JP2006229615A - Interpolated pixel generation circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an interpolated pixel generation circuit for generating scaling interpolated pixels in which any noise is hardly generated in a display image, or resolution is hardly deteriorated. <P>SOLUTION: The pixels of a current field adjacent to an interpolated phase are read from a field memory 1. The pixels decided to be still images by a movement deciding part 4 among the pixels of one field before the current field adjacent to the interpolated phase are read from a field delay memory 2, and stored in an adjacent pixel storage part 7. Correlation between the stored pixels is detected by an inter-adjacent pixel correlation detecting part 8, and the direction of the combination of the pixels whose correlation is the highest is decided as an interpolation direction by an interpolation direction deciding part 9. The combination of the pixels for interpolated pixel generation is selected by a pixel selecting part 10 on the basis of the decision, and the pixel values of the interpolated pixels are generated by an interpolated pixel generating part 11 by using the pixel values of the selected pixels, and outputted as a scaling interpolation output. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a scaling process for an interlaced scanned image, and more particularly to an interpolation pixel generation circuit that generates an interpolation pixel in a scaling phase.

  In recent years, a dot matrix type plasma display device or a liquid crystal display device having a number of display pixels in various formats is often used as a device for displaying a video signal such as a television broadcast. When displaying an interlaced scanning video signal on such a dot matrix type display device, it is necessary to generate interpolation pixels according to the number of pixels of the display device.

  Conventionally, as a circuit for generating such an interpolated pixel, a circuit for performing a scaling process for enlarging / reducing an image after once converting a video signal for interlace scanning into a video signal for progressive scanning has been used. (For example, refer to Patent Document 1).

  At this time, in the process of converting the video signal of the interlace scanning into the video signal of the progressive scanning, a progressive conversion interpolation line is formed at an intermediate position of the scanning line of the current field, and a scanning line interpolation pixel is generated on the progressive conversion interpolation line. Progressive interpolation is first performed. Thereafter, scaling processing is performed using the scanning line interpolation pixels to generate scaling interpolation pixels.

  Of these, in the execution of progressive interpolation, motion determination is performed using the pixels in the current field and two fields before the pixel position to be interpolated, and if it is determined as a still image, the pixel in the previous field is set as the interpolation pixel, If it is determined, the correlation is determined between the pixels in the upper, lower, left, and right directions of the current field, the interpolation direction is determined based on the pixel value of the pixel with the highest correlation, and the pixel of the pixel in the interpolation direction A pixel value of a scanning line interpolation pixel is generated based on the value (see, for example, Patent Document 2).

  However, the inter-pixel correlation determination in such scanning line interpolation pixel generation may be erroneous determination because the determination is performed using only the pixels in the current field. For example, when luminance is taken as a pixel value and a scanning line interpolation pixel is generated at the position of the pixel b2 determined to be a moving image with respect to the video signal having the pixel value array shown in FIG. 3A, FIG. As shown in FIG. 5, it is determined that the correlation of the pixel combination (a1, c3) is the highest, and the pixel value of the scanning line interpolation pixel m5 is generated based on the pixel value. However, the pixel value of the scanning line interpolation pixel m5 is not in harmony with the pixel values of the surrounding pixels, and is a value regarded as noise in the entire surrounding pixels.

  Thereafter, an enlargement / scaling process of 2 × horizontal and 4 × vertical is performed based on the pixel value of the scanning line interpolation pixel m5 and the pixel values of neighboring pixels (a1 to a3, b1, b3, c1 to c3). If it does, the scaling pixels m1-m4 and m6-m9 as shown in FIG.10 (b) will be produced | generated, and noise will further increase.

