JP5166159B2 - Image display circuit and screen display device - Google Patents

Description

  The present invention relates to an image display technique, and in particular, at a screen end portion of a display device that generates an image corresponding to two images by detecting a motion vector from the movement of two pieces of image information moving back and forth in time. Related to high image quality technology.

  Large screens such as liquid crystal television devices are being developed. Furthermore, there is an increasing demand for high image quality by users.

  Under such circumstances, image generation processing at the periphery of the screen is an important technique for improving image quality. In view of this, a method has been proposed in which an image is generated by interpolating from one of the front and rear frames when generating an image of the periphery of the screen (see, for example, Patent Document 1 below). According to this method, the original image signal of the part that is off the screen in only one of the two consecutive frames corresponds to only the original image signal of the corresponding part in the other of the two consecutive frames instead of the weighted addition. The processing is simplified by forming a partial frame number conversion output image signal.

JP-A-62-221784

However, the technique described in Patent Document 1 has the following problems.
(1) There is no movement in the image at the edge of the screen. This problem is caused by the loss of continuity because the images of the previous and next frames are used as they are for the portion where there is motion.
(2) When the motion is fast, the judgment itself as to whether the motion detection is correct is erroneous. This problem is caused by performing an incorrect comparison because there is no corresponding comparison target before and after.
(3) Since processing is performed with incorrect information, many errors are likely to occur. This problem is due to the fact that errors propagate and big mistakes occur.

  Further, in a device that generates and displays an image while moving back and forth in time by detecting a motion vector from information of two images before and after, when performing high-speed panning in which the image moves at high speed, It may appear to wave at the edges (both sides) of the screen. This is caused by jumping from the outside of the screen. FIG. 6 is a diagram illustrating a state of a defect that appears to wave at the screen edges (both sides) when panning at high speed in this way. In FIG. 6, when the display screen is schematically shown, an area from the screen edge 203 to a certain distance on the display screen 201 is referred to as a peripheral portion 205 (considering that the maximum N pixels are the peripheral portion). In this screen, when panning to the right (hereinafter referred to as “pan”), the images 211 and 221 in the peripheral portion 205 move to the images 215 and 225 in (1) and (2). In this case, the images 213 and 223 between them can be obtained by interpolation (arrows 217 and 227). However, in the case as shown in (3), since the original image 231 exists outside the screen, there is no temporally previous (past) image side data, and the image 233 using the current image 235 is not present. Cannot be obtained by interpolation. For example, as shown in (4), since interpolation is performed based on an incorrect motion vector (243 is obtained based on 241 and 245), there is a problem that a wavy display is made.

  FIG. 7 is a diagram illustrating a state where panning is uniformly performed from the center side of the screen toward the peripheral edge 305 (left side). Similar to the case of FIG. 6, in (1) and (2), when the images 311 and 321 in the center side 301 move to the images 315 and 325, the images 313 and 323 between them are obtained by interpolation. Yes (arrows 317 and 327). However, in the case shown in (3), since the current image 335 exists outside the screen, there is no time-side (future) screen-side data, and the original image 331 is used for the image. The motion vector of 333 cannot be obtained by interpolation. For example, as shown in (4), since interpolation is performed based on an incorrect motion vector (343 is obtained based on 341 and 345), there is a problem that a wavy display is made.

Thus, in the motion detection process at the edge of the screen, if the motion is large, the target to be compared before and after is outside the screen and does not exist. May lead to results.
It is an object of the present invention to improve the display at the screen edge.

  The present invention is characterized by determining the possibility of occurrence of a defect at the edge of the screen, and when the defect is likely to occur, the processing is performed by replacing with an alternative motion vector without performing the motion detection process at the edge of the screen. . No comparison is made in the range where an error is likely to occur (the comparison result is not referred to). If it is necessary to generate an image, it is replaced with a motion vector with few errors instead.

