JP2009296181A - Progressive scan signal conversion circuit, progressive scan signal conversion method, and television receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide smooth interpolated images without erroneously deciding a change point in an oblique direction even in an image having an edge in the oblique direction. <P>SOLUTION: The progressive scan signal conversion circuit includes: a comparison range setting means 103 for successively setting a comparison object pair in which a first scanning line interpolation candidate pixel data string which is the string of the prescribed number of successive pixel data of a first scanning line is combined with a second scanning line interpolation candidate pixel data string which is the string of the prescribed number of the successive pixel data of the second scanning line; a correlation decision means 104 for deciding the correlation of the first scanning line interpolation candidate pixel data string and the second scanning line interpolation candidate pixel data string configuring the comparison object pair; and an interpolated pixel data generation means 105 for selecting one of the set comparison object pairs on the basis of a decision result, and generating two or more pieces of successive interpolated pixel data from the first scanning line interpolation candidate pixel data string and the second scanning line interpolation candidate pixel data configuring the selected comparison object pair. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a progressive scanning signal conversion circuit and a progressive scanning signal conversion method for converting an interlace scanning signal type video signal into a progressive scanning signal type video signal, and a television receiver using the same.

  Conventionally, an interlace scanning (interlaced scanning) method and a progressive scanning (sequential scanning) method are known as image data scanning methods. The interlaced scanning method is a scanning method in which image data scanning is repeated alternately between a field where scanning is performed on odd lines and a field where scanning is performed on even lines. On the other hand, the progressive scanning method is a sequential scanning method in which image data is sequentially scanned in all scanning lines without skipping scanning lines.

  Therefore, in the case of the interlace scanning method, since the display of one field is every other line, there is a problem that flicker noise is likely to occur. However, the number of lines scanned in one field is ½ compared to the progressive scanning method. Therefore, there is an advantage that the horizontal synchronization frequency can be kept low, and the interlace scanning method has been often adopted in television receivers.

  However, in recent years, some high-resolution displays adopt a progressive scanning method instead of an interlaced scanning method with “flicker”. In order to display image information based on the NTSC system, which is an interlaced signal, on such a high-resolution display, it is necessary to convert the interlaced scanning signal into a progressive scanning signal.

  Conventionally, in a progressive scanning signal conversion circuit used as a means for converting the number of scanning lines, pixel data for two fields composed of interlace scanning signals is written in a field memory, and between two consecutive fields. A method having a field memory that interpolates odd lines and even lines using correlation, or writing pixel data for two lines in the same field composed of interlaced scanning signals to the line memory, and correlating the two lines A system having a line memory that generates interpolated pixel data from odd lines to even lines and generates interpolated pixel data from odd lines to odd lines is known.

  In the former method having the field memory, the pixel data of the odd field and the even field are written in separate field memories, respectively expanded to double the number of lines, and the pixel data of each line is added by 1/2. Is a method of generating interpolation data of odd lines and even lines (see, for example, the example of Patent Document 1 and FIG. 3).

  In the latter system having the line memory, pixel data for two lines in the same field composed of interlaced scanning signals is written to the line memory, and the correlation between the two lines is used to change the odd lines to the even lines. There is a method for generating interpolated pixel data from even lines to odd lines.

  In the latter system having the line memory, specifically, for example, based on the pixel data of the first scanning line written in the line memory and the pixel data of the second scanning line after one horizontal synchronization period. A vertical average value method in which the interpolated pixel data between two lines is an average value of the pixel data of the first and second scanning lines in the vertical direction, and is symmetrical with respect to the interpolated pixel data between the two lines. Select a combination that minimizes the weighted difference between the pixel data of a certain first scanning line and the second scanning line, and use the average value of the pixel data of the first scanning line and the second scanning line as the interpolated pixel data. There is an average value method (see, for example, Patent Document 2).

  FIG. 8 illustrates an example of the conversion result in the vertical average value method in which the average value of the pixel data of the first scanning line and the second scanning line in the vertical direction is the interpolation pixel data, among the methods having the latter line memory. It is a schematic diagram for doing.

  As shown in FIG. 8, the interpolated pixel data 603a to 603e are generated by an average value of the pixel data 601a to 601e of the first scanning line and the pixel data 602a to 602e of the second scanning line. For example, the interpolation pixel data 603a is calculated by (pixel data 601a + pixel data 602a) / 2.

  FIG. 9 shows a combination in which the weighted difference value between the pixel data of the first scanning line and the second scanning line that is point-symmetric about the interpolated pixel data between the two lines is the smallest among the methods having the latter line memory. Is a schematic diagram for explaining an example of a conversion result in the point-symmetric average value method in which the average value of the pixel data of the first scanning line and the second scanning line is set as interpolation pixel data.

  Specifically, on the upper and lower scanning lines sandwiching the interpolated pixel data 703c, a combination of pixel data having a point-symmetric positional relationship with respect to the interpolated pixel data 703c is selected, and a difference value between these is calculated. For convenience of explanation, it is assumed that five sets of pixel data close to the interpolated pixel data are used as combinations of pixel data for which difference values are calculated.

  Next, a predetermined threshold value is added to the difference value calculated for each combination. This threshold value is weighted in advance so that the value increases as the combination of pixel data farther from the pixel column of the interpolated pixel data increases, and the value decreases as the combination of pixel data closer to the pixel column of the interpolated pixel data. It is determined in the state. That is, in FIG. 9, the threshold value in the combination of the pixel data 701a and 702e and the combination of the pixel data 701e and 702a is the largest, and conversely, the threshold value in the combination of the pixel data 701c and 702c is set to be the smallest. Yes.

