JP2019184743A - Video processing device, video processing method, television receiver, control program, and recording medium - Google Patents

Abstract

To minimize video quality degradation when applying the conventional fixed frame rate video technology to variable frame rate videos.SOLUTION: A video processing device 10 is provided, comprising an acquisition unit 12 and a correction unit 13, where the acquisition unit 12 is configured to acquire a video signal, and the correction unit 13 is configured to weaken or turn off correction applied to the video signal when the correction unit determines that the acquired video signal includes a video signal with a variable frame interval.SELECTED DRAWING: Figure 1

Description

  One embodiment of the present invention relates to a video processing device, a video processing method, a television receiver, a control program, and a recording medium.

  In recent years, a liquid crystal display device compatible with G-SYNC (registered trademark) capable of scanning with variable timing is known. Also, HDMI 2.1 (registered trademark) is known as a communication interface standard capable of transmitting a variable frame rate video.

  Patent Document 1 below discloses a display device that performs an appropriate voltage setting for an input video signal having a variable frame rate. In Patent Document 2 below, a display control device capable of suppressing the occurrence of transfer is disclosed.

Japanese Patent Application No. 2015-552882 (published on January 14, 2013) International Publication No. 2016/171069 (Released on October 27, 2016)

  However, the conventional technology as described above is temporarily applied when conventional video technology at a fixed frame rate such as overdrive, dithering, or shadow correction is applied to a video with a variable frame rate as usual. There is a problem that a defect such as a part of the screen becoming too bright may occur and the video quality may deteriorate.

  One aspect of the present invention has been made in view of the above-described problem, and suppresses deterioration in video quality when a conventional video technology at a fixed frame rate is used for a video at a variable frame rate. Objective.

  In order to solve the above problem, a video processing apparatus according to an aspect of the present invention is a video processing apparatus including an acquisition unit and a correction unit, wherein the acquisition unit acquires a video signal and performs the correction. The unit determines whether or not the video signal acquired by the acquisition unit includes a video signal whose frame interval may vary, and determines that the video signal includes a video signal whose frame interval may vary. The degree of correction for the video signal acquired by the acquisition unit is reduced, or correction for the video signal acquired by the acquisition unit is turned off.

  According to one aspect of the present invention, it is possible to suppress degradation in video quality when a conventional video technology at a fixed frame rate is used for video at a variable frame rate.

It is a functional block diagram of the television receiver which concerns on this embodiment. It is a figure which shows the operation | movement of overdrive correction | amendment. 3 is a flowchart illustrating a processing flow according to the first embodiment. It is a figure which shows the brightness of each partial area | region of the display screen of a liquid crystal display device. 6 is a flowchart illustrating a processing flow according to the second embodiment. FIG. 10 is a block diagram schematically illustrating an image signal processing circuit in a correction unit according to a third embodiment. It is a figure which shows typically the 1st row | line and 2nd row | line pixel in a liquid crystal display device, and the two source lines arrange | positioned at the both sides of the 1st row | line pixel. It is a figure which shows typically the fluctuation | variation between 1 frames of the source potential of the object pixel of a liquid crystal display device. (A) is a figure which shows an example of the source potential of the pixel when correction | amendment by the correction | amendment part is not made in the liquid crystal display device of Embodiment 1 of this invention, (b) is a liquid crystal display of the said Embodiment 1. FIG. FIG. 6C is a diagram illustrating an example of correction values calculated by the correction unit in the device, and FIG. 8C illustrates an example of a source potential of a pixel when the source voltage is corrected by the correction unit in the liquid crystal display device of the first embodiment. FIG. (A) is a figure which shows typically the fluctuation | variation in the period from the part for a previous frame to the part for the following frame of the source potential in the liquid crystal display device which applies a source voltage by 1 frame inversion, (b), It is a figure which shows typically the fluctuation | variation of the source potential in the period from the present time to the next one frame among (a). It is a figure which shows the example when a blanking period arises in the fluctuation | variation of a source potential. It is a figure which shows the input / output of the video signal from which a frame rate fluctuates.

  The embodiment of the present invention will be described with reference to FIGS.

Embodiment 1
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a configuration for controlling the degree of overdrive processing according to the frame rate of the video signal will be described.

(Configuration of television receiver 1)
FIG. 1 is a functional block diagram of a television receiver 1 according to the present embodiment. As shown in FIG. 1, the television receiver 1 includes a video processing device 10, a television control unit 14, and a display unit 16. The television receiver 1 is a device that displays a video input from an external device such as the video output device 100 and a television broadcast via a tuner (not shown in FIG. 1).

  The video processing device 10 is a device that performs correction for improving the video quality of the acquired video signal, and includes a device control unit 11. The device control unit 11 is a control device that controls the entire video processing device 10, and also functions as the acquisition unit 12 and the correction unit 13. The acquisition unit 12 acquires a video signal from an external device such as the video output device 100. The correction unit 13 performs overdrive correction processing on the video signal acquired by the acquisition unit 12. The overdrive correction process is realized by the correction unit 13 interfering with the screen display process performed by the display unit 16. Details of overdrive correction will be described later.

  The television control unit 14 is a control device that controls the entire television receiver 1, and also functions as a display control unit 15. The display control unit 15 performs a process related to the screen display process of the display unit 16. The display unit 16 is a display panel that displays a moving image.

  The video output device 100 is a device that supplies a video signal. The video signal may be generated by the video output device 100. Examples of the video output device 100 include a game machine.

  Note that each member included in the television receiver 1 is not limited to a single member, and may include a plurality of the members.

(Overdrive correction processing)
Hereinafter, an example of overdrive correction (overdrive drive) processing that is a premise of the present embodiment will be described with reference to FIG. 2 by taking a liquid crystal display device having an overdrive correction function as an example.

  Each drawing of FIG. 2 is a diagram showing an overdrive correction operation. Overdrive correction is a technique for temporarily increasing the voltage applied to a liquid crystal element to shorten the time until the liquid crystal element reaches a desired pixel voltage, that is, the time until a color having a desired brightness is developed.

