JP4702340B2 - Image display device - Google Patents

Description

  The present invention relates to an image display device for confirming or quantitatively evaluating a correction processing effect.

  When judging which part of the display image the image quality correction such as gamma correction or enhancer is currently working on, the image quality evaluator looks at the displayed image and at what strength the image quality correction is applied to which part. It is subjectively judged whether it depends.

Further, as a conventional quantitative image quality evaluation method, there is an image quality evaluation (presence / absence of noise) based on a difference between video signals and a motion vector (Patent Document 1).
JP 2003-47029 A

  However, in the conventional method, it is possible to detect a significant change from the original video signal, such as when noise is superimposed, but it is not possible to detect a slight change such as the presence or absence of image quality correction. Further, when a plurality of types of image quality correction are performed, the judgment by visual evaluation by individual image quality evaluators may be erroneous. In addition, there is a problem that it is difficult to visually confirm even if the side effects of image quality correction have a slight adverse effect on image quality.

  The present invention aims to solve the above-mentioned problems, and specifies an image-corrected portion and quantitatively displays the portion on the screen with an OSD or the like, thereby evaluating the image quality. It is an object of the present invention to provide an image display device that enables a person to easily specify a portion on which image quality correction is applied.

  An image display device according to the present invention outputs an image quality corrected video signal, which is a video signal that has been subjected to image quality correction by performing one or a plurality of types of image quality corrections that change a luminance signal or a color signal on an input video signal. A correction unit, an image quality comparison unit that calculates a difference between the input video signal and the image quality correction video signal as difference data, and at least one of the plurality of pattern matrices matches the difference data calculated by the image quality comparison unit A pattern comparison unit that determines whether or not, a correction region that is determined to match, and a display unit that displays on the screen at least one of the image quality correction information of the matched pattern matrix.

  An image quality evaluator can easily identify a portion on which image quality correction is applied. Further, since it becomes easy for the image quality evaluator to notice the effect of the image quality correction of details that are easily overlooked and the effect of the image quality correction on the fast-moving video signal, it is easy to compare with the image quality correction designed by other designers.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram showing the configuration of the image display apparatus according to the first embodiment. An image quality correction unit 110 that performs image correction and an image quality comparison unit 120 that compares input and output video signals of the image quality correction unit 110; The difference data calculated by the image quality comparison unit 120 is compared with a pattern prepared in advance to specify a correction region, and the correction region data obtained by the pattern comparison unit 130 is displayed or notified in an image. , And a composite display unit 140 that synthesizes the image after the image quality correction from the image quality correction unit 110 and outputs it to the video monitor.

  FIG. 2 is a block diagram showing a circuit configuration for explaining the schematic configuration diagram described in FIG. 1 in more detail, and FIG. 3 is an operation flowchart for explaining the operation of the circuits of FIGS. A digital signal is obtained by the A / D conversion unit 101 that converts an analog signal into a digital signal, and is output to the image quality correction unit 110 and the image quality comparison unit 120 (step S1). The image quality correction unit 110 has a gamma correction circuit 111 having a function of correcting gradation intensity suitable for screen display from a luminance signal, and a function of making the contour stand out in order to correct the blurring of the contour in a low frequency band. After the processing of the video signal, the image quality comparison unit 120 for comparing before and after correction is generated, and the OSD signal is generated, combined with the video signal, and output to the monitor display 140 (step S2). . The image quality comparison unit 120 inserts a buffer 121 into the signal before the image quality correction so as to compensate for the delay caused by the processing in the image quality correction unit 110 in order to compare the image signal before and after the image quality correction. (Step S 3), the A matrix conversion circuit 123 having a function of converting signal data as a 3 × 3 A matrix with 3 × 3 pixels as one block, and outputs the result to the pattern comparison unit 130. (Step S4). The pattern comparison unit 130 performs correction processing on the matrix stylization circuit 131 (step S5) having a function of stylizing the 3 × 3 pixel A matrix and the difference pattern output from the matrix stylization circuit 131 by the image quality correction unit 110. A pattern comparison circuit 134 (step S6) having a function of comparing with a stored pattern associated with the stored pattern is output to the composite display unit 140 (step S7). The calculation processing of the matrix stylization circuit 131 and the pattern comparison circuit 134 is performed by the CPU 132, and the ROM 133 storing the comparison pattern data is used. In the composite display unit 140, in order to compensate for the delay processing in the image quality comparison unit 120 and the pattern comparison unit 130, a buffer 141 is inserted into the image signal after image quality correction from the image quality correction unit 110, and an OSD is generated and output to the monitor. The data obtained from the pattern comparison unit 130 is OSD synthesized by the OSD synthesis circuit 142 having (Step S9) and output to the video monitor (Step S10).

