JP4371907B2 - Pixel feature determination device, pixel interpolation device, and video signal processing device - Google Patents

Description

  The present invention relates to a pixel feature determination device, a pixel interpolation device, and a video signal processing device, and more particularly, to determine a characteristic of a pixel to be interpolated in order to interpolate an interlaced video signal in a field. And a video signal processing apparatus such as a television receiver suitable for obtaining a high-quality progressive image from an interlaced image provided with the apparatus. .

  In many video signals, interlaced scanning is used as the scanning mode. However, when this video signal is displayed on the interlaced scanning image display unit, interlace interference such as line flickering occurs and the image quality deteriorates. This interlace interference is eliminated by IP conversion, that is, by converting an interlaced video to a progressive video and displaying it in the form of progressive scanning. The IP conversion is also performed for up-conversion of a television system having a different number of scanning lines and for high-resolution images.

  As the scanning line interpolation method when performing IP conversion, intra-frame interpolation is performed for still pixels, and for moving pixels, the frame correlation is broken, and the vertical line with motion is erroneously jagged in intra-frame interpolation. In-field interpolation is performed because of problems such as conversion.

  As a method of intra-field interpolation, a simple method includes a line interpolation method using the upper line as it is as a line to be interpolated, and a line interpolation method using the average value of the upper and lower lines. In the former interpolation method, an image having no correlation in the vertical direction such as a slanted line is accompanied by image deterioration such as a jagged edge in the image outline, and the latter interpolation method is blurred in the image.

  As methods for solving these drawbacks, various intra-field interpolation methods have been proposed (see, for example, Patent Documents 1 and 2). The interpolation method described in Patent Document 1 interpolates each pixel of a line to be interpolated using pixel information in a direction having the strongest correlation around the pixel. First, in order to know in which direction the pixel signal extending radially from the interpolated pixel has the strongest correlation, the absolute value of the difference between adjacent pixels in the vertical direction, right diagonal direction, and left diagonal direction is obtained. It is determined that the direction in which the absolute value of the difference is minimum is the direction having the strongest correlation, and an average value of each pixel in the direction is obtained and used as the value of the interpolation pixel.

  The interpolation method described in Patent Document 2 incorporates interpolation by pixel rows and improves the processing speed as compared with the interpolation method by pixel unit that is generally performed. In the interpolation method described in the publication, each pixel of adjacent lines of a two-dimensional image is compared to detect an edge portion, and interpolation is performed using any adjacent pixel other than the edge portion, and the edge portion is adjacent. A neighboring pixel column centered on the pixel of interest on one of the lines is set, and a pixel column having a correlation therewith is selected from adjacent lines, and the position of the selected pixel column and the neighboring pixel column is selected. The number of pixels corresponding to the amount of deviation is obtained, and interpolation is performed using a pixel row obtained by shifting the selected pixel row or the neighboring pixel row in the direction opposite to the positional deviation direction by half of the obtained number of pixels. This interpolation method is a method of smoothing the contour of an image, and has a problem that it cannot be repaired when an image is interrupted between lines, as in a thin line image close to horizontal.

  FIG. 22 is a diagram for explaining an example of a video signal obtained by intra-field interpolation according to the prior art, FIG. 22A is an example of an image represented by the video signal, and FIG. 22B is an example of FIG. FIG. 22C is an enlarged view showing an arcuate edge portion in the image of FIG. 22A. FIG. 23 is a diagram illustrating an example of typical pixel values of the video signal in FIG.

  As shown in FIGS. 22B and 22C, if there is an oblique line or an edge in the oblique direction, the interpolation becomes jagged and blurred. The example of FIG. 22B will be described with reference to FIG. 23A as a typical luminance value arrangement example. When an oblique line as shown in FIG. 22B exists, in an interlaced image, FIG. In (A), the luminance values are arranged as shown in the actual pixel line represented by *. FIG. 23A shows an example in which an interlaced image is interpolated with an average value of upper and lower pixels, but the value of the pixel of interest represented by x is 50 because both the upper and lower values are 50.

Note that the motion information is detected by the magnitude of the difference signal between frames, and the mixing ratio between the intra-frame interpolation suitable for the still image region and the intra-field interpolation suitable for the moving image region is changed according to the detected motion information of the image. A motion adaptive interpolation process has also been proposed. A motion compensation type interpolation process has also been proposed for the purpose of interpolation that substantially matches the motion of the image. In this motion compensation type interpolation processing, the motion of an image is detected as motion vector information, and signal processing for motion compensation is performed on the signals of the preceding and following fields using this motion vector information to generate an interpolation scanning line signal. To do.
JP-A-63-187785 JP-A-5-30487

  However, in the intra-field interpolation processing according to the prior art as described above, when a highly correlated pixel is detected, it is performed in units of pixels or even in units of lines, so that an accurate interpolation direction is obtained. Therefore, an erroneous interpolation value is calculated especially for an oblique line (in particular, an oblique line with a shallower angle) or an image portion having an oblique edge. For example, the example of FIG. 23A actually has a slanting line in the 45 degree direction that is descending to the left. Ideally, the pixel of interest x is to be interpolated with 0, but the luminance value is determined by interpolation with the upper and lower pixel average values. Will be interpolated at 50. Further, even if the interpolation is not performed by the upper and lower pixel average values, in each direction indicated by the arrow in FIG. 23B, even if the luminance value difference between the actual pixels is executed, no difference occurs in each direction. It is not determined whether interpolation can be performed on actual pixels. As a result, interpolation is performed with the upper and lower pixel average values and the upper or lower actual pixels.

  Even if an oblique edge is detected and the portion is interpolated as described above, or even if interpolation is performed using a further improved oblique edge detection method, it is difficult to detect an oblique edge. In addition, for example, it cannot be distinguished from a vertical line or a corner pattern, resulting in an erroneous correction, resulting in an excessive blur of the pattern. Therefore, it is desirable to accurately determine a pattern other than the diagonal edge in advance.

  In addition, in motion adaptive interpolation processing, motion information is detected based on the magnitude of the difference signal between frames, so that it is not always possible to correspond to the exact motion of the image, and in the moving image area, the removal of interlace interference is incomplete. The image quality improvement effect is small. In addition, in motion compensation type interpolation processing, in order to perform accurate motion compensation signal processing, it is indispensable to detect motion vectors with high accuracy. Therefore, enormous signal processing is required.

The present invention has been made in view of such circumstances described above, when the field interpolation video signal of interlaced scanning, for each interpolated pixel, the features of its diagonal line and other oblique direction A pixel feature determination device that can accurately determine from the characteristics of the surrounding real pixels so that it can be distinguished from the edges. Provided are a pixel interpolation device capable of performing optimal interpolation without any change, and a video signal processing device including the device and capable of interpolating pixels to convert an interlaced video signal into a high-quality progressive video signal. That is the purpose.

In order to solve the above-described problems, the present invention is constituted by the following technical means .

The first technical means, when performing IP conversion for converting an interlaced scanning video signal into a progressive scanning video signal, assigns the feature of the target pixel to a peripheral actual target for the target pixel to be interpolated in the field. A pixel feature determination apparatus for determining from a feature of a pixel, wherein a horizontal direction difference unit that calculates a difference value of pixel information between respective real pixels adjacent in the horizontal direction in the field, and a pixel to be interpolated Out of the difference values in the horizontal direction of the real pixels calculated by the horizontal direction difference means, the area specification means for specifying a predetermined range of real pixel areas centered on the target pixel for the pixel, the area specification means Based on the horizontal difference value in the designated real pixel area, the horizontal complexity judgment means for judging the horizontal complexity for each real pixel line and the horizontal complexity judgment means , Based on the horizontal complexity of the upper line and the lower line of the pixel of interest, and a complex determination means for the pixel of interest to determine whether a part of a pixel of complicated pattern, the horizontal complexity Means for comparing the difference value of the pixel information between the respective real pixels adjacent in the horizontal direction with two threshold values having the same absolute value; and, based on the result of the comparison, the difference value is a negative value, Means for encoding to zero value and positive value; means for determining whether the difference value is the same or different code based on the encoded value; and the result of the determination Means for counting the number of the same or different codes for each line, and means for selecting the complexity of the line from a plurality of predetermined complexity levels for each line based on the number of the counted results. And the complexity determination means includes the horizontal complexity determination means. In the determination result in, either on line or below the line of the pixel of interest, if having a predetermined complexity or complexity, it is determined that the pixel of interest is part of a pixel of complicated pattern It is a feature.

According to a second technical means, in the first technical means, the area designating unit further includes means for designating a predetermined range of actual pixel regions suitable for determination by the complex determination unit, and the complex determination unit includes: The determination is performed in the designated actual pixel region.

A third technical means includes a vertical direction difference means for calculating a difference value of pixel information between respective real pixels adjacent in the vertical direction in the field in the first or second technical means, and one line of the target pixel. The difference value of the pixel information between the real pixels that are equidistant from the target pixel and the difference value of the pixel information between the real pixels that are equidistant from the target pixel under one line of the target pixel are calculated. The difference value in the vertical direction within the actual pixel area designated by the area designating means among the difference values in the vertical direction of the real pixels calculated by the vertical direction difference means, and the separated pixel difference means based on the difference value calculated by the difference means, the pixel of interest is further a determining angle determining means for determining whether or not a part of the pixels of the picture corners, angular determining means, said vertical direction In the area designation means calculated by the difference means Among the determined difference values, the difference value between the real pixel line two above the target pixel and the real pixel line one above, and the real pixel line one below and the real pixel two below the target pixel When the difference values with the line are all smaller than a predetermined threshold, and the difference value calculated by the separated pixel difference means, the difference value corresponding to either the upper line or the lower line of the target pixel is When larger than a predetermined threshold value, it is determined that the pixel of interest is a partial pixel of a corner picture .

According to a fourth technical means, in the third technical means, the area designating means further includes means for designating a predetermined range of actual pixel areas suitable for determination by the angle determining means, wherein the corner determining means is The determination is performed in the designated actual pixel region.

According to a fifth technical means, in the first or second technical means, a vertical direction difference means for calculating a difference value of pixel information between respective real pixels adjacent in the vertical direction in the field, and the horizontal complexity determination Of the horizontal complexity of the upper and lower lines of the target pixel determined by the means and the vertical difference value of the actual pixel calculated by the vertical direction difference means. on the basis of the difference value in the vertical direction in the pixel area, the pixel of interest further feature a vertical line determining means for determining whether a part of the pixels of the vertical line pattern, said longitudinal line determining means, In the determination result in the horizontal complexity determination means, when either the upper line or the lower line of the target pixel has a complexity equal to or higher than a predetermined complexity, the area calculated by the vertical direction difference means Finger with designation means In the difference values of all the real pixels on the vertical line located within several pixels on both the left and right sides of the target pixel, the difference value between the line one above and the line below the target pixel Are all smaller than a predetermined threshold, or the difference values of the vertical lines passing through the target pixel are all smaller than a predetermined threshold, or an actual pixel line two above and one actual pixel line above the target pixel And the difference value between the actual pixel line one lower than the target pixel and the actual pixel line two lower than the target pixel are all smaller than a predetermined threshold, the target pixel is a part of a vertical line pattern pixel. It is characterized by determining that there is.

A sixth technical means is the fifth technical means, wherein the area designating means further comprises means for designating a predetermined range of actual pixel areas suitable for determination by the vertical line determination means, and the vertical line determination The means is characterized in that the determination is performed in the designated actual pixel region.

A seventh technical means includes the vertical direction difference means for calculating a difference value of pixel information between each real pixel adjacent in the vertical direction in the field in the first or second technical means, and the vertical direction difference means. Based on the calculated vertical difference value of the real pixel and the vertical difference value in the real pixel area specified by the area specifying means, the target pixel is a part of a flat picture. anda flat determination means for determining whether or not, the flat determination unit, wherein among the specified difference value by the area designating means are calculated in the vertical direction differentiating means, both the number of pixels left from the pixel of interest In the difference values of all the actual pixels on the vertical line located within, if the difference values between the line immediately above and the line below the pixel of interest are all smaller than a predetermined threshold, the pixel of interest is flat Picture Is obtained by the determining means determines that a part of the pixels.

