JP2011070036A - Video signal processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video processor suppressing the influence of color shift or the like caused by afterglow and formation of color boundaries in the display area of a display. <P>SOLUTION: The video signal processor 100 includes: a motion vector detection part 103 for detecting a motion vector for each block of a processing target frame; a disorder degree calculation part 102 for calculating, for each partial area including a plurality of blocks, disorder degree of a plurality of motion vectors of the partial area; a determination part 108 for determining, for each partial area, whether the partial area is a first area or a second area larger in disorder degree than the first area; and a signal correction part 110 for correcting a video signal so as to suppress the influence of the afterglow of a preceding frame and outputting the corrected video signal. The signal correction part 110 corrects the video signal of the first area by using a pixel of the first area or a motion vector of each block and outputs the corrected video signal, and corrects the video signal of the second area by using a light-emitting quantity indicated by the video signal of the preceding frame without using any motion vector and outputs the corrected video signal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a video signal processing apparatus that outputs a video signal to a display that displays an image using a plurality of phosphors having different characteristics.

  Conventionally, halftone display on a plasma display panel (hereinafter referred to as “PDP”), which is a type of display that displays images using a plurality of phosphors having different characteristics, is performed by changing the weight of luminance in one field. This is realized by dividing and displaying in subfields.

  PDP image display is realized by emitting phosphors of three colors (blue, green, red), but the phosphors have different characteristics for each color. Downlink timing is different.

  In particular, the rise and fall timing of light emission is earlier than that of green and red in blue, and the difference between these characteristics is perceived as color shift or afterglow in a moving image.

  As a means for solving these problems, Patent Document 1 discloses a method of calculating an amount leaked into the current frame from a light emission amount of a preceding frame which is a frame immediately before the current frame and subtracting it from the light emission amount of the current frame. Has been.

  Further, Patent Document 2 discloses a method for approximately correcting the remaining light amount based on the motion amount of the current frame.

JP 2001-255863 A Japanese Patent No. 4079138

  The method disclosed in Patent Document 1 calculates the residual light amount that leaks from the previous frame to the current frame, and subtracts the calculated residual light amount from the video signal of the current frame, thereby affecting the influence of the residual light such as the color shift. It is to suppress. However, this method cannot sufficiently suppress the influence of afterglow when there is movement.

  The reason is simply shown in FIG. FIG. 11A is a diagram in which the light emission 800 is moving in the right direction, and shows a state in which the light emission 800 has moved in the right direction after 1/60 second has elapsed in the upper stage.

  Here, when the light emission 800 moves, an afterglow 801 and an afterglow 802 are generated due to a difference in phosphor characteristics.

  The afterglow 802 indicates the amount of leakage into the next frame. In the figure, the broken arrow indicates a state in which a person's line of sight follows the moving light emission 800.

  The afterglow behind the light emission 800 is caused by integrating and looking at the afterglow of the previous frame.

  FIG. 11B shows a state in which the afterglow 802 leaking into the next frame is removed as in Patent Document 1.

  However, when looking at a moving object, the afterglow of the preceding frame is not lost, so that afterglow is perceived behind the light emission 800 by integrating the afterglow 801 of the preceding frame. Will be. Thus, it can be seen that the method according to Patent Document 1 is not effective in suppressing the afterglow for a moving object.

  Patent Document 2 tries to suppress the influence of afterglow by correcting the remaining light amount perceived in the current frame in a pseudo manner based on the amount of motion obtained from the current frame and using the approximated remaining light amount for correction. That's it.

  In this method, the correction accuracy is determined by the detection accuracy of the motion vector and the motion region, and correction is performed on a portion with motion. However, in general, it is difficult to obtain a region of motion with 100% accuracy, and if it is erroneously detected, there is a possibility of erroneously correcting afterglow.

  Even if the movement is detected correctly, the human gaze does not always follow the direction of movement. There is a possibility.

  On the other hand, since the correction accuracy is affected by the motion detection accuracy, the correction is suppressed by the speed indicated by the magnitude of the motion vector or the measure of the reliability of the motion vector, thereby avoiding side effects caused by erroneous detection of the vector. There is a way to try.

  However, this has the following problems. If there are areas in the screen where motion vectors could be obtained correctly and areas where motion vectors could not be obtained correctly, areas that could be obtained correctly were areas where afterglow correction was performed correctly and were determined to have failed. Since the afterglow correction is suppressed, the color of the entire screen looks different.

  In addition, since correction is performed on a region where there is a motion, there is an adverse effect that the color of the entire screen looks different at a portion where there is motion and a portion where there is no motion.

  The present invention is a video signal processing apparatus that outputs a video signal to a display that displays an image using a plurality of phosphors having different characteristics from each other in consideration of the above-described conventional problems. An object of the present invention is to provide a video signal processing apparatus capable of suppressing the occurrence of color boundaries in the display area of a display.