  Here, in each diagram of FIG. 2, the horizontal axis of the graph represents time (seconds). The liquid crystal display device refreshes the screen every 1/60 seconds. In other words, the refresh rate of the liquid crystal display device is 60 Hz. A waveform constituted by a straight line represents an output gradation which is a voltage applied to the liquid crystal element, and a waveform including a curve represents a liquid crystal response over time, that is, a color development degree or luminance of the liquid crystal element.

  FIG. 2A is a diagram showing an overdrive correction operation when the frame rate of the video signal input to the liquid crystal display device does not fluctuate.

  In the example shown in FIG. 2A, the liquid crystal element corresponds to an applied voltage that reaches a desired brightness after one frame from the start of voltage application, that is, 1/60 seconds, in other words, the value B on the vertical axis. An applied voltage that is set to reach a desired pixel voltage and corresponding to a value of C that is higher than B in the figure is first applied. Note that a waveform including a dotted curve represents a liquid crystal response when overdrive correction is not used. When overdrive correction is not performed, a voltage corresponding to the value B is applied to the liquid crystal element from the beginning.

  FIG. 2B is a diagram showing an overdrive correction operation when the interval of video signal frames input to the liquid crystal display device fluctuates. In the example shown in FIG. 2B, the time for applying the voltage corresponding to the value of C to the liquid crystal element is longer than in the case of FIG. Therefore, the pixel voltage of the liquid crystal element is temporarily higher than the desired pixel voltage corresponding to the value B. That is, the brightness of the liquid crystal element temporarily becomes higher than a desired value, and there is a possibility that the image quality is lowered.

  FIG. 2C is a diagram illustrating the operation of the liquid crystal display device when the degree of overdrive correction processing in FIG. 2B is weakened. When the liquid crystal display device determines that the input video signal includes a video signal whose frame interval may vary, as shown in FIG. Control is performed so that the voltage is lowered by a preset amount in a range equal to or higher than the voltage corresponding to the value. In other words, the liquid crystal display device weakens the degree of overdrive correction for the video signal. Alternatively, in the case described above, the liquid crystal display device may turn off overdrive correction for the video signal.

  According to the configuration shown in FIG. 2 (c), it is possible to suppress a reduction in video quality due to a part of the liquid crystal becoming too bright.

(Process flow)
The flow of processing in this embodiment using the configuration of FIG. 1 will be described step by step with reference to FIGS. FIG. 3 is a flowchart showing a processing flow of the present embodiment.

(S101)
In step S <b> 101, the acquisition unit 12 acquires a video signal from the video output device 100.

(S102)
Subsequently, in step S102, the correction unit 13 determines whether or not the frame rate of the video signal acquired by the acquisition unit 12 in step S101 has changed from the previous determination in step S102. If the frame rate has changed, the process of step S103 is subsequently executed. If the frame rate has not changed, the process of S104 is subsequently executed. In addition, when it changes to this step first, the process of step S104 is performed subsequently.

(S103)
In step S103, the correction unit 13 determines to weaken the degree of overdrive correction for the video signal as described above with reference to FIG. Alternatively, in this step, the correction unit 13 may determine to turn off the overdrive correction for the video signal.

(S104)
In step S104, the correction unit 13 determines to perform normal overdrive correction processing on the video signal.

(S105)
In step S105, the display control unit 15 displays the video indicated by the video signal acquired by the acquisition unit 12 in step S101. In displaying the video, the correction unit 13 performs overdrive correction according to the degree determined in step S103 or step S104.

  The television receiver 1 repeatedly executes the above-described processing from step S101 to step S105 until the user performs a predetermined end operation. The above is the flow of processing based on the flowchart of FIG.

[Embodiment 2]
A second embodiment of the present invention will be described below. In the present embodiment, a configuration for controlling on / off of dithering processing according to the frame rate of a video signal will be described. For convenience, members having the same functions as those described in the above embodiment are given the same reference numerals, and description thereof is omitted.

(Configuration of television receiver 1)
Also in this embodiment, the configuration shown in FIG. 1 is used. However, the correction unit 13 according to the present embodiment has a function of performing dithering correction processing.

(Dithering correction processing)
Hereinafter, with reference to FIG. 4, a dithering correction process that is a premise of the present embodiment and a brightness deviation that may occur on the display screen will be described using a liquid crystal display device having a dithering correction function as an example. .

  Dithering is a technique for expressing intermediate colors by arranging pixels of different colors in a mixed manner. By performing dithering, for example, gradation can be expressed using only two-color pixels.

  However, pixels with a small number of colors are arranged in a specific pattern in the area subjected to the dithering process, and the dithering pattern is used not only when the area is enlarged but also when the area becomes brighter than necessary. May stand out.

  On the other hand, when the frame rate of the video signal input to the display device fluctuates, a part of the screen may appear temporarily bright. Hereinafter, an example of the above case will be described using a simplified model.

  FIG. 4 is a diagram showing the brightness of each partial area of the display screen of the liquid crystal display device. Each graph in FIGS. 4A and 4B corresponds to the display regions I to IV in order from the top, and the horizontal axis of the graph represents time (seconds). Further, the refresh rate of the liquid crystal display device is normally 60 Hz, but scanning can be performed at a timing according to the frame rate of the input video signal. Further, predetermined corrections are sequentially performed on the partial areas I to IV of the display screen. Here, it is assumed that the luminance value of the partial area increases from 512 to 513 while the correction is performed.

  FIG. 4A shows the brightness of each partial area of the display screen when the frame rate does not change. For example, the display area I has a luminance value of 513 in the first frame, and a luminance value of 512 in the other three frames. As a result, the accumulated value of the luminance values for four frames is 2049. In the other partial regions II to IV, the luminance value is 513 for any one frame, and the luminance value is 512 in the other three frames. It becomes.

  In the first frame, since the luminance value of the partial area I is 513 and the luminance values of the other partial areas II to IV are 512, the accumulated luminance value of the entire screen is 2049. Also in the second to fourth frames, since the luminance value of any partial area is 513 and the luminance value of the other partial areas is 512, the accumulated luminance value of the entire screen is 2049. Since the screen switching of each frame is performed at a high speed, it usually appears that there is no brightness deviation between the partial areas between the four frames described above.