In this way, a combination of pixel data indicating the minimum value is selected from the difference values to which the threshold is added, and the value of the interpolated pixel data 703c is determined based on the average value of the selected pixel data. .
JP 2004-147285 A JP 2006-148827 A

  However, the former method having a field memory requires a plurality of field memories, and there is a problem that the circuit scale and power consumption increase.

  Among the methods having the latter line memory, in the vertical average value method in which the average value of the pixel data of the first scanning line and the second scanning line in the vertical direction is the interpolation pixel data, an image having an edge in the diagonal direction is used. Cannot obtain a smooth interpolated image, and in the point symmetric average value method in which the difference value is compared symmetrically with respect to the interpolated pixel data, a misjudgment is made depending on the weighting threshold value, thereby generating noise. There was a problem.

  The present invention solves the above-described conventional problems, and suppresses an increase in circuit scale due to a field memory, and even in an image having an edge in an oblique direction, smooth determination without erroneously determining an oblique change point. An object of the present invention is to provide a progressive scanning signal conversion circuit, a progressive scanning signal conversion method, and a television receiver using the same, which can obtain an interpolated image.

  The progressive scanning signal conversion circuit according to the present invention is a progressive scanning signal conversion circuit that generates interpolated pixel data from a video signal of an interlace scanning signal system by scanning line interpolation and converts it into a video signal of a progressive scanning signal system. Stored in the first line storage means, the second line storage means for storing the pixel data of the second scanning line after one horizontal synchronization period of the first scanning line, and the first line storage means. Pixel data for consecutive n pixels (n is an integer of 2 or more) among the plurality of pixel data obtained, and each of n pixels continuous among the plurality of pixel data stored in the second line storage means Comparison range setting means for combining pixel data with a comparison range within a predetermined comparison range including an oblique direction centered on the interpolation pixel position, and setting the comparison range Correlation determining means for determining a correlation between each pixel data for n pixels of the first line storage means set by the means and each pixel data for n pixels of the second line storage means, and from the correlation determination means And interpolated pixel data generating means for generating the interpolated pixel data from the pixel data stored in each of the first line storage means and the second line storage means based on the determination result of This achieves the above object.

  Preferably, the comparison range setting means in the progressive scanning signal conversion circuit according to the present invention is configured such that the data for n pixels continuous from the interpolation pixel position a of the pixel data stored in the first line storage means is Data for n pixels continuous from the interpolation pixel position a of the pixel data stored in the second line storage means is obtained from the interpolation pixel position a to a pixel position b (= a + m) in one direction for m pixels. The pixels are sequentially shifted one pixel at a time and combined to be set as a comparison target in the predetermined comparison range.

  Further preferably, the comparison range setting means in the progressive scanning signal conversion circuit according to the present invention is configured such that the data for n pixels continuous from the interpolation pixel position a of the pixel data stored in the second line storage means is Data for n pixels continuous from the interpolation pixel position a of the pixel data stored in the first line storage means is obtained from the interpolation pixel position a to a pixel position b (= a + m) in one direction for m pixels. The pixels are sequentially shifted one pixel at a time and combined to be set as a comparison target in the predetermined comparison range.

  Further preferably, the correlation determination means in the progressive scanning signal conversion circuit of the present invention comprises each pixel data for n consecutive pixels in the first line storage means set by the comparison range setting means, and the first In the combination with each pixel data for n consecutive pixels in the two-line storage means, when the maximum absolute value of the difference value between the pixel data is smaller than a threshold value, it is determined that there is a correlation, Among the combinations determined to be “correlated”, the combination having the smallest absolute value of the difference value between the pixel data is determined to be the “most correlated” combination.

  Further preferably, the correlation determination means in the progressive scanning signal conversion circuit of the present invention comprises each pixel data for n consecutive pixels in the first line storage means set by the comparison range setting means, and the first In the combination with each pixel data for consecutive n pixels in the two-line storage means, the maximum absolute value of the difference value between the pixel data is the smallest and the maximum absolute value of the difference value is When it is smaller than the threshold, it is determined that the combination is “the most correlated”.

  Further preferably, the interpolated pixel data generating means in the progressive scanning signal conversion circuit of the present invention is characterized in that in the combination of pixel data for n pixels determined to be “most correlated” by the correlation determining means, The first line is located at an intermediate line position between the pixel position of each pixel data for continuous n pixels in the line storage means and the pixel position of each pixel data for continuous n pixels in the second line storage means. Each average value of each pixel data for n consecutive pixels in the storage means and each pixel data for n consecutive pixels in the second line storage means is generated as each interpolated pixel data.

  Further preferably, the interpolated pixel data generating means in the progressive scanning signal conversion circuit of the present invention is characterized in that, in the combination of the pixel data of n pixels determined to be “most correlated” by the correlation determining means, When the pixel position of each pixel data for consecutive n pixels in one line storage means and the pixel position of each pixel data for consecutive n pixels in the second line storage means are shifted by an even number of pixels. Between the pixels of the pixel data for the consecutive n pixels in the first line storage means and the pixel data for the consecutive n pixels in the second line storage means at the intermediate line position. Each average value is generated as each interpolated pixel data.

  Further preferably, the interpolated pixel data generating means in the progressive scanning signal conversion circuit of the present invention is characterized in that, in the combination of the pixel data of n pixels determined to be “most correlated” by the correlation determining means, When the pixel position of each pixel data for consecutive n pixels in one line storage means and the pixel position of each pixel data for consecutive n pixels in the second line storage means are shifted by an odd number of pixels Between the pixels of the pixel data for the consecutive n pixels in the first line storage means and the pixel data for the consecutive n pixels in the second line storage means at the intermediate line position. From each average value, an average value obtained by interpolating each pixel data between adjacent pixel data is generated as each interpolation pixel data.