According to an eighth technical means, in the seventh technical means, the area designating means further comprises means for designating a predetermined range of actual pixel areas suitable for judgment by the flat judgment means, and the flat judgment means comprises The determination is performed in the designated actual pixel region.
According to a ninth technical means, in the first or second technical means, a vertical direction difference means for calculating a difference value of pixel information between respective real pixels adjacent in the vertical direction in the field, and one line of the target pixel The difference value of the pixel information between the real pixels that are equidistant from the target pixel and the difference value of the pixel information between the real pixels that are equidistant from the target pixel under one line of the target pixel are calculated. The difference value in the vertical direction within the actual pixel area designated by the area designating means among the difference values in the vertical direction of the real pixels calculated by the vertical direction difference means, and the separated pixel difference means Based on the difference value calculated by the difference means, the angle determination means for determining whether or not the pixel of interest is a part of the corner picture, and the horizontal complexity determination means, Water on the upper and lower lines of the pixel of interest Based on the direction complexity and the vertical difference value of the actual pixel calculated by the vertical direction difference means, the difference value in the vertical direction within the actual pixel area designated by the area designation means, the target pixel Of the vertical line difference means calculated by the vertical direction difference means, the vertical line determination means for determining whether or not is a partial pixel of the vertical line picture, and is specified by the area specifying means was based on the difference value in the vertical direction of the actual pixel region, the pixel of interest is further a flat determination unit that determines whether a part of the pixels of the flat pattern, the angle determining means, Of the difference values specified by the region specifying means calculated by the vertical direction difference means, the difference value between the real pixel line two above the target pixel and the real pixel line one above and the pixel of interest One lower real pixel line and two lower real pixels When the difference values with the in are all smaller than a predetermined threshold, and among the difference values calculated by the separated pixel difference means, the difference value corresponding to either the upper line or the lower line of the target pixel is When the pixel of interest is larger than a predetermined threshold, it is determined that the pixel of interest is a partial pixel of a corner picture, and the vertical line determination unit determines whether the upper line of the pixel of interest is the result of determination by the horizontal complexity determination unit. Or, if any of the lower lines has a complexity greater than or equal to a predetermined complexity, and the difference value calculated by the vertical direction difference means and specified by the area specifying means, both the left and right sides from the target pixel Among the difference values of all the actual pixels on the vertical line located within the pixels, the difference values between the line one above and the line below the pixel of interest are all smaller than a predetermined threshold, or the pixel of interest is Through Or the difference value between the actual pixel line two above the target pixel and the actual pixel line one above and the actual pixel one below the target pixel. When the difference values between the line and the next lower real pixel line are all smaller than a predetermined threshold, it is determined that the target pixel is a part of the vertical line pattern, and the flat determination unit Among the difference values calculated by the difference means and specified by the area specifying means, the difference values of all the real pixels on the vertical line located within several pixels on both the left and right sides of the target pixel are one above the target pixel. When the difference values between the line and the next lower line are all smaller than a predetermined threshold value, it is determined that the target pixel is a part of a flat pattern, so that the target pixel is a complex pattern, Corner pattern, vertical line pattern, font Tsu bets a picture, or of those other than the picture is obtained by said determining whether corresponds to the pattern of pixels of any feature.
According to a tenth technical means, in the ninth technical means, the area designating means designates an actual pixel area in the predetermined range for the difference value in the horizontal direction for the target pixel, and the difference in the vertical direction. With respect to the value, the actual pixel region is specified so that an appropriate number of difference values are specified from the predetermined range of the actual pixel region.

According to an eleventh technical means, in the ninth technical means, the calculation of the difference value in the separated pixel difference means and the calculation of the difference value in the horizontal direction difference means and the vertical direction difference means are specified by the area specifying means. It is characterized by executing one field before.

According to a twelfth technical means, in the ninth technical means, the calculation of the difference value in the separated pixel difference means and the calculation of the difference value in the horizontal direction difference means and the vertical direction difference means are specified by the area specifying means. Before the process, the minimum required actual pixel area is executed by the designation by the area designating means.

According to a thirteenth technical means, in the ninth technical means, the calculation of the difference value in the separated pixel difference means, or the calculation of the difference value in the horizontal direction difference means and the vertical direction difference means is performed for each target pixel. On the other hand, the process is performed after the real pixel area in the predetermined range is designated by the area designation means.

A fourteenth technical means is a pixel interpolation device comprising the pixel feature determination device of the ninth technical means, wherein any one of a complex picture, a corner picture, a vertical line picture, and a flat picture in the pixel feature judgment apparatus. Kano for some of the determined pixel of interest is a pixel, the interpolation value calculating means that issues calculate the interpolated values from the pixel information of the real pixels in the predetermined positional relationship with each picture, inter該補Interpolation means for interpolating each pixel of interest with the interpolation value calculated by the value calculation means is further provided.

The fifteenth technical means further comprises a pixel interpolation direction detecting device for detecting the direction of interpolation for the pixels to be interpolated in the field in the fourteenth technical means, the pixel interpolation direction detecting device comprising: An area centered on the target pixel, a central pixel area including at least a plurality of real pixels existing in the current field, and an area not surrounding the target pixel, A pixel area specifying means for specifying a plurality of peripheral pixel areas including at least a plurality of real pixels arranged in a circle at a substantially equal distance from the target pixel; a central pixel area specified by the pixel area specifying means; and Total calculation means for calculating the total pixel information of the pixels included in the plurality of peripheral pixel areas for each pixel area, and the total for each pixel area calculated by the total calculation means, and the total was made. Based on the positional relationship of the pixel region, to detect the strongest direction of the correlation comprises determining the interpolation direction determination hand stage a direction the detected as the interpolation direction, the interpolation value calculating means, the complexity in the pixel feature determining device For each pixel of interest determined to be a pixel of a picture other than a simple picture, a corner picture, a vertical line picture, and a flat picture, the interpolation direction based on the interpolation direction detected by the pixel interpolation direction detection device An interpolation value is calculated from the upper real pixel.

A sixteenth technical means includes the pixel interpolating apparatus according to the fourteenth or fifteenth technical means, interpolates a signal of a pixel determined not to move among interlaced scanning video signals, and performs interlaced scanning video. A video signal processing apparatus characterized in that a signal of a pixel determined to be moving among signals is interpolated by the pixel interpolation device to convert an interlaced scanning video signal into a progressive scanning video signal.

According to the present invention, when the field interpolation video signal of interlaced scanning, for each interpolated pixel, the features of its so as to be distinguished from the oblique line or other diagonal edge, near real pixels It is possible to accurately determine from the characteristics of If this determination is used, when interlaced video signals are interpolated in the field, even if diagonal lines or other diagonal edges exist for each interpolated pixel, it is an optimal real pixel. In addition, this interpolation can convert interlaced video signals into high-quality progressive video signals that can be clearly displayed without blurring or flickering even if there are diagonal edges. It becomes possible.

  FIG. 1 is a diagram illustrating a configuration example of a pixel feature determination device according to an embodiment of the present invention, a pixel interpolation device including the pixel feature determination device, and a video signal processing device. Movie element determination device, 2 is an intra-frame interpolation device, 3 is an intra-field interpolation device, 11 is a pixel feature determination means, 12 is a pixel interpolation direction detection means, 13 is a pixel interpolation means, 14 is a horizontal direction difference means, and 15 is vertical Direction difference means, 16 is a region designation means, 17 is a separated pixel difference means, 18 is a horizontal direction complexity determination means, 19 is a complexity determination means, 20 is a corner determination means, 21 is a vertical line determination means, and 22 is a flat determination means. , 23 is a pixel area specifying unit, 24 is a total calculation unit, 25 is an interpolation direction determination unit, 26 is an interpolation direction correction unit, 27 is an interpolation value calculation unit (interpolation value generation unit), 28 is an interpolation value determination unit, and 29 is Interpolation means .

Pixel feature determining apparatus according to the present invention, when performing the IP conversion for converting an image signal of the interlaced scanning video signal of a progressive scanning, to the pixel to be interpolated in the field, near the features of its real pixels This is a device for judging from features, and will be described as pixel feature judging means 11 hereinafter. The present invention relates to an apparatus for improving the image quality of a moving image portion in IP conversion from an interlaced image to a progressive image, and a circuit constituting the apparatus.

  The pixel interpolating apparatus according to the present invention is characterized by comprising the pixel feature determining means 11 and is an apparatus for interpolating pixels with real pixels in the optimum interpolation direction. The intra-field interpolation device 3 mainly includes a pixel feature determination process for determining a pixel feature in the pixel feature determination unit 11 as the preceding process, and a pixel interpolation direction detection process in the pixel interpolation direction detection device as an intermediate process. Then, the subsequent processing includes interpolation processing (and interpolation check processing). Here, the pixel interpolation direction detecting device is a device that detects the direction of interpolation for pixels to be interpolated in a field when performing IP conversion for converting an interlaced scanning video signal into a progressive scanning video signal. Hereinafter, the pixel interpolation direction detection unit 12 will be described. Note that the pixel interpolation apparatus according to the present invention may employ a mode that does not include the pixel interpolation direction detection apparatus exemplified by the pixel interpolation direction detection unit 12. That is, the pixel feature determination apparatus according to the present invention functions effectively even in general intra-field interpolation. In the pixel interpolating device according to the present invention, when performing up-conversion of a television system with a different number of scanning lines or converting from an interlaced scanning video signal to a sequential scanning video signal, line interpolation is performed when generating a frame image from a field image. It can be performed accurately.

  Furthermore, the video signal processing apparatus according to the present invention is characterized by including the intra-field interpolation device 3 including at least the pixel feature determination means 11, and is a device for interpolating pixels and converting from an interlaced video signal to a progressive video signal. An example including a still pixel / moving pixel determination device 1 and an intra-frame interpolation device 2 is shown in FIG. 1 as a whole.

  FIG. 2 is a diagram for explaining pixels near a target pixel in one field. In FIG. 2, F is a field (also referred to as a field image), T is a pixel of interest, E is a real pixel, N is a pixel to be interpolated, Lt is an interpolation line where the pixel of interest T is located (hereinafter referred to as a pixel of interest), Lnua Is an interpolation line one above the pixel of interest T, Lnub is an interpolation line two above the pixel of interest T, Lnda is an interpolation line one pixel below the pixel of interest T, and Lndb is an interpolation line two pixels below the pixel of interest T , Leua is an actual pixel line that is one pixel above the target pixel T, Leub is an actual pixel line that is two pixels above the target pixel T, Leda is an actual pixel line that is one pixel below the target pixel T, and Ledb is 2 of the target pixel T. A lower actual pixel line, Lnua, is an interpolation line one above the target pixel T.

  Here, E generally indicates an actual pixel that exists in the input field F, and N generally indicates a pixel that does not exist in the input field F, and generally indicates a pixel to be interpolated (interpolated pixel). Further, the target pixel T is the target interpolation pixel (that is, the target interpolation pixel) among the interpolation pixels N, and this target pixel T is sequentially assigned to all the interpolation pixels N. However, this assignment of the pixel of interest T to the interpolation pixel N may be omitted by the pre-processing described later. The video signal of one field is. . . , Lnub, Lnua, Lnda, Lndb,. . . It can be handled that each real pixel E is located on the following real pixel line, and if it is an odd field, an interpolation line (..., Leua, Lt, Leda, Ledb, ..) Is located, and if it is an even field, an interpolation line is located on each actual pixel line. In FIG. 2, the pixels in the field F are extracted and shown in a 9 pixel × 9 line region, but this is for the purpose of describing the pixel of interest T as a center in consideration of the paper surface.

<Pre-stage processing (pixel feature determination processing)>
First, processing in the pixel feature determination apparatus, which is a characteristic part of the present invention, will be described. The pre-processing described here is to avoid increasing the number of processes by detecting the interpolation direction with the pixel interpolation direction detection device for all interpolation target pixels in the intermediate process, and to increase the detection accuracy of the interpolation direction. In the stage before determining the interpolation direction, a pixel of interest that is not a constituent pixel such as a diagonal line or a diagonal edge may be omitted in advance from the processing (and interpolation processing based thereon) by the pixel interpolation direction detection device, or the pixel interpolation device The main purpose is to make the interpolation processing in the (intra-field interpolation device 3) accurate. In FIG. 1, the pixel feature determination unit 11 is illustrated as a component of the intra-field interpolation device 3 so as to be distinguished from the pixel interpolation direction detection unit 12, but the pixel feature determination unit 11 detects the interpolation direction. It can also be said that it is a constituent element of the pixel interpolation direction detection means 12 for performing it more accurately.

Pixel feature determining means 11, such as prior to determining the direction of interpolation in the pixel interpolation direction detection means 12, a means for determining the feature of the pixel of interest from the feature of the actual pixels in the vicinity. The image has a pattern with various features in the image, and the pixel feature determination unit 11 is a unit that determines what feature the pixel of interest can be considered as a part of the pattern. The image feature determination unit Some say it. Accordingly, in the case where the intra-field interpolation is executed by incorporating the pixel interpolation direction detecting means 12, the pixel region specifying 23, the total calculating means 24, the interpolation, as will be described later, for the target pixel having a predetermined feature based on the determination result. The processing in the direction determination unit 25 may not be substantially executed.

The pixel feature determination unit 11 according to an embodiment of the present invention calculates a difference value of pixel information between two real pixels positioned above and below in the same field of the target pixel with respect to the target pixel as a pixel to be interpolated. A subtractor, a subtractor for calculating a difference value of pixel information between two real pixels located adjacent to each other in the same field of the target pixel, and a number on the upper line of the target pixel. A stage such as a hand subtractor for calculating a difference value of pixel information between two real pixels located at a distance from the pixel, and pixel information between two real pixels located several pixels away on the lower line of the target pixel And a means such as a differentiator for calculating the difference value. And the pixel feature determination means 11 in this form is the result of the difference between the two real pixels located above and below, the result of the difference between the two real pixels located on the left and right, and between the two real pixels located above and below the difference between the results, any one or more results of between a few pixels apart two pixels of 2 original pixels and between the upper and lower lines located to determine features of the target pixel.

  The pixel feature determination device (pixel feature determination unit 11) according to an embodiment of the present invention includes at least a horizontal direction difference unit 14, a vertical direction difference unit 15, a region designation unit 16, and a separated pixel difference unit 17. These means correspond to each of the above-described means exemplified by a differentiator or the like. As a more preferred embodiment of the present invention, the pixel feature determination unit 11 includes a horizontal complexity determination unit 18.