  According to one aspect of the present invention, a motion vector detection unit that detects a motion vector, and whether or not the motion vector in the entire screen of the display screen detected by the motion vector detection unit is greater than a preset threshold value. A motion vector determination unit that determines whether or not the motion vector of the entire screen is larger than a threshold by the motion vector determination unit, and a replacement processing unit that replaces the average motion vector of the entire screen on the entire screen as a motion vector on the screen end. , An image display circuit is provided. The possibility of occurrence of a problem at the edge of the screen is determined, and if a problem is likely to occur, the motion detection process at the edge of the screen is not performed and replaced with an alternative motion vector.

  Also, a motion vector detection unit that detects a motion vector, and a motion vector determination unit that determines whether or not the motion vector in the entire display screen detected by the motion vector detection unit is larger than a preset threshold value And a replacement processing unit that replaces a partial screen average motion vector in a certain partial screen as a motion vector at the screen end when the motion vector determination unit determines that the motion vector of the entire screen is larger than the threshold value. An image display circuit is provided. Thereby, it is possible to adjust the screen edge processing according to the content to be displayed.

  It is preferable to have a partial region designating unit that designates the region of the part. Moreover, it is preferable to provide the threshold value adjustment part which adjusts the said threshold value. The width of several blocks at the screen edge may be fixed. The width of several blocks at the screen edge may be variable. The block width of the screen edge may be variable according to the total screen average vector amount. The position of the motion vector referred to for the replacement may be varied. Instead of the average vector, a vector in which the weight of the central part is increased and the peripheral part is reduced may be used. The present invention may be an image display device having the image display circuit described above.

  According to the present invention, since the determination is performed in advance and the calculation outside the screen is not performed, erroneous detection due to a calculation error does not occur, and the image generation error associated therewith is reduced. In addition, by replacing a portion where detection is not performed with an alternative vector, a continuous video can be generated without being separated from the motion of the picture at the center of the screen.

In this specification, the width of the screen edge can be defined as follows.
(1) Fixed block width: The maximum width is obtained by replacing the size of a motion vector that can be processed with the number of blocks. Here, the fixed block width <the number of motion vector blocks that can be processed, and the motion vector that can be processed is a predetermined value that depends on the capacity of the frame cache memory when implemented as hardware.

  (2) Variable block width: Quantizes the average vector size into the number of blocks. As the average vector, a full screen average vector can be used, or a partial screen average vector can be used. Here, variable block width = α * average vector <number of motion vector blocks that can be processed, and α is an arbitrary coefficient.

  Before describing embodiments of the present invention, considerations made by the inventors will be described. In a scene where a problem occurs at the edge of the screen, panning is generally performed, and in a scene with fast movement, the size of the full-screen average vector should be large. Thus, the inventor has come up with the idea that when the size of the full screen average vector is sufficiently large, for example, several blocks of motion vectors constituting the screen edge are replaced with the full screen average vector. Thereby, the movement of the entire screen can be reflected on the screen edge.

  In this specification, the full screen average vector is a vector obtained by averaging motion vectors calculated over the entire screen, and takes a large value in one direction when the entire screen moves in one direction such as panning. The partial screen average vector is obtained by dividing a screen into several regions and averaging motion vectors detected therein. The replaced motion vector is a vector for preventing an erroneous error by replacing the motion vector at the screen end.

  Hereinafter, a video display technique according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an example of screen edge countermeasures related to the video display technique according to the present embodiment. As shown in FIG. 1, the display screen 1 will be described by dividing it into a central portion 3, and a screen left end portion 5a and right end portion 5b. INTP_FRAME_END_WIDTH is the width of the screen left end 5a and right end 5b.

  In the present embodiment, when the full screen average motion vector 7 is larger than the threshold value INTP_FRAME_END_VECTOR_THLD, the left end vector 11 or the right end vector 15b is replaced with the full screen average motion vector 7. This threshold is determined by the product specification, but may be set by the manufacturer or the user. When INTP_FRAME_END = 1, screen edge processing is performed. Here, if the threshold value is too small, it is determined that the entire screen is moving with a slight error, and a malfunction that erroneously replaces the vector at the screen end can be considered. Therefore, a certain size is preferable so that it can be correctly determined that the entire screen is moving.

