodiment is such that the luminance of the input video based on the input signal of the white correction circuit matches the luminance of the output video based on the output signal.
- the first video signal input / output conversion processing for adjusting the correction coefficient is performed. If it does in this way, a correction coefficient will be divided into a component of 1 or more and a component of less than 1. For a component having a correction coefficient of 1 or more, saturation suppression is performed in the same manner as in the second video signal input / output conversion process according to the first embodiment. For components with a correction factor of less than 1, as shown in Fig.
- the brightness of the display image can be stored even on the high luminance side of the input.
- the “parameter determination method” will be described below. The following parameters to be used are set in a register or the like before starting the white processing.
- the correction coefficient (A x ) is determined so as to preserve the input / output luminance.
- the weighting of R, G, and B is a weighting coefficient for each color determined based on the degree of contribution to luminance.
- the initial correction value (initial correction coefficient) coefficient obtained so as to output a predetermined white is A RI , A GI , A Assuming BI , the magnifications (A R , A G , A B ) used in Principle 2 can be determined as follows.
- the following parameters are automatically generated in the white correction circuit using the magnification (A x ).
- 3B is with respect to X linear, X lcurve, a diagram showing a state determining one is whether it is appropriate for the X ucurve.
- the present embodiment is characterized in that the correction coefficient is adjusted so that the luminance of the input video and the luminance of the output video of the white correction circuit match. In this way, the correction coefficient is divided into components of 1 or more and components of less than 1.
- X linear indicating the input / output characteristics in a practical luminance range is The Xucurve , which shows the input / output characteristics in the luminance range beyond that, was successfully connected.
- the correction coefficient is divided into a component of 1 or more and a component of less than 1, so it may be necessary to switch the curve connected in the practical luminance range or more depending on each component. That is, X ucurve , which is a quadratic curve convex upward , is smoothly connected to the straight line of X11 having a correction coefficient of 1 or more (X12). For the correction coefficient is a component of less than 1 X13, smoothly connecting the X Lcurve a quadratic curve downwardly convex (X14). As described above, whether the correction coefficient is connected to the upward convex curve or the downward convex curve is determined depending on whether the correction coefficient is 1 or more or less than 1. When the correction coefficient is in a range close to 1, it is not necessary to connect the correction coefficient as it is to the curve. It is preferable to determine in advance whether the lower or upper convex curve is connected based on the degree of deviation from 1 of the correction coefficient.
- 4A and 4B are diagrams illustrating specific examples of the image processing technique according to the first embodiment of the present invention.
- an initial correction value (initial correction coefficient) coefficient (A xi ) is obtained so as to output a predetermined white color.
- X in the initial correction coefficient (A xi ) is one of R, G, and B.
- the predetermined white output can be obtained.
- a ri 1.07
- step S2 since the initial correction coefficient of B is the minimum, the coefficient (A x ) is generated so that the minimum value (A bi ) becomes 1.0.
- the RGB correction value can be made substantially the same as the RGB ratio of the initial correction coefficient.
- the RGB ratio may be substantially the same as the RGB ratio of the initial correction coefficient.
- the curvature (C x ) is determined by the control unit so that the straight line portion and the quadratic curve portion are smoothly connected (step S3).
- This process can be performed by, for example, parameter fitting.
- step S5 the parameters stored as described above are read from the storage unit, and white correction processing is performed based on the input / output characteristics shown in FIG. 4B.
- the luminance can be maintained so that the white display can be performed, and the white display can be made continuous even at the joint between AR1 and AR2.
- FIG. 5A and FIG. 5B are specific diagrams showing a correction example in the second embodiment.
- an initial correction coefficient (A xi ) is obtained so as to output a predetermined white color. This process is performed by connecting a product to which the present invention is applied and a measuring instrument in a production line or the like.
- a ri 1.07
- a gi 1
- a bi 0.92
- a coefficient (A x ) is generated so that the input luminance matches the output luminance. This process is performed by the control unit (step S12).
- the G correction coefficient is substantially “1”.
- a r 1.06
- a g 0.99
- a b 0.91
- the curvature (C x , D x ) is determined by, for example, parameter fitting so that the straight line portion and the quadratic curve portion are well connected (step S13). This process is also performed by the control unit.