  The horizontal direction difference means 14 is a means for calculating a difference value of pixel information between respective real pixels adjacent in the horizontal direction in the field (horizontal direction between the real pixels). The vertical direction difference means 15 is a means for calculating a difference value of pixel information between each real pixel adjacent in the vertical direction in the field (vertical direction between each real pixel).

  The area designating unit 16 is a unit that designates an actual pixel area in a predetermined range centered on the target pixel with respect to the target pixel that is a pixel to be interpolated. As a more preferred form, the area designating unit 16 designates a predetermined range of actual pixel areas for the difference value in the horizontal direction and a vertical direction difference value for the target pixel. The actual pixel region may be designated so that an appropriate number of difference values are designated.

  The separated pixel difference means 17 also includes a pixel information difference value between real pixels that are equidistant from the target pixel on one line of the target pixel, and real pixels that are equidistant from the target pixel under one line of the target pixel. It is a means for calculating a difference value of pixel information between them. Further, the horizontal complexity determination unit 18 converts the horizontal difference value of the actual pixel calculated by the horizontal direction difference unit 14 into the horizontal difference value in the actual pixel area designated by the region designation unit 16. Based on this, it is a means for determining the horizontal complexity for each actual pixel line. As a more preferable form, the calculation of the difference value in the separated pixel difference means 17 or the calculation of the difference value in the horizontal direction difference means 14 and the vertical direction difference means 15 is performed for each target pixel by the area specifying means 16. It is preferable to execute the process after designating a predetermined range of actual pixel areas.

  In addition, as a feature to be determined by the pixel feature determination unit 11, any one or more of a complex pattern, a vertical line pattern, a flat pattern, and a corner pattern may be used. For the target pixel T determined to be present, for example, the interpolation direction can be unified and determined in the vertical direction. Of course, it is preferable to make a determination on all the patterns among complex patterns, vertical line patterns, flat patterns, and corner patterns. In any case, the accuracy of interpolation (and the accuracy of interpolation direction detection) can be improved by extracting and determining image features in advance.

Further, the calculation of the difference value in the separated pixel difference unit 17 and the calculation of the difference value in the horizontal direction difference unit 14 and the vertical direction difference unit 15 are performed for one field before the designation by the area designation unit 16. It is preferable to do. First, may calculate a difference value of each field of, then calculate the feature of the pixel of interest T and designated in the area designation means 16. In another embodiment, the calculation of the difference value in the separated pixel difference unit 17 and the calculation of the difference value in the horizontal direction difference unit 14 and the vertical direction difference unit 15 are performed before the designation by the region designation unit 16. It is also possible to execute the minimum necessary actual pixel area by the designation by the designation means 16.

  As in these embodiments, each difference value is calculated and prepared in advance for one field, or each difference value is calculated as a minimum number around the pixel of interest, and then complicated. A means for selecting and using the necessary difference values (difference values appropriate for the respective means) for each judgment means of judgment / vertical judgment / flat judgment / corner judgment, or means for assigning each difference value to each judgment means as much as necessary. Each difference value may be given to each determination means. As a result, not only the number of vertical differences, but also the number of horizontal differences used in complex determination or the like, and the separation distance of the separated pixel difference (how many pixels are apart from the target pixel) are also determined by each determination means. Can be arbitrarily given.

  In such a form, the area designating unit 16 further includes a unit for designating a predetermined range of actual pixel areas suitable for determination by the flat determining unit 22, and the flat determining unit 22 uses the actual pixel specified there. The determination may be performed in the area. Note that designation of an actual pixel region within a predetermined range suitable for determination means that an appropriate number of difference values are adopted centering on the pixel of interest T. For example, the actual pixel area used in the later-described corner picture determination process and the actual pixel area used in the flat picture determination process may be specified separately. Similarly, the area designating means 16 further includes means for designating a predetermined range of actual pixel areas suitable for determination by the vertical line determining means 21, and the vertical line determining means 21 includes the actual pixel area specified there. The determination may be made at. The area designating unit 16 further includes means for designating a predetermined range of actual pixel areas suitable for the determination by the corner determination unit 20, and the corner determination unit 20 performs the determination using the actual pixel area specified there. You just have to do it. Further, the area designating unit 16 further includes a unit for designating a predetermined range of actual pixel areas suitable for the determination by the complexity determining unit 19, and the complex determining unit 19 performs the determination using the actual pixel area specified there. You just have to do it. It goes without saying that only one of the area designations in each of these determination means may be applied.

  In the following, a suitable determination method for a complicated pattern, a vertical line pattern, a flat pattern, and a corner pattern will be described. As described above, the complicated pattern, vertical line pattern, flat pattern, and corner pattern are determined by the complex determination unit 19, the vertical line determination unit 21, the flat determination unit 22, and the corner determination unit 20, respectively.

  FIG. 3 is a schematic diagram for explaining pixel feature determination means in the intra-field interpolation apparatus of FIG. 1. FIG. 3A shows an example of an actual pixel used for feature determination with respect to the target pixel and its difference portion. FIGS. 3B, 3C, 3D, 3E, and 3F are horizontal line complexity determination, flat pattern determination, and vertical line pattern determination in FIG. It is a figure which shows the real pixel used when performing a corner pattern determination and a complicated pattern determination, and its difference location. In FIG. 3, the same elements as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.

[Horizontal line complexity judgment processing]
In the pixel feature determination unit 11, as illustrated in FIG. 3B, before the execution of the vertical line pattern determination, the complex pattern determination, the corner pattern determination, and the flat pattern determination, the actual pixel E and the arrow direction (or The difference in the opposite direction) is executed to determine the complexity of the horizontal line. Note that the flat pattern determination and the corner pattern determination can be performed in advance since they can be performed without executing the complexity determination described here.

  In the complexity determination, first, a difference value of pixel information between each real pixel adjacent in the horizontal direction in the field, that is, a difference value in the horizontal direction between each real pixel is calculated. Pixel information refers to pixel values such as luminance values. Then, for a target pixel T that is a pixel to be interpolated, a real pixel region in a predetermined range centered on the target pixel T is designated. Here, the calculation of the difference value in the horizontal direction may be executed after designating a predetermined range of actual pixel areas for each pixel of interest T. In the example of FIG. 3B, for one target pixel T, nine actual pixels in the horizontal direction are centered around the horizontal position of the target pixel T in the line one line above and one line below it. The pixel E is designated, and the difference value of eight lines (16 in total) is calculated.

  Then, the horizontal direction (horizontal line) complexity determination unit 18 determines, for each actual pixel line, based on the calculated horizontal difference value of the actual pixel in the horizontal direction difference value in the designated actual pixel region. Determine the horizontal complexity of.

  For the target pixel T, there is no problem even if only the complexity of the upper line and the lower line is determined. Here, for each line, the complexity is determined by whether or not the pixel value (luminance value) is uneven in the line direction. As a preferred form of complexity determination in the horizontal direction complexity determination means 18, first, the difference value of the pixel information between each real pixel E adjacent in the horizontal direction is compared with two threshold values having the same absolute value, Based on the comparison result, the difference value is encoded into a negative value, a zero value, and a positive value. For example, reference numeral 1 is used when the difference value from the neighbor is larger than the threshold value, reference numeral -1 is used when the difference value from the neighbor is smaller than the threshold value, and reference numeral 0 is the others. Then, based on the encoded value, the difference value determines whether adjacent codes are the same code or different codes, and as a result of the determination, the number of the same code or different codes is counted for each line. Thus, the complexity of the line is selected from a predetermined plurality of levels of complexity for each line based on the number of results counted. For example, when the count value (added value) is equal to or greater than another predetermined threshold (which may be an integer), it is determined that there is no unevenness, and when it is the predetermined threshold-1, it is determined that it is V, and the predetermined threshold-2. If it is, it is determined that it is S, if it is the predetermined threshold value -3, it is determined that it is M, and if it is the predetermined threshold value -4, it is determined that it is uneven. Thus, the complexity increases as it is determined that V → S → M → concave / convex. V, S, M, etc. are used for vertical line pattern determination and complex pattern determination.

[Flat pattern judgment processing]
To execute the flat pattern determination process, first, a vertical difference is executed. In this vertical direction difference, a difference value of pixel information between each real pixel E adjacent in the vertical direction in the field, that is, a vertical direction difference value between each real pixel E is calculated. Here, the calculation of the difference value in the vertical direction may also be executed after designating a predetermined range of actual pixel regions for each pixel of interest T.

  Then, the flat determination unit 22 determines that the pixel of interest T is a flat picture (flat image) based on the vertical difference value in the designated real pixel area among the calculated vertical difference values of the real pixels. ) To determine whether the pixel is a part of the pixel. Here, in the flat pattern determination process, although it depends on the number of pixels to be determined to be a flat pattern, if it is determined that a pixel over a very long distance is a flat pattern, the determination that it is a flat pattern is the result. Is no longer output. Therefore, as a preferred form of flat pattern determination in the flat determination means 22, of the vertical direction difference values in the actual pixel area (actual pixel area used in the corner pattern determination process described later) designated by the area designation means 16 The difference values for several pixels from the left and right ends may not be used for the determination.

  In this flat picture determination process, for example, as shown in FIG. 3C, the target pixel T of each pixel of the actual pixel line Leua one above the target pixel T and the actual pixel line Leda one below the target pixel T is displayed. Five real pixels E centering on the horizontal position are designated, and a vertical difference value between the real pixel E on the real pixel line Leua and the real pixel E on the real pixel line Leda is calculated. Then, when all of the upper and lower difference values are smaller than a predetermined threshold value, the target pixel T is determined to be a pixel included in the flat image.

[Vertical line pattern judgment processing]
The vertical line determination unit 21 determines the horizontal complexity of the upper and lower lines of the target pixel T determined by the horizontal complexity determination unit 18 and the vertical difference of the actual pixel calculated by the vertical direction difference unit 15. Whether the target pixel is a part of the vertical line (vertical line pattern) based on the vertical difference value in the actual pixel area specified by the area specifying unit 16 among the values (upper and lower difference values). Determine whether or not. Therefore, in the vertical line pattern determination process, both the horizontal line complexity and the vertical direction difference described above are required. Here, in order to determine the horizontal line complexity, a horizontal direction difference is required, but regardless of the vertical line pattern determination process, both the horizontal direction difference value and the vertical direction difference value are required. The range of the actual pixel area to be specified may be different. If the actual pixel area to be specified for the difference value in the horizontal direction with respect to the target pixel T is a predetermined range X, the range of the difference value in the vertical direction is the predetermined range. The actual pixel area may be specified so that an appropriate number of difference values are specified in the X actual pixel area.

  As a preferred form of the vertical line pattern determination in the vertical line determination unit 21, either the upper line or the lower line of the pixel of interest T is a predetermined value in the horizontal complexity determination result in the horizontal direction complexity determination unit 18. A vertical line (vertical line) located within several pixels on both the left and right sides of the target pixel T among the difference values calculated by the vertical direction difference unit 15 and specified by the area specifying unit 16 when the complexity is greater than the complexity. (Column)) In all the difference values of the actual pixel E above, the difference values between the line immediately above and the line below the pixel of interest T are all smaller than a predetermined threshold value, or are perpendicular to the pixel of interest T. The difference values of the lines (vertical lines (columns)) are all smaller than a predetermined threshold value, or the difference value between the actual pixel line two above the target pixel T and the actual pixel line one above and one of the target pixel T The actual pixel line below When the difference value between the actual pixel line of the lower two are all smaller than a predetermined threshold value, it is determined that the pixel of interest T is part of the pixels of the vertical line pattern.

  In this vertical line pattern determination processing, for example, as shown in FIG. 3D, the actual pixel line Leua one above the target pixel T or the actual pixel line Leda one below the target pixel T has a complexity of V or more, In the vertical direction difference values of all the real pixels E on the vertical line (that is, three vertical lines) located within one pixel on both the left and right sides of the pixel T, the real pixel line Leua that is one pixel below the target pixel T and one pixel below The vertical direction difference values with the actual pixel line Leda are all smaller than a predetermined threshold value, or the difference values of vertical lines (vertical lines (columns)) passing through the target pixel T are all smaller than the predetermined threshold value, or the target pixel T Vertical method difference value between the real pixel line Leub two above and the real pixel line Leua one above, and the vertical direction between the real pixel line Leda one below the target pixel T and the real pixel line Ledb two below All difference values Is smaller than a predetermined threshold value, it is determined that the pixel of interest T is part of the pixels of the vertical line pattern. That is, in this example, the upper line or the lower line of the pixel of interest T has a complexity of V or more, and all the three upper and lower difference values are smaller than a predetermined threshold value, or the upper, middle, and lower 3 If all the upper and lower difference values are smaller than a predetermined threshold value, or if all six upper and lower difference values are smaller than the predetermined threshold value, the pixel of interest T is a pixel representing a vertical line. judge.

[Corner pattern determination processing]
The angle determination means 20 includes the vertical difference value in the actual pixel area designated by the area designation means 16 and the separated pixel difference among the vertical difference values of the real pixel E calculated by the vertical direction difference means 15. Based on the difference value calculated by the means 17, it is determined whether or not the target pixel T is a partial pixel of a corner (corner pattern). Accordingly, in the corner pattern determination process, a difference between the separated real pixels obtained by the separated pixel difference means 17 is required. Here, in the separated pixel difference processing in the separated pixel difference means 17, the separated difference value is calculated in the actual pixel area designated by the area designation means 16. As described above, the calculation of the separated pixel difference value may be executed after designating a predetermined range of the actual pixel region for each target pixel T.