  In order to achieve the above object, a video signal processing apparatus according to the present invention outputs a video signal for displaying a moving image on a display that displays an image using a plurality of phosphors having different characteristics. A motion vector detection unit that detects a motion vector for each block of a processing target frame that is a frame constituting the moving image, and a partial region including a plurality of blocks of the processing target frame. A randomness calculation unit that calculates the randomness of a plurality of motion vectors of the partial region, and based on a calculation result by the randomness calculation unit, each partial region is a first region or the first region A determination unit that determines whether the second region has a greater degree of randomness, and a preceding frame that is a frame immediately before the processing target frame according to a determination result by the determination unit A signal correction unit that corrects and outputs the video signal of the frame to be processed so as to suppress the influence of afterglow of the image, and the signal correction unit is provided for each pixel or block included in the first region. Correct and output the video signal of the first area using the motion vector, and correct the video signal of the second area using the light emission amount shown in the video signal of the preceding frame without using the motion vector. Output.

  With this configuration, the video signal processing device according to the present invention calculates the randomness for each partial region for the processing target frame, and uses the motion vector for each region according to the calculated randomness. And correction without using a motion vector can be adaptively switched.

  As a result, it is possible to suppress the occurrence of color boundaries in the entire display area of the display while suppressing the influence of afterglow such as color misregistration.

  Further, the signal correction unit uses the video signal of the processing target frame and a motion vector for each pixel or block included in the processing target frame to estimate the preceding frame with respect to the processing target frame. A first signal processing unit that corrects the video signal of the processing target frame by subtracting or adding the estimated residual light amount from the video signal of the processing target frame by obtaining a residual light amount, and the video signal of the preceding frame The residual light amount that leaks into the processing target frame calculated from the amount of emitted light is calculated, and the video signal of the processing target frame is subtracted or added from the video signal of the processing target frame. The second signal processing unit to be corrected and the partial region determined by the determination unit as the first region are obtained from the first signal processing unit. A corrected video signal obtained from the second signal processing unit is selected for the partial region determined by the determination unit as the second region, and the selected video is selected. And a selection unit that outputs a signal.

  With this configuration, for example, the correction process of the video signal can be performed while the motion vector is detected and the degree of randomness is being calculated. Therefore, the entire process related to the correction of the video signal can be efficiently performed.

  Further, the randomness calculation unit calculates a variance value of a plurality of motion vectors for each block included in the partial area for each partial area, and calculates a larger randomness degree as the calculated variance value is larger. Also good.

  As described above, since the degree of randomness is based on a quantitatively obtained value called a variance value of a plurality of motion vectors for each block included in the partial region, it is possible to accurately determine the degree of randomness.

  The determination unit compares the randomness for each partial region calculated by the randomness calculation unit with a predetermined threshold, and determines a partial region in which the randomness is greater than the threshold for the randomness in the second region. It may be determined that there is a partial area in which the degree of randomness is equal to or less than a threshold value for the degree of randomness as the first area.

  Further, the randomness calculation unit calculates, for each partial region, a sum of absolute value difference sums when motion vectors of each of a plurality of blocks included in the partial region are obtained, and the sum is If it is larger than the threshold for the sum, a predetermined value may be subtracted from the threshold for the degree of randomness.

  In addition, the randomness calculation unit calculates, for each partial region, a sum of absolute value difference sums when motion vectors of a plurality of blocks included in the partial region are obtained, and the sum is large. The threshold for the degree of randomness may be made smaller.

  As described above, when the sum of the absolute value difference sums is large, in other words, when the reliability of the motion vector is low, the threshold value may be changed so that the threshold value for the degree of randomness becomes small. Thereby, it becomes easy to determine that the partial region to be determined is the second region, and as a result, the afterglow correction by the motion vector having low reliability is adjusted.

  Note that the present invention can be realized not only as a video signal processing device but also as a television including the video signal processing device and a display.

  The present invention can also be realized as a video signal processing method including each process by each component of the video signal processing apparatus of the present invention.

  The present invention can also be realized as a program for causing a computer to execute each process included in the video signal processing method of the present invention.

  The program can also be widely distributed via a recording medium such as a DVD (Digital Versatile Disc) or a transmission medium such as the Internet.

  Also, some or all of the components constituting the video signal processing apparatus of the present invention may be configured by one system LSI (Large Scale Integration). The system LSI is an ultra-multifunctional LSI manufactured by integrating a plurality of components on one chip. Specifically, a microprocessor, a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. It is a computer system comprised including.

  According to the present invention, when an image is displayed on a display that displays an image using a plurality of phosphors having different characteristics, such as a PDP, the influence of afterglow such as color misregistration is suppressed, and the display area of the display The occurrence of color boundaries can be suppressed in

It is a block diagram which shows the main function structures of the video signal processing apparatus which concerns on embodiment of this invention. It is a flowchart which shows the flow of a basic process of the video signal processing apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the relationship between the light emission characteristic of fluorescent substance, and time. It is a conceptual diagram which shows the state which the afterglow like a tail can be seen behind the light emission which has a motion. It is a figure for demonstrating the principle by which afterglow is perceived behind the light emission with a motion. It is a figure for demonstrating the process of the randomness calculation part which concerns on embodiment of this invention. It is a figure for demonstrating the procedure in which the 1st signal processing part which concerns on embodiment of this invention calculates | requires the motion amount of an attention block. It is explanatory drawing for demonstrating the filter process to the video signal by the 1st signal processing part which concerns on embodiment of this invention. It is a figure which shows the external appearance and main structures of a television provided with the video signal processing apparatus which concerns on embodiment of this invention. It is a figure which shows an example of circuit integration in the video signal processing apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the state which cannot suppress afterglow in a prior art.