  In the above description, “screen edge processing is performed when INTP_FRAME_END = 1” means that screen edge processing is performed when a threshold value is exceeded.

  If the full-screen average vector is a left-right vector, the motion vectors at the left end, right end, and left and right ends are replaced. If the full-screen average vector is in the vertical direction, the vectors at the upper end, the lower end, or the upper and lower ends are replaced. If the full-screen average vector is a composite of left and right and top and bottom, the replacement area is both.

  As described above, the possibility of occurrence of a malfunction at the screen edge is determined, and if a malfunction is likely to occur, the motion detection process at the edge of the screen is not performed, but an alternative motion vector, for example, the average of the entire screen Perform replacement with a vector. Thereby, panning at the edge of the screen can be prevented.

  FIG. 2 is a functional block diagram showing a configuration example of the image display apparatus according to this embodiment. As shown in FIG. 2, the image display device 81 according to the present embodiment receives a motion vector between a motion vector interpolation processing circuit 85, a frame memory 83, and a motion vector interpolation processing circuit 85 that receives an image input. An output image generation circuit that generates an output image and outputs an image by receiving a motion vector memory 87 for storing motion vectors, an output from the motion vector interpolation processing circuit 85 and an output from the frame memory 83 89.

  FIG. 3 is a functional block diagram showing a detailed configuration example of the motion vector interpolation processing circuit 85. As shown in FIG. 3, the motion vector interpolation circuit 85 includes a buffer memory 90a that receives an N-1 frame image input, a buffer memory 90b that receives an N frame image input, and both buffer memories 90a and 90b. A motion vector detection unit 91 that receives the output and detects a motion vector, and a motion vector determination unit 92 that compares the size of the motion vector of the surrounding area based on the detected motion vector (determines the speed of motion) And a motion vector evaluation unit 93 that evaluates a motion vector based on the comparison determination result, a motion vector memory 87 that stores the motion vector, and an interpolation vector assignment from the motion vector from the motion vector memory 87 An interpolation vector allocating unit 98 for performing interpolation and an output from the interpolation vector allocating unit 98 is an interpolation vector And Mori 99, is composed of the interpolation vector evaluating unit 101 Prefecture, and outputs an interpolation vector to the output image generation circuit 89.

  The new configuration will be described below. The output from the motion vector detection unit 91 includes a full screen average vector calculation unit 95 that calculates an average vector of the entire screen, a partial screen average vector calculation unit 96 that calculates an average vector of a partial screen, and a calculated partial average. Replacement of interpolation vector based on partial average vector memory 97 for storing vector, partial area specifying unit (for example, specifying a range with a mouse or the like) 105 for specifying a partial area, and full-screen average vector and partial average vector A replacement processing unit 98a that performs processing. In addition, the replacement processing unit 98a may be provided with a threshold adjustment unit 107 that can adjust a value (threshold) to be compared with the full screen vector in step S2 below. By adjusting the threshold value, if the threshold value is increased, the replacement is difficult to be performed (it is easy to proceed to step S8 in step S2 of FIG. 4), and if the threshold value is decreased, the replacement is easily performed (step S2 of FIG. 4). Thus, it is easy to proceed to step S3), and for example, it is possible for the user to adjust whether or not the replacement process is easily generated.

  In the above example, as a means for determining that the movement is fast, determination is made based on the magnitude of the full-screen average vector. If it is determined that the motion is fast, the motion detection of the screen edge is not performed (the motion detection result is not referred to). Then, the motion vectors of several blocks at the edge of the screen are replaced. The width of the several blocks to be replaced may be fixed to, for example, about 1/10 of the entire width, or the width of these several blocks may be variable. In this case, it is preferable to make the width of several blocks variable in accordance with the entire screen average vector amount. Since the movement is faster as the average vector amount is larger, it is preferable to increase the block width.