  As a preferred form of the corner pattern determination, among the vertical direction difference values calculated and designated by the vertical direction difference means 15 and the area designation means 16, the actual pixel line two above the target pixel T and the actual one above When the vertical direction difference value with respect to the pixel line and the vertical direction difference value between the actual pixel line one lower and the second actual pixel line below the target pixel T are all smaller than a predetermined threshold, and the calculated separation Among the pixel difference values, when the difference value corresponding to either the upper line (one upper actual pixel line) or the lower line (one lower actual pixel line) of the target pixel T is larger than a predetermined threshold value , It is determined that the target pixel T is a partial pixel of the corner picture.

  In this corner pattern determination process, for example, as shown in FIG. 3E, the vertical direction difference value between the actual pixel line Leub two above the target pixel T and the actual pixel line Leua one above the target pixel T and the target pixel T When the vertical direction difference values between the lower actual pixel line Leda and the lower actual pixel line Ledb are all smaller than a predetermined threshold, and either the upper line Leua or the lower line Leda of the target pixel T When the corresponding separated pixel difference value (the separated difference value between the real pixels separated by 2 pixels from the horizontal position of the pixel of interest T and the real pixels separated by 3 pixels) is larger than a predetermined threshold, the pixel of interest T is a square picture Is determined to be a part of the pixels. In other words, in this example, when the upper and lower ends of the target pixel T are larger than the predetermined threshold value, and all the 14 upper and lower difference values are lower than the predetermined threshold value, It is determined that the pixel represents one corner.

[Complex pattern judgment processing]
Based on the horizontal complexity of the upper and lower lines of the target pixel T determined by the horizontal direction complexity determination unit 18, the complex determination unit 19 is a pixel that is a part of a complex picture. It is determined whether or not (the periphery of the target pixel T is complicated). Accordingly, in the complex picture determination process, the horizontal complexity of the actual pixel line is used for the determination. Based on the horizontal complexity of the actual pixel line one above and below the target pixel T, it is determined whether or not the target pixel T is a part of a complex picture.

  As a preferable form of the complex picture determination, in the horizontal direction complexity determination result in the horizontal direction complexity determination unit 18, either the upper line or the lower line of the target pixel T has a predetermined complexity (vertical line determination). If it has a complexity higher than that used in the above, it is determined that the pixel of interest T is a part of a complex picture.

  In this complex picture determination process, for example, as shown in FIG. 3F, when either the upper line Leua or the lower line Leda of the target pixel T has a complexity of M or more, the target pixel T is a complex picture. Is determined to be a part of the pixels.

  By executing the pre-stage processing as described above, for example, various setting values in interpolation direction detection described later (various setting values such as filter weighting coefficients described later) are set in consideration of only edges such as diagonal lines. Therefore, not only the number of interpolation target pixels in the pixel interpolation direction detection unit 12 is reduced, but also the accuracy of the interpolation direction detection in the pixel interpolation direction detection unit 12 is improved. Furthermore, by executing the pre-processing as described above, based on the result of the feature determination, an interpolation value that matches each feature pixel is calculated from the actual pixel in the field, and each pixel of interest is optimized using the interpolation value. Can be interpolated.

<Intermediate processing and subsequent processing>
Next, a pixel interpolation device that includes the pixel feature determination device (pixel feature determination unit 11) of each embodiment as described above and further includes a pixel interpolation direction detection device (pixel interpolation direction detection unit 12) will be described. The pixel interpolation device (intra-field interpolation device 3) includes the pixel interpolation unit 13 including at least the interpolation value calculation unit 27 and the interpolation unit 29, but the pixel interpolation direction detection device is arbitrary. First, intermediate processing in the pixel interpolation direction detection device will be described, and pixel interpolation will be described in later stage processing.

<< Intermediate processing (pixel interpolation direction detection processing) >>
[Pixel area specification / pixel information total calculation processing (circular filter set)]
FIG. 4 is a diagram for explaining an example of a pixel region specified by the pixel interpolation direction detection device in the pixel interpolation device according to the embodiment of the present invention, and FIGS. 4A and 4B show the pixel region. It is a figure which shows a different example.

In FIG. 4, A is a central image region, B _{0 to} B ₆ (often represented by B), C _{0 to} C ₆ (often represented by C) are peripheral image regions, and Fh is a field in which an interpolation line is inserted as a temporary interpolation value. Image H is an interpolation pixel to be interpolated on the interpolation line. In addition, in FIG. 4, the same code | symbol is attached | subjected to the element similar to FIG. 2, and description is abbreviate | omitted. However, in FIG. 4 (A), E generally indicates an actual pixel existing in the input field F, whereas in FIG. 4 (B), an actual pixel existing in the field Fh is generally indicated. Point to. 4A, N is a pixel that does not exist in the input field F and generally indicates a pixel to be interpolated (interpolated pixel), whereas in FIG. 4B, H is temporary. Generally, the pixel to be interpolated in the field Fh in which the interpolation line is inserted by the interpolation value is indicated. Also, in FIG. 4B, the target pixel T is the target interpolation pixel (that is, the target interpolation pixel) of the interpolation pixels H, and this target pixel T is sequentially assigned to all the interpolation pixels H. is there. However, this assignment of the target pixel T to the interpolation pixel H may be omitted by the above-described pre-processing.

  The pixel interpolation direction detection unit 12 includes at least a pixel area specifying unit 23, a total calculation unit 24, and an interpolation method determination unit 25. The pixel area specifying means 23 is a means for specifying the center image area A and the plurality of peripheral pixel areas B and C with respect to the target pixel T which is a pixel to be interpolated (pixel to be interpolated). The interpolation direction is detected based on the pixel group in the pixel region specified here. In the present specification, the specified pixel region is illustrated as a circular region, but the specified pixel region is not limited to the circular region.

Here, the central pixel region refers to a pixel region including at least a plurality of real pixels E existing in the current field F with the target pixel T as the center, for example, a region A in FIG. Also, as shown in the figure, the plurality of peripheral pixel regions are pixel regions including at least a plurality of real pixels E arranged in a circle at a substantially equal distance from the target pixel T. For example, FIG. Regions B _{0 to} B ₆ and C _{0 to} C ₆ . Each of the plurality of peripheral pixel regions does not include the target pixel T in the region. That is, the peripheral pixel region is a region that does not surround the target pixel T. For later explanation, the peripheral pixel region B is the peripheral pixel region where the pixels on the line above the target pixel line Lt are main, and the peripheral pixel region where the pixels on the lower line are the main peripheral pixel regions. Although C may be illustrated and described as C, the peripheral pixel regions B and C are both peripheral pixel regions of the central pixel region A. Further, the circular arrangement means an arrangement at a position rotated about a certain angle around the target pixel T, and the center of the surrounding pixel area is located at the rotated substantially equidistant position. It should be arranged.

  The substantially equidistant from the target pixel T is based on the actual pixel E and the interpolation pixel H (or interpolation pixel N: no value or 0 value) obtained by sampling the video signal of one field in a lattice shape. It means that the distance is substantially equal. For example, in FIG. 4B, if the distances between the real pixels E adjacent in the horizontal direction and the vertical direction are 1 and 2, respectively, the distance from the target pixel T to the central pixel or the center of the peripheral pixel regions B and C is 2.00 to 3.16, and the distance between them may be treated as a substantially equal distance. Here, the substantially equidistant distance is a distance that is substantially equal in determining the interpolation direction of the target pixel T. The distance from the target pixel T may be defined by the distance from the end of the target pixel T or the central pixel region A on the peripheral pixel region side to the end of the peripheral pixel region on the central pixel region A side.

  These pixel regions A, B, and C are real pixels obtained by sampling one field video signal (input video signal) of interlaced scanning in a lattice shape in consideration of interpolation lines as shown in FIG. Based on E, the signal may be specified by sequentially selecting a signal corresponding to each real pixel E from the input video signal.

  Further, as shown in FIG. 4B, the central pixel area A and the peripheral pixel areas B and C include not only the actual pixel E but also the actual pixel E and the provisional temporarily obtained from them. A form including an interpolation pixel H having an interpolation value can also be adopted. In the case of this embodiment, these pixel areas A, B, and C are arranged in a lattice pattern in the pixel area specifying means 23 in consideration of an interpolation line, for example, as shown in FIG. Among the interpolated pixels H obtained by calculating the average value of the upper and lower pixels from the input video signal based on the real pixels E sampled at the same time, and the real pixels E and the interpolated pixels H among them The signal may be identified by sequentially selecting signals corresponding to the above.

  Therefore, the pixel interpolation direction detection unit 12 according to this embodiment needs to further include a preliminary interpolation unit that performs predetermined interpolation from an actual pixel existing in the current field and generates an interpolation line in advance. However, as the preliminary interpolating means, if the same interpolating means is provided in the pixel interpolating means 13 described later, it may be used. The pixel area specifying means 23 in this embodiment specifies the pixels on the interpolation line interpolated by the preliminary interpolation means as the central pixel area A and the plurality of peripheral pixel areas B and C. In this case, it is preferable to set the weight of the pixel (interpolation pixel H) on the interpolation line to be lighter than the weight for the actual pixel E by weighting. In addition, the form regarding weighting is mentioned later.

  On the other hand, in the pixel area specifying means 23 described with reference to FIG. 4A, a pixel area (centered on the target pixel T) including only a plurality of real pixels E existing in the current field F is set as the central pixel area A. Identify the peripheral pixel regions B and C that include only a plurality of real pixels E arranged in a circle (on the circumference) at a substantially equal distance from the target pixel T as a plurality of peripheral pixel regions B and C. is doing. Of course, in the form of the pixel area specifying means 23 described with reference to FIG. 4A, not only the pixel areas A, B, and C are specified so as to include the interpolated pixels N that do not include the provisional interpolation value. The pixel regions A, B, and C are specified so as to be included as interpolation pixels N having zero values that do not contribute to the total calculation in the subsequent stage, or the pixel regions A, B, and C include substantially only the actual pixel E. This corresponds to specifying C.

  4A and 4B, the plurality of peripheral pixel regions B and C are arranged with the same number of pixels as the central pixel region A (or on the same grid). It is preferable in terms of the circuit configuration that the pixel region is specified as a (wide) pixel region. However, when performing weighting, which will be described later, it may be specified as a pixel region having the same number of pixels in consideration of the weight.

Further, when the peripheral pixel areas B and C are specified, all the pixels existing around the specified central pixel area A are assigned to any one of the peripheral pixel areas B _{0 to} B ₆ and C _{0 to} C _6. It is preferable to specify the pixel region so that it is included. This form is also applicable to the pixel region specifying means 23 illustrated in any of FIGS. 4A and 4B. In this embodiment, since the periphery of the central pixel region A is surrounded without omission by the plurality of peripheral pixel regions B and C, the interpolation direction calculation contributes not only to the region A but also the pixels in all directions around it. This means that the pixels close to the target pixel T can be used as much as possible when calculating the interpolation direction, and as a result, the accuracy of the interpolation direction detection and interpolation can be improved. In this embodiment, even if it is specified that the peripheral pixel regions B and C are arranged around the central pixel region A, the central pixel region A and the peripheral pixel regions B and C are overlapped (there are overlapping pixels). You may specify as follows.

  Further, as shown in FIGS. 4A and 4B, the pixel area specifying unit 23 includes any one or a plurality (all peripheral pixel areas) of the plurality of peripheral pixel areas B and C. ) May be specified so as to overlap the central pixel region A with some pixels. By providing such an overlap, it becomes possible to determine the interpolation direction in a limited range of pixel regions, and as a result, avoiding an increase in the scale of the circuit compared to the case in which no overlap is provided. Not only is this possible, but the interpolation direction can be determined based on more neighboring information. Note that the pixel area to be specified may be, for example, an area of 3 × 3 pixels or 3 × 4 pixels including pixels to be interpolated as illustrated in FIG.

In addition, it is preferable that the pixel region specifying unit 23 specifies a plurality of pairs of two peripheral pixel regions B and C, each paired with two peripheral pixel regions positioned symmetrically with respect to the target pixel T. Here, the direction in which each pair is arranged is specified at a position rotated around the target pixel T. 4A and 4B, a pair of region B ₀ and region C _0, a pair of region B ₁ and region C _1, a pair of region B ₂ and region C ₂ , and a region B ₃ It is illustrated as a pair of region C _{3 and} a pair of region B ₄ and region C ₄ .

As will be described later in the determination of the interpolation direction, the interpolation direction is determined by the direction (or the normal direction) formed by the set of the pair and the central pixel region, in other words, determined by the pair direction (or the normal direction). is doing. Therefore, after specifying the pixel area, it may be determined between the pixel areas whose directions from the target pixel coincide with each other, but it is efficient to specify the pixel area in pairs as described above as described above. . The interpolation direction is determined in this direction using three consecutive regions (for example, regions B ₁ , A, C ₁ ) consisting of a pair of peripheral pixel regions and a central pixel region on a straight line. Therefore, such a filter composed of the pixel area specifying means 23 and the total calculating means 24 described later is often referred to as a “circular filter set”. Note that each region (e.g., region B ₁ and area A, etc.) is called a circular pixel area, further, the pixel area specifying means 14 for specifying the circular pixel area, such as multiplying the coefficients to real pixel information The total calculation means 15 for calculating the total value is collectively referred to as a “circular filter”, and three consecutive regions (circular pixel regions) on a straight line are referred to as a “circular pixel region set”. However, in these terms, “circular shape” is used, but it is of course not limited to the circular shape, and the area may be specified in any shape such as “circular” or “rectangular”, and the whole Needless to say, the shape is circular but may actually be rattled.