When scaling processing is performed using the scanning line pixels generated based on such erroneous determination, there is a problem that the determination error is diffused and noise of the display image is increased or the resolution of the display image is deteriorated. It sometimes occurred.
JP 2003-324695 A (page 4-5, FIG. 1) JP 2003-230109 A (page 5-6, FIG. 2)

  SUMMARY OF THE INVENTION An object of the present invention is to provide an interpolation pixel generation circuit that generates an interpolation pixel that hardly causes noise in a display image or deteriorates resolution even when scaling processing is performed.

  According to one aspect of the present invention, for each field of a video signal for interlace scanning, a motion determination unit that performs a motion determination for each pixel, whether the pixel included in the field is a moving image or a still image, and the video signal For the interpolated phase on the interpolated scan line generated by scaling that compresses or expands in the horizontal or vertical direction, or in the horizontal and vertical directions, and the adjacent pixel on the adjacent scan line of the current field of the video signal A plurality of combinations of pixels adjacent to the interpolation phase are generated from among the pixels on the scanning line one field ahead positioned in the middle of the scanning line and the pixels determined as the still image by the motion determination means, and each pixel is generated. A correlation value between pixels for calculating a correlation value between pixels for each combination of pixels, and detecting a correlation between adjacent pixels; Based on the determination result of the interpolation direction determining means, the interpolation direction determining means for determining the direction of the combination of pixels having the highest correlation among the combinations of pixels whose correlation has been detected by the inter-pixel correlation detecting means as the interpolation direction, and A pixel combination for generating an interpolation pixel is selected from the pixels in the current field adjacent to the interpolation phase and the pixel in the previous field determined to be a still image, and the pixel value of the interpolation pixel in the interpolation phase is selected using the pixel value. There is provided an interpolation pixel generation circuit comprising interpolation pixel generation means for generating a value.

  According to the present invention, it is possible to perform scaling interpolation without performing progressive interpolation on an interlaced video signal, and therefore, it is possible to generate an interpolation pixel that is less likely to cause noise in the display image or deteriorate in resolution. Can do.

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

  FIG. 1 is a block diagram illustrating an example of the configuration of an interpolation pixel generation circuit according to an embodiment of the present invention.

  The interpolated pixel generation circuit according to this embodiment includes a field memory 1 that stores a pixel value of a current field of each pixel of an input interlaced video signal, a field delay memory 2 that stores a pixel value of the previous field, The field delay memory 3 that stores the pixel values two fields before, that is, one frame before, and the pixel values are read from the field memory 1 and the field delay memory 3 to calculate the inter-frame difference from the difference between the pixel values of the pixels having the same phase. It has a motion determination unit 4 that performs motion determination for each pixel and a motion determination result storage unit 5 that stores a motion determination result of the pixel one field before.

  Further, the interpolation pixel generation circuit of this embodiment is adjacent to the interpolation phase based on the interpolation phase signal generation unit 6 that generates an interpolation phase signal that indicates the generation position of the interpolation pixel for the pixel in the current field. An adjacent pixel storage unit 7 that reads out and stores the pixel value of the pixel from the field memory 1 and the field delay memory 2 is provided. However, from the field delay memory 2, the motion determination result of the pixel one field before is read from the motion determination result storage unit 5, and only the pixel value of the pixel determined to be a still image is read.

  Further, the interpolation pixel generation circuit according to the present embodiment calculates a correlation value of pixel values between pixels adjacent to the interpolation phase indicated by the interpolation phase signal using the pixel values stored in the adjacent pixel storage unit 7. The inter-adjacent-pixel correlation detection unit 8 that detects a combination of pixels having a correlation, and the direction of the pixel combination having the highest correlation among the pixel combinations detected by the correlation detection unit 8 between adjacent pixels is an interpolation direction. The combination of the pixels in the interpolation direction determined by the interpolation direction determination unit 9 among the pixels adjacent to the interpolation phase indicated by the interpolation phase signal is selected from the adjacent pixel storage unit 7. A pixel selection unit 10 and an interpolation pixel generation unit that calculates the pixel value of the interpolation phase indicated by the interpolation phase signal using the pixel value of the pixel selected by the pixel selection unit 10 and outputs it as a scaling interpolation output Having one and.