  The progressive scanning signal conversion method of the present invention is a progressive scanning signal conversion method for generating interpolated pixel data from a video signal of an interlace scanning signal system by scanning line interpolation and converting it into a video signal of a progressive scanning signal system. A first line storing step for storing the pixel data of the second scanning line in the first line storing means, and a second line for storing the pixel data of the second scanning line after one horizontal synchronization period of the first scanning line in the second line storing means The storage step and the comparison range setting means center each pixel data for each n pixels from each pixel data stored in the first line storage step and the second line storage step, with the interpolation pixel position as the center. A comparison range setting step for sequentially combining within a predetermined comparison range including an oblique direction and setting as a comparison target; Between each pixel data for n pixels in the first line set in the comparison range setting step and each pixel data for n pixels in the second line set in the comparison range setting step. A correlation determination step for determining a correlation, and an interpolated pixel data generation means that stores each pixel data in the first line storage step and the second line storage step based on the determination result received from the correlation determination step. Interpolating pixel data generating step for generating interpolating pixel data from the above, and thereby the above object is achieved.

  The television receiver of the present invention includes a display means for displaying a video signal of a progressive scanning signal system, and a video signal for converting the video signal of an interlace scanning signal system into a video signal of a progressive scanning signal system and outputting the video signal to the display means. And the video signal processing means uses the progressive scanning signal conversion circuit of the present invention, thereby achieving the above object.

  With the above configuration, the operation of the present invention will be described below.

  In the present invention, pixel data corresponding to consecutive n pixels among the plurality of pixel data stored in the first line storage means and data corresponding to consecutive n pixels among the plurality of pixel data stored in the second line storage means. Are combined as a comparison target within a predetermined comparison range including an oblique direction, and the pixel data for n pixels in the first line storage means and the pixel data for n pixels in the second line storage means Further, based on the determination result, interpolated pixel data is generated from the pixel data stored in the first line storage means and the second line storage means.

  As a result, the first line storage unit and the second line storage unit are used to correlate the pixel data in a predetermined number of consecutive pixel units in consideration of the deviation of the pixel data in the horizontal direction within the predetermined comparison range including the diagonal direction. Therefore, a smooth interpolated image can be obtained even in an image having an edge in a diagonal direction without erroneously determining a change point in the diagonal direction. It becomes possible.

  As described above, according to the present invention, in the first scanning line and the second scanning line, the correlation is determined in consideration of the deviation of the left and right m pixels in units of continuous n pixel data, so that the circuit scale by the field memory is determined. Even in an image having an edge in an oblique direction, a smooth interpolated image can be obtained without erroneously determining an oblique change point.

  Hereinafter, the progressive scanning signal conversion circuit and the progressive scanning signal conversion method according to the first embodiment of the present invention will be described, and then the television scanning apparatus of the present invention using the progressive scanning signal conversion circuit and the progressive scanning signal conversion method will be described. Embodiment 2 will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration example of a main part of the progressive scanning signal conversion circuit according to the first embodiment of the present invention.

  As shown in FIG. 1, the progressive scanning signal conversion circuit 100 according to the first embodiment includes a first line storage unit 101 that stores pixel data of two continuous lines in one field composed of interlace scanning signals, and a first line storage unit 101. From the pixel data stored in each of the two-line storage means 102, the first line storage means 101, and the second line storage means 102, pixel data for consecutive n (an integer of 2 or more) pixels is displayed in an oblique direction. A comparison range setting unit 103 that is set as a comparison target in combination with a predetermined comparison range including the pixel data for n pixels in the first line storage unit 101 and the second line storage unit 102 set by the comparison range setting unit 103 Correlation determination means 104 for determining the correlation between the pixel data of n pixels, and the correlation determination result from the correlation determination means 104 It has the interpolated pixel data generating means 105 for generating an interpolated pixel data, an interpolation pixel line memory 106 for storing the generated interpolated pixel data based on.

  Further, the progressive scanning signal conversion circuit 100 according to the first embodiment includes a first line storage unit 101 that stores interlaced first scanning lines of an interlaced scanning signal, and interpolation scanning between the interlaced first scanning line and the interlaced second scanning line. The switching means 107 for switching the interpolation pixel line memory 106 storing the interpolation pixel data with the line, the first line storage means 101, the second line storage means 102, the interpolation pixel line memory 106 and the switching means 107 are switched every horizontal scanning period. And the pixel data of the second scanning line is stored in the second line storage means, and the pixel data of the second scanning line before one horizontal scanning period is transferred from the second line storage means to the first line storage means. It is stored as pixel data of one scanning line, and alternately from the first line storage means every other line. Output control means (not shown) for controlling the output of each pixel data and each pixel data from the interpolated pixel line memory 106, and interpolated pixel data is obtained by scanning line interpolation from an interlaced scanning signal video signal. It is generated and converted into a video signal of a progressive scanning signal system, and a progressive scanning signal is output.

  The first line storage unit 101 stores pixel data of the first scanning line 201 that constitutes an interlace scanning signal given from the outside of the progressive scanning signal conversion circuit 100.

  The second line storage unit 102 is provided in the preceding stage of the first line storage unit 101 and stores the pixel data of the second scanning line 202 after one horizontal synchronization period of the first scanning line 201.