  Note that the comparison pattern stored in the pattern comparison unit 130 is associated with the image quality correction unit 110, and a pattern for recognizing effects other than gamma correction and enhancers may be prepared.

  A matrix of 3 rows and 3 columns with 3 × 3 pixels as one block may use an arbitrary integer (m, n), and is an m row and n column matrix with m × n pixels as one block. May be.

  Here, the image quality correction unit 110 will be described in detail. The image quality correction unit 110 has functions of enhancer and gamma correction. FIG. 7 shows signal input / output through the enhancer circuit. The enhancer is a process for providing a step difference in signal change in order to sharpen the boundary of the contour where the change in luminance is small. Although the change 220 of the input signal of the enhancer circuit is a small step-like change, the change 221 of the output signal of the enhancer circuit is an uneven signal, and the change in luminance at the boundary of the contour can be increased. As a result, even a small luminance change can be recognized, and the outline can be clear. FIG. 8 shows a gamma correction curve. In the gamma correction, the gamma curve 230 indicating the relationship between the input luminance signal and the output luminance signal is changed to a characteristic that is optimal for monitoring or necessary for increasing the contrast in a local region. As the level of the input signal of the gamma curve 230 becomes flat, the gradation becomes poorer. Therefore, the curve is ideally processed so as to be linear according to the output characteristics of the monitor. FIG. 6 shows an example before and after image quality correction at the time of input / output of the image quality correction unit 110. Also, the cloud / sky outline 201 and the mountain / sky outline 202 in FIG. 4 before the image quality correction are clear due to the effect of the enhancer in FIG. 5 after the image quality correction. Also, the sky gradation in FIG. 4 is increased, and in FIG. 5 the gamma correction increases the brightness range.

Next, details of the image quality comparison unit 120 will be described. In the image quality comparison unit 120, the subtractor 122 calculates the difference. When the A matrix conversion circuit sets the number of 3 × 3 pixels as one block, the horizontal direction of the number of pixels of the entire screen is a, and the vertical direction is b. (See FIG. 9). Therefore, as shown in FIG. 11, the values of a and b are determined so that the block 261 having the number of pixels of 3 × 3 becomes one block 250 and becomes a minimum unit region for determining image quality correction. As a result, the block 263 storing the difference data is calculated by subtraction of the block 262 and the block 261 in the same area before and after the image quality correction (see FIG. 12). That is, when the block storing the difference data is considered as a matrix, it becomes a 3 × 3 matrix, and (a + 1) × (b + 1) from A ₁₁ to A _{(a + 1) (b + 1)} ) A matrix having 3 × 3 matrices is created (see FIG. 10).

  Note that 3 × 3 may be m × n, and 3 rows and 3 columns may be m rows and n columns.

Next, details of the pattern comparison unit 130 will be described. In the value of the A matrix calculated by the image quality comparison unit 120, it is conceivable that a plurality of multiples of a certain matrix pattern are calculated depending on the magnitude of the luminance difference value. Therefore, normalization is performed with the absolute minimum value set to 1 in each A matrix, and a plurality of patterns are considered as constant patterns, so that the number of stored patterns as a comparison reference is reduced. Can be compared. Referring to FIG. 13 as an example, since the absolute minimum value of the matrix 263 in the A matrix is 2, if it is standardized with 2 being x, it can be changed to a standardized matrix 270. When this standardized matrix 270 is compared with the stored pattern matrix, it can be seen that it matches the gamma correction pattern (P1) 271. Therefore, the compared matrix, that is, a certain block area on the screen, is detected as x = 2 and P1, and is output as information data of the OSD signal.
Next, details of the composite display unit 140 will be described. In order to express the region 280 of the result detected by the pattern comparison unit 130, the synthesis display unit 140 has an OSD synthesis circuit that creates an OSD signal and synthesizes it with the signal from the image quality correction unit 110 (see FIG. 14). The area detected by the pattern comparison unit 130 and the detected intensity are alternately blinked and displayed on the screen. Here, the blinking time is arbitrary, and the display method may be a method other than blinking. FIG. 15 shows an example of screen display when the pattern comparison unit 130 detects an enhancer pattern, and FIG. 16 shows an example of screen display when a gamma correction pattern is detected. Each area recognized as image quality correction is displayed by the OSD, and the image quality correction level is also displayed in the same area.