  Here, the interpolation direction determination unit 9 adds the correlation value of the combination of the pixels whose correlation is detected by the adjacent pixel correlation detection unit 8 for each direction of the combination, and compares the added value to determine the interpolation direction. To do.

  The interpolation pixel generation unit 11 interpolates the pixel selected by the pixel selection unit 10 and the interpolation coefficient generation unit 111 that generates a horizontal interpolation coefficient and a vertical interpolation coefficient using the interpolation phase signal and the interpolation direction determination result. A horizontal interpolation unit 112 that generates a horizontal interpolation pixel as a preprocessing of interpolation processing on a scanning line adjacent to the interpolation phase using the horizontal interpolation coefficient calculated by the coefficient generation unit 111, and a horizontal pixel generated by the horizontal interpolation unit 112 The final interpolation unit 113 generates a pixel value of the final interpolation pixel by linear interpolation using the vertical interpolation coefficient generated by the interpolation coefficient generation unit 111.

  The horizontal interpolation unit 112 determines the generation position of the horizontal interpolation pixel depending on whether the interpolation direction determined by the interpolation direction determination unit 9 is oblique to the scanning line, vertical, or horizontal. That is, when the interpolation direction is diagonal, a horizontal interpolation pixel is generated on the scanning line adjacent to the interpolation phase where the line passing through the interpolation phase intersects with the same inclination as the interpolation direction, and the interpolation direction is vertical or horizontal. If it is, the horizontal interpolation pixel is generated in the same horizontal phase as the interpolation phase on the scanning line adjacent to the interpolation phase.

  FIG. 2 is a diagram illustrating an example of a combination of pixels for which the correlation detection unit 8 between adjacent pixels calculates a correlation value for correlation determination. Here, the pixels in the horizontal, vertical, and diagonal directions indicated by arrows in FIG. 2 are determined from the pixels on the Nth and N + 1th line scanning lines in the current field and the pixels on the Nth scanning line one field before. Generating combinations. At this time, only the pixels determined to be still images are read out from the field delay memory 2 to the adjacent pixel storage unit 7 and the correlation value in the adjacent pixel correlation detection unit 8 is read out. Used as a calculation pixel.

  Accordingly, as shown in FIG. 2A, when all the pixels on the Nth scanning line one field before are still images, the number of combinations of pixels for calculating the correlation value is the largest, and FIG. As shown in FIG. 5, when all the pixels on the scanning line of the Nth line before one field are moving images, the combination of pixels for calculating the correlation value is the smallest.

  Next, an example of correction pixel generation by the interpolation pixel generation circuit of this embodiment will be described with reference to FIGS.

  Here, as shown in FIG. 3A, among the pixels one field before, only the pixel at the position b2 is determined to be a moving image, and the scaling process is performed twice horizontally and vertically four times. An example in which interpolation pixels are generated at the positions m1 to m9 shown in FIG. In each figure, the difference in color density of pixels represents the difference in pixel values.

  The generation of the interpolation pixel m1 will be described with reference to FIGS.

  When generating the interpolated pixel m1, the inter-adjacent pixel correlation detection unit 8 uses the absolute difference value of the pixel value between the five sets of pixels adjacent to the interpolated pixel m1 indicated by arrows D1 to D5 in FIG. And a pixel set D1, D2, D3 having a correlation value equal to or lower than the threshold value is detected as being correlated, and a pixel set D4 having a correlation value greater than the threshold value is detected. D5 is detected as uncorrelated.

  Next, the interpolation direction determination unit 9 makes the correlation values of the pixel sets D1, D2, and D3 whose correlations are detected based on the interpolation phase signal non-linearly inversely proportional to the distance from the interpolation phase to each pixel. The correlation evaluation values d1, d2, and d3 are calculated by multiplying the coefficients, and the value (d1 + d2) and d3 added for each correlation direction are obtained, and the magnitudes thereof are compared. In this case, since (d1 + d2)> d3 is satisfied, the interpolation direction determination unit 9 determines that the diagonally lower left direction indicated by the arrows D1 and D2 is the interpolation direction.