  The comparison range setting unit 103 converts the pixel data stored in the first line storage unit 101 into pixel data for n (n is an integer greater than or equal to 1) pixels from the interpolation pixel position a (a is an integer greater than or equal to 1). On the other hand, the data for n pixels continuous from the interpolation pixel position a of the pixel data stored in the second line storage means 102 is m pixels (m is an integer of 1 or more) from the interpolation pixel position a in the right direction. The pixels up to the pixel position b (= a + m) are sequentially shifted one pixel at a time to be combined and set as a comparison target, and n pixels continuous from the interpolation pixel position a of the pixel data stored in the second line storage means 102 The data for n pixels continuous from the interpolated pixel position a of the pixel data stored in the first line storage unit 101 is converted into the right pixel position b (m pixels from the interpolated pixel position a). = + M) is shifted one by one pixel until the set as compared to combination.

  In other words, the comparison range setting unit 103 is continuous among the pixel data stored in the first line storage unit 101 in a predetermined comparison range including an oblique direction from the interpolation pixel position a to the rightward interpolation pixel position (a + m + n). The data for n pixels and the data for n pixels continuous among the pixel data stored in the second line storage means 102 are combined.

  The correlation determination unit 104 is a combination of pixel data for n pixels set by the comparison range setting unit 103, and includes pixel data for consecutive n pixels in the first line storage unit 101 and second line storage unit. When the maximum absolute value of the difference value between the pixel data is smaller than a predetermined threshold in the combination with the pixel data for n consecutive pixels in 102, it is determined that there is a correlation, Among the combinations of the pixel data determined to be “correlated”, the combination having the smallest absolute value of the difference value between the pixel data is determined to be “the most correlated”. That is, the correlation determination unit 104 includes pixel data for n pixels stored in the first line storage unit 101 set by the comparison range setting unit 103 and pixels for n pixels stored in the second line storage unit 102. In a combination with data, a combination in which the absolute value of the difference between the pixel data is smaller than a predetermined threshold and the maximum absolute value of the difference between the pixel data is the smallest is “the most correlated. It is determined that the pixel data is a combination.

  The interpolated pixel data generating means 105 is a pixel of continuous n pixels in the first line storage means 101 in the combination of pixel data for each of n pixels determined to be “most correlated” by the correlation determining means 104. When the top pixel position of the data and the top pixel position of the data for the continuous n pixels in the second line storage means 102 are shifted by an even number of pixels, the first line storage is performed at the intermediate position. An average value between each pixel data of the pixel data for the continuous n pixels in the means 101 and the pixel data for the continuous n pixels in the second line storage means 102 is generated as an interpolation pixel. The interpolated pixel data generation unit 105 also includes the top pixel position of the pixel data for the continuous n pixels in the first line storage unit 101 and the pixel data for the continuous n pixels in the second line storage unit 102. When the leading pixel position is shifted by the odd number of pixels, the pixel data for the continuous n pixels in the first line storage unit 101 and the continuous data in the second line storage unit 102 are located at the intermediate position. A value obtained by interpolating data between adjacent pixels is generated as interpolated pixel data from an average value between the pixel data and pixel data for n pixels.

  FIG. 2 is a schematic diagram showing interlaced scanning signal type pixel data and interpolated pixel data.

  As shown in FIG. 2, the pixel data of the first scanning line 201 constituting the interlaced scanning signal input to the progressive scanning signal conversion circuit 100 is composed of pixel data 201a, 201b, 201c. Similarly, the pixel data of the second scanning line 202 after one horizontal synchronization period of the first scanning line 201 is composed of pixel data 202a, 202b, 202c. In addition, the interpolated pixel data 203a, 203b, 203c,... Are generated by interpolating the pixel data of the first scanning line 201 and the pixel data of the second scanning line 202 after one horizontal synchronization period. Data.

  The operation of the above configuration will be described below.

  3 and 4 are schematic diagrams for explaining the comparison range setting processing procedure of the comparison range setting means of FIG. In the first embodiment, pixel data for five pixels continuous from each line are combined by sequentially shifting one pixel at a time from the interpolation pixel position a to the pixel position in the right direction of four pixels. Here, the case where n is 5 and m is 4 will be described. However, n is not limited to 5, and may be an integer of 2 or more, and m is not limited to 4, but may be an integer of 1 or more. .

  In the comparison range setting process, first, as shown in FIG. 3A, five consecutive pixel data 301a to 301e are set from the interpolation pixel position a of the pixel data stored in the first line storage unit 101. . Further, as shown in FIG. 3B, for these pixel data 301a to 301e, pixel data 302a for five pixels continuous from the interpolation pixel position a of the pixel data stored in the second line storage means 102. To 302e are set as comparison targets.

  Next, as shown in FIG. 3C, the second line storage is performed on the pixel data 301a to 301e for five pixels continuous from the interpolation pixel position a of the pixel data stored in the first line storage unit 101. The pixel data 302b to 302f for five pixels continuous from the pixel position in the right direction by one pixel of the interpolation pixel position a of the pixel data stored in the means 102 are set as comparison targets.

  Thereafter, the data for five pixels in the second line storage unit 102 are sequentially shifted one pixel at a time, and pixel data 301a to 301e for five pixels continuous from the interpolation pixel position a stored in the first line storage unit 101 are obtained. In addition, as shown in FIG. 4A, a range from the interpolated pixel position a to the pixel data 302e to 302i for five consecutive pixels from the pixel position in the right direction by four pixels is set as a comparison target.