  FIG. 4B is a diagram illustrating the brightness of each partial area of the display screen when the frame rate varies. Also in the example shown in FIG. 4B, since the luminance value of any partial area is 513 and the luminance value of the other partial areas is 512 in each frame, the accumulated luminance value of the entire screen is , 2049.

  On the other hand, the display area I has a longer luminance value of 513 than the case shown in FIG. Therefore, the accumulated value of the luminance values in the display area I over 4 frames exceeds 2049 and is higher than the accumulated value of the luminance values in the other display areas II to IV. In addition, the display area II has a shorter time during which the luminance value is 513 than in the case illustrated in FIG. Therefore, the accumulated value of the luminance values in the display area II between the four frames is less than 2049 and is lower than the accumulated value of the luminance values in the other display areas I, III, and IV.

  As a result, only the display area I looks brighter than the other display areas II to IV between the four frames described above, and the dithering pattern may stand out.

  When it is determined that the input video signal includes a video signal whose frame interval may vary, the liquid crystal display device turns off dithering correction for the video signal, thereby suppressing a reduction in video quality. be able to.

(Process flow)
A process flow in the present embodiment using the configuration of FIG. 1 will be described step by step with reference to FIGS. 1 and 5. FIG. 5 is a flowchart showing a processing flow of the present embodiment.

(S101, S102)
In step S101 and step S102, processing similar to that in the first embodiment is performed. If the frame rate of the video signal acquired by the acquisition unit 12 in step S101 has changed from the previous determination in step S102, then the process of step S203 is executed, and if the frame rate has not changed, then in step S204. Processing is executed. In addition, when it changes to this step first, the process of step S204 is performed subsequently.

(S203)
In step S203, the correction unit 13 turns off dithering correction for the input video signal.

(S204)
In step S204, the correction unit 13 performs dithering correction on the video signal.

(S205)
In step S205, the display control unit 15 displays the video indicated by the video signal acquired by the acquisition unit 12 in step S101.

  The television receiver 1 repeatedly executes the above-described processing from step S101 to step S205 until the user performs a predetermined end operation. The above is the flow of processing based on the flowchart of FIG.

[Embodiment 3]
A third embodiment of the present invention will be described below. In the present embodiment, a configuration for controlling on / off of the shadow correction according to the frame rate of the video signal will be described. For convenience, members having the same functions as those described in the above embodiment are given the same reference numerals, and description thereof is omitted.

(Configuration of television receiver 1)
Also in this embodiment, the configuration shown in FIG. 1 is used. However, the correction unit 13 according to the present embodiment has a configuration shown in FIG. 6 and a function of performing shadow correction processing.

  FIG. 6 is a block diagram schematically showing an image signal processing circuit in the correction unit 13 according to the present embodiment. The correction unit 13 includes an input unit 31, a gradation voltage conversion unit 32, a vertical voltage integration unit 33, a reference voltage integration unit 34, an addition / subtraction unit 35, a coefficient multiplication unit 36, a correction value calculation unit 37, a correction value addition unit 38, and an output. Part 39 is included.

  Further, the television receiver 1 according to the present embodiment performs screen display by a frame inversion driving method in which the polarity of the voltage applied to the liquid crystal element is inverted every frame.

(Overview of display control)
Hereinafter, with reference to FIG. 6 to FIG. 10, the shadow correction processing and the parameter calculation method used for the shadow correction, which are the premise of the present embodiment, are listed for each item taking a liquid crystal display device having a shadow correction function as an example. Explained. The liquid crystal device includes a correction unit 13 as in the television receiver 1 according to the present embodiment.

  The correction unit 13 calculates the correction value of the source potential of the target pixel 20 using the displacement amount in the next frame of the source potential of the target pixel 20 (displacement amount for the next frame). Other than the calculation of the amount of displacement of the source voltage of the target pixel, the correction value of the source voltage applied to the target pixel by the correction unit 13 can be calculated by, for example, a known method as described in Patent Document 2 Is possible.

  First, image data of an image to be displayed on the liquid crystal display device is input to the input unit 31. The input unit 31 outputs the image data to the subsequent gradation voltage conversion unit 32.

  The gradation voltage conversion unit 32 converts the image data (input gradation) input from the input unit 31 into a source voltage. For example, the gradation voltage conversion unit 32 uses the LUT (look-up table) with the voltage (Vcom) of the common electrode as a reference, a voltage lower than that to be negative, and a voltage higher than that to be positive, and the above input gradation is converted. Convert to source voltage. The gradation voltage converting unit 32 outputs the source voltage to the subsequent vertical voltage integrating unit 33 and the reference voltage integrating unit 34.

  Operations in the vertical voltage integration unit 33, the reference voltage integration unit 34, and the subsequent addition / subtraction unit 35 will be described later. Thus, the amount of displacement in the next one frame of the source potential of the target pixel 20 is obtained. The adder / subtractor 35 outputs the displacement amount to the subsequent coefficient multiplier 36.

  The coefficient multiplication unit 36 multiplies the displacement amount by a coefficient, and outputs the displacement amount obtained by multiplying the coefficient to the subsequent correction value calculation unit 37. The coefficient is, for example, the ratio (Csou1 / ΣC) of the parasitic capacitance (Csou1) due to the source line S1 in the pixel 20 to the total capacitance (ΣC) of the pixel 20.

  The correction value calculation unit 37 calculates a correction value (correction gradation) from the displacement amount obtained by the coefficient multiplication unit 36 and the gradation of the pixel 20 and outputs the correction value (correction gradation) to the subsequent correction value addition unit 38.

  The correction value addition unit 38 adds the correction value (correction gradation) by the correction value calculation unit 37 to the gradation of the display image. In this way, the correction value adding unit 38 calculates the corrected output gradation and outputs it to the output unit 39.

  The correction value calculated by the correction value calculation unit 37 can be either positive or negative. For example, when the source potential of the pixel 20 is shifted in the direction of brightening the pixel 20, the correction value is a negative number, and in the pixel 20 shifted in the direction of darkening, the correction value is positive. Become a number.

  The output unit 39 sends the corrected output gradation from the correction value adding unit 38 to the source driver.

(Calculation method of displacement)
Next, a method for calculating the displacement amount of the source potential of the target pixel performed by the correction unit 13 will be described. The displacement amount is calculated by the vertical voltage integration unit 33, the reference voltage integration unit 34, and the subsequent addition / subtraction unit 35.