  Next, the pixel selection unit 10 determines the pixel adjacent to the intersection of the line having the inclination in the interpolation direction determined by the interpolation direction determination unit 9 and passing through the interpolation pixel m1 and the scanning line adjacent to the interpolation pixel m1. Here, a2, a3, b1, and b3 are selected.

Further, the interpolation coefficient generation unit 111 generates horizontal interpolation coefficients Kh0 and Kh1 for the interpolation pixel m1 based on the interpolation phase signal and the interpolation direction determination result. In this case, as shown in FIG. 4B, when the phase between the pixels a1 and a2 and between the lines a and b is 1.0, the horizontal phase of the interpolation pixel m1 is Hm, and the vertical phase is Vm, the horizontal Interpolation coefficients Kh0 and Kh1 are calculated by the following equations.
Kh0 = (Vm−0.5) + (Hm−0.5)
Kh1 = (Vm−0.5) / 2 + (Hm−0.5) / 2
The horizontal interpolation unit 112 uses the interpolation coefficients Kh0 and Kh1 to create a horizontal interpolation pixel k1 on the line a and a horizontal interpolation pixel k2 on the line b using the following equations. However, the horizontal interpolation pixels k1 and k2 are virtually generated as preprocessing before the interpolation pixel m1 is generated, and are not generated as actual pixels.
k1 = {a2 × (1-Kh0)} + a3 × Kh0
k2 = {b1 × (1−Kh1)} + b3 × Kh1
Assuming that Hm = 0.5 and Vm = 0.5, Kh0 = 0 and Kh1 = 0, so k1 = a2.
k2 = b1
As shown in FIG. 4C, the horizontal interpolation pixels k1 and k2 are generated at the positions of the pixel a2 and the pixel b1, respectively, and the pixel values are also equal to the pixel values of the pixels a2 and b1, respectively.

  Finally, the final interpolation unit 113 calculates the pixel value of the interpolation pixel m1 by linearly interpolating the pixel values of the horizontal interpolation pixels k1 and k2, and outputs it as a scaling interpolation output.

  Next, generation of the interpolation pixel m5 will be described with reference to FIGS.

  When generating the interpolation pixel m5, the inter-adjacent pixel correlation detection unit 8 uses the absolute difference value of the pixel value between the eight sets of pixels adjacent to the interpolation pixel m5 indicated by arrows D1 to D8 in FIG. And a pixel group D1, D2, D3, D5 having a correlation value equal to or less than the threshold value is detected as being correlated, and a pixel group having a correlation value greater than the threshold value. D4, D6, D7, and D8 are detected as having no correlation.

  Next, the interpolation direction determination unit 9 is non-linearly inversely proportional to the distance from the interpolation phase to each pixel with respect to the correlation values of the pixel sets D1, D2, D3, and D5 whose correlation is detected based on the interpolation phase signal. The correlation evaluation values d1, d2, d3, and d5 are calculated by multiplying the calculated coefficients, the value (d1 + d2 + d3) and d5 added for each correlation direction are obtained, and the magnitudes thereof are compared. In this case, since (d1 + d2 + d3)> d5 is satisfied, the interpolation direction determination unit 9 determines the diagonally descending left direction indicated by the arrows D1, D2, and D3 as the interpolation direction.

  Next, the pixel selection unit 10 has a slope of the interpolation direction determined by the interpolation direction determination unit 9 and is a pixel adjacent to the intersection of the line passing through the interpolation pixel m5 and the adjacent scanning line, here a3, Select a4, c1, and c2.