The total calculation unit 24 includes pixels (real pixel E / real pixel E and interpolation pixel H / real pixel E and zero-value interpolation pixel) included in the central pixel region and the plurality of peripheral pixel regions specified by the pixel region specifying unit 23. N) is a means for calculating the sum of the pixel information for each pixel area, and functions together with the pixel area specifying means 23 as a circular filter that removes high-frequency components in each area. A combination of the circular filters related to the regions B ₁ , A, and C ₁ is a “circular filter set”. Here, the pixel information of a pixel refers to a pixel value such as a luminance value.

  5 and 6 are diagrams for explaining examples of weighting coefficients at the time of total calculation in the pixel interpolation direction detection apparatus of the pixel interpolation apparatus according to another embodiment of the present invention. Interpolated pixels are not used for total calculation. It is a figure which shows the example of the weighting coefficient in each direction in a form. 5 and 6, the same reference numerals are given to the same elements as those in FIGS. 2 and 4, and descriptions thereof are omitted.

  In a preferred form, the total calculation means 24 is configured to obtain pixel information of each pixel in the pixel area for each pixel area of the central pixel area A and the plurality of peripheral pixel areas B and C specified by the pixel area specifying means 23. It is assumed that a means for weighting is provided. This means corresponds to the circular filter described above. In this means, it is preferable that the pixel information of each pixel is multiplied by a weighting coefficient in accordance with the direction of the surrounding pixel regions B and C with respect to the target pixel T. Then, the total calculation unit 24 calculates the sum of the weighted pixel information for each pixel area. Note that the interpolation pixel H may be weighted, or a weighting filter (circular filter) considering the interpolation pixel H is prepared in advance, and the calculation of the interpolation pixel H is not performed. If the sum of the information is calculated, a total value may be calculated in consideration of the provisional interpolation.

  Examples of the interpolation direction to be detected and the weighting coefficient for each direction are 0 to the clockwise around the target pixel T with respect to each interpolation direction in which the direction close to the horizontal direction is defined finely and the direction close to the vertical direction is roughly defined. The 11th direction is illustrated in FIGS. 5 and 6. Here, the 11th direction is the horizontal direction, the 5th direction is the vertical direction, and the 10th direction, 9th direction, 8th direction, 7th direction, and 6th direction are the 0th direction, 1st direction, The second direction, the third direction, and the fourth direction are symmetric with respect to a vertical line passing through the target pixel T. Further, the 2nd direction and the 8th direction are not taken as interpolation directions to be detected because the difference between the 1st and 3rd directions and the 7th and 9th directions are small, and the illustration is omitted. , 8 may be incorporated as an interpolation direction for detecting the direction. Further, the direction of interpolation to be detected may be a direction rotated by a predetermined angle. For example, the direction of about 15 degrees clockwise around the target pixel T is set to the 0th to 11th directions. Although mentioned above, you may make it not specify the direction which does not contribute much to interpolation direction determination among them as mentioned above.

  Here, the directions such as the first to eleventh directions are preferably made to correspond to the positions of the actual pixels of the interpolation source to be used in the later-described interpolation value creation executed after the interpolation direction is determined. That is, the directions 1 to 11 described here preferably correspond to the direction of the real pixel of the interpolation source that finally creates the interpolation value. When there are a plurality of pairs of real pixels of the interpolation source, It is preferable to correspond to the direction based on the intermediate position. The real pixel of this interpolation source will be described later with reference to FIG. 8, but in the examples of FIGS. 5 and 6, as the interpolation direction for determining the direction corresponding to the direction from the target pixel T to the real pixel of the interpolation source of FIG. Adopted.

5 and 6, the areas B ₀ , B ₁ , B ₉ , B _{10 in} the _0th , _1st , _9th , _10th directions as the peripheral pixel area B and ₀ , ₁ , ₉ , ₉ as the peripheral pixel area C are shown. The region C ₀ , C ₁ , C ₉ , C ₁₀ in the _tenth direction is composed of 3 pixels in the horizontal direction and 5 pixels in the vertical direction, including the actual pixel E and the interpolation pixel N (the total number of pixels is 3 actual pixels E in the horizontal direction). X shows an example of three real pixels E) in the vertical direction. In the other direction area, the actual pixel E and the interpolated pixel N are combined to be 3 pixels in the horizontal direction × 3 pixels in the vertical direction (the total pixels are 3 actual pixels E in the horizontal direction × 2 actual pixels E in the vertical direction). It is said. In FIG. 5A, as an example of the central pixel area A and the peripheral pixel areas B ₀ and C _{0 in} the _0th direction, each original pixel is weighted so that the center actual pixel becomes a larger weighting coefficient for each area. An example in which coefficients are assigned is shown. Similarly, FIG. 5B is the first direction, FIG. 5C is the third direction, FIG. 5D is the fourth direction, FIG. 5E is the fifth direction, and FIG. 6 (A) corresponds to the 10th direction, FIG. 6 (B) corresponds to the 9th direction, FIG. 6 (C) corresponds to the 7th direction, and FIG. 6 (D) corresponds to the 6th direction. The example of the weighting coefficient to perform is shown.

[Interpolation direction judgment processing]
The interpolation direction determination means 25 detects the direction with the strongest correlation based on the total for each pixel area calculated by the total calculation means 24 and the positional relationship of each pixel area where the total is made, and the detected direction is determined. It is a means to determine as an interpolation direction. In other words, the interpolation direction determination unit 25 determines, based on the total calculated by the total calculation unit 24, the direction with the strongest correlation among the directions in which the central pixel area and the peripheral pixel areas are summed. Judge as. As described above, the interpolation direction determination unit 25 determines an interpolation direction having a higher correlation than the circular filter result.

  First, in the embodiment including the pixel feature determination unit 11, the interpolation direction determination unit 25 specifies a pixel region for a target pixel having a predetermined feature based on the determination result of the pixel feature determination unit 11. It is determined that there is no interpolation direction without calculating the total. When it is determined that there is no interpolation direction, an interpolation value calculation unit 27 (to be described later) may calculate an interpolation value from a real pixel that is determined in advance, and the interpolation unit 29 may perform interpolation. In this way, the interpolation direction is not determined, and the interpolation direction is determined by the method described here only for the target pixel that has a different pattern. It is possible to improve the accuracy of interpolation by extracting and determining image features in advance.

  In particular, the pixel feature determination means 11 is a means for determining from the characteristics of the surrounding real pixels whether the pixel of interest corresponds to a complicated picture, vertical line picture, flat picture, or corner picture feature. Thus, the interpolation direction determination unit 25 applies a pixel of interest that is a partial pixel of any one of a complex pattern, a vertical line pattern, a flat pattern, and a corner pattern based on the determination result of the pixel feature determination unit 11. Therefore, it is determined that there is no interpolation direction without specifying the pixel region and calculating the total. When it is determined that there is no interpolation direction, an interpolation value calculation unit 27 (to be described later) calculates an interpolation value from pixel information of actual pixels in the field by a predetermined unit predetermined for each picture (for example, interpolation) An interpolation value is calculated from the original real pixel), and the interpolation means 29 may perform the interpolation. The interpolation direction is determined by the method described here only for the target pixel that has a different pattern. Here, with respect to the pixel of interest which is a picture other than that, it is preferable to calculate an interpolation value from the pixel information of the actual pixel in the field by means other than the predetermined means described above. It is preferable to interpolate with interpolation values other than the upper and lower pixel average values, the upper pixel value, and the lower pixel value. It is possible to improve the accuracy of interpolation by extracting and determining image features in advance. Here, the predetermined interpolation source determined in advance for each picture is, as the simplest method of determination, the actual pixels in the vertical direction for all these pictures, and finally interpolating with the upper and lower pixel average values. You may do it. In addition, as actual pixels that are preferable predetermined interpolation sources, real pixels in the upward direction different from the vertical direction, real pixels in the direction of all directions, etc. are prepared, and it is determined that the picture is complicated For the actual pixel in the upper direction, the same pixel value (brightness) as the upper line is set, and when it is determined to be a flat picture, the average value of the surrounding pixels is set as the actual pixel in all directions. When the corner pattern is determined, the upper and lower pixel average values may be used as the actual pixels in the vertical direction.

  Next, the processing in the interpolation direction determination unit 25 will be described in detail with reference to FIG. In FIG. 7, the pattern is hatched, and the same reference numerals are given to the same elements as those in FIGS. 2 and 4 and the description thereof is omitted.

  FIG. 7 is a diagram for explaining interpolation direction determination processing in a pixel interpolation direction detection device in a pixel interpolation device according to another embodiment of the present invention, and a black line (color line) facing diagonally right upward on a white background. It is a figure which shows what applied the circular filter set when there exists a pattern of.

The interpolation direction determining means 25 in this embodiment is a means for calculating the absolute value of the difference between the total for the central pixel area A calculated by the total calculation means 24 and the total for each of the surrounding pixel areas B and C. Have. That is, the absolute value of the difference between the circular filter result of the region A including the target pixel T and the circular filter results of the plurality of regions B and C arranged in a circle is obtained. Here, the peripheral pixel areas B and C indicate all areas specified by the pixel area specifying means 23, and in FIG. 7, areas B ₀ , B ₁ , B ₂ , B ₃ , B ₄ (each 0th) Direction, 3rd direction, 5th direction, 7th direction, 10th direction) and areas C ₀ , C ₁ , C ₂ , C ₃ , C ₄ (0th direction, 3rd direction, 5th direction respectively) , 7th direction, and 10th direction). Then, the calculated total difference absolute value will be described by the name of the area. | A-B ₀ |, | A-B ₁ |, | A-B ₂ |, | A-B ₃ |, | A−B ₄ |, | A−C ₀ |, | A−C ₁ |, | A−C ₂ |, | A−C ₃ |, and | A−C ₄ |.

The interpolation direction determination means 25 in this embodiment further includes means for adding the absolute values of differences relating to peripheral pixel areas located symmetrically with respect to the target pixel T. In the example of FIG. 7, D _n = | A−B _n | + | A−C _n | is obtained for n = 0, 1, 2, 3, and 4, respectively. Then, the interpolation direction determination means 25 detects a direction (selector or the like) that selects the minimum value among the added values D _n and a direction having the selected minimum value as the direction having the strongest correlation, and the detected direction is detected. And a means for determining as an interpolation direction. In this configuration, the relationship between the three circular filters D _n = | A−B _n | + | A−C _n |, that is, the minimum value direction is set as the diagonal correlation direction by the circular filter set of D _n. To detect.

As shown in FIG. 7, when a set of three circular pixel regions (B ₃ , A, C ₃ ) is on the diagonal line, three circular filter results (the luminance of the circular filter coefficient is multiplied by the luminance). The difference between the three circular filters (B ₁ , A, C ₁ or B ₀ , A, C ₀ ) orthogonal to the diagonal line is large. In this case, D ₃ = | A−B ₃ | + | A−C ₃ | becomes a small value, and D ₀ = | A−B ₀ | + | A−C ₀ | and D ₁ = | A−B ₁ | + | A−C ₁ | is a large value. Thus, _if the direction of the small difference D _n = | A−B _n | + | A−C _n | between the three circular filters positioned symmetrically with respect to the interpolation pixel T is a direction having a strong correlation, it is so-called. Yeah.

[Interpolation direction correction processing]
The interpolation direction for each pixel of interest determined by any of the interpolation direction determination means 25 as described above may be determined as the interpolation direction as it is, but in order to determine the interpolation direction more accurately, the determined interpolation direction Is preferably corrected. This correction is performed by the interpolation direction correction means 26.

  The interpolation direction correction unit 26 is a unit that corrects the interpolation direction of each target pixel determined by the interpolation direction determination unit 25. In this unit, when correcting the interpolation direction of the target pixel (referred to as the target pixel Ta), Correction is performed based on the information on the interpolation direction of the target pixel Ta and the information on the interpolation direction of one or more other target pixels located in the vicinity of the target pixel Ta. Here, the other one or more target pixels located in the vicinity of the target pixel Ta means, for example, two target pixels adjacent to the target pixel Ta in the horizontal direction. A more preferable example of the interpolation direction correcting means 26 will be described later in the embodiment. For example, the direction is numbered as information on the interpolation direction (for example, the first direction, the second direction,. It is preferable to obtain the corrected interpolation direction by averaging the values of the numbers.

<< Back-end processing (interpolation processing / interpolation check processing) >>
[Interpolation processing]
Next, interpolation processing will be mainly described as subsequent processing. The pixel interpolating apparatus described here corresponds to the intra-field interpolating apparatus 3 in FIG. 1, but at least one of the pixel feature determining apparatuses (pixel feature determining means 11) according to each embodiment described above with reference to FIGS. 1 to 7. Preferably, the pixel interpolation direction detection device (pixel interpolation direction detection means 12) described above is also provided. Since this pixel interpolation device (intra-field interpolation device 3) generates an interpolation signal, it is also called an interpolation signal generation device, and includes any pixel interpolation means 13 described below.