  The correcting unit 13 sets the displacement amount in the next frame of the source potential of the target pixel 20 (the displacement amount for the next one frame) as the starting point of the writing timing of the target pixel 20. The source potential is calculated with reference to the integrated value for the past one frame.

  The time required for vertical scanning for one frame is, for example, a very short time of 1/60 seconds when the frame rate is 60 frames per second. Therefore, in both the moving image and the still image, the source potential in a certain frame is a good approximation of the source potential in the previous frame. Therefore, in obtaining the displacement amount, for example, the integrated value for the next one frame with respect to the current time can be substantially replaced with the integrated value for the previous one frame. In this way, by referring to the accumulated amount of the source potential for the most recent one frame, the accumulated value for the next one frame can be obtained without performing a great deal of processing for actually calculating it. It can be obtained by simple processing.

  The method of using the integral value for obtaining the displacement amount can be appropriately determined within a range in which the displacement amount can be obtained. For example, the correction unit 13 calculates the displacement amount for the next one frame of the source potential of the target pixel 20 based on the difference between the two integral values. The first integrated value is an integrated value of the actual source potential of the target pixel 20 in the period of the past one frame starting from the writing timing of the target pixel 20. The second integrated value is a value obtained by integrating the source potential from the write timing of the target pixel 20 as a starting point for a period of one frame.

  Next, how to determine the first and second integrated values will be described. FIG. 7 is a diagram schematically showing pixels in the first and second columns and two source lines arranged on both sides of the pixels in the first column in the liquid crystal display device. FIG. 7 shows, by way of example, a first column of pixels 20 in a liquid crystal display device having 4320 rows of pixels, and two source lines S1 and S2 to be connected to the gate lines in the pixels 20. FIG. 8 is a diagram schematically showing fluctuations in the source potential of the target pixel of the liquid crystal display device during one frame. In FIG. 8, Vs represents the source potential, and Vcom represents the potential of the common electrode. In FIG. 8, the polarity (sign) of the source potential Vs above Vcom is + (plus), and the polarity (sign) of the source potential Vs below Vcom is-(minus).

  In the column of the pixels 20, the source voltage is sequentially applied from the source driver to the pixels 20 in the first row from the pixels 20 in the first row to the pixels 20 in the last row 4320 in one vertical scanning period. A period required for the source voltage to be applied once to all the pixels 20 belonging to a certain column is called one frame or one vertical scanning period. Assume that the source potential is currently written in the pixel 20 in the nth row (1 ≦ n ≦ 4320) of the f frame.

  As described above, the first integrated value is an integrated value of the source potential in the period of the past one frame in the pixel 20 to which the source voltage is actually applied. The first integrated value is the integrated value of the source potential Vs1 at the pixel 20 from the nth line to the 4320th line of the f-1 frame, and the integrated value from the first line to the nth line of the f frame, Is the sum of

  As described above, the second integrated value is a value obtained by integrating the source potential with the writing timing of the target pixel 20 as a starting point for a period of one frame. The second integrated value is the integrated value of the source potential Vs1 (f, n) at the pixel 20 in the nth row of the f frame, from the nth row to the 4320th row of the f frame, and one row in the f + 1 frame. It is the sum of the integrated values from the eye to the nth row.

  The displacement amount of the source potential of the target pixel 20, that is, the displacement amount of the source potential of the pixel 20 in the n-th row in the f + 1 frame is, as described above, the first integral value and the second integral value. It is calculated by the difference between The displacement amount in the f frame in the pixel 20 in the n-th row is expressed by the following formula (1), and in FIG. 8 is expressed by the area of the shaded portion Δc. The displacement amount in the f + 1 frame in the pixel 20 in the n-th row is represented by the following formula (2), and is represented by the area of the shaded portion Δd in FIG. Therefore, the displacement amount (ΔVs1 (f + 1, n)) of the potential of the target pixel 20 is obtained by Expression (3).

  Typically, the vertical voltage integrating unit 33 obtains an integrated value of the source potential in a period corresponding to an intended one frame in the pixel to which the source voltage is actually applied. Further, the reference voltage integrating unit 34 obtains an integrated value of the above-described period of the reference source potential. Then, the addition / subtraction unit 35 performs a calculation process on these integrated values as necessary to obtain a difference between the integrated values.

  As shown in the above formulas (1) to (3), the displacement amount of the source potential of the target pixel 20 is divided for each frame to obtain the difference between the integral values, and then add the difference in each frame. May be calculated. Alternatively, the displacement amount may be calculated by adding and subtracting each integrated value after obtaining each integrated value for a period of one frame.

  The displacement of the source potential of the target pixel 20 is the difference obtained by subtracting the reference source potential (Vs1 (f, n) in the above formula) from the actual source potential (Vs1 (k) in the above formula). It may be calculated for each pixel 20 and may be calculated by integrating the difference for one frame. In this case, the correction unit 13 may have an appropriate configuration for obtaining the integrated value of the difference instead of the vertical voltage integration unit 33, the reference voltage integration unit 34, and the addition / subtraction unit 35. For example, in the above case, the correction unit 13 may include a subtraction unit that calculates the difference for each pixel 20 and an integration unit that integrates the calculated difference for one frame.

(Effect of correction)
FIG. 9A is a diagram illustrating an example of the source potential of a pixel when correction by the correction unit 13 is not performed in the liquid crystal display device. FIG. 9B is a diagram illustrating an example of correction values calculated by the correction unit 13 in the liquid crystal display device. FIG. 9C is a diagram illustrating an example of the source potential of the pixel when the source voltage is corrected by the correction unit 13 in the liquid crystal display device.

  When the correction value of the source voltage applied by the correction unit 13 is not corrected, the amount of fluctuation due to the polarity inversion of the source voltage applied to the pixel 20 may increase. For this reason, as shown in FIG. 9A, the source potential of the pixel 20 when correction is not performed may gradually decrease toward the end of one frame.