The interpolation coefficient generation unit 111 generates horizontal interpolation coefficients Kh0 and Kh1 for the interpolation pixel m5 based on the interpolation phase signal and the interpolation direction determination result. In this case, as shown in FIG. 5B, when the phase between the pixels a2 and a3 and between the lines a and b is 1.0, the horizontal phase of the interpolation pixel m5 is Hm, and the vertical phase is Vm, the horizontal Interpolation coefficients Kh0 and Kh1 are calculated by the following equations.
Kh0 = Vm / 2 + Hm / 2
Kh1 = Vm / 2 + Hm / 2
The horizontal interpolation unit 112 uses the interpolation coefficients Kh0 and Kh1 to create a horizontal interpolation pixel k1 on the line a and a horizontal interpolation pixel k2 on the line c using the following equations. However, the horizontal interpolation pixels k1 and k2 are virtually generated as preprocessing before generating the interpolation pixel m5, and are not generated as actual pixels.
k1 = {a3 × (1-Kh0)} + a4 × Kh0
k2 = {c1 * (1-Kh1)} + c2 * Kh1
Assuming that Hm = 0.0 and Vm = 0.0, Kh0 = 0 and Kh1 = 0, so k1 = a3
k2 = c1
As shown in FIG. 5C, the horizontal interpolation pixels k1 and k2 are generated at the positions of the pixel a3 and the pixel c1, respectively, and the pixel values are also equal to the pixel values of the pixel a3 and the pixel c1, respectively.

  Finally, the final interpolation unit 113 calculates the pixel value of the interpolation pixel m5 by linearly interpolating the pixel values of the horizontal interpolation pixels k1 and k2, and outputs it as a scaling interpolation output.

  Next, generation of the interpolation pixel m2 will be described with reference to FIGS.

  When generating the interpolation pixel m2, the inter-adjacent pixel correlation detection unit 8 uses the absolute difference value of the pixel value between the six sets of pixels adjacent to the interpolation pixel m2 indicated by arrows D1 to D6 in FIG. And a pixel set D1, D2, D4 having a correlation value less than or equal to the threshold is detected as being correlated, and a pixel set D3 having a correlation value greater than the threshold is detected. D5 and D6 are detected as having no correlation.

  Next, the interpolation direction determination unit 9 makes the correlation values of the pixel sets D1, D2, and D4 whose correlation is detected based on the interpolation phase signal non-linearly inversely proportional to the distance from the interpolation phase to each pixel. The correlation evaluation values d1, d2, and d4 are calculated by multiplying the coefficients, and the value (d1 + d2) and d4 added for each correlation direction are obtained, and the magnitudes thereof are compared. In this case, since (d1 + d2)> d4 is satisfied, the interpolation direction determination unit 9 determines that the diagonally lower left direction indicated by the arrows D1 and D2 is the interpolation direction.

  Next, the pixel selection unit 10 has a slope of the interpolation direction determined by the interpolation direction determination unit 9 and is a pixel adjacent to the intersection of the line passing through the interpolation pixel m2 and the adjacent scanning line, here a2, Select a3, c0, and c1.