  Next, the flow of interpolation vector assignment processing will be described with reference to the flowchart shown in FIG. As shown in FIG. 4, when the process is started in step S1, it is determined in step S2 whether or not the full-screen average vector is larger than a threshold value. In the case of Yes, it progresses to step S3 and calculates a replacement area. In step S4, it is determined whether or not the region is a replacement region. If N, the region is not a replacement region, so the process proceeds to step S8, the motion vector is read, and the process proceeds to step S9. If Y in step S4, the process proceeds to step S4 ', the motion vector at the screen edge is replaced with a full screen vector, an interpolation vector is assigned in step S9, and the process ends in step S10. In the case of N in step S4, the process proceeds to step S8, the motion vector is read out, the process proceeds to step S9, the interpolation vector is assigned, and the process ends in step S10. The process of this flowchart is repeated on all screens.

  As described above, the entire motion vector including the screen edge can be made the same by replacing the replacement area, in this case, using the full screen average vector as the motion vector in the screen edge area. There is also an advantage that there is no sense of discomfort in the display.

  Next, an image processing apparatus according to a second embodiment of the present invention will be described. FIG. 5 is a diagram illustrating a screen edge countermeasure different from the screen edge countermeasure according to the first embodiment. In the screen edge countermeasure according to the present embodiment, on the display screen 21, the end area vector is not replaced with only the full screen average vector 35, but the partial vector in the partial area is replaced according to the situation. The motion vector of the end region is replaced with a partial average vector that is the average of the partial regions close to the end region. For example, the motion vector 41 of the end region 31a is replaced with the partial vector 37 of the region 25a close to the region. The same applies to other regions. Also in this case, the point of replacement when the full-screen average vector is larger than INTP_FRAME_END_VECTOR_THLD is the same, and only the point of replacement by the partial average vector is different. In this way, it is possible to display at a fine edge.

In the present embodiment, in FIG. 4, if it is a replacement area (if Y) from step S4, it is a replacement area, so that the process proceeds to step S5, and an alternative position is calculated. Next, in step S6, the partial average vector is read out, in step S7, the motion vector at the screen edge is replaced with the partial average vector, and in step S9, an interpolation vector is assigned, and the process ends in step S10. In the case of N in step S4, the process proceeds to step S8 as in the first embodiment, the motion vector is read, the process proceeds to step S9, an interpolation vector is assigned, and the process ends in step S10. The process of this flowchart is repeated on all screens.
In this case, since the determination is made in advance and the calculation outside the screen is not performed, erroneous detection due to a calculation error does not occur. By replacing with, there is an advantage that a continuous video can be generated without being separated from the movement of the picture at the center of the screen.

  It is also possible to change the position of the motion vector referred to for replacement. Further, a non-image portion at the screen edge may be detected. Note that the no image portion at the edge of the screen refers to the upper and lower black belt portions when displaying images with different aspect ratios such as 4: 3 and 16: 9, or when displaying movie material. It is. When the screen edge is replaced, the no-image portion is detected in advance and replaced in consideration of the portion, thereby preventing a malfunction such as assigning a motion to a portion having no motion and generating noise. In addition, it is preferable to use not the full-screen average vector but the weighting of the central part is large and the peripheral part is small.

  As to whether to use the method according to the first embodiment or the method according to the second embodiment, it may be possible to select one by detecting the movement of the content.

  As described above, in the present embodiment, the case of a fast motion pattern is detected, and the motion detection result of a certain range of edges is calculated on the average of all the screens without performing the motion detection calculation of the screen edges where an error occurs. Replace with a vector. As a result, it is possible to suppress the failure of the image due to the motion vector that has been largely calculated erroneously. At this time, it is possible to determine that the movement is fast using the full-screen average vector. Further, as in the second embodiment, the replacement motion vector can be replaced using not only the full-screen average vector but also the partial average vector. Further, as shown in FIG. 5, the reference location of the partial average vector to be replaced can be changed actively.