  Similarly, the line for sequentially shifting one pixel at a time from the state of FIG. 4B to the state of FIG. 4C is changed from the second line storage unit 102 to the first line storage unit 101. The pixel data stored in the first line storage means 101 are sequentially shifted one pixel at a time from the right pixel position of the interpolated pixel position a by one pixel to the right pixel position by four pixels, and the shifted pixel data And the pixel data 302a to 302e for five pixels continuous from the interpolation pixel position a stored in the second line storage means 102 are combined and set as a comparison target.

  FIGS. 5A and 5B are schematic diagrams for explaining the correlation determination processing procedure in the correlation determination unit 104 of FIG. Here, the threshold value for determining the correlation is set to “10” as an example, but is not limited thereto.

  First, the comparison range setting unit 103 stores the pixel data 401 a to 401 e for five pixels continuous from the interpolation pixel position a of the pixel data stored in the first line storage unit 101 and the second line storage unit 102. The pixel data 402a to 402e for five pixels continuous from the interpolation pixel position a of the pixel data thus set are set as comparison targets.

  In the correlation determination process by the correlation determination unit 104 in this case, the absolute value of the difference between the pixels is calculated in the combination set as the comparison target by the comparison range setting unit 103. As shown in FIG. 5A, the absolute values of the differences between the pixels are “1”, “2”, “49”, “100”, and “49” in order from the left.

  Next, the absolute value of the difference between each pixel is compared with a predetermined threshold value, and if all are smaller than the threshold value, it is determined that “there is a correlation”. In FIG. 5A, there are three values such as “49”, “100”, and “49” in which the absolute value of the difference between the pixels is larger than the threshold “10” for determining the correlation. Thus, if there is at least one absolute value of the difference between the pixels that is greater than the threshold “10”, it is determined that there is no correlation.

  In this way, all combinations set by the comparison range setting unit 103 are determined, and a combination having “there is correlation” and having the smallest absolute value of the difference is determined to be “the most correlated”. It is determined that the pixel data is a combination.

  In FIG. 5B, each pixel data 401a to 401e for the five pixels in the first line storage unit 101 and each pixel data 402c to 402g for the five pixels in the second line storage unit 102 are combined. Since the absolute value of the difference between the data is “2” at the maximum, and this is the combination with the smallest absolute value of the difference, it is determined to be the combination of the “most correlated” pixel data.

  The interpolated pixel data generating unit 105 determines the interpolated pixel data by the following procedures (1) and (2) in the combination of the pixel data for the five pixels determined to be “most correlated” by the correlation determining unit 104. Generate.

  (1) The pixel position of the pixel data for five pixels stored in the first line storage unit 101 and the pixel position of the pixel data for five pixels stored in the second line storage unit 102 are shifted by an even number of pixels. If it is, the pixel data for 5 pixels stored in the first line storage unit 101 and the second line storage unit 102 are stored in the intermediate position (intermediate line position of the upper and lower lines caused by the shift). An average value of each pixel data with each pixel data for five pixels is generated as interpolation pixel data.

  (2) The pixel position of the pixel data for five pixels stored in the first line storage unit 101 and the pixel position of the pixel data for five pixels stored in the second line storage unit 102 are an odd number of pixels, If there is a shift, the pixel data for the five pixels stored in the first line storage unit 101 and the second line storage unit 102 are stored at the intermediate position (intermediate line position of the upper and lower lines caused by the shift). From the average value of each pixel data with the pixel data for five pixels, an average value between the adjacent pixel data of these five pixels is generated as interpolation pixel data.

  As described above, the interpolation pixel data generation unit 105 according to the first embodiment selects the combination of the pixel data for the five pixels determined to be “the most correlated”, and sets the pixel data for the selected five pixels. From the combination, a plurality of interpolated pixel data are generated in succession at the intermediate line position of the pixel data for the five pixels.

  The interpolation pixel data generation processing procedure (1) and (2) will be described below with reference to FIG.

  FIG. 6 is a schematic diagram showing a procedure for generating interpolation pixel data in the interpolation pixel data generation means 105 of FIG.

  As shown in FIG. 6A, when the combination of each “most correlated” pixel data is shifted by an even number, for example, two pixels, interpolation pixel data is generated by the processing procedure (1). In this case, the pixel data 501a to 501e for the five pixels stored in the first line storage unit 101 and the diagonal directions of the pixel data 502c to 502g for the five pixels stored in the second line storage unit 102 ( Interpolated pixel data 503b to 503f for five consecutive pixels from a position shifted to the right by one pixel of the interpolated pixel position a, which is the intermediate position, are set as the interpolated pixel data, with the average value of each pixel from the upper left to the lower right) And stored in the interpolation pixel line memory 106. At this time, only one pixel at the interpolated pixel position a is not interpolated, but the average value of the upper and lower pixel data is taken and stored in the interpolated pixel line memory 106 as interpolated pixel data as in the prior art. Specifically, an average value of “0” of the upper line pixel data 501 a and “1” of the lower line pixel data 502 a is taken, and “1” is stored in the interpolation pixel line memory 106 as the interpolation pixel data 503 a. To do.

  As shown in FIG. 6B, when the head pixel position is shifted by an odd number of, for example, three pixels, the most correlated combination, the interpolated pixel data is generated by the procedure (2). In this case, first, the pixel data 501a to 501e for five pixels stored in the first line storage unit 101 and the pixel data 502d to 502h for five pixels stored in the second line storage unit 102 are first slanted. The average value data 504a to 504e of each pixel in the direction (from the upper left to the lower right) is obtained, and the average value calculated by linear interpolation between the adjacent pixels of the obtained five average value data 504a to 504e is interpolated pixel data. As a result, the interpolated pixel data 503c to 503f for four pixels continuous from the right side by two pixels of the interpolated pixel position a which is the intermediate position are stored in the interpolated pixel line memory 106.