Further, the interpolation coefficient generation unit 111 generates horizontal interpolation coefficients Kh0 and Kh1 for the interpolation pixel m2 based on the interpolation phase signal and the interpolation direction determination result. In this case, as shown in FIG. 6B, when the phase between the pixels a2 and a3 and between the lines a and b is 1.0, the horizontal phase of the interpolation pixel m2 is Hm, and the vertical phase is Vm, the horizontal Interpolation coefficients Kh0 and Kh1 are calculated by the following equations.
Kh0 = Vm + Hm
Kh1 = Vm + Hm
The horizontal interpolation unit 112 uses the interpolation coefficients Kh0 and Kh1 to create a horizontal interpolation pixel k1 on the line a and a horizontal interpolation pixel k2 on the line c using the following equations. However, the horizontal interpolation pixels k1 and k2 are virtually generated as preprocessing before generating the interpolation pixel m2, and are not generated as actual pixels.
k1 = {a2 × (1-Kh0)} + a3 × Kh0
k2 = {c0 × (1-Kh1)} + c1 × Kh1
If Hm = 0.0 and Vm = 0.5, Kh0 = 0.5 and Kh1 = 0.5, so k1 = 0.5 × a2 + 0.5 × a3.
k2 = 0.5 × c0 + 0.5 × c1
As shown in FIG. 6C, the horizontal interpolation pixel k1 is generated in the middle between the pixel a2 and the pixel a3, and the horizontal interpolation pixel k2 is generated in the middle between the pixel c0 and the pixel c1. The pixel value of the horizontal interpolation pixel k1 is an intermediate value between the pixel value of the pixel a2 and the pixel value of the pixel a3, and the pixel value of the horizontal interpolation pixel k2 is an intermediate value between the pixel value of the pixel c0 and the pixel value of the pixel c1. It becomes.

  Finally, the final interpolation unit 113 calculates the pixel value of the interpolation pixel m2 by linearly interpolating the pixel values of the horizontal interpolation pixels k1 and k2, and outputs the result as a scaling interpolation output.

  FIG. 7 shows a result of generating the remaining interpolation pixels by performing the same processing. When the pixel values of the interpolation pixels m1 to m9 shown in FIG. 7 are compared with the pixel values obtained by the conventional interpolation method shown in FIG. 10, the pixel value shown in FIG. 7 clearly matches the pixel values of the pixels around the interpolation pixel. It is removed.

  The example of interpolation pixel generation when the interpolation direction is oblique has been described so far. Next, an example of interpolation pixel generation when the interpolation direction is vertical or horizontal will be described.

  FIGS. 8A to 8C are diagrams illustrating an example of generating an interpolation pixel when the interpolation direction is determined to be vertical.

  When the interpolation pixel m1 is generated for the pixel arrangement shown in FIG. 8A, the inter-adjacent pixel correlation detection unit 8 has five sets adjacent to the interpolation pixel m1 indicated by arrows D1 to D5 in FIG. Interpolation determination is performed by obtaining a correlation value based on the absolute difference value of the pixel values between the pixels, but in this case, the group of pixels determined to have correlation is only D4. Therefore, the interpolation direction determination unit 9 determines that the vertical direction indicated by the arrow D4 is the interpolation direction.

  In response to this determination, the pixel selection unit 10 detects the pixels a1, a2, and the pixels adjacent to the point having the same horizontal phase as the horizontal phase Hm of the interpolation pixel m1 shown in FIG. 8B on the scanning line adjacent to the interpolation pixel m1. b1 and b3 are selected.

  Next, the horizontal interpolation unit 112 generates horizontal interpolation pixels k1 and k2 at points having the same horizontal phase as the horizontal phase Hm of the interpolation pixel m1 shown in FIG. 8C on the scanning line adjacent to the interpolation pixel m1. However, the horizontal interpolation pixels k1 and k2 are virtually generated as preprocessing before generating the interpolation pixel m1, and are not generated as actual pixels.

At this time, the interpolation coefficient generation unit 111 generates horizontal interpolation coefficients Kh0 and Kh1 for the interpolation pixel m1 based on the interpolation phase signal and the interpolation direction determination result. In this case, assuming that the phase between the pixels a1 and a2 is 1.0, the horizontal interpolation coefficients Kh0 and Kh1 are calculated by the following equations.
Kh0 = Hm
Kh1 = Hm / 2
The horizontal interpolation unit 112 uses the interpolation coefficients Kh0 and Kh1 to obtain the pixel values of the horizontal interpolation pixels k1 and k2 using the following equation.
k1 = {a1 × (1-Kh0)} + a2 × Kh0
k2 = {b1 × (1−Kh1)} + b3 × Kh1
If Hm = 0.5, Kh0 = 0.5 and Kh1 = 0.25, so k1 = 0.5 × a1 + 0.5 × a2.
k2 = 0.75 × b1 + 0.25 × b3
Finally, the final interpolation unit 113 calculates the pixel value of the interpolation pixel m1 by linearly interpolating the pixel values of the horizontal interpolation pixels k1 and k2, and outputs it as a scaling interpolation output.