- a high luminance range is represented by smoothly connecting the first straight line with a quadratic curve convex upward, and for B having a correction coefficient smaller than 1.
- FIG. 6 is a diagram illustrating an example in which the image processing technique according to the first embodiment of the present invention is implemented by a circuit.
- the video signal processing circuit 31 includes a register 33 that temporarily captures the magnification and curvature of each color stored in the storage unit, that is, A R , C R , A G , C G , A B , and C B.
- the correction coefficient A X and the video input X in (R in , G in , B in ) are input from among the outputs from the register 33, and for each color, X linear is obtained by the above equation (1-5).
- the first arithmetic circuit 45 that calculates the above and the curvature C X and the video input X in (R in , G in , B in ) out of the outputs from the register 33 are input.
- FIG. 7 is a diagram showing an example in which the image processing technique according to the second embodiment of the present invention is realized by a circuit.
- the video signal processing circuit 51 has the magnification and curvature of each color stored in the storage unit, that is, A R , C R , D R , A G , C G , D G , A B , C B, D G Are input temporarily from the register 53 for temporarily capturing the image and the correction coefficient AX and the video input X in (R in , G in , B in ) out of the outputs from the register 53 for each color.
- the first arithmetic circuit 65 that calculates X linear by the equation (2-6) and Ex is obtained from Ax by the above equation (2-9), and the curvature D is calculated from the Ex and each output from the register 53.
- a second arithmetic circuit 68 that obtains X lcurve by the above equation (2-8) for each color by using X and video input X in (R in , G in , B in ) as inputs;
- a circuit 73 for outputting the larger one of the force X linear and X lcurve third calculation that outputs X Ucurve performs calculation of the above formula (2-7) and C x and X in the input
- the circuit 71, the circuit 75 that receives the output X ucurve of the circuit 73 and the output X ucurve of the third arithmetic circuit 71 as inputs, and outputs the smaller one as Xout according to the equation (2-5) (the output in this
- FIG. 8 is a functional block diagram showing a configuration example of a portable terminal having a video signal processing circuit according to the first and second embodiments of the present invention.
- the mobile terminal 100 used in the present embodiment includes a wireless unit 103 for performing wireless communication, a camera 105, a television receiver (TV receiver) 107, and a battery.
- Power supply unit 111, video generation unit 113, video (image) processing unit 121, register 127, LCD display device 131, external memory interface unit 133, memory unit 135 including ROM / RAM, speaker / A voice output unit such as a microphone 137, an operation unit 141, and a control unit (CPU) 143 for controlling the whole are included. Note that not all of these components are essential, and other components may be provided.
- the video generation unit 113 includes a video decoder 115 and a video memory 117.
- the video (image) processing unit 121 includes a color adjustment unit 123 and a white color correction unit 125 for videos acquired from the wireless unit 103, the camera 105, the TV reception unit 107, an external memory, and the like.
- the memory unit 135 is provided with a parameter storage unit 135a that stores the above-described parameters.
- the input video signal (digital RGB) output from the video generation unit 113 is input to the color adjustment unit 123, and then temporarily stored in the register 127 from the parameter storage unit 135a in the color correction unit that is a feature of the present embodiment.
- the output video signal (digital RGB) corrected based on the parameters taken in is output to the display device 131. Whether or not white correction is to be performed may be determined based on whether the acquired video is from the wireless unit 103, the camera 105, or the TV receiver 107.
- FIG. 9 is a diagram illustrating an external configuration example of the mobile terminal 100 illustrated in FIG. 8, and illustrates an external appearance on the side where the display device 131 is visible.
- the mobile terminal 100 includes an operation unit 141 and an antenna 151.
- the white correction setting value can be changed by the operation unit 141 using the slide bars 153, 155, 157, 161 and the like displayed on the display device 131.
- a display unit 163 for confirming the adjusted image is provided.
- the slide bar 153 can be adjusted correction value A R of the red (R).
- the green (G) correction value AG can be adjusted by the slide bar 155.
- the curvature Cx may be adjusted by the slide bar 161.
- the user operation by the slide bar further adjusts the correction value and can be said to be white adjustment.
- the correction value and the adjustment value by the user are preferably stored and managed independently.