  As described above, the pixel interpolation unit 13 includes at least an interpolation value generation unit (also referred to as an interpolation value calculation unit) 18 and an interpolation unit 29. The interpolation value calculation unit 27 is a unit that calculates an interpolation value that matches each feature pixel from the actual pixel in the field based on the feature determination result of each pixel of interest determined by the pixel feature determination unit 11. . The interpolation unit 29 is a unit that interpolates each pixel of interest with the interpolation value calculated by the interpolation value calculation unit 27.

  In particular, the interpolation value calculation unit 27 focuses attention on a pixel of interest that has been determined by the pixel feature determination unit 11 to be a partial pixel of any one of a complex picture, a vertical line picture, a flat picture, and a corner picture. An upper and lower pixel average value of pixel information of a pixel is calculated as an interpolation value, and a pixel other than the upper and lower pixel average values of the pixel information of the target pixel is determined for the target pixel determined to be a picture other than that by the pixel feature determination unit 11. It is preferable that the interpolation value is calculated from the actual pixels in the field.

  Further, when the intra-field interpolation device 3 includes the pixel interpolation direction detection unit 12, the interpolation value calculation unit 27 determines whether each pixel of interest is determined by the pixel interpolation direction detection unit 12 or corrected after the determination. Based on the detected and determined interpolation direction (regardless of the circular filter set), an interpolation value is calculated from the actual pixels in the interpolation direction. There are various methods for determining actual pixels in the interpolation direction, examples of which will be described later. In addition, the creation of the interpolation value may be obtained by uniformly calculating the average value of the pixel information of the interpolation source, but particularly when creating the interpolation value using pixel information of three or more actual pixels, You may devise suitably, such as performing weighting. The interpolation unit 29 interpolates each pixel of interest with the interpolation value calculated by the interpolation value calculation unit 27. The interpolation means 29 actually generates a post-interpolation signal (interpolation signal) based on the interpolation value of each pixel of interest.

[Determination of actual pixels in the interpolation direction]
FIG. 8 is a schematic diagram for explaining the interpolation processing in the intra-field interpolation apparatus of FIG. 1, and FIGS. 8 (A) to (F), (G) to (K), and (L) each have an interpolation direction. It is a figure for demonstrating an example of the real pixel used for interpolation when it determines with it being the direction of 0th-5th, 10th-6th, and 11th. In FIG. 8, G is an actual pixel that is an interpolation source (actual pixel used for interpolation), and other elements equivalent to those in FIG. 2 are denoted by the same reference numerals and description thereof is omitted.

  The actual pixel in the interpolation direction is determined by predetermining the position of the actual pixel with respect to the target pixel T corresponding to each interpolation direction as the simplest method. For example, as shown in FIG. 8A, when it is determined that the interpolation direction is the 0th direction, the pixel T of interest is 3 left on the left and 3 up on the right, and 3 on the right and 1 on the bottom. One set of real pixels G with the one is determined as the interpolation source pixel. Similarly, as shown in FIG. 8B, when it is determined that the interpolation direction is the first direction, the pixel T of interest is 2 to the left and 2 to the left and 2 to the right and 2 to the bottom. One set of real pixels G with the pixel is determined as an interpolation source pixel. Further, as shown in FIG. 8C, when it is determined that the interpolation direction is the second direction, the pixel T of interest is separated by 2 to the left and 1 to the left, and to the right by 2 and to the bottom by 1 A set of real pixels G and a set of real pixels G, one left and one up, and one right and one down are determined as interpolation source pixels. . Similarly, when it is determined that the interpolation direction is the third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, or eleventh direction, FIGS. 8D, 8E, 8F, and 8K are used. , (J), (I), (H), (G), and (L), the actual pixel G at the position shown is determined as an interpolation source pixel. If it is determined that the direction is the 11th direction, there is basically no actual pixel in the 11th direction of the target pixel T. Therefore, for example, as illustrated in FIG. In addition, each of the three real pixels G in the lower line Leda may be determined as an interpolation source pixel.

  Further, the interpolation value calculation means 27 may calculate the interpolation value from the actual pixels in the pixel area specified in the interpolation direction based on the interpolation direction detected by the pixel interpolation direction detection means 12. Good.

[Interpolation check processing]
FIG. 9 is a schematic diagram for explaining an interpolation value check process in the intra-field interpolation apparatus of FIG. In FIG. 9, the same elements as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.

  It is preferable that the pixel interpolation unit 13 further includes an interpolation value determination unit 28 that determines whether or not the interpolation value calculated by the interpolation value calculation unit 27 is appropriate, thereby improving the interpolation accuracy. The interpolation value determination means 28 is also called an interpolation value check means because it checks the interpolation value calculated by the interpolation value calculation means 27.

  The interpolation value determination means 28 includes means for calculating a difference value between the interpolation value calculated by the interpolation value calculation means 27 and the upper and lower pixel average values of the target pixel T. In the example of FIG. 9, the interpolation value calculated by the interpolation value calculation unit 27 is an interpolation value (for example, an average value) from a pair of real pixels E at the tip of an oblique arrow drawn from the target pixel T. Point to. Further, the interpolation value determination means 28 has means for determining that the interpolation value is not an appropriate value (correct value) when the calculated difference value is larger than a predetermined threshold value. Then, the interpolation unit 29 interpolates the upper and lower pixel average values of the target pixel, not the interpolation value calculated by the interpolation value calculation unit 27, for the target pixel determined to be invalid by the interpolation value determination unit 28. Interpolate as a value (replace). Here, instead of the upper and lower pixel average values, the value of the actual pixel above or below the target pixel may be interpolated as an interpolation value.

  Further, the interpolation value determination means 28, when the interpolation value calculated by the interpolation value calculation means 27 is not between the pixel information of the real pixel above the target pixel T and the pixel information of the real pixel below, Means for determining that the interpolation value is not a valid value may be included. Further, the interpolation value determination means 28 calculates the difference value between the interpolation source actual pixels (for example, the actual pixel G in FIG. 8) with respect to the interpolation value calculated by the interpolation value calculation means 27, and the calculation is performed there. Means for determining that the interpolation value is not a valid value when the difference value is greater than a predetermined threshold value. By combining these three forms, a more accurate check can be performed.

<Video signal processing>
Next, the video signal processing apparatus exemplified in FIG. 1 as a whole will be briefly described. This video signal processing apparatus determines and distinguishes a pixel determined to be non-moving (hereinafter referred to as “still pixel”) and a pixel determined to be moving (hereinafter referred to as “moving pixel”). The apparatus includes a prime determination apparatus 1, an intra-frame interpolation apparatus 2 that mainly performs interpolation between a pair of fields, and an intra-frame interpolation apparatus 3 as described above. This video signal processing device includes any one of the pixel interpolation devices according to the above-described embodiments as its constituent elements.

  This video signal processing apparatus applies general IP conversion with motion detection to the characteristic part of the present invention, and an interlaced scanning video signal is generated between a still pixel and a moving pixel in the still pixel / moving pixel determination apparatus 1. The interlaced video signal is inter-frame interpolated by the intra-frame interpolating device 2 and the inter-scanned video signal is converted into the moving pixel signal by the intra-field interpolating device. The interlace scanning video signal is converted into a progressive scanning video signal by interpolating in step 3. In this way, inter-field interpolation (= intra-frame interpolation) is performed on non-moving parts such as subtitles and backgrounds, and intra-field interpolation which is a characteristic part of the present invention is performed on moving parts. In addition, the motion detection basically needs to be able to determine a still pixel / moving pixel for each pixel, such as determining whether it is moving or not based on the magnitude of the difference value from the previous field. Note that the still pixel / moving pixel determination device 1 is configured to detect a portion corresponding to a still pixel even in a moving image signal to the intra-frame interpolation device 2 and a moving pixel portion to the intra-field interpolation device 3 based on motion detection. In this case, the output video signal may be generated by being combined when output to an output device or the like.

<Example of intra-field interpolation device>
FIG. 10 is a block diagram showing a circuit configuration example of the intra-field interpolation apparatus in FIG. 1, in which 31 is a block area synthesis circuit, 32 is a direction determining circuit, 33 and 34 are delay units (D), and 35 is a direction. LPF (directional low-pass filter), 36 is an interpolation value generation circuit, 37 is an interpolation value selection circuit (SEL), 38 is a miss determination circuit, 39 is a horizontal pixel subtractor, 40 is a horizontal complexity determination circuit, and 41 is vertical. A directional pixel subtractor, 42 is a complex determination circuit, 43 is a vertical line determination circuit, 44 is a flat determination circuit, 45 is an angle determination circuit, 46 and 47 are or gates, and 48 is an interpolation value selection circuit (SEL).

  The intra-field interpolation apparatus illustrated in FIG. 10 includes a block area synthesis circuit 31 as an example of a pixel area specifying unit 23 and a total calculation unit 24, a direction determination circuit 32 as an example of an interpolation direction determination unit 25, and an interpolation direction correction unit 26. As an example, delay units 33 and 34 and direction LPF 35, interpolation value calculation means (interpolation value generation means) 27, interpolation value creation circuit 36, interpolation value selection circuit 37, and interpolation value determination means 28 as an example The determination circuit 38, the horizontal pixel subtractor 39 as an example of the horizontal direction difference means 14, the horizontal complexity determination circuit 40 as an example of the horizontal direction complexity determination means 18, and the vertical direction as an example of the vertical direction difference means 15 The pixel subtractor 41, the complexity determination circuit 42 as an example of the complexity determination means 19, the vertical line determination circuit 43 as an example of the vertical line determination means 21, The signal is detected when the flat determination circuit 44 is an example of the dot determination unit 22, the corner determination circuit 45 is an example of the corner determination unit 20, or any of a complex pattern, a vertical line pattern, a flat pattern, and a corner pattern. Or gate 46 to output, or gate 47 to output a signal when any of these patterns is a determination error, and interpolation value selection that finally selects an interpolation value as an example of a part of interpolation means 29 A circuit 48 is provided.

  FIG. 11 is a flowchart for explaining an example of intra-field interpolation processing in the intra-field interpolation apparatus of FIG. 12 to 21 are schematic diagrams for explaining an example of intra-field interpolation processing in the intra-field interpolation apparatus of FIG. FIG. 12 shows an example of horizontal line complexity judgment processing, FIG. 13 shows an example of flat picture judgment processing, FIG. 14 shows an example of vertical line picture judgment processing, FIG. 15 shows an example of corner picture judgment processing, and FIG. FIG. 17 shows an example of an interpolation direction determination process using a circular filter set, FIG. 18 shows an example of a weighting coefficient of a circular filter, a circular filter result and a circular filter set result, and FIG. 19 shows a direction LPF. For example, FIG. 20 is a diagram for explaining an example of an image determined to be a mistake in the interpolation value check processing example, and FIG. 21 is a diagram for explaining an example of a video signal obtained by the intra-field interpolation. In FIGS. 12 to 17, 19, and 20, the numerical value shown at the pixel position represents the luminance value of the actual pixel as 0 (black) to 100 (white). Of course, the luminance value corresponds to the processing unit such as a value of 0 to 255 if it is 8 bits.

  This intra-field interpolation processing is also called a pixel unit IP conversion algorithm because it performs IP conversion on a pixel basis. Hereinafter, an example of the intra-field interpolation processing according to the present invention will be described in accordance with the flow of FIG. 11 and with reference to FIGS. 10 and 12 to 21.

  The horizontal pixel subtractor 39 receives the actual pixels in the field of 4 lines × 9 pixels centered on the pixel of interest, and calculates the horizontal difference value of the actual pixels (step S1). Here, among the actual pixels in the field of 4 lines × 9 pixels, the horizontal difference value (horizontal difference value) between the actual pixels may be calculated using the actual pixels in the field of 2 lines × 9 pixels centered on the target pixel. Further, in step S1, the vertical pixel subtracter 41 receives the actual pixels in the field of 4 lines × 9 pixels centered on the pixel of interest, and calculates the vertical difference value of the actual pixels. Here, among the actual pixels in the field of 4 lines × 9 pixels, the vertical difference value (vertical difference value) between the actual pixels may be calculated using the actual pixels in the field of 4 lines × 7 pixels centered on the target pixel.

  Next, from the horizontal direction difference value between the actual pixels of the horizontal direction pixel subtractor 39, the horizontal direction complexity determination circuit 40 determines the horizontal direction complexity of the upper line and the lower line (here, 9 actual pixels) of the target pixel. Is determined (step S2). FIGS. 12A to 12F show examples of the complexity of horizontal lines, and FIG. 12G schematically shows the difference in luminance value between adjacent real pixels as schematically shown by the unevenness of the graph. It is determined that the smaller the interval is, the less uneven (not complicated). These determinations can be obtained by the encoding described with reference to FIG. 3B. An example of the tendency will be described with reference to FIG.

  As shown in FIG. 12A, when there is almost no difference in luminance value between adjacent real pixels, it is determined as “uncomplicated 1”. As shown in FIG. 12B, when there is not much difference in luminance value between adjacent real pixels, but is gradually changing in the same direction in the horizontal direction, it is determined as “uncomplicated 2”. As shown in FIG. 12C, there is a difference in luminance value between adjacent real pixels, but since the line is viewed with a limited number of real pixels, there is a certain amount of one peak or valley in the line. In some cases, it is determined as “complexity V”. As shown in FIG. 12D, there is a difference in luminance value between adjacent real pixels, and there is one peak or valley in a line with a limited number of actual pixels, and the other changes in the same direction in the horizontal direction. If there is a portion that is present, it is determined as “complexity S”. As shown in FIG. 12E, when there is a difference in luminance value between adjacent real pixels and there are two peaks or valleys in the line, it is determined as “complexity M”. As shown in FIG. 12F, when there is a difference in luminance value between adjacent real pixels and the line is uneven, it is determined as “uneven”.