  FIGS. 9A to 9C are diagrams illustrating an example of generating an interpolation pixel when the interpolation direction is determined to be horizontal.

  When the interpolation pixel m1 is generated for the pixel arrangement shown in FIG. 9A, the inter-adjacent pixel correlation detection unit 8 has five sets adjacent to the interpolation pixel m1 indicated by arrows D1 to D5 in FIG. 9A. Interpolation determination is performed by obtaining a correlation value based on the absolute difference value of the pixel values between the pixels, but in this case, the group of pixels determined to have correlation is only D5. Therefore, the interpolation direction determination unit 9 determines the horizontal direction indicated by the arrow D5 as the interpolation direction.

  In response to this determination, the pixel selection unit 10 detects the pixels a1, a2, and the pixels adjacent to the point having the same horizontal phase as the horizontal phase Hm of the interpolation pixel m1 shown in FIG. 9B on the scanning line adjacent to the interpolation pixel m1. b1 and b3 are selected.

  Next, the horizontal interpolation unit 112 generates horizontal interpolation pixels k1 and k2 at points having the same horizontal phase as the horizontal phase Hm of the interpolation pixel m1 shown in FIG. 9C on the scanning line adjacent to the interpolation pixel m1. However, the horizontal interpolation pixels k1 and k2 are virtually generated as preprocessing before generating the interpolation pixel m1, and are not generated as actual pixels.

At this time, the interpolation coefficient generation unit 111 generates horizontal interpolation coefficients Kh0 and Kh1 for the interpolation pixel m1 based on the interpolation phase signal and the interpolation direction determination result. In this case, assuming that the phase between the pixels a1 and a2 is 1.0, the horizontal interpolation coefficients Kh0 and Kh1 are calculated by the following equations.
Kh0 = Hm
Kh1 = Hm / 2
The horizontal interpolation unit 112 uses the interpolation coefficients Kh0 and Kh1 to obtain the pixel values of the horizontal interpolation pixels k1 and k2 using the following equation.
k1 = {a1 × (1-Kh0)} + a2 × Kh0
k2 = {b1 × (1−Kh1)} + b3 × Kh1
If Hm = 0.5, Kh0 = 0.5 and Kh1 = 0.25, so k1 = 0.5 × a1 + 0.5 × a2.
k2 = 0.75 × b1 + 0.25 × b3
Finally, the final interpolation unit 113 calculates the pixel value of the interpolation pixel m1 by linearly interpolating the pixel values of the horizontal interpolation pixels k1 and k2, and outputs it as a scaling interpolation output.

  According to such an interpolation pixel generation circuit of this embodiment, a scaling interpolation pixel is directly generated using a pixel determined to be a current field pixel and a still image one field before, without performing progressive interpolation in the middle. Therefore, it is possible to reduce the occurrence of noise in the display image and the deterioration of the resolution.