  Embodiments of an image processing apparatus according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing the main functional configuration of a video signal processing apparatus 100 according to an embodiment of the present invention.

  The video signal processing apparatus 100 is built in a television including a display that displays an image using a plurality of phosphors having different characteristics, such as a PDP, and outputs a video signal for displaying a moving image on the display. Device.

  The video signal processing apparatus 100 includes a memory 101, a randomness calculation unit 102, a motion vector detection unit 103, a memory 106, a determination unit 108, and a signal correction unit 110. The signal correction unit 110 includes a first signal processing unit 104, a second signal processing unit 105, and a signal selection unit 107.

  The same video signal is input to the first signal processing unit 104 and the second signal processing unit 105. The motion vector detection unit 103 receives the video signal delayed in the frame in the memory 101 and the video signal not delayed in the frame.

  The motion vector detection unit 103 detects a motion vector for each block by block matching in units of blocks including a plurality of pixels. Note that the motion vector detection unit 103 may obtain a motion vector by performing matching processing in units of one pixel as necessary.

  The randomness calculation unit 102 receives a motion vector detected by the motion vector detection unit 103 and an absolute value difference sum (SAD: Sum of Absolute Difference) used at the time of detection. The randomness calculation unit 102 calculates the degree of dispersion and reliability of the motion vector in the partial area including a plurality of blocks from the input information, and calculates the randomness of the motion vector for each partial area.

  The second signal processing unit 105 receives a video signal of a frame immediately before the current frame to be processed (hereinafter referred to as “preceding frame”) and a video signal of the current frame. The second signal processing unit 105 corrects the video signal of the current frame by adding or subtracting the signal level for each color from the video signal of the current frame in accordance with the signal level of the preceding frame.

  The first signal processing unit 104 is given the motion vector and SAD value detected by the motion vector detection unit 103 in addition to the video signal of the current frame. The first signal processing unit 104 corrects the video signal of the current frame by adding or subtracting the signal level for each color from the video signal of the current frame based on the motion vector information.

  Based on the result from the randomness calculation unit 102, the signal selection unit 107 selects the second signal processing unit 105 when the motion vector randomness is large, and selects the first signal processing unit 104 when the randomness is small. To do.

  Specifically, the determination unit 108 determines whether each of the partial areas including a plurality of blocks is the first area or the second area having a greater degree of randomness than the first area. This determination is performed, for example, by comparing the randomness for each partial region obtained from the randomness calculation unit 102 with a predetermined threshold value.

  The signal selection unit 107 selects the video signal corrected by the first signal processing unit 104 for the partial region determined to be the first region. For the partial area determined to be the second area, the video signal corrected by the second signal processing unit 105 is selected. The signal selection unit 107 further outputs the selected video signal.

FIG. 2 is a flowchart showing a basic processing flow of the video signal processing apparatus 100.
The basic processing flow of the video signal processing apparatus 100 will be described with reference to FIG.

  First, the motion vector detection unit 103 calculates a motion vector for each block of the processing target frame (S10).

  The randomness calculation unit 102 calculates the randomness of the motion vector for each partial region including a plurality of blocks from the motion vector for each block obtained from the motion vector detection unit 103 (S20).

  The determination unit 108 determines whether each partial region is the first region or the second region having a higher degree of randomness than the first region, from the randomness for each partial region obtained from the randomness calculation unit 102. (S30).

  The signal correction unit 110 corrects and outputs the video signal of the processing target frame according to the determination result by the determination unit 108 (S40).

  Specifically, the video signal in the first area is corrected using the light emission signal amount indicated in the video signal of the preceding frame and the motion vector for each block in the first area.

  In addition, the motion vector is not used for the video signal in the second region, and the light emission signal amount indicated in the video signal of the preceding frame is used for correction.

  As described above, the video signal processing apparatus 100 according to the embodiment calculates a randomness for each partial region for a processing target frame, and uses a motion vector according to the calculated randomness, A correction method that does not use a motion vector is adaptively switched. Further, the corrected video signal is output to the display. As a result, the influence of afterglow such as color misregistration can be suppressed, and the occurrence of color boundaries in the display area of the display can be suppressed.

  Note that a series of processing including motion vector detection, randomness calculation, and video signal correction processing by the video signal processing apparatus 100 is performed for a CPU (Central Processing Unit), a storage medium, and information input / output. It can also be realized by a computer configured with an interface or the like and a program for causing the computer to execute the above-described processes.