- the correction value is a correction value for the mobile terminal, and the adjustment value can be said to be an adjustment value for the content, and is preferably stored in association with the content.
- FIG. 10 is a diagram illustrating a usage example of the mobile terminal according to the present embodiment.
- a mobile terminal 100A (a mobile terminal used by the user A) having a plurality of display units 131a and antennas 151a (a mobile terminal used by the user A) and a display unit 131b
- a mobile terminal 100B having an antenna 151b (a mobile terminal used by the user B) is disposed.
- the mobile terminal 100 ⁇ / b> A receives 1-segment broadcasting from the radio tower 173.
- the portable terminal 100B is connected to the server 175.
- the mobile terminal 100A and the mobile terminal 100B are connected via a network 171.
- a setting value such as a correction coefficient of the portable terminal 100A can be transmitted to the portable terminal 100B via the network 171 so that the setting value can be used in the portable terminal 100B.
- the setting of users can be shared. That is, it is possible to share the adjustment value described with reference to FIG. 9 by the user who subtracts the correction value of the white variation of the display devices 131a and 131b.
- a set value may be given to broadcast data (for example, 1-segment content itself). Furthermore, the setting value can be downloaded and used via the server 175. In this manner, a parameter obtained by combining the adjustment value matched with the video content to be displayed and the white variation correction value can be generated and set in the register of the white correction unit 125 (FIG. 8).
- FIG. 11 is a functional relationship diagram centering on the white correction unit 125 in the video signal processing unit 121. As shown in FIG. 11, the description will focus on a video signal processing unit 121 having a white color correction unit 125.
- the correction value from the storage unit (ROM / RAM) 135 is read to the control unit 143 (L3).
- the parameter setting value L1 acquired from the wireless unit 103a through wireless communication is transmitted to the control unit (CPU) 143.
- the parameter setting value L2 by the user input from the operation unit 141 is transmitted to the control unit (CPU) 143.
- setting (L4) based on broadcast data L4 from the TV receiver 107 is also made.
- the control unit 143 temporarily sets the parameter setting value in the register 127 (L5).
- the parameter stored in the register is transmitted to the video signal processing unit 121 (L6).
- the video signal itself includes one segment L7 from the TV receiving unit 107, a moving image / still image L8 from the external memory I / F memory 133, a moving image / still image L9 from the camera 105, and a wireless communication unit 103b.
- the moving image / still image L10, the input video signal L7-10 are input to the video signal processing unit 121, the white correction unit 125 performs white correction by the parameter L10, and the output video signal L11 is output to the display device 131.
- Video display is
- FIG. 12 shows a flow of processing when the function of the hardware configuration (circuit) according to the first embodiment shown in FIG. Show.
- a calculation formula used in the processing shown in the flowchart shown in FIG. 12 is shown in the upper left of FIG.
- step S102 the magnitude relationship between X linear and X ucurve is compared.
- FIG. 13 shows the flow of processing when the function of the hardware configuration (circuit) according to the second embodiment shown in FIG. Show.
- X lcurve (E x ⁇ D x ) ⁇ X in 2 + D x ⁇ X in is calculated.
- the image processing technique according to this embodiment can be executed regardless of the hardware configuration or the software configuration.
- the above software processing describes an example of software processing according to the hardware configuration.
- FIG. 14 is a flowchart optimized for software processing for executing the image processing technique according to the first embodiment.
- the intersection (X cross ) of X linear and X ucurve is obtained in advance (before executing the flowchart shown in FIG. 14).
- This intersection (X cross ) may be stored in the storage unit described above and read before execution.
- FIG. 15 is a flowchart optimized for software processing for executing the image processing technique according to the second embodiment.
- the intersection of the X technicallyar and X Ucurve (referred to as upper intersection X ucross.),
- the intersection of the X technicallyar and X Lcurve (lower intersection: referred to as X LCROSS. )
- the upper intersection / lower intersection (X ucross , X lcross ) may be stored in the storage unit and read out before execution.
- the upper intersection point (X ucross ) can be obtained in the same manner as the above intersection point (X cross ).
- the Xout obtained as described above is output to the display device.
- the above flow chart shows an example of a flow of processing for easily obtaining the first embodiment and the second embodiment of the image processing technique according to the present embodiment described above by software processing.