The block diagram which shows the example of a structure of the interpolation pixel production | generation circuit which concerns on the Example of this invention. The figure which shows the example of the combination of the pixel for correlation determination in the interpolation pixel production | generation circuit which concerns on the Example of this invention. The figure which shows the example of the arrangement | sequence of the pixel which performs an interpolation pixel production | generation. The figure which shows the example of the interpolation pixel production | generation in the interpolation pixel production | generation circuit which concerns on the Example of this invention. The figure which shows the example of the interpolation pixel production | generation in the interpolation pixel production | generation circuit which concerns on the Example of this invention. The figure which shows the example of the interpolation pixel production | generation in the interpolation pixel production | generation circuit which concerns on the Example of this invention. The figure which shows the example of the interpolation pixel production | generation in the interpolation pixel production | generation circuit which concerns on the Example of this invention. The figure which shows the example of the interpolation pixel production | generation in the interpolation pixel production | generation circuit which concerns on the Example of this invention. The figure which shows the example of the interpolation pixel production | generation in the interpolation pixel production | generation circuit which concerns on the Example of this invention. The figure which shows the example of the conventional scaling interpolation pixel production | generation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Field memory 2, 3 Field delay memory 4 Motion determination part 5 Motion determination result memory | storage part 6 Interpolation phase signal generation part 7 Adjacent pixel storage part 8 Correlation detection part between adjacent pixels 9 Interpolation direction determination part 10 Pixel selection part 11 Interpolation pixel generation 111 Interpolation coefficient generation unit 112 Horizontal interpolation unit 113 Final interpolation unit

Claims (5)

A motion determination means for performing a motion determination for each pixel of each field of the video signal of the interlaced scanning, whether the pixel included in the field is a moving image or a still image;
Pixels on a scan line adjacent to the current field of the video signal for an interpolation phase on the interpolation scan line generated by scaling that compresses or decompresses the video signal horizontally or vertically, or horizontally and vertically; A plurality of combinations of pixels adjacent to the interpolation phase are generated from the pixels on the scanning line one field before located in the middle of the adjacent scanning lines and the pixels determined to be a still image by the motion determination unit. Calculating a correlation value between pixels for each combination of pixels, and detecting a correlation between adjacent pixels for detecting a combination of pixels having a correlation;
Interpolation direction determination means for determining the direction of the combination of pixels having the highest correlation among the combinations of pixels detected by the correlation detection means between adjacent pixels as the interpolation direction;
Based on the determination result of the interpolation direction determination means, a combination of pixels for generating an interpolation pixel is selected from the pixels in the current field adjacent to the interpolation phase and the pixels in the previous field determined as a still image, and the pixels An interpolation pixel generation circuit comprising: interpolation pixel generation means for generating a pixel value of an interpolation pixel of the interpolation phase using a value.   The interpolation direction determining means calculates a correlation evaluation value that is nonlinearly weighted according to the distance between the interpolation phase and a combination of pixels for which the correlation detection means between adjacent pixels has detected correlation, and based on the correlation evaluation value The interpolation pixel generation circuit according to claim 1, wherein one direction is determined as an interpolation direction from vertical, horizontal, or oblique directions with respect to the scanning line.   The interpolation direction determination means adds the correlation evaluation value for each direction of the combination of pixels when there are a plurality of combinations of pixels in which the correlation is detected by the correlation detection means between adjacent pixels, and the addition The interpolation pixel generation circuit according to claim 2, wherein the interpolation direction is determined based on a value. The interpolation pixel generation means includes
Horizontal interpolation means for generating horizontal interpolation pixels as preprocessing of interpolation processing;
When the interpolation direction determined by the interpolation direction determination means is oblique to the scanning line, the horizontal interpolation means intersects the lines passing through the interpolation phase with the same inclination as the interpolation direction. The horizontal interpolation pixel is generated on the scanning line adjacent to the phase, and when the interpolation direction determined by the interpolation direction determination unit is vertical or horizontal with respect to the scanning line, the scanning line adjacent to the interpolation phase Generating the horizontal interpolation pixel in the same horizontal phase as the interpolation phase;
4. The interpolation pixel generation circuit according to claim 1, wherein the interpolation pixel of the interpolation phase is generated by using the horizontal interpolation pixel generated by the horizontal interpolation unit as final interpolation. 5.   When the pixel to be used for the interpolation is on the scanning line one field before and is determined to be a moving image, the horizontal interpolation means replaces the pixel on the scanning line of the current field adjacent to the pixel. The interpolation pixel generation circuit according to claim 4, wherein the horizontal interpolation pixel is generated using a pixel.

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