  Specifically, the interpolation pixel data 503c is calculated as (average value data 504a + average value data 504b) / 2 = 1, and the interpolation pixel data 503d is calculated as (average value data 504b + average value data 504c) / 2 = 25. calculate. The interpolation pixel data 503e is calculated as (average value data 504c + average value data 504d) / 2 = 50, and the interpolation pixel data 503f is calculated as (average value data 504d + average value data 504e) / 2 = 100.

  In the first embodiment, the interpolation pixel data is calculated by linear interpolation between the five adjacent pixels, but may be calculated by interpolating between the five adjacent pixels by a sinc function or the like. The sinc function is sin (πx) / (πx), where x represents the distance from the interpolation position to each pixel.

  At this time, only two pixels are not interpolated from the interpolation pixel position a, but the average value of each upper and lower pixel data is taken and stored in the interpolation pixel line memory 106 as interpolation pixel data, as in the conventional case. Specifically, an average value of “0” of the upper line pixel data 501 a and “100” of the lower line pixel data 502 a is taken, and “50” is stored in the interpolation pixel line memory 106 as the interpolation pixel data 503 a. To do. Further, an average value of “2” of the upper line pixel data 501b and “1” of the lower line pixel data 502b is taken, and “2” is stored in the interpolation pixel line memory 106 as the interpolation pixel data 503a.

  Thereafter, in the case of FIG. 6A in which the combination of the pixel data “most correlated” is shifted by an even number, for example, two pixels, it is expected that this time is also the case of FIG. After the processing is performed so as to be interpolated from the interpolation pixel data 503g next to the interpolation pixel data 503b to 503f for five pixels, the position of the interpolation pixel position a is updated to the position of the interpolation pixel data 503f. Return to the procedure. That is, a comparison range is set, correlation is determined, and each interpolated pixel data is obtained.

  Therefore, in order to re-determine the correlation, the previous case may be the case of FIG. 6A and the current case of FIG. 6B may occur. In this case, since the position of the interpolation pixel position a is updated to the position of the interpolation pixel data 503f of the interpolation pixel position f, only one pixel is not interpolated from the interpolation pixel position f. The average value of the upper and lower pixel data is taken and stored in the interpolation pixel line memory 106 at the interpolation pixel position 503g as interpolation pixel data.

  As described above, the procedure from the comparison range setting unit 103 to the interpolation pixel data generation unit 105 is repeated while moving the interpolation pixel position a from the left end to the right end of the line, and the interpolation pixel data is stored in the interpolation pixel line memory 106.

  Finally, progressive scanning is performed by alternately outputting pixel data from the first line storage unit 101 storing the interlace scanning signal and the interpolation pixel line memory 106 storing the interpolation pixel data by the switch unit 107 every other line. A signal can be output.

  As described above, in the first exemplary embodiment, the predetermined number of consecutive pixel data of the first scanning line interpolation candidate pixel data sequence and the second scanning line are the predetermined number of consecutive pixel data columns of the first scanning line. A comparison range setting means 103 for sequentially setting a comparison target pair in combination with a second scanning line interpolation candidate pixel data string that is a column, and a first scanning line interpolation candidate pixel data string and a second scanning line that constitute the comparison target pair. Correlation determination means 104 that determines the correlation with the interpolation candidate pixel data string, and selects one comparison target pair from the set comparison target pairs based on the determination result, and configures the selected comparison target pair Interpolation pixel data generation means 105 for generating a plurality of continuous interpolation pixel data from the first scanning line interpolation candidate pixel data string and the second scanning line interpolation candidate pixel data string. Thereby, in the first scanning line and the second scanning line, the correlation is determined in consideration of the deviation of the left and right m pixels in units of continuous n pixel data using the line memory. Even in an image having an increase in scale and having an edge in an oblique direction, a smooth interpolation image can be obtained without erroneously determining a change point in the oblique direction.

  In the first embodiment, the absolute value of the difference value between the lines of pixel data for five pixels is compared with a certain threshold value. However, the difference value between adjacent pixels in the same line is A threshold value may be set accordingly.

  In the first embodiment, when determining whether the combination set by the comparison range setting unit 103 has a correlation, the correlation determination unit 104 determines the absolute value of the difference between the pixels and a predetermined threshold value. When the absolute value of the difference is smaller than the threshold, it is determined that there is a correlation, and among the combinations determined to be correlated, the combination having the smallest absolute value of the difference is determined to be “the most correlated”. Although it demonstrated as determining with it being a combination, it is not restricted to this. The determination of whether the absolute value of the difference is smaller than the threshold value may be omitted, and the combination having the smallest absolute value of the difference may be directly determined as having the most correlation.

(Embodiment 2)
FIG. 7 is a block diagram showing a configuration example of a TV (television receiver) 111 using the progressive scanning signal conversion circuit 100 of the first embodiment as the second embodiment of the present invention.

  In FIG. 7, a TV 111 includes an antenna 112, a tuner 113, a transport decoder 114, an AV decoder 115 using the progressive scanning signal conversion circuit 100 of the first embodiment, and a display unit 116.

  The antenna 112 is a receiving means that receives a broadcast wave of a digital BS (Broadcasting Satellite) broadcast and converts it into an electrical signal.

  The tuner 113 is a demodulator that demodulates a broadcast signal converted into an electric signal and outputs an MPEG (Moving Picture Experts Group) 2 transport stream.