  In the image quality comparison unit 120, the A matrix conversion circuit 123 may be deleted and used. In this case, the matrix stylization circuit 131 of the pattern comparison unit 130 is not necessary, and the circuit scale can be reduced. However, since the number of stored patterns to be compared by the pattern comparator 134 increases, Usage increases. When deleted as described above, a matrix of m × n pixels centered on one pixel can be compared over the total number of pixels. Of course, m × n pixels may be a 3 × 3 pixel matrix. Since it is difficult to reliably determine the value of the pattern matrix, it is effective to use a method that preserves a pattern that causes a defect by visual evaluation.

  In the embodiment described above, the display method using the OSD is an example for informing the image quality evaluation result, and any method may be used as long as the image quality evaluation result is informed.

  It can be used as an image display device that can be used when checking image quality in a manufacturing process or when an image quality evaluator evaluates image quality.

1 is a schematic configuration diagram of an image display apparatus according to Embodiment 1 of the present invention. 1 is a circuit configuration diagram of an image display apparatus according to Embodiment 1 of the present invention. Flowchart for explaining the operation of the image display apparatus according to the first embodiment of the present invention. The figure which shows the example of the image before image quality correction | amendment in the image display apparatus which concerns on Embodiment 1 of this invention. The figure which shows the example of the image after image quality correction | amendment in the image display apparatus which concerns on Embodiment 1 of this invention. The figure which shows the example of the input / output of the image quality correction | amendment part 110 in the image display apparatus which concerns on Embodiment 1 of this invention. The figure which shows the example of the enhancer signal in the image display apparatus which concerns on Embodiment 1 of this invention. The figure which shows the example of the gamma correction signal in the image display apparatus which concerns on Embodiment 1 of this invention. Conceptual diagram of screen division in image display apparatus according to Embodiment 1 of the present invention The figure which shows the example of an area | region division by A matrix transformation in the image display apparatus which concerns on Embodiment 1 of this invention. The figure which shows the example of the m * n matrix in the image display apparatus which concerns on Embodiment 1 of this invention. The figure which shows the example of the subtraction of the image quality comparison part in the image display apparatus which concerns on Embodiment 1 of this invention. The figure which shows the example of a detection of the pattern comparison part in the image display apparatus which concerns on Embodiment 1 of this invention. The figure which shows the example of entering / exiting the composite display in the image display apparatus which concerns on Embodiment 1 of this invention The figure which shows the example of the detection of the enhancer in the image display apparatus which concerns on Embodiment 1 of this invention. The figure which shows the example of the detection of the gamma correction in the image display apparatus which concerns on Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 A / D converter 110 Image quality correction part 111 Gamma correction circuit 112 Enhancer circuit 120 Image quality comparison part 121 Buffer 122 Subtractor 123 A matrix conversion circuit 130 Pattern comparison part 131 Matrix stylization circuit 132 CPU
133 ROM
134 Pattern Comparison Circuit 140 Composition Display Unit 141 Buffer 142 OSD Composition Circuit

Claims (6)

An image quality correction unit that outputs one or more types of image quality corrections that change the luminance signal and color signal to the input video signal, and outputs an image quality corrected video signal that is an image signal that has undergone image quality correction;
And quality ratio 較部 calculating a difference between the input video signal and the image quality corrected video signal as difference data,
A pattern comparison unit that determines whether or not at least one of a plurality of pattern matrices matches the difference data calculated by the image quality comparison unit;
A display unit that displays on the screen at least one of the correction area determined to match and the image quality correction information of the matched pattern matrix;
An image display device comprising: 2. A plurality of m × n number of pixel matrices, that is, m × n pattern matrices associated with at least one of the plurality of types of image quality correction as image quality correction information are stored. Image display device. The display unit creates an OSD signal that displays both the correction area determined to be matched and the image quality correction information associated with the matched pattern matrix, and the image quality corrected video signal output from the image quality correction unit and the OSD 3. The image display device according to claim 1, wherein a signal obtained by synthesizing the signals is displayed on a monitor. The image quality comparison unit divides each of the input video signal and the image quality corrected video signal into areas each having m × n pixels as one block, and m is a difference between the input video signal and the image quality corrected video signal for each block. The image display device according to claim 1, wherein the image display device is calculated as difference data that is a difference matrix of a × n matrix. The pattern comparison unit performs at least one of a process of dividing the value of the difference matrix calculated by the image quality comparison unit by a minimum value in the difference matrix or a process of normalizing the minimum value as 1. The image display device according to claim 1, wherein the image display device is standardized. 6. The image display device according to claim 1, wherein the correction area data is stored in a storage unit capable of storing data as a detection result, or is output as data from a display unit.

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