  As described above, the correcting unit 13 uses the difference between the integrated value of the source potential of the target pixel 20 for the past one frame and the integrated value of the source potential of the target pixel 20 for one frame, as a target pixel. The amount of displacement of the source potential can be calculated. More specifically, the correction unit 13 calculates the displacement amount of the actual source potential with respect to the reference potential (Vs (f, n)) of the source potential of the pixel 20 over the past one frame, based on the difference between the integrated values, and this displacement The correction value is calculated based on the amount. For example, when the source potential gradually decreases during one frame as described above, the correction unit 13 corrects the applied value of the source voltage that gradually increases during one frame as shown in FIG. Calculate as a value.

  By applying the corrected source voltage to the pixel 20 from the source line S1, the gradual decrease of the source potential due to the polarity inversion during one frame is canceled. As a result, an expected source potential substantially the same as the reference potential as shown in FIG. 9C is realized.

  As described above, the correction unit 13 calculates the displacement amount of the source potential of the target pixel 20 for calculating the correction value of the source voltage applied to the target pixel 20 based on the difference between the integrated values. The difference between the integrated values is the integrated value for the past one frame of the source potential of the target pixel 20 and the one frame of the source potential of the target pixel 20 when the writing timing of the target pixel 20 is the starting point. This is the difference from the integrated value. Therefore, a source potential that fluctuates unintentionally between one frame can be maintained at a desired potential as in the case where the source potential decreases during one frame.

(Supplementary information on source potential)
Hereinafter, the displacement amount in the pixels 20 in a predetermined column (for example, the first column) is determined by the sum of the displacement amount and the displacement amount in the pixels 20 (for example, in the second column) connected to the adjacent source line. The case where it calculates | requires is demonstrated.

  For example, the displacement amount in the next frame of the source potential of the source line S1 shown in FIG. 7 is obtained by the method described above. The displacement amount of the source potential of the source line S2 is, for example, the displacement amount in the next frame of the source potential in the pixel 20 in the first column in the pixel 20 in the n-th row, that is, the pixel 20 in the second column. It is. This displacement amount is obtained in the same manner as that of the source line S1 except that the target pixel 20 and the source line are different. That is, the amount of displacement of the source voltage in the source line S2 is expressed by an expression in which “s1” in the above expressions (1) to (3) is replaced with “s2”.

  As described above, the displacement amount in the next one frame of the source potential of the pixel 20 of the target (n row, m column) is the displacement amount of the source potential by the source line Sm of the pixel 20 in the n row and m column, and n rows. , The sum of the displacement amount of the source potential by the source line Sm + 1 of the pixels 20 in the (m + 1) th column. Here, m and n are both positive integers. Therefore, when the displacement amount to be obtained is “ΔV1 (n)”, the displacement amount can be obtained by the following equation (4).

  Typically, the vertical voltage integrating unit 33 obtains an integrated value of the source potential in a period corresponding to an expected one frame in each of the two adjacent pixels 20. In addition, the reference voltage integrating unit 34 obtains an integrated value of the above-described period of the source potential serving as a reference in each of the two adjacent pixels 20. Then, the addition / subtraction unit 35 obtains the difference between the integrated values. The adder / subtractor 35 appropriately performs calculation processing on the integrated value as necessary.

  Thus, the displacement amount of the potential of the target pixel 20 is the sum of the first displacement amount and the second displacement amount. The first displacement amount is a difference between integrated values when the source line S1 arranged on one side of the pixel 20 is used as the source line of the target pixel 20 (for example, the m-th column). The second displacement amount is a difference between integrated values when the source line S2 arranged on the other side of the target pixel 20 is used as the source line of the target pixel 20 (for example, m + 1 column).

  According to the above configuration, the displacement of the source potential of the target pixel due to the influence of a source line that is adjacent to the pixel in the single source line structure but is not electrically connected, for example, parasitic capacitance, is further increased. Required precisely. For this reason, the correction unit 13 can calculate a more precise correction value. Therefore, even in the second half of one frame (lower part of the screen), it is more effective from the viewpoint of displaying a desired high-definition image.

(Frame inversion drive)
Hereinafter, the above method will be described on the assumption that the liquid crystal display device operates by the frame inversion driving method.

  FIG. 10A is a diagram schematically showing the fluctuation of the source potential in the period from the previous frame to the next frame in the liquid crystal display device that applies the source voltage by one frame inversion. FIG. 10B is a diagram schematically showing the variation of the source potential in the period from the present time to the next one frame in FIG. 10A. The pixel 20 currently written is the pixel in the nth column in the f frame. Here, the time required for vertical scanning for one frame is, for example, a very short time of 1/60 seconds when the frame rate is 60 frames per second. Therefore, in both the moving image and the still image, the source potential in the frame (f) one frame before is a good approximation of the source potential in the previous frame (f-1).

  The integrated value σa of the source potential of the previous frame (f-1 frame) is expressed by Expression (5). Further, the integrated value σb of the source potential up to the current pixel in the current frame (f frame) is expressed by Expression (6). Then, the integrated value σ0 for one frame of the source potential Vn at the current time in the pixels 20 in the n-th column is expressed by Expression (7).

  Δc shown in FIG. 10B is an integrated value of the displacement amount with respect to the source potential Vn of the pixel in the n-th column at the current source potential after the current time in the current frame. Δc is obtained by subtracting the integrated value of Vn of pixels in the nth and subsequent columns from σc. Since the source potential of the previous frame (f-1 frame) is a good approximation of the source potential of the current frame (f frame), from (a) of FIG. 10, in terms of absolute value, σc is changed from σa to σb. It is a value obtained by subtracting. Therefore, Δc is expressed by Expression (8).

  From (b) of FIG. 10, Δd is obtained as an absolute value by subtracting the integrated value σb of the actually applied source potential from the integrated value of the source potential Vn of the pixel in the nth column in the f + 1 frame.

  Here, the sign of the integrated value is appropriately adjusted according to the difference in the polarity of the source potential between frames. For example, σa is the value of the f−1 frame, and the polarity of the source potential is opposite to the polarity of the source potential in the f frame. Therefore, in Equation (8), the sign of σa is inverted. Further, the polarity of Δd is inverted in the f + 1 frame with respect to the f frame. Therefore, for Δd, the sign of the actual integrated value of the source potential is reversed. Therefore, Δd is expressed by Equation (9).