  In the process of actively changing the reference location of the partial average vector to be replaced, it is preferable to determine, for example, by referring to the partial average vector of the adjacent portion to be replaced as to which variable the variable is to be changed. . However, in that case, depending on the amount of movement, it may not be an appropriate reference destination. Here, “actively variable” includes, for example, referring to a partial average vector at a location away from a vector to be replaced in proportion to the magnitude direction of the full-screen average vector.

(Summary)
According to the present embodiment, the possibility of occurrence of a problem at the edge of the screen is determined, and if a problem is likely to occur, the motion detection process at the edge of the screen is not performed and replaced with an alternative motion vector.

  Instead of generating an image, a process of replacing with a motion vector with few errors is performed. A range in which an error is likely to occur may be a structure that does not perform comparison (a structure that does not refer to a comparison result).

  As a result, the determination is made in advance and the calculation outside the screen is not performed, so that erroneous detection due to a calculation error does not occur, and the image generation error associated therewith is eliminated.

  In addition, by replacing a portion where detection is not performed with an alternative vector, a continuous video can be generated without being separated from the motion of the picture at the center of the screen. This is particularly effective in a large-screen liquid crystal display device.

  The present invention can be used as an image processing circuit of a display device.

It is a schematic diagram which shows an example of the screen edge countermeasure regarding the image | video display technique by this Embodiment. It is a functional block diagram which shows the example of 1 structure of the image display apparatus by this Embodiment. 5 is a functional block diagram illustrating a detailed configuration example of a motion vector interpolation processing circuit 85. FIG. It is a flowchart figure which shows the flow of the allocation process of the interpolation vector in 1st and 2nd embodiment. It is a figure which shows the screen edge countermeasure by the image processing apparatus by the 2nd Embodiment of this invention. It is a figure which shows the mode of the malfunction which seems to wave at the screen edge (both sides), when panning at high speed. It is a figure which shows a mode that it pans uniformly toward the peripheral part (left side) from the center side of a screen.

Explanation of symbols

DESCRIPTION OF SYMBOLS 81 ... Image display apparatus, 83 ... Frame memory, 85 ... Motion vector interpolation processing circuit, 87 ... Motion vector memory, 89 ... Output image generation circuit, 90a, 90b ... Buffer memory, 91 ... Vector detection part, 92 ... Motion vector Determination unit, 93 ... motion vector evaluation unit, 95 ... full screen average vector calculation unit, 96 ... partial screen average vector calculation unit, 97 ... partial average vector memory, 98 ... interpolation vector allocation unit, 98a ... replacement processing unit 98a, 99... Interpolation vector memory, 101... Interpolation vector evaluation unit, 105... Partial region designation unit, 107.

Claims (8)

A motion vector detection unit for detecting a motion vector;
A motion vector determination unit that determines whether or not a motion vector in the entire screen of the display screen detected by the motion vector detection unit is greater than a preset threshold;
A replacement processing unit that replaces a partial screen average motion vector in a certain partial screen as a motion vector at a screen end when the average motion vector of the entire screen is larger than a threshold by the motion vector determination unit;
An image display circuit comprising: The image display circuit according to claim 1 , further comprising a partial area designating unit that designates an area of the partial screen. The image display circuit according to claim 1 or 2, characterized in that it comprises a threshold adjustment unit configured to adjust the threshold. The image display circuit according to claim 1 or 2, characterized in that to fix the width of several blocks of the screen edge. The image display circuit according to claim 1 or 2, characterized in that varying the width of several blocks of the screen edge. 6. The image display circuit according to claim 1 , wherein a position of a motion vector referred to for replacement is variable. The full screen average instead of the motion vector, increasing the weighting of the central portion, an image display circuit according to any one of claims 1 to 6, which comprises using a smaller the vector periphery. An image display device having an image display circuit as claimed in any one of claims 1 to 7.

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