Next, the principle of how a person perceives afterglow will be briefly described.
FIG. 3 is a diagram for explaining the relationship between the light emission characteristics of the phosphor and time.

  In FIG. 3, the vertical axis represents the luminance of the phosphor that emits light by the discharge pulse, and the horizontal axis represents time (seconds). As shown in FIG. 3, when the phosphor is caused to emit light within a period of 1/60 seconds, the emission luminance is attenuated over the next 1/60 seconds. The rate of decay (attenuation rate) depends on the phosphor material and varies depending on the colors green, red, and blue.

  In this way, when a person perceives the process in which the emission luminance is attenuated, it appears colored in the next frame or looks different in hue.

  When the image is stationary, the afterglow is added to the light emission after the next frame and is not easily perceived because the position does not move. However, if the afterglow of the previous frame leaks into the light emission of the next frame, the signal is raised by the amount of the afterglow as a whole. As a result, the color of the video may appear different.

  FIG. 4 is a conceptual diagram showing a state in which afterglow such as tailing can be seen behind the light emission with movement.

  As shown in FIG. 4, a rectangular figure 400 moves from right to left, and afterglow 401 is perceived behind it. Thus, when there is a motion in the image, the afterglow is perceived as a tail remarkably behind the motion. This is because, when a person sees a moving object, the afterglow that follows the movement and leaks into the next frame is integrated and viewed in an oblique direction in FIG.

FIG. 5 is an explanatory diagram for explaining the principle that afterglow is perceived behind the light emission with movement.
FIG. 5 shows the relationship between light emission and time when the rectangular figure 400 shown in FIG. 4 is moving from right to left. FIG. 5 shows a case in which the time axis is taken downward in the drawing and the light emission position moves in the left direction. Further, light emission at the start time of the first 1/60 seconds is emitted as light emission 500, light emission at the next frame time (2/60 seconds) is emitted as light emission 501, and afterglow leaking into the next frame of light emission 500 is as afterglow 502. Show.

  As described above, a person has a habit of chasing and watching what is moving with his / her line of sight, and in the state shown in FIG.

  The same applies to the afterglow 502, and the person perceives the afterglow 502 that has leaked into the next frame with the movement of the line of sight in the oblique direction in FIG. The reason why the afterglow is perceived behind the movement is that the afterglow is chased in the line-of-sight direction 503. The amount of afterglow is integrated at a position close to light emission, and the integration amount increases as the distance increases. Less. That is, a person perceives like light emission 504 and afterglow 505.

  Further, as described above, the decay rate of the emission luminance of the phosphor depends on the material of the phosphor and varies depending on the colors of green, red, and blue.

  In this way, how the afterglow looks is determined by the difference in the light emission characteristics of the phosphors and the relationship between the line of sight of the person.

  The feature of the present invention is that it shows how the human gaze follows the motion and how the afterglow is perceived by a parameter called randomness, and for the region where the human gaze easily follows the motion, the motion vector is used to follow the gaze. Determine the direction and correct the afterglow based on it, and for the area where there is almost no movement, the area where the line of sight does not move, or the area where the line of sight is difficult to follow, the amount of light emitted from the previous frame is not used. The afterglow is corrected based on this.

  Here, the degree of randomness is a value obtained from the direction and magnitude of a motion vector, the degree of dispersion thereof, and the SAD value in a partial region including a plurality of blocks. Specifically, it is assumed that the greater the number of motion vectors in various directions, the greater the degree of randomness that is determined as the accuracy of motion vectors detected with a larger SAD value is worse. Be treated. That is, the randomness is an index indicating the degree of motion vector distribution.

  When the degree of randomness is small, it can be determined that there is a certain similar distribution in the motion vector and the accuracy of the motion vector is reasonably high. In this case, the video signal processing apparatus 100 determines that it is easy for a person to follow the movement with the eyes, and performs afterglow correction using the motion vector.

  On the other hand, when the degree of randomness is large, it can be determined that there is a complicated movement and it is difficult for a person to follow the movement with his eyes, or that the person is almost stationary. In this case, the video signal processing apparatus 100 corrects the afterglow according to the light emission level in the preceding frame.

Hereinafter, the calculation of the randomness will be specifically described.
When a video signal is input to the video signal processing apparatus 100, a video signal of one frame or more is buffered in the memory 101. The motion vector detection unit 103 detects a motion vector by detecting a difference between the current frame and the buffered previous frame.

  A block matching method is used for motion vector detection, and it is obtained by searching for a location where the absolute value difference sum (SAD) for each matching is minimized. Of course, the motion vector detection method is not limited to the block matching method, and any method may be used as long as a motion vector is obtained.

  The randomness calculation unit 102 obtains the motion vector obtained by the motion vector detection unit 103 and the SAD value when the positional relationship between the preceding frame and the current frame is matched with the motion vector (in other words, the motion vector is obtained). The degree of randomness is calculated based on the SAD value at that time.