  The amount of displacement of the source potential at the pixel 20 in the nth row of the current frame (f + 1 frame) is obtained from the sum of Δc and Δd. Therefore, the displacement amount of the source potential in the pixel 20 in the n-th row of the current frame can be obtained from Expression (10).

  The amount of displacement of the integrated value of the source potential can be calculated by the vertical voltage integration unit 33, the reference voltage integration unit 34, and the addition / subtraction unit 35 described above. For example, the vertical voltage integrating unit 33 calculates σa, σb and the difference between them based on the past integrated value of the actual source potential. The reference voltage integrating unit 34 calculates an integrated value ((4320−n) × Vn) of the source potential Vn in the nth column of the f frame in the f frame. Then, the adder / subtractor 35 performs a sign reversal process by polarity reversal on the calculated values by the above-described two accumulators as necessary, and calculates Δc and Δd in the equations (8) and (9). Calculate the sum.

  Or the calculation of the said displacement amount can be performed by the correction | amendment part 13 containing another component as needed. For example, the amount of displacement can be calculated by the correction unit 13 that further includes a sign inversion unit that changes the sign of the source potential due to the inversion of the polarity of the source potential. The sign inversion unit is, for example, between the vertical voltage integration unit 33, the reference voltage integration unit 34, and the addition / subtraction unit 35, and changes the sign of each of the calculated values of both integration units as necessary.

  As described above, when the polarity of the source potential is inverted between successive frames, the correction unit 13 uses the positive and negative signs of the integrated value reversed according to the polarity inversion. Therefore, the liquid crystal display device is configured to apply a source voltage whose polarity is inverted every frame to the source line. Then, the correction unit 13 calculates the amount of displacement of the source potential of the target pixel 20 by replacing the integrated value of the source potential of the previous frame with the integrated value of the source potential of the current frame. This is more effective from the viewpoint of obtaining the displacement amount more easily.

(Blanking period)
The fact that an error occurs in the parameter Δ described above when the frame rate of the video signal input to the liquid crystal display device changes will be described with reference to FIG.

  FIG. 11 is a diagram illustrating an example in which a blanking period occurs in the variation of the source potential illustrated in FIG.

  In the example shown in FIG. 11, a blanking period in which a voltage for updating the display screen is not applied to the liquid crystal element occurs due to a difference between the refresh rate of the liquid crystal display device and the frame rate of the input video signal. . Since the voltage Vcom in the blanking period is included in the calculation of Δc, an error occurs in the value of the parameter Δ. Therefore, the shadow correction performed using the parameter Δ including an error may further deteriorate the video quality of the display screen.

  When it is determined that the input video signal includes a video signal whose frame interval may vary, the liquid crystal display device suppresses the degradation of the video quality by turning off the shadow correction for the video signal. Can do.

(Process flow)
The processing flow described with reference to FIG. 5 in the second embodiment can be applied to the present embodiment by replacing the dithering process with shadow correction.

  As described above in the first to third embodiments, the video processing device 10 is the video processing device 10 including the acquisition unit 12 and the correction unit 13, and the acquisition unit 12 acquires the video signal, and the correction unit 13. Is determined whether the video signal acquired by the acquisition unit 12 includes a video signal whose frame interval may vary, and when it is determined that a video signal whose frame interval may vary is included, The degree of correction for the video signal acquired by the acquisition unit 12 is reduced, or correction for the video signal acquired by the acquisition unit 12 is turned off.

  According to said structure, the fall of the image quality at the time of using the image technology in the conventional fixed frame rate with respect to the image | video of a variable frame rate can be suppressed.

  The correction process applied by the correction unit 13 may include at least one of overdrive, dithering, and shadow correction.

  According to said structure, when applying each correction process mentioned above to the input video signal, the fall of the image quality when the frame rate of the said video signal fluctuates can be suppressed.

[Embodiment 4]
A fourth embodiment of the present invention will be described below. In the present embodiment, a configuration that can be applied to the above-described first to third embodiments and in which the video processing device 10 detects a change in the frame rate of an input video signal will be described. For convenience, members having the same functions as those described in the above embodiment are given the same reference numerals, and description thereof is omitted.

(Configuration of television receiver 1)
Also in this embodiment, the configuration shown in FIG. 1 is used. However, when the first output method described later is used, the video processing apparatus 10 further includes a frame memory for storing moving images.

(Process flow)
The flow of processing in this embodiment will be described with reference to FIG. FIG. 12 is a diagram illustrating input / output of a video signal whose frame rate varies. FIG. 12A is a diagram showing a video signal input to the video processing device 10. As shown in FIG. 12A, the video signal changes from 60 Hz to 30 Hz, and further changes to 60 Hz after three frames. FIG. 12B is a diagram illustrating a first output method of the input video signal. FIG. 12C is a diagram showing a second output method of the input video signal. In the example shown in FIGS. 12B and 12C, it is assumed that any correction processing by the correction unit 13 is performed on the video signal with a frame rate of 60 Hz that is initially output.

  First, the first output method described above will be described with reference to FIG. In the first output method, the video signal output from the video processing device 10 is delayed by one frame using a frame memory for storing moving images. Specifically, the acquisition unit 12 stores the acquired video signal in a frame memory, and then the correction unit 13 determines whether the frame rate has changed for each frame of the video signal. When the correction unit 13 detects that the frame rate of the video signal has changed to 30 Hz, the correction unit 13 turns off the degree of correction processing described in Embodiments 1 to 3 or weakens it if possible.

  For example, in a period in which a frame of a 60 Hz video signal is input, the correction unit 13 determines the frame rate when a signal for synchronizing with the refresh rate of the display screen cannot be detected in the input video signal. You may determine with having changed. Moreover, the correction | amendment part 13 may perform the original correction | amendment process again, when detecting that the frame rate of the said video signal changed to 60 Hz again.

  According to the first output method, as indicated by the arrow in FIG. 12B, the correction process can be accurately applied to a frame having a frame rate different from the refresh rate of the video processing apparatus 10.

  Next, the second output method described above will be described with reference to FIG. In the second output method, when a frame is output, it is determined whether or not the frame rate has changed from the previous frame. When the change of the frame rate is detected, the correction unit 13 turns off or weakens the degree of correction processing described above in the first to third embodiments for the subsequent frames. Moreover, the correction | amendment part 13 may perform the original correction | amendment process again, when detecting that the frame rate of the said video signal changed to 60 Hz again.