  The transport decoder 114 is a separating unit that separates the MPEG2 transport stream output from the tuner 3.

  The AV decoder 115 decompresses the compressed data of the elementary stream output from the transport decoder 114. If the decompressed video signal is an interlace scanning signal video signal, the AV decoder 115 converts the progressive video signal to a progressive scanning signal video. It is a means for converting a video signal that has been converted into a signal into an analog signal and outputting the analog signal. As the AV decoder 115, the progressive scanning signal conversion circuit 100 described in the first embodiment is used.

  The display unit 116 is, for example, a liquid crystal display, and is a unit that displays a progressive scanning signal video signal.

  Note that the AV decoder 115 of the second embodiment is an example of the video signal processing means of the present invention.

  Next, the operation of the second embodiment will be described.

  A digital BS broadcast is broadcast as an MPEG2 transport stream from a broadcast station (not shown). A digital BS broadcast broadcast as an MPEG2 transport stream from a broadcast station is uplinked to a broadcast satellite (not shown), further downlinked from the broadcast satellite to the ground, and converted into an electrical signal by an antenna 112.

  Next, the tuner 113 demodulates the broadcast signal converted into the electric signal, and outputs the MPEG2 transport stream to the transport decoder 114.

  Thereafter, the transport decoder 114 separates the transport stream, converts the separated transport stream into an elementary stream, and outputs the elementary stream to the AV decoder 115.

  Subsequently, the AV decoder 115 decompresses the compression of the elementary stream. Thereafter, when the expanded video data is an interlace scanning video signal, the progressive scanning signal conversion circuit 100 constituting the AV decoder 115 converts it into a progressive scanning video signal. Further, the AV decoder 115 converts the progressive scanning video signal into an analog signal and outputs it to the display means 116.

  Finally, the display unit 116 displays the analog signal.

  In this way, the digital BS broadcast is displayed on the display screen of the display means 116.

  In addition, although TV111 of this Embodiment 2 demonstrated as receiving digital BS broadcast, it is not restricted to this, Terrestrial analog broadcast, terrestrial digital broadcast, analog BS broadcast, digital CS (Communications Satellite: communication satellite) ) Broadcasting, analog CS broadcasting, CATV (Cable Television: cable television) broadcasting or the like may be received. When the TV 111 according to the second embodiment receives analog broadcast such as terrestrial analog broadcast, the tuner 113 performs the above processing after converting the analog video signal into a digital video signal. .

  As described above, according to the TV 111 of the second embodiment, even when the video signal carried on the received broadcast signal is an interlaced scanning signal system, an increase in circuit scale due to the field memory is suppressed, and in an oblique direction. Even in an image having an edge, a smooth interpolated image can be displayed on the display means 116 without erroneously determining an oblique change point.

  As mentioned above, although this invention was illustrated using preferable Embodiment 1, 2 of this invention, this invention should not be limited and limited to this Embodiment 1,2. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge, from the description of specific preferred embodiments 1 and 2 of the present invention. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  The present invention relates to a progressive scan signal conversion circuit and a progressive scan signal conversion method for converting an interlace scan signal type video signal into a progressive scan signal type video signal, and a circuit using a field memory in the field of a television receiver using the same. Even in an image having an increase in scale and having an edge in an oblique direction, a smooth interpolation image can be obtained without erroneously determining a change point in the oblique direction.

1 is a block diagram illustrating an exemplary configuration of a main part of a progressive scanning signal conversion circuit according to a first embodiment of the present invention. FIG. It is a schematic diagram which shows the pixel data and interpolated pixel data of an interlace scanning signal system. (A)-(c) is a schematic diagram for demonstrating the comparison range setting process sequence (the 1) of the comparison range setting means of FIG. (A)-(c) is a schematic diagram for demonstrating the comparison range setting process sequence (the 2) of the comparison range setting means of FIG. (A) And (b) is a schematic diagram for demonstrating the correlation determination processing procedure in the correlation determination means of FIG. (A) And (b) is a schematic diagram for demonstrating the interpolation pixel data production | generation procedure in the interpolation pixel data production | generation means of FIG. It is a block diagram which shows the structural example of the television receiver which concerns on Embodiment 2 of this invention. In the conventional progressive scanning signal conversion circuit, it is a schematic diagram for explaining an example of the conversion result in the vertical average value method using the average value of the pixel data of the first scanning line and the second scanning line in the vertical direction as interpolation pixel data. is there. In a conventional progressive scanning signal conversion circuit, a combination is selected that minimizes the weighted difference value of the pixel data of the first and second scanning lines that are point-symmetric about the interpolated pixel data between the two lines. It is a schematic diagram for demonstrating the example of a conversion result in the point-symmetric average value system which uses the average value of the pixel data of 1 scanning line and 2nd scanning line as interpolation pixel data.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Progressive scanning signal conversion circuit 101,102 Line memory for interlaced scanning signal storage 103 Comparison range setting means 104 Correlation determination means 105 Interpolation pixel data generation means 106 Interpolation pixel line memory 111 TV (television receiver)
112 Antenna 113 Tuner 114 Transport Decoder 115 AV Decoder 116 Display Means

Claims (10)