FIG. 6 is a diagram for explaining the processing of the randomness calculation unit 102.
Specifically, FIG. 6 shows an example of a partial area that is a part of the frame, which is composed of one target block 301 in the processing target frame and 5 blocks in the periphery and 5 blocks in the periphery. Has been.

  The randomness calculation unit 102 includes a line buffer for several lines that can store the motion vector and SAD value of each block. Thereby, it is possible to refer to the motion vector and SAD value of each of the surrounding blocks as well as the target block 301 shown in FIG.

  The randomness calculation unit 102 first obtains a variance value for each x component and y component of the motion vector of the 5 × 5 block area. The determination unit 108 determines that the variance is large if both of the x component dispersion value and the y component dispersion value obtained from the randomness calculation unit 102 are equal to or greater than the threshold value a. That is, it is determined that the partial area is the second area.

The threshold value a may be fixed to a predetermined value or may be changed dynamically.
For example, the randomness calculation unit 102 obtains the sum of the respective SAD values when the motion vectors of the plurality of blocks in the 5 × 5 region are obtained, and the determination unit 108 determines the sum from the threshold value b. If larger, α is subtracted from the threshold value a.

  This is because there is a high possibility that the motion vector of the block having a large SAD value is wrong. Therefore, the determination unit 108 lowers the threshold value a for determining that the motion vector variance is large (the degree of randomness is large) when the sum of the SAD values of each of the plurality of blocks included in the partial region is larger than the threshold value b.

Or the determination part 108 makes the threshold value a small, so that the sum total of the said SAD value is large.
As described above, when the sum of the SAD values is large, in other words, when the reliability of the motion vector is low, the threshold value a is changed so that the threshold value a becomes small. Thereby, it becomes easy to determine that the partial region to be determined is the second region, and as a result, the afterglow correction by the motion vector having low reliability is adjusted.

  Of course, when the sum of the SAD values is large, this adjustment process is also realized by an equivalent process such as increasing the randomness by a predetermined value or increasing it by a predetermined ratio while fixing the threshold value a.

  Further, when the randomness calculation unit 102 determines from the edge information of the video, the motion vector distribution, the SAD value, and the like that the partial area to be calculated is an area including a block displaying a telop (telop area), This is notified to the determination unit 108. When the determination unit 108 receives the notification, the determination unit 108 determines that the partial area has a small degree of randomness. That is, it is determined that the partial area is the first area. In this way, processing that prioritizes afterglow correction using a motion vector may be performed.

  Note that the determination unit 108 may determine whether the partial area to be calculated is a telop area by receiving information necessary for the determination from the randomness calculation unit 102.

  In addition, as a condition for determining that the partial area to be calculated is a telop area, for example, there is an edge of a video in the partial area, and the motion vector distribution of the edge part is a vector of only horizontal or vertical components An example is a condition of having a component and having an SAD value equal to or greater than the threshold value c.

  In this embodiment, the partial area determined by the randomness calculation unit 102 is 5 × 5 blocks. However, the size of the partial area may be 2 blocks or more, and is not limited to 5 × 5 blocks. .

  In addition, the randomness calculation unit 102 calculates the variance values of the x component and the y component of a plurality of motion vectors in calculating the randomness, but the randomness may be calculated by other methods. For example, a histogram of motion vectors in a 5 × 5 block may be obtained, and the number of motion vectors included in a certain range may be handled as a numerical value indicating variance. In this case, the determination unit 108 determines that the larger the number of motion vectors included in the certain range, the smaller the variance, that is, the smaller the degree of randomness.

  When the determination unit 108 determines that the partial region is the second region because the determination unit 108 has a high degree of randomness, the signal selection unit 107 selects the processing result of the second signal processing unit 105. If it is determined that the partial area is the first area, the processing result of the first signal processing unit 104 is selected. The signal selection unit 107 further outputs the selected processing result (corrected video signal).

  The memory 106 holds the video signal that is the target of afterglow correction for the purpose of delaying the video signal by the processing time of the motion vector detection unit 103 and the randomness calculation unit 102. Thereby, the memory 106 also plays a role of holding video signal data for one frame for calculating the remaining light amount to be subtracted or added in the next frame.

  Note that the memory 101 and the memory 106 can be shared, and there is no problem even if they are shared as long as there is no memory access conflict. Further, since the video signal for one frame held in the memory 106 only needs to know the difference amount of the color signal to be subtracted in the next frame, only the remaining light amount calculated from the light emission amount may be held in advance.

  The second signal processing unit 105 obtains the residual light amount that leaks into the current frame to be processed, which is calculated from the light emission amount of the video signal of the preceding frame, and subtracts the residual light amount from the video signal of the current frame.

  The phosphor has the light emission characteristics as shown in FIG. 3, and the amount of afterglow in the current frame can be determined according to the light emission amount in the preceding frame. For example, the second signal processing unit 105 holds table data in which a light emission amount and a remaining light amount (estimated remaining light amount) approximated by the light emission amount are associated with each color in a predetermined storage area. Thereby, the second signal processing unit 105 can obtain the remaining light amount to be subtracted from the current frame according to the light emission amount of the preceding frame.