  Since the second output method does not use a frame memory, as shown in FIG. 12C, there is an aspect that the timing for detecting the change in the frame rate is delayed by about a half frame compared to the first output method. However, there is an advantage that the frame memory is unnecessary and the delay of the video signal to be output is at least less than that of the first output method.

  As described above, the correction unit 13 may detect a change in the frame interval in the video signal acquired by the acquisition unit 12 with reference to the video signal acquired by the acquisition unit 12. According to said structure, the video processing apparatus 10 which can detect the fluctuation | variation of a frame interval with reference to the said video signal is realizable.

[Modification 1]
When the correction unit 13 determines whether or not the video signal acquired by the acquisition unit 12 includes a video signal whose frame interval may vary, the correction unit 13 includes metadata included in the video signal or the video signal. It is also possible to refer to a video signal acquired along with the video signal.

  For example, when transmitting the video signal in conformity with the HDMI standard, the metadata includes an identifier indicating whether or not the frame interval can be changed in the InfoFrame, and the correction unit 13 refers to the identifier. It can be configured to determine whether or not a video signal whose frame interval may fluctuate is included.

  As described above, the correction unit 13 refers to the metadata included in the video signal acquired by the acquisition unit 12 or the control signal acquired along with the video signal, to the video signal acquired by the acquisition unit 12. Alternatively, it may be configured to determine whether or not a video signal whose frame interval may fluctuate is included.

  This modification may or may not be used in combination with the determination process described in the fourth embodiment. When combined with the determination process described in the fourth embodiment, for example, when it is determined that a video signal whose frame interval may change is included by referring to the metadata or the control signal, the degree of the correction process Furthermore, when a change in the frame interval is detected by the determination process described in the fourth embodiment, it is possible to perform multi-step control such as further reducing the degree of the correction process or setting it to zero.

  According to said structure, the video processing apparatus 10 which can detect the fluctuation | variation of a frame interval with reference to the said metadata or the said control signal is realizable.

[Modification 2]
The video processing apparatus 10 according to the modified example 2 further includes a user operation reception unit that receives a user operation for setting the degree of correction processing by the correction unit 13. In the above configuration, the degree of correction processing by the correction unit 13 can be arbitrarily set by the user switching, for example, strong, medium, weak, or off through the user operation receiving unit. Good.

  As described above, the video processing apparatus 10 is the video processing apparatus 10 including the acquisition unit 12, the correction unit 13, and the user operation reception unit. The acquisition unit 12 acquires a video signal, and the user operation reception unit Receives a user operation related to the degree of correction by the correction unit 13, and the correction unit 13 performs a correction process on the video signal acquired by the acquisition unit 12 at the correction level indicated by the user operation. The correction processing by includes at least one of overdrive, dithering, and shadow correction.

  According to said structure, the video processing apparatus 10 which performs each correction process mentioned above according to the correction | amendment degree which user operation shows is realizable.

[Modification 3]
The video processing apparatus 10 may control the degree of correction processing according to the type of content indicated by the input video signal. For example, in the case of content with a lot of movement in the display screen, such as an action game or a shooting game, it is determined that the video processing burden such as GPU calculation in the video output device 100 is large, and the frame rate is lowered. The correction process may be turned off or weakened if possible. That is, the video processing apparatus 10 may determine whether or not the video signal includes a video signal whose frame interval may vary depending on the type of content.

  The content type determination method is not limited to a specific method. For example, the video processing device 10 may separately acquire information indicating the content type from the video output device 100, or may estimate the content type from the amount of color change in the video indicated by the input video signal. Also good.

  As described above, the correction unit 13 determines whether or not the video signal acquired by the acquisition unit 12 includes a video signal whose frame interval may vary according to the type of content indicated by the video signal. May be. According to said structure, the video processing apparatus 10 which judges the fluctuation | variation of a frame interval according to the kind of content is realizable.

  This modification may or may not be used in combination with the determination process described in the fourth embodiment. When combined with the determination process described in the fourth embodiment, for example, the content indicated by the input video signal is content with a lot of movement in the display screen, and includes a video signal whose frame interval may vary. When the determination is made, the degree of correction processing is weakened, and when the variation in the frame interval is detected by the determination processing described in the fourth embodiment, the degree of correction processing is further reduced or zeroed. Control can also be performed.

  Note that the above-described embodiments and modifications may be implemented in combination with other embodiments or modifications.

[Example of software implementation]
The control blocks (particularly the acquisition unit 12 and the correction unit 13) of the video processing apparatus 10 may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may be realized by software. Good.

  In the latter case, the video processing apparatus includes a computer that executes instructions of a program that is software for realizing each function. The computer includes, for example, at least one processor (control device) and at least one computer-readable recording medium storing the program. In the computer, the processor reads the program from the recording medium and executes the program, thereby achieving the object of the present invention. As the processor, for example, a CPU (Central Processing Unit) can be used. As the recording medium, a “non-temporary tangible medium” such as a ROM (Read Only Memory), a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. Further, a RAM (Random Access Memory) for expanding the program may be further provided. Further, the program may be supplied to the computer via any transmission medium (such as a communication network or a broadcast wave) that can transmit the program. Note that one embodiment of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[Summary]
The video processing device according to aspect 1 of the present invention is a video processing device including an acquisition unit and a correction unit, wherein the acquisition unit acquires a video signal, and the correction unit is acquired by the acquisition unit. The video signal acquired by the acquisition unit when it is determined whether the video signal includes a video signal whose frame interval may vary and when the video signal includes a video signal whose frame interval may vary. The degree of correction of the image signal is weakened, or the correction for the video signal acquired by the acquisition unit is turned off. According to said structure, the fall of the image quality at the time of using the image technology in the conventional fixed frame rate with respect to the image | video of a variable frame rate can be suppressed.

  In the video processing device according to aspect 2 of the present invention, in the above aspect 1, the correction unit refers to the video signal acquired by the acquisition unit, and changes the frame interval in the video signal acquired by the acquisition unit. It is good also as a structure to detect. According to said structure, the video processing apparatus 10 which can detect the fluctuation | variation of a frame interval with reference to the said video signal is realizable.