- software processing can be simplified and processing load can be reduced. That is, a program for causing a computer to execute the function as the video signal processing circuit described above also falls within the scope of the present invention.
- each embodiment of the present invention it is possible to suppress a decrease in the maximum luminance due to correction processing while maintaining a white hue in a practical luminance range (0 to 70%) of a TV image or the like. it can. Furthermore, the brightness of the display image can be maintained.
- the present invention can be used for an image display device.
Abstract
Description
以下に、「パラメータ決定方法」について説明を行う。使用する下記のパラメータは、白色処理を開始する前にレジスタ等に設定しておく。
Ag = 1.09
Ab = 1
このように、Abが“1”になるようにする。このように、RGBの補正値を、初期補正係数のRGBの比率と実質的に同じようにすることができる。尚、RGBの比率は、実質的に初期補正係数のRGBの比率と同じようにすれば良いのであって、例えば、Ar=1.15、Ag=1.10、Ab=1.00のように、きりの良いような近似値を用いるようにしても良い。
Cg = 0.56
Cb = 0
このようにして算出した上記のパラメータ(Ax, Cx)を、ステップS4において記憶部に格納する。
Agi = 1
Abi = 0.92
入力輝度と出力輝度とが一致するように係数(Ax)を生成する。この処理は制御部で処理する(ステップS12)。尚、ここでは、Gの補正係数がほぼ“1”になっている。
Ar = 1.06
Ag = 0.99
Ab = 0.91
直線部分と2次曲線部分がうまく接続するように、例えばパラメータフィッチングにより、曲率(Cx, Dx)を決定する(ステップS13)。この処理も、制御部で行う。
Cg = 0
Cb = 0
Dr = 0
Dg = 0
Db = 0.25
算出したパラメータ(Ax, Cx, Dx)を、記憶部に格納する(ステップS14)。次いで、映像表示時に記憶部から上記パラメータを読み出し、図5Bに示す入出力特性に従って白色補正処理を行う。尚、ここでは、全輝度範囲(実用的輝度範囲AR3、高輝度範囲AR4)で、Gはほぼ1次直線で表することができ、オリジナル映像の明るさを表現することができ、処理が簡単化する。また、補正係数が1よりも大きいRについては、1次直線に対して、上に凸の2次曲線により滑らかにつなぐことで高輝度範囲を表し、また、補正係数が1よりも小さなBについては、1次直線に対して、下に凸の2次曲線により滑らかにつなぐことで高輝度範囲を表す。このように、1次直線と、上に凸の2次曲線と、下に凸の2次曲線とにより、RGBをそれぞれ補正することにより、Gを中心にしてバランス良く白色の色調整を行いつつ輝度を保つことができるという利点がある。
(1 - Cx)・Xcross 2+ (Cx - Ax)・Xcross = 0
(1 - Cx)・Xcross= - (Cx - Ax)
以上より、交点は、Xcross= (Ax - Cx) / (1 - Cx)と求まる。
(Ex - Dx)・Xlcross 2+ (Dx - Ax)・Xlcross = 0
(Ex - Dx)・Xlcross= - (Dx - Ax)
以上より、下交点は、Xlcross= (Ax - Dx) / (Ex - Dx)となる。
Claims (12)
- RGB映像信号の入力値をRGB映像信号の出力値に変換する映像信号入出力変換処理部を有し、前記映像信号入出力変換処理部の出力値を表示部に出力する映像信号処理回路であって、
1次直線で表されRGB各色のそれぞれの第1の入出力特性の傾きで定義され、所定の白色を表示するための初期補正値を、その最小値が実質的に1以上になるように調整し、かつ、その他の色について前記初期補正値のRGBの比率が実質的に保たれるように前記第1の入出力特性をRGBのそれぞれの補正値により補正するとともに、前記補正値が1を超える色の前記第1の入出力特性を、高輝度領域においてn(n>1)次曲線により表される上に凸の第2の入出力特性により置き換える白色補正部を有することを特徴とする映像信号処理回路。 - 前記第1の入出力特性と前記第2の入出力特性とは、入力輝度の範囲内において交点を有し、該交点を境にして前記第1の入出力特性から前記第2の入出力特性に切り替えることを特徴とする請求項1に記載の映像信号処理回路。