  In general, the afterglow increases in the order of green (G), red (R), and blue (B), and the level at which blue is afterglow in the next frame does not matter. Therefore, the green and red signals having a large remaining light amount are subtracted from the light emission of the next frame.

  If there is not enough light emission to subtract in the next frame, afterglow will remain. However, in this case, coloring by afterglow may be reduced by adding blue to the next frame and making it achromatic.

  The first signal processing unit 104 obtains an estimated residual light amount from the preceding frame from the video signal of the current frame and the motion vector calculated by the motion vector detecting unit 103, and adds the estimated residual light amount from the video signal of the current frame or Subtract.

  The first signal processing unit 104 performs a filter operation based on the motion vector of the block of interest. For example, assuming that the video is scrolling from right to left, the estimated remaining light amount is obtained by performing filter processing according to the magnitude and direction of the movement.

The process will be specifically described with reference to FIG.
When it is determined from the motion vector of the pixel 601 that the motion direction of the video is from right to left, the first signal processing unit 104 performs LPF (Low Pass) shown in (Equation 1) for each pixel in the left to right direction. Filter) is applied continuously.

  P ′ (x, y) = α × P (x, y) + (1−α) × P (x−1, y) (Formula 1)

  α is a parameter that varies depending on the magnitude of the motion vector, and takes a value of 0 <α ≦ 1. In addition, the first signal processing unit 104 adjusts so that the value of α decreases as the detected motion vector increases.

  When the motion vector is obtained in units of blocks, the first signal processing unit 104 generates a motion vector in units of pixels by interpolation processing using a plurality of motion vectors. Also, these motion vectors are smoothed so that the motion vectors do not differ greatly across the block boundary.

  When the motion vector is obtained in units of blocks, the motion vector itself of the block including the pixel to be corrected may be adopted as the motion vector of the pixel to be corrected.

  The first signal processing unit 104 refers to a previously created table in which the magnitude of the motion vector is associated with α, and determines the value of α according to the detected or generated motion vector. Note that the correspondence between the magnitude of the motion vector and the value of α is defined independently for each color of the phosphor.

  In (Expression 1), P (x, y) is the signal level of the pixel of interest that is the pixel to be corrected, and corresponds to the signal level of the pixel 601 in the example of FIG. P (x−1, y) is the signal level of the pixel adjacent to the target pixel in the direction of movement, and corresponds to the signal level of the pixel 602 adjacent to the left of the target pixel in the example of FIG.

  If it is determined that the direction of motion of the video is from left to right, the signal level of the adjacent pixel is P (x + 1, y). If the direction of motion of the video is determined from upper right to lower right, the signal level of the adjacent pixel is P (x + 1, y + 1). Thus, the position of the adjacent pixel in (Equation 1) changes according to the direction of motion of the video.

  FIG. 8 is a diagram illustrating examples of a video signal, a signal subjected to LPF processing, and a differential signal.

  A video signal 702 is P ′ (x, y), which is a result of applying the LPF processing of (Equation 1) to the video signal 701 before the LPF processing. A difference signal 703 is obtained by subtracting the video signal 702 from the video signal 701.

  The difference signal 703 is treated as an approximation of the level of afterglow that is visible when there is motion. Specifically, in FIG. 8, a difference signal 703 is generated for the rise and fall of the video signal 701, which approximates the response of the rise and fall of the phosphor.

  In the afterglow correction, a correction amount according to the difference signal 703 for each color is given to the original signal. For example, the difference signal 703 shown in FIG. 8 indicates an amount that is insufficient for rising, and an offset is given to the input pixel value so as to correct this amount.

  For example, at the time of start-up, green and red are delayed with respect to blue, which has a quick response, so that the insufficient amount is corrected by causing extra light to be emitted as an offset.

  However, since the amount that can be corrected is limited by the amount that can be displayed on the panel, if it exceeds that amount, blue is subtracted by that amount, and light is emitted weakly to make it achromatic. Similarly, since green and red afterglow with respect to blue at the fall, correction is performed by subtracting the amount of extra afterglow as an offset and emitting light.

  Also in this case, when the value that can be displayed is exceeded, blue is added to achromatic color to suppress coloring.

  As described above, the video signal processing apparatus 100 according to the embodiment calculates a randomness for each partial region for a processing target frame, and uses a motion vector according to the calculated randomness, A correction method not using a motion vector can be adaptively switched.

  Specifically, the video signal processing apparatus 100 determines, for each partial region of the frame to be processed, whether the human line of sight is easy to follow, an area that is difficult to follow, or does not need to move the line of sight. Further, for a region where a person's line of sight is easy to follow, the video signal is corrected using a motion vector for each pixel or block included in the region.

  In addition, for an area where it is difficult for a person's line of sight to follow or where it is not necessary to move the line of sight, the video signal is corrected using the remaining light amount from the preceding frame without using the motion vector.