  In the video processing device according to aspect 3 of the present invention, in the above aspect 1 or 2, the correction unit acquires the metadata included in the video signal acquired by the acquisition unit or accompanying the video signal. With reference to the control signal, it may be configured to determine whether or not the video signal acquired by the acquisition unit includes a video signal whose frame interval may vary. According to said structure, the video processing apparatus 10 which can detect the fluctuation | variation of a frame interval with reference to the said metadata or the said control signal is realizable.

  The video processing device according to aspect 4 of the present invention is the video processing apparatus according to any one of the aspects 1 to 3, wherein the correction unit applies the video signal acquired by the acquisition unit according to the type of content indicated by the video signal. A configuration may be adopted in which it is determined whether or not a video signal whose frame interval may fluctuate is included. According to said structure, the video processing apparatus 10 which judges the fluctuation | variation of a frame interval according to the kind of content is realizable.

  In the video processing device according to aspect 5 of the present invention, in any of the above aspects 1 to 4, the correction process applied by the correction unit includes at least one of overdrive, dithering, and shadow correction. A configuration may be used. According to said structure, when applying each correction process mentioned above to the input video signal, the fall of the image quality when the frame rate of the said video signal fluctuates can be suppressed.

  A video processing apparatus according to an aspect 6 of the present invention is a video processing apparatus including an acquisition unit, a correction unit, and a user operation reception unit, wherein the acquisition unit acquires a video signal, and the user operation reception unit Receives a user operation related to the degree of correction by the correction unit, and the correction unit performs a correction process on the video signal acquired by the acquisition unit at a correction level indicated by the user operation, and the correction unit performs The correction process includes at least one of overdrive, dithering, and shadow correction. According to said structure, the video processing apparatus 10 which performs each correction process mentioned above according to the correction | amendment degree which user operation shows is realizable.

  A video processing method according to aspect 7 of the present invention is a video processing method by an apparatus, and includes an acquisition step of acquiring a video signal, and a video signal whose frame interval may vary in the video signal acquired in the acquisition step. If it is determined that a video signal whose frame interval may fluctuate is included, the degree of correction of the video signal acquired in the acquisition step is reduced, or in the acquisition step And a correction step of turning off the correction for the acquired video signal. According to the above method, it is possible to suppress a decrease in video quality when the conventional video technology at a fixed frame rate is used for a video with a variable frame rate.

  A television receiver including the video processing device according to the aspect 8 of the present invention may include the video processing device according to any one of the above aspects 1 to 6. According to said structure, the television receiver 1 with the same effect as the video processing apparatus 10 is realizable.

  A control program according to an aspect 9 of the present invention is a control program for causing a computer to function as the video processing apparatus 10 according to any one of the above aspects 1 to 6, wherein the computer includes the acquisition unit 12 and the correction unit. It is good also as a structure made to function as 13. FIG.

  The recording medium according to aspect 10 of the present invention may be a computer-readable recording medium in which the control program according to aspect 9 is recorded.

  The video processing apparatus according to each aspect of the present invention may be realized by a computer. In this case, the video processing apparatus is operated on each computer by causing the computer to operate as each unit (software element) included in the video processing apparatus. Also included in the scope of the present invention are a control program for the video processing apparatus to be realized and a computer-readable recording medium on which the control program is recorded.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

DESCRIPTION OF SYMBOLS 1 Television receiver 10 Image processing apparatus 11 Device control part 12 Acquisition part 13 Correction part 14 Television control part 15 Display control part 16 Display part 20 Pixel 31 Input part 32 Gradation voltage conversion part 33 Vertical voltage integration part 34 Reference voltage integration Unit 35 addition / subtraction unit 36 coefficient multiplication unit 37 correction value calculation unit 38 correction value addition unit 39 output unit 100 video output device

Claims (10)

An image processing apparatus including an acquisition unit and a correction unit,
The acquisition unit acquires a video signal,
The correction unit is
It is determined whether the video signal acquired by the acquisition unit includes a video signal whose frame interval may vary,
When it is determined that a video signal that can change the frame interval is included,
A video processing apparatus characterized by weakening the degree of correction of the video signal acquired by the acquisition unit or turning off correction of the video signal acquired by the acquisition unit. The video processing apparatus according to claim 1, wherein the correction unit detects a change in a frame interval in the video signal acquired by the acquisition unit with reference to the video signal acquired by the acquisition unit. The correction unit is
A video signal whose frame interval may vary in the video signal acquired by the acquisition unit with reference to metadata included in the video signal acquired by the acquisition unit or a control signal acquired accompanying the video signal. 3. The video processing apparatus according to claim 1, wherein it is determined whether or not a video is included. The correction unit determines whether the video signal acquired by the acquisition unit includes a video signal whose frame interval may vary according to a type of content indicated by the video signal. The video processing apparatus according to any one of claims 1 to 3. The video processing apparatus according to claim 1, wherein the correction process applied by the correction unit includes at least one of overdrive, dithering, and shadow correction. A video processing apparatus including an acquisition unit, a correction unit, and a user operation reception unit,
The acquisition unit acquires a video signal,
The user operation reception unit receives a user operation related to the degree of correction by the correction unit,
The correction unit is
A correction process is performed on the video signal acquired by the acquisition unit at a correction level indicated by the user operation.
In the correction process by the correction unit,
An image processing apparatus comprising at least one of overdrive, dithering, and shadow correction. A video processing method by an apparatus,
An acquisition step of acquiring a video signal;
Determining whether the video signal acquired in the acquisition step includes a video signal whose frame interval may fluctuate;
When it is determined that a video signal that can change the frame interval is included,
A video processing method comprising: a correction step of weakening a degree of correction for the video signal acquired in the acquisition step or turning off correction for the video signal acquired in the acquisition step.   A television receiver comprising the video processing device according to any one of claims 1 to 6.   A control program for causing a computer to function as the video processing apparatus according to any one of claims 1 to 6, wherein the control program causes the computer to function as the acquisition unit and the correction unit.   A computer-readable recording medium on which the control program according to claim 9 is recorded.

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