Next, it is determined whether the periphery of the target pixel (target interpolation point) is complicated, whether it is a flat pattern, a vertical line pattern, or a corner pattern (step S3). In this determination, the pixel of interest is a complex pattern, the flat picture, the vertical line pattern, whether Ru corner picture der, and determining whether the Ru der otherwise et al.

  In the flat determination circuit 44, it is determined from the vertical direction difference value of the actual pixel of the vertical direction pixel subtractor 41 whether the periphery of the target interpolation point is a flat image. Here, for the target pixel indicated by x in FIG. 13, vertical difference values for five horizontal pixels including the target pixel are used, and as a result, if each difference value is equal to or less than a predetermined threshold value, it is determined that the pattern is a flat pattern. . In the example of FIG. 13, any of the five difference values is 0, and it is determined that the pattern is a flat pattern.

  In the vertical line determination circuit 43, the interpolation point of interest is determined based on the horizontal complexity of the upper line and the lower line determined in the horizontal complexity determination circuit 40 and the vertical difference value of the actual pixel of the vertical pixel subtractor 41. Is a partial image of a vertical line. Here, as shown in FIG. 14A, a vertical difference of three pixels is taken in the horizontal direction around the target pixel, and as shown in FIG. 14B, three vertical lines on the vertical line of the target pixel are taken. As shown in FIG. 14C, the difference between the vertical line of the target pixel from 2 lines to 1 line with respect to the vertical line of 3 pixels in the horizontal direction around the target pixel and 1 of the target pixel is obtained. The vertical difference from the bottom of the line to the bottom of the second line is taken, and whether or not it is a vertical line pattern is determined based on the result and the horizontal complexity of the upper and lower lines. When all of these vertical difference values are within a predetermined threshold and the horizontal complexity of the upper line or the lower line is V or more, it is determined as a vertical line pattern. In the example of FIG. 14, since this condition is met, it is determined as a vertical line pattern.

  In the corner determination circuit 45, whether or not the interpolation point of interest is a partial image of a corner from the horizontal direction difference value of the actual pixel of the horizontal direction pixel subtractor 39 and the vertical direction difference value of the actual pixel of the vertical direction pixel subtractor 41. judge. Here, as the horizontal direction difference value, the difference value between the actual pixels separated from the target pixel by 3 pixels to the left and right with respect to the upper line and the lower line of the target pixel, and the actual pixel spaced from the target pixel by 2 pixels to the left and right The difference value between them is used. Also, as the vertical direction difference value, with respect to the vertical line of 7 pixels in the horizontal direction around the target pixel, the vertical difference from the upper line of the target pixel to the upper line and the lower line of the target pixel from the lower line to the second line The vertical difference to is taken. When these horizontal direction difference values are larger than a predetermined threshold value and all of the 14 vertical difference values (upper and lower difference values) of the upper and lower stages are smaller than the predetermined threshold value, it is determined that the pattern is a corner picture. In the example of FIG. 15, the pixel of interest corresponds to a corner picture.

  The complexity determination circuit 42 determines whether or not the periphery of the interpolation point of interest is complicated based on the horizontal complexity of the upper line and the lower line determined by the horizontal complexity determination circuit 40 (step S3). Here, if any line is more than complexity M, it is determined as a complex picture. FIG. 16A shows an example of complex picture determination processing, and FIG. 16B shows a graph for schematically showing it. From this graph, it can be seen that in the example of FIG. 16, the upper and lower lines have a complexity of M or more, and are determined to be complex pictures.

  Then, the results of the complexity determination circuit 42, the vertical line determination circuit 43, the flat determination circuit 44, and the corner determination circuit 45 are input to the or gate 46 to obtain the pre-process determination result.

  On the other hand, the actual pixels in the field of 4 lines × 9 pixels are also input to the block region synthesis circuit 31 and the interpolation value creation circuit 36. The block area synthesis circuit 31 applies a circular filter arranged at equal distances around the interpolation value to calculate a block area (circular pixel area set) synthesis value in each direction (step S5). The circular filters used here are number 0, number 1, number 3, number 4, number 5, number 9, number 7, number 7, number 11, and number 11 shown in FIGS. A circular filter set rotated in the clockwise direction. In FIG. 17, * is an actual pixel line, and the second and eighth directions are omitted because there is little difference between the first and third directions and the seventh and ninth directions. FIG. 18A illustrates the weighting coefficients used for each circular filter in FIG. 17. In this example, the coefficient array is weighted at the center of the circular filter, but other trends (for example, all are the same) Coefficient array of coefficients) may be used.

  In step S5, the block area (circular pixel area set) combined value of each direction of the block area combining circuit 31 is received by the direction determining circuit 32, and | A−B | + | A−C | In step S6, the minimum value among them is detected, and the direction No. is detected. Is output.

  FIG. 18B has a pattern as shown in FIG. 17, and each circular filter A, B, C when the weighting coefficient of FIG. 18A is used in the circular filter set shown in FIG. And the sum of absolute difference values (D = | A−B | + | A−C |) of the difference between the filter and the circular filter (center filter) A at the center of each of the peripheral filters B and C. . For the center filter A, A = 1 × 100 + 2 × 50 + 1 × 0 + 2 × 50 + 4 × 50 + 2 × 50 + 1 × 0 + 2 × 50 + 1 × 100 = 800. The value of the sum D of absolute differences is, for example, the direction No. 4 (FIG. 17D), B = 1 × 100 + 2 × 100 + 1 × 100 + 2 × 100 + 4 × 100 + 2 × 75 + 1 × 100 + 2 × 100 + 1 × 50 = 1500, similarly C = 1500, and from A = 800, D = 1400. The smallest value among the calculated values D is 0. No. 7 and the seventh direction is determined as the interpolation direction. Therefore, in FIG. 17, it is determined that there is a black line that falls to 45 degrees diagonally to the left, and it can be seen from the color coding in FIG. 17 that this is the preferred interpolation direction.

  Next, in step S7, the direction determined by the direction determination circuit 32 is set to DIR_l, delayed by the delay unit 33, and the output value of the delay unit 33 is set to DIR_c. Further, DIR_c is delayed by the delay unit 34 to be DIR_r. In step S7, when the preparation is completed, the direction values (DIR_l, DIR_c, DIR_r) for three horizontal pixels are input to the direction LPF 35. In the direction LPF 35, the LPF is applied in the direction.

  Processing in the direction LPF 35 will be described. FIG. 19A shows the interpolation direction before correction by the direction LPF 35 (interpolation direction of the pixel of interest corresponding to the pixels surrounded by the five cells in the figure), and an interpolation value when the interpolation direction is used for interpolation ( (Brightness value) is illustrated. It can be seen that the luminance value of the pixel in the middle square among the five squares in FIG. 19A is lower, and the value is actually lower than that of the left and right pixels, indicating that this interpolation is not correct. Actually, the interpolation direction of these five squares before correction is 3, 3, 10, 0, 0, which is a direction far apart by the middle square, and the luminance value corrected in this direction is the middle three squares. Thus, 59, 44, and 55 are obtained. This depends on the interval (angular pitch) in the direction of the peripheral pixel region, and in the case of the slanted line as shown in the figure, an error occurs in the interpolation direction determination by the interpolation direction determination means (direction determination circuit 32). It is a result.

  In order to correct this erroneous interpolation direction determination, the direction LPF 35 is all passed through the interpolation direction of each pixel of interest. Note that the calculation here is such that the interpolation direction without error is not corrected. FIG. 19B shows a result obtained by calculating the obtained interpolation direction for each horizontal pixel by three pixels and averaging (horizontal weighting may be performed as appropriate) in the horizontal direction. When the weight is doubled at the center, the pixel of interest in the second cell from the right in the five squares is (3 × 1 + 3 × 2 + 10 × 1) / 4 = 5, and the pixel of interest in the third square from the right of the five cells is (3 × 1 + 10) × 2 + 0 × 1) / 4 = 6 The pixel of interest in the fourth cell from the right in the fifth cell is (10 × 1 + 0 × 2 + 0 × 1) / 4 = 3, which is the fifth direction, the sixth direction, and the third direction, respectively. As a result, the interpolation direction is corrected correctly. Here, in order to obtain an accurate correction value, the calculation results 0 to 5 are rounded off to the nearest decimal place, and the calculation results 5 to 10 are rounded down to 0.5 or less and larger than 0.5. When rounding up. When interpolation is performed based on these directions, the luminance values of the second, third, and fourth squares from the right of the five squares are 55, 55, and 53, respectively, and the directionality with the uncomfortable feeling can be corrected to the correct result.

  Next, in step S8, the interpolation value creation circuit 36 calculates interpolation values in all directions from the actual pixels in the two lines above and below the interpolation value. For example, what is necessary is just to obtain | require with the average value of the real pixel G of each direction of FIG. Also, the upper and lower pixel average values are included in the calculated interpolation value (step S4). In step S8, when this preparation is completed, the interpolation value selection circuit 37 selects one interpolation value calculated by the interpolation value generation circuit 36 from the result of the direction LPF 35.

  Next, the output result of the interpolation value selection circuit 37 is input to the error determination circuit 38 and compared with the average value of the upper and lower pixels or the upper and lower actual pixels, or based on the difference value between the actual pixels for which the interpolation values are created, the interpolation value selection circuit 37 Correct / incorrect determination of the determined interpolation value is performed (step S9). Then, the correct / incorrect determination result by the error determination circuit 38 and the pre-process determination result of the or gate 46 are passed through the or gate 47 and whether the calculated value up to the interpolation value selection circuit 37 should be an interpolation value, or the upper and lower pixel average values are determined. A determination signal as to whether or not to make an interpolation value is obtained. The output of the interpolation value selection circuit 37 and the upper and lower pixel average values calculated by the interpolation value creation circuit 36 are input to the interpolation value selection circuit 48, and the optimum interpolation value is selected from the output signal of the or gate 47.

  20A and 20B show an example of a typical pixel value arrangement in which a mistake occurs in the output result of the interpolation value selection circuit 37. FIG. In the examples of FIGS. 20A and 20B, it is difficult to determine the directionality, and it is difficult to determine by vertical line, flat, corner, and complex pattern determination. In the example of FIG. 20A, the interpolation direction is determined as the third direction, and the interpolation value based on that direction is obtained by the actual pixel G of FIG. 8D, and is (100 + 0) / 2 = 50. If this interpolation value is adopted as it is, it will become conspicuous as a miss interpolation like a black dot. In fact, in the example of FIG. 20A, it is ideal to employ a value between 100 and 90 as the interpolation value. Therefore, if the interpolation value (50) calculated by the error determination circuit 38 is too different from the upper and lower pixel average value (95), the upper and lower pixel average value 95 is set as the interpolation value. In the example of FIG. 20B, an example in which an upper and lower pixel average value is input as an interpolation value in advance is shown, but it is ideal that the target pixel has the upper and lower pixel average value 100. However, in this case as well, since the determination is made in the other direction, the upper and lower pixel average values are set as the interpolation values.

  The output value from the interpolation value selection circuit 48 becomes the final interpolation value. FIG. 21A shows an example of an image represented by the video signal obtained by the intra-field interpolation. Of these, the diagonal line portion is appropriately interpolated as shown in an enlarged view in FIG. (See the comparison with FIG. 22B). At the same time, it can be seen that the arc-shaped edge portion is appropriately interpolated as shown in the enlarged view of FIG. 21C (see comparison with FIG. 22C).