- 前記第1の入出力特性は、実用的輝度範囲である0~70%程度の範囲をカバーし、前記第2の入出力特性は前記70%以上の範囲をカバーすることを特徴とする請求項1又は2に記載の映像信号処理回路。
- RGB映像信号の入力値をRGB映像信号の出力値に変換する映像信号入出力変換処理部を有し、前記映像信号入出力変換処理部の出力値を表示部に出力する映像信号処理回路であって、
1次直線で表されRGB各色のそれぞれの第1の入出力特性の傾きで定義され、所定の白色を表示するための初期補正値を、入力輝度と出力輝度とが実質的に同じになるように調整し、かつ、その他の色について前記初期補正値のRGBの比率が実質的に保たれるように前記第1の入出力特性をRGBのそれぞれの補正値により補正するとともに、前記補正値が1を超える色については前記第1の入出力特性を、高輝度領域においてn(n>1)次曲線により表される上に凸の第2の入出力特性により置き換え、前記補正値が1より小さくなる色については前記第1の入出力特性を、高輝度領域においてn(n>1)次曲線により表される下に凸の第3の入出力特性により置き換える白色補正部を有することを特徴とする映像信号処理回路。 - 前記第1の入出力特性と、前記第2・第3の入出力特性とは、入力輝度の範囲内において交点を有し、該交点を境にして前記第1の入出力特性から前記第2又は第3の入出力特性に切り替わることを特徴とする請求項4に記載の映像信号処理回路。
- 前記第1の入出力特性は実用的輝度範囲である0~70%程度の範囲をカバーし、前記第2・第3の入出力特性は実用的輝度範囲である前記70%以上の範囲をカバーすることを特徴とする請求項4又は5に記載の映像信号処理回路。
- 前記白色補正部が機能すると、表示装置のγ補正処理が停止することを特徴とする請求項1から6までのいずれか1項に記載の映像信号処理回路。
- 前記所定の白色は、映像ソース側で定義されている標準白色点又は動画・静止画コンテンツで用いられる色空間で定義される白色点に基づいて生成される白色であることを特徴とする請求項1から7までのいずれか1項に記載の映像信号処理回路。
- 請求項1から8までのいずれか1項に記載の映像信号処理回路と、
該映像信号処理回路により処理された映像信号に基づいて映像表示される表示部と
を備えた表示装置。 - さらに、前記補正値又は前記n(n>1)次曲線の曲率のうちの少なくもといずれか一方を変更する操作を行う操作部を有することを特徴とする請求項9に記載の表示装置。
- 請求項9又は10に記載の表示装置と、通信を行う通信部と、を備えた携帯端末。
- コンピュータに、請求項1から8までのいずれか1項に記載の映像信号処理回路としての機能を実行させるためのプログラム。
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CN2009801219136A CN102057674A (zh) | 2008-04-11 | 2009-04-06 | 视频信号处理电路、显示设备、移动终端、以及程序 |
US12/937,170 US8416257B2 (en) | 2008-04-11 | 2009-04-06 | Video signal processing circuit, display device, mobile terminal, and program |
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JP2012169929A (ja) * | 2011-02-15 | 2012-09-06 | Funai Electric Co Ltd | 画像表示装置 |
JP2012169930A (ja) * | 2011-02-15 | 2012-09-06 | Funai Electric Co Ltd | 画像表示装置 |
JP2013123190A (ja) * | 2011-12-12 | 2013-06-20 | Sharp Corp | 白色調整制御デバイス、その制御方法、制御プログラム、および記録媒体、並びに、表示装置 |
CN110379380A (zh) * | 2018-04-13 | 2019-10-25 | 夏普株式会社 | 灰度校正数据生成装置及方法、灰度校正装置、电子设备 |
WO2022244073A1 (ja) * | 2021-05-17 | 2022-11-24 | 三菱電機株式会社 | 画像処理装置、プログラム及び画像処理方法 |
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JP2014194499A (ja) * | 2013-03-29 | 2014-10-09 | Panasonic Liquid Crystal Display Co Ltd | 液晶表示装置及びその駆動方法 |
CN108171646B (zh) * | 2016-12-07 | 2021-07-23 | 展讯通信(上海)有限公司 | 基于亮度保持的图像色调调节方法及装置 |
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