  Further, the video signal corrected in this way is output to the display. That is, the video signal processing apparatus 100 according to the embodiment selects an appropriate correction method for each partial region based on how a person views the displayed image, and outputs the corrected video signal. .

  Thereby, in the whole display area of the display, it is possible to suppress the occurrence of the boundary of the color while suppressing the influence of afterglow such as color shift.

  In the present embodiment, (Equation 1) is applied as the LPF, but any filter that can approximate a signal that attenuates may be used, and the present invention is not limited to this filter.

  In addition, the motion vector one frame before the target block is calculated from the distribution of surrounding motion vectors, but the motion vector one frame before is stored in the memory, and if it is used, a more accurate motion vector one frame before Can be used.

  In addition, the signal correction unit 110 in the embodiment includes a signal selection unit 107 subsequent to the first signal processing unit 104 and the second signal processing unit 105 (see FIG. 1).

  However, the signal selection unit 107 may be provided before the first signal processing unit 104 and the second signal processing unit 105.

  In this case, the signal selection unit 107 receives a determination result indicating whether the partial region to be processed is the first region or the second region from the determination unit 108. When the determination result indicates that the partial area to be processed is the first area, the signal selection unit 107 reads out the video signal of the partial area from the memory 106 and inputs it to the first signal processing unit 104.

  If the determination result received from the determination unit 108 indicates that the partial area to be processed is the second area, the signal selection unit 107 reads the video signal of the partial area from the memory 106 and performs the second signal processing. Input to the unit 105.

  Each of the first signal processing unit 104 and the second signal processing unit 105 to which the video signal is input from the signal selection unit 107 performs processing for correcting the input video signal as described above.

  Even with such a processing flow, a video signal that has been appropriately corrected for each region can be obtained, as in the video signal processing apparatus 100 configured as shown in FIG.

  Further, as described above, the video signal processing apparatus 100 is built in, for example, a television provided with a PDP. An example of a television incorporating the video signal processing apparatus 100 is shown in FIG.

  FIG. 9A is a perspective view showing an appearance of the television 200 incorporating the video signal processing apparatus 100 according to the embodiment.

FIG. 9B is a block diagram illustrating a main configuration of the television 200.
Note that in FIG. 9B, illustration of components included in a normal television such as a tuner that receives broadcast waves is omitted.

  As shown in FIG. 9A and FIG. 9B, the television 200 includes a video signal processing device 100 and a PDP 210. When a video signal is input from a tuner or the like, the video signal processing apparatus 100 corrects the video signal as described above and outputs it to the PDP 210.

  As a result, the PDP 210 displays an image in which color misregistration, afterglow blur, and the like are suppressed by the correction, and the occurrence of the color boundary is suppressed.

  Further, part or all of the configuration of the video signal processing apparatus 100 according to the embodiment can be realized by one or a plurality of integrated circuits.

  FIG. 10 is a diagram illustrating an example of circuit integration in the video signal processing apparatus 100 according to the embodiment.

  An LSI 120 illustrated in FIG. 10 is an example of an integrated circuit including a plurality of functional blocks included in the video signal processing apparatus 100.

  The plurality of functional blocks may be included in a plurality of LSIs instead of one LSI.

  Further, the method of circuit integration is not limited to LSI's, and implementation using dedicated circuitry or general purpose processors is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

  Furthermore, if integrated circuit technology that replaces LSI or the like appears as a result of progress in semiconductor technology or other derived technology, it is naturally also possible to carry out function block integration using this technology.

  The present invention is a video signal processing apparatus that outputs a video signal for displaying a moving image on a display that displays an image using a plurality of phosphors having different characteristics, as well as a video signal processing apparatus in a plasma television. It can be applied as

DESCRIPTION OF SYMBOLS 100 Video signal processing apparatus 101 Memory 102 Randomness calculation part 103 Motion vector detection part 104 1st signal processing part 105 2nd signal processing part 106 Memory 107 Signal selection part 108 Judgment part 110 Signal correction part 120 LSI
200 TV 210 PDP

Claims (10)