It is a figure which shows the example of 1 structure of the pixel feature determination apparatus which concerns on one Embodiment of this invention, the pixel interpolation apparatus provided with the pixel feature determination apparatus, and a video signal processing apparatus. It is a figure for demonstrating the pixel vicinity of the attention pixel in 1 field. It is a schematic diagram for demonstrating the pixel feature determination means in the intrafield interpolation apparatus of FIG. It is a figure for demonstrating the example of the pixel area specified with the pixel interpolation direction detection apparatus in the pixel interpolation apparatus concerning one Embodiment of this invention. FIG. 6 is a diagram for explaining an example of a weighting coefficient at the time of total calculation in a pixel interpolation direction detection device of a pixel interpolation device according to another embodiment of the present invention, and weighting in each direction in a mode in which interpolation pixels are not used for total calculation. It is a figure which shows the example of a coefficient. FIG. 6 is a diagram for explaining an example of a weighting coefficient at the time of total calculation in a pixel interpolation direction detection device of a pixel interpolation device according to another embodiment of the present invention, and weighting in each direction in a mode in which interpolation pixels are not used for total calculation. It is a figure which shows the example of a coefficient. It is a figure for demonstrating the interpolation direction determination process in the pixel interpolation direction detection apparatus in the pixel interpolation apparatus concerning other embodiment of this invention. It is a schematic diagram for demonstrating the interpolation process in the intrafield interpolation apparatus of FIG. It is a schematic diagram for demonstrating the interpolation value check process in the intrafield interpolation apparatus of FIG. It is a block diagram which shows the circuit structural example of the intra-field interpolation apparatus in FIG. It is a flowchart for demonstrating the example of an intra-field interpolation process in the intra-field interpolation apparatus of FIG. It is a figure for demonstrating the complexity determination process example of the horizontal direction line in the intrafield interpolation apparatus of FIG. It is a figure for demonstrating the example of a flat pattern determination process in the inter-field interpolation apparatus of FIG. It is a figure for demonstrating the example of a vertical line pattern determination process in the intra-field interpolation apparatus of FIG. It is a figure for demonstrating the example of a corner picture determination process in the intra-field interpolation apparatus of FIG. It is a figure for demonstrating the example of a complicated picture determination process in the inter-field interpolation apparatus of FIG. It is a figure for demonstrating the example of an interpolation direction determination process by the circular filter set in the intra-field interpolation apparatus of FIG. It is a figure for demonstrating the example of the weighting coefficient of a circular filter in the intra-field interpolation apparatus of FIG. 10, a circular filter result, and a circular filter set result. It is a figure for demonstrating the example of direction LPF in the intra-field interpolation apparatus of FIG. It is a figure for demonstrating the example of the image determined to be a mistake in the example of the interpolation value check process in the intra-field interpolation apparatus of FIG. It is a figure for demonstrating the example of the video signal obtained by the intrafield interpolation in the intrafield interpolation apparatus of FIG. It is a figure for demonstrating the example of the video signal obtained by the intrafield interpolation by a prior art. It is a figure which shows the example of the typical pixel value of the video signal of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Still pixel / moving pixel determination apparatus, 2 ... Inter-frame interpolation apparatus, 3 ... In-field interpolation apparatus, 11 ... Pixel feature determination means, 12 ... Pixel interpolation direction detection means, 13 ... Pixel interpolation means, 14 ... Horizontal direction difference Means 15 ... Vertical direction difference means 16 ... Area designation means 17 ... Separate pixel difference means 18 18 Horizontal direction complexity determination means 19 19 Complexity determination means 20 20 Corner determination means 21 21 Vertical line determination means 22 ... Flat determining means, 23 ... Pixel area specifying means, 24 ... Total calculating means, 25 ... Interpolating direction determining means, 26 ... Interpolating direction correcting means, 27 ... Interpolated value calculating means, 28 ... Interpolated value determining means, 29 ... Interpolated Means 31... Block region synthesis circuit 32. Direction determining circuit 33. Delay device 34. Delay device 35. Direction LPF 36 36 Interpolation value creation circuit 37 Interpolation value selection circuit 38 Miss determination circuit DESCRIPTION OF SYMBOLS 9 ... Horizontal direction pixel subtractor, 40 ... Horizontal direction complexity determination circuit, 41 ... Vertical direction pixel subtractor, 42 ... Complexity determination circuit, 43 ... Vertical line determination circuit, 44 ... Flat determination circuit, 45 ... Angle determination circuit, 46 ... or gate, 47 ... or gate, 48 ... interpolation value selection circuit.

Claims (16)

A pixel for determining the feature of the target pixel from the features of the surrounding real pixels for the target pixel to be interpolated in the field when performing IP conversion for converting the interlaced scan video signal into the progressive scan video signal. A feature determination device,
Horizontal direction difference means for calculating a difference value of pixel information between each real pixel adjacent in the horizontal direction in the field;
An area designating unit for designating an actual pixel area within a predetermined range centered on the target pixel for the target pixel which is a pixel to be interpolated;
Of the horizontal difference values of the real pixels calculated by the horizontal direction difference means, the horizontal direction value for each real pixel line is determined based on the horizontal difference value in the real pixel area designated by the area designation means. A horizontal complexity determination means for determining complexity;
Based on the horizontal complexity of the upper and lower lines of the target pixel determined by the horizontal complexity determination means, it is determined whether or not the target pixel is a part of a complex picture. and a complex decision means,
The horizontal direction complexity determination unit is configured to compare a difference value of pixel information between respective real pixels adjacent in the horizontal direction with two threshold values having the same absolute value, and based on a result of the comparison, the difference value Means for encoding a negative value, a zero value, and a positive value, and means for determining, based on the encoded value, whether the adjacent value is the same code or a different code. As a result of the determination, a means for counting the number of the same or different codes for each line and the complexity of the line for each line based on the number of the counted results are determined from among a plurality of predetermined complexity levels. Has a means to select,
In the determination result in the horizontal direction complexity determination unit, the complexity determination unit determines that the target pixel is complicated when either the upper line or the lower line of the target pixel has a complexity greater than or equal to a predetermined complexity. image containing feature judging apparatus characterized by determining that the part of the pixels of the picture. The area specifying means further includes means for specifying a predetermined range of actual pixel areas suitable for determination by the complexity determining means, and the complexity determining means performs determination in the specified actual pixel area. The pixel feature determination apparatus according to claim 1, wherein the pixel feature determination device is a feature. Vertical direction difference means for calculating a difference value of pixel information between each real pixel adjacent in the vertical direction in the field;
A difference value of pixel information between real pixels equidistant from the target pixel on one line of the target pixel and pixel information between real pixels equidistant from the target pixel under one line of the target pixel. A difference pixel difference means for calculating a difference value;
Of the difference values in the vertical direction of the real pixels calculated by the vertical direction difference means, the difference value in the vertical direction in the real pixel area specified by the area specifying means and the difference calculated by the separated pixel difference means based on the value, further comprising a determining angle determining means for determining whether or not the pixel of interest is part of a pixel of the picture corners,
The corner determination means is a difference between a real pixel line two above the target pixel and a real pixel line one above the difference value designated by the area designation means calculated by the vertical direction difference means. The difference value between the value and the actual pixel line one lower than the target pixel and the actual pixel line two lower than the target pixel are all smaller than a predetermined threshold, and among the difference values calculated by the separated pixel difference means When the difference value corresponding to either the upper line or the lower line of the target pixel is larger than a predetermined threshold, it is determined that the target pixel is a partial pixel of a corner picture. Item 3. The pixel feature determination device according to Item 1 or 2 . The area specifying means further includes means for specifying a predetermined range of actual pixel areas suitable for determination by the corner determination means, and the corner determination means performs determination in the specified actual pixel area. The pixel feature determination apparatus according to claim 3, wherein the pixel feature determination device is a feature. Vertical direction difference means for calculating a difference value of pixel information between each real pixel adjacent in the vertical direction in the field;
Of the horizontal complexity of the upper and lower lines of the target pixel determined by the horizontal complexity determination unit and the vertical difference value of the actual pixel calculated by the vertical direction difference unit, the region designation on the basis of the difference value in the vertical direction in the actual pixel area specified by means further includes a vertical line determination unit that determines whether the pixel of interest is part of a pixel of the vertical line pattern,
The vertical line determination unit is configured so that, in the determination result in the horizontal direction complexity determination unit, either the upper line or the lower line of the pixel of interest has a complexity greater than a predetermined complexity, and the vertical direction Among the difference values calculated by the difference means and specified by the area specifying means, the difference values of all the real pixels on the vertical line located within several pixels on both the left and right sides of the target pixel are one above the target pixel. The difference values between the line and the next lower line are all smaller than a predetermined threshold value, or the difference values of the vertical lines passing through the target pixel are all smaller than the predetermined threshold value, or the actual values above two of the target pixel are When the difference value between the pixel line and the actual pixel line immediately above and the difference value between the actual pixel line one lower than the target pixel and the second actual pixel line are all smaller than a predetermined threshold, the attention Pixel is vertical Pixel feature judging device according to claim 1 or 2, characterized in that determined as a part of the pixels of the picture. The area specifying means further includes means for specifying an actual pixel area within a predetermined range suitable for determination by the vertical line determining means, and the vertical line determining means performs determination in the designated actual pixel area. The pixel feature determination apparatus according to claim 5 . Vertical direction difference means for calculating a difference value of pixel information between each real pixel adjacent in the vertical direction in the field;
Based on the vertical difference value in the actual pixel area designated by the area designating means among the vertical difference values of the real pixels calculated by the vertical direction difference means, the pattern in which the target pixel is flat anda flat determination unit that determines whether a part of the pixels of,
The flat judging means is the difference value of all the actual pixels on the vertical line located within several pixels on both the left and right sides of the target pixel among the difference values calculated by the vertical direction difference means and specified by the area specifying means. When the difference values between the line immediately above and the line below the pixel of interest are all smaller than a predetermined threshold, it is determined that the pixel of interest is a partial pixel of a flat picture. The pixel feature determination apparatus according to claim 1 or 2 . The area specifying means further includes means for specifying an actual pixel area within a predetermined range suitable for determination by the flat determining means, and the flat determining means performs determination in the specified actual pixel area. The pixel feature determination apparatus according to claim 7, wherein the pixel feature determination device is a feature. Vertical direction difference means for calculating a difference value of pixel information between each real pixel adjacent in the vertical direction in the field;
A difference value of pixel information between real pixels equidistant from the target pixel on one line of the target pixel and pixel information between real pixels equidistant from the target pixel under one line of the target pixel. A difference pixel difference means for calculating a difference value;
Of the difference values in the vertical direction of the real pixels calculated by the vertical direction difference means, the difference value in the vertical direction in the real pixel area specified by the area specifying means and the difference calculated by the separated pixel difference means Corner determining means for determining whether or not the pixel of interest is a partial pixel of a corner picture based on a value;
Of the horizontal direction complexity of the upper line and the lower line of the target pixel determined by the horizontal direction complexity determination unit and the vertical direction difference value of the actual pixel calculated by the vertical direction difference unit, the region designation Vertical line determination means for determining whether or not the pixel of interest is a partial pixel of the vertical line pattern based on the vertical difference value in the actual pixel region designated by the means;
Based on the vertical difference value in the actual pixel area designated by the area designating means among the vertical difference values of the real pixels calculated by the vertical direction difference means, the pattern in which the target pixel is flat anda flat determination unit that determines whether a part of the pixels of,
The corner determination means is a difference between a real pixel line two above the target pixel and a real pixel line one above the difference value designated by the area designating means calculated by the vertical direction difference means. The difference value between the value and the actual pixel line one lower than the target pixel and the actual pixel line two lower than the target pixel are all smaller than a predetermined threshold, and among the difference values calculated by the separated pixel difference means When the difference value corresponding to either the upper line or the lower line of the target pixel is larger than a predetermined threshold, the target pixel is determined to be a part of a corner picture,
The vertical line determination unit is configured so that, in the determination result in the horizontal direction complexity determination unit, either the upper line or the lower line of the pixel of interest has a complexity greater than a predetermined complexity, and the vertical direction Among the difference values calculated by the difference means and specified by the area specifying means, the difference values of all the real pixels on the vertical line located within several pixels on both the left and right sides of the target pixel are one above the target pixel. The difference values between the line and the next lower line are all smaller than a predetermined threshold value, or the difference values of the vertical lines passing through the target pixel are all smaller than the predetermined threshold value, or the actual values above two of the target pixel are When the difference value between the pixel line and the actual pixel line immediately above and the difference value between the actual pixel line one lower than the target pixel and the second actual pixel line are all smaller than a predetermined threshold, the attention Pixel It is determined to be a part of the pixels of the line pattern,
The flat determining means is the difference value of all the real pixels on the vertical line located within several pixels on both the left and right sides of the target pixel among the difference values calculated by the vertical direction difference means and specified by the area specifying means. When the difference values between the line one above and the line below the pixel of interest are all smaller than a predetermined threshold, it is determined that the pixel of interest is a part of a flat picture,
It is determined whether the pixel of interest corresponds to a pixel having a characteristic pattern among a complex pattern, a corner pattern, a vertical line pattern, a flat pattern, or other patterns. 3. The pixel feature determination device according to 1 or 2 . The area designating means specifies “the actual pixel area in the predetermined range for the difference value in the horizontal direction with respect to the target pixel, and the appropriate pixel area in the predetermined range for the difference value in the vertical direction”. The pixel feature determination apparatus according to claim 9, wherein the actual pixel region is specified so that a large number of difference values are specified. The difference value calculation in the separated pixel difference means and the difference value calculation in the horizontal direction difference means and the vertical direction difference means are executed for one field before the designation by the area designation means. The pixel feature determination apparatus according to claim 9 . The difference value calculation in the separated pixel difference means and the difference value calculation in the horizontal direction difference means and the vertical direction difference means are at least required by designation by the area designation means before designation by the area designation means. The pixel feature determination apparatus according to claim 9, wherein the pixel feature determination is performed for each actual pixel region. The calculation of the difference value in the separated pixel difference unit, or the calculation of the difference value in the calculation and the horizontal direction difference unit and the vertical direction difference unit is performed by the region designating unit for each target pixel in the predetermined range. The pixel feature determination device according to claim 9, wherein the pixel feature determination device is executed after designating a region. A pixel interpolation device comprising the pixel feature determination device according to claim 9 , wherein in the pixel feature determination device, a part of pixels of any of a complex pattern, a corner pattern, a vertical line pattern, and a flat pattern to the pixel of interest it is determined that the interpolation value calculating means that issues calculate the interpolated values from the pixel information of the real pixels in the predetermined positional relationship with each picture, calculated by the interpolation value calculating means Interpolating means for interpolating each pixel of interest with an interpolation value. The pixel interpolation device according to claim 14, further comprising a pixel interpolation direction detection device that detects a direction of interpolation for a pixel to be interpolated in a field,
The pixel interpolation direction detection device is a region centered on the target pixel with respect to the target pixel that is a pixel to be interpolated, and includes a central pixel region including at least a plurality of real pixels existing in the current field; A