In a progressive scanning signal conversion circuit that generates interpolated pixel data from a video signal of an interlace scanning signal system by scanning line interpolation and converts it into a video signal of a progressive scanning signal system,
First line storage means for storing pixel data of the first scanning line;
Second line storage means for storing pixel data of the second scanning line after one horizontal synchronization period of the first scanning line;
Of the plurality of pixel data stored in the first line storage means, each pixel data for consecutive n (n is an integer of 2 or more) pixels, and the plurality of pixel data stored in the second line storage means Comparison range setting means for combining each pixel data of continuous n pixels within a predetermined comparison range including an oblique direction centered on the interpolation pixel position and setting as a comparison target;
Correlation determining means for determining a correlation between each pixel data for n pixels of the first line storage means set by the comparison range setting means and each pixel data for n pixels of the second line storage means;
Interpolation pixel data generation means for generating the interpolation pixel data from the pixel data stored in each of the first line storage means and the second line storage means based on the determination result from the correlation determination means Progressive scanning signal conversion circuit. The comparison range setting means includes
For data of n pixels continuous from the interpolation pixel position a of the pixel data stored in the first line storage means,
The data of n pixels continuous from the interpolation pixel position a of the pixel data stored in the second line storage means is obtained from the interpolation pixel position a to the pixel position b (= a + m) in one direction for m pixels. The progressive scanning signal conversion circuit according to claim 1, wherein the pixels are sequentially shifted pixel by pixel and set as a comparison target in the predetermined comparison range. The comparison range setting means includes
For data of n pixels continuous from the interpolation pixel position a of the pixel data stored in the second line storage means,
The data for n pixels continuous from the interpolation pixel position a of the pixel data stored in the first line storage means is obtained from the interpolation pixel position a to the pixel position b (= a + m) in one direction for m pixels. The progressive scanning signal conversion circuit according to claim 1, wherein the pixels are sequentially shifted one pixel at a time and are combined and set as a comparison target in the predetermined comparison range.   The correlation determination unit is configured by the comparison range setting unit, each pixel data for the consecutive n pixels in the first line storage unit, and each of the continuous n pixels in the second line storage unit. In the combination with the pixel data, when the maximum absolute value of the difference value between the pixel data is smaller than the threshold, it is determined as “correlated”, and among the combinations determined as “correlated”, The progressive scanning signal conversion circuit according to claim 1, wherein the combination having the smallest absolute value of the difference value between the pixel data is determined to be the “most correlated” combination.   The correlation determination unit is configured by the comparison range setting unit, each pixel data for the consecutive n pixels in the first line storage unit, and each of the continuous n pixels in the second line storage unit. In the combination with the pixel data, the combination that is the most correlated when the maximum absolute value of the difference value between the pixel data is the smallest and the maximum absolute value of the difference value is smaller than the threshold value The progressive scanning signal conversion circuit according to claim 1, wherein it is determined that   The interpolated pixel data generating means is configured such that each pixel corresponding to consecutive n pixels in the first line storage means in a combination of pixel data corresponding to n pixels determined to be “most correlated” by the correlation determining means. Each pixel data for n consecutive pixels in the first line storage means at an intermediate line position between a pixel position of the data and a pixel position of each pixel data for the consecutive n pixels in the second line storage means 2. The progressive scanning signal conversion circuit according to claim 1, wherein each of the average values of the pixel data for n consecutive pixels in the second line storage means is generated as each interpolation pixel data.   The interpolated pixel data generating means is configured such that, in the combination of pixel data for n pixels determined to be “most correlated” in the correlation determining means, each of the consecutive n pixels in the first line storage means. When the pixel position of the pixel data and the pixel position of each pixel data for consecutive n pixels in the second line storage means are shifted by an even number of pixels, the first line storage is performed at the intermediate line position. And generating each average value between the respective pixels of the pixel data for the consecutive n pixels in the means and the pixel data for the consecutive n pixels in the second line storage means as the interpolated pixel data. Item 4. A progressive scanning signal conversion circuit according to Item 1.   The interpolated pixel data generating means is configured such that, in the combination of pixel data for n pixels determined to be “most correlated” in the correlation determining means, each of the consecutive n pixels in the first line storage means. When the pixel position of the pixel data and the pixel position of each pixel data for consecutive n pixels in the second line storage means are shifted by an odd number of pixels, the first line storage is performed at the intermediate line position. Each pixel data between adjacent pixel data from each pixel average value of each pixel data for consecutive n pixels in the means and each pixel data for successive n pixels in the second line storage means The progressive scanning signal conversion circuit according to claim 1, wherein an average value obtained by interpolating each is generated as each interpolated pixel data. In a progressive scanning signal conversion method for generating interpolated pixel data from a video signal of an interlaced scanning signal system by scanning line interpolation and converting it to a video signal of a progressive scanning signal system,
A first line storage step of storing pixel data of the first scanning line in the first line storage means;
A second line storage step of storing pixel data of the second scanning line after one horizontal synchronization period of the first scanning line in the second line storage means;
The comparison range setting means includes each pixel data for each n pixels continuous from each pixel data respectively stored in the first line storage step and the second line storage step, including an oblique direction with the interpolation pixel position as the center. A comparison range setting step for sequentially combining within a predetermined comparison range and setting as a comparison target;
Correlation determining means includes pixel data for n pixels in the first line set in the comparison range setting step, and pixel data for n pixels in the second line set in the comparison range setting step, A correlation determination step of determining a correlation between
The interpolation pixel data generating means stores the interpolation pixel data from each pixel data stored in each of the first line storage step and the second line storage step based on the determination result received from the correlation determination step. A progressive scanning signal conversion method comprising: a data generation step. Display means for displaying a progressive scanning signal video signal;
Video signal processing means for converting a video signal of an interlace scanning signal system into a video signal of a progressive scanning signal system and outputting the video signal to the display means;
A television receiver using the progressive scanning signal conversion circuit according to claim 1 as the video signal processing means.

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