A video signal processing device that outputs a video signal for displaying a moving image on a display that displays an image using a plurality of phosphors having different characteristics from each other,
A motion vector detection unit for detecting a motion vector for each block of a frame to be processed which is a frame constituting the moving image;
For each partial region including a plurality of blocks of the processing target frame, a randomness calculation unit that calculates the randomness of a plurality of motion vectors of the partial region;
Based on the calculation result by the randomness calculation unit, a determination unit that determines whether the partial region is a first region or a second region having a larger randomness than the first region;
According to the determination result by the determination unit, the video signal of the processing target frame is corrected and output so as to suppress the influence of afterglow of the preceding frame that is the frame immediately before the processing target frame. A signal correction unit,
The signal correction unit is
Correct and output the video signal of the first region using a motion vector for each pixel or block included in the first region,
A video signal processing apparatus that corrects and outputs the video signal of the second region using the light emission amount indicated in the video signal of the preceding frame without using the motion vector. The signal correction unit is
Using the video signal of the processing target frame and a motion vector for each pixel or block included in the processing target frame, an estimated remaining light amount of the preceding frame with respect to the processing target frame is obtained, and the processing target A first signal processing unit that corrects the video signal of the frame to be processed by subtracting or adding the estimated remaining light amount from the video signal of the frame,
By calculating a residual light amount leaking into the processing target frame calculated from the light emission amount of the video signal of the preceding frame, and subtracting or adding the residual light amount from the video signal of the processing target frame, the processing target A second signal processing unit for correcting the video signal of the frame,
For the partial region determined to be the first region by the determination unit, the corrected video signal obtained from the first signal processing unit is selected and determined to be the second region by the determination unit. The video signal processing apparatus according to claim 1, further comprising: a selection unit that selects a corrected video signal obtained from the second signal processing unit and outputs the selected video signal. 2. The randomness calculation unit calculates a variance value of a plurality of motion vectors for each block included in the partial area for each partial area, and calculates a larger randomness degree as the calculated variance value is larger. Or the video signal processing apparatus according to 2. The determination unit
The randomness for each partial area calculated by the randomness calculation unit is compared with a predetermined threshold, and the partial area having a randomness larger than the threshold for the randomness is determined as the second area, and the randomness is The video signal processing device according to claim 1, wherein a partial region that is equal to or less than a threshold value for the degree of randomness is determined to be a first region. The randomness calculation unit calculates, for each partial region, a sum of absolute value difference sums when motion vectors of a plurality of blocks included in the partial region are obtained, and the sum is the sum The video signal processing device according to claim 4, wherein a predetermined value is subtracted from the threshold value for the degree of randomness when the threshold value is larger than the threshold value for The randomness calculation unit calculates, for each partial area, a sum of absolute value difference sums when motion vectors of each of a plurality of blocks included in the partial area are obtained, and the larger the sum, The video signal processing apparatus according to claim 4, wherein a threshold value for the degree of randomness is reduced. A video signal processing apparatus according to claim 1;
A television comprising: a display for displaying an image using a plurality of phosphors having different characteristics from each other, the display receiving and displaying a video signal output from the video signal processing device. A video signal processing method for outputting a video signal for displaying a moving image on a display for displaying an image using a plurality of phosphors having different characteristics from each other,
A motion vector detection step of detecting a motion vector for each block of a frame to be processed which is a frame constituting the moving image;
For each partial region including a plurality of blocks of the processing target frame, a randomness calculation step for calculating a randomness of a plurality of motion vectors of the partial region;
Based on the calculation result in the randomness calculation step, a determination step for determining whether the partial area is a first area or a second area having a larger randomness than the first area;
According to the determination result in the determination step, the video signal of the processing target frame is corrected and output so as to suppress the influence of afterglow of the preceding frame that is the frame immediately before the processing target frame. Signal correction step,
In the signal correction step,
Correct and output the video signal of the first region using a motion vector for each pixel or block included in the first region,
A video signal processing method for correcting and outputting the video signal of the second region using the light emission amount indicated in the video signal of the preceding frame without using the motion vector. A program for outputting a video signal for displaying a moving image on a display for displaying an image using a plurality of phosphors having different characteristics from each other,
A motion vector detection step of detecting a motion vector for each block of a frame to be processed which is a frame constituting the moving image;
For each partial region including a plurality of blocks of the processing target frame, a randomness calculation step for calculating a randomness of a plurality of motion vectors of the partial region;
Based on the calculation result in the randomness calculation step, a determination step for determining whether the partial area is a first area or a second area having a larger randomness than the first area;
According to the determination result in the determination step, the video signal of the processing target frame is corrected and output so as to suppress the influence of afterglow of the preceding frame that is the frame immediately before the processing target frame. A program for causing a computer to execute a signal correction step and
In the signal correction step,
Correct and output the video signal of the first region using a motion vector for each pixel or block included in the first region,
A program for correcting and outputting the video signal of the second area using the light emission amount indicated in the video signal of the preceding frame without using the motion vector. An integrated circuit that outputs a video signal for displaying a moving image on a display that displays an image using a plurality of phosphors having different characteristics from each other,
A motion vector detection unit for detecting a motion vector for each block of a frame to be processed which is a frame constituting the moving image;
For each partial region including a plurality of blocks of the processing target frame, a randomness calculation unit that calculates the randomness of a plurality of motion vectors of the partial region;
Based on the calculation result by the randomness calculation unit, a determination unit that determines whether the partial region is a first region or a second region having a larger randomness than the first region;
According to the determination result by the determination unit, the video signal of the processing target frame is corrected and output so as to suppress the influence of afterglow of the preceding frame that is the frame immediately before the processing target frame. A signal correction unit,
The signal correction unit is
Correct and output the video signal of the first region using a motion vector for each pixel or block included in the first region,
An integrated circuit that corrects and outputs the video signal of the second region using the light emission amount indicated in the video signal of the preceding frame without using the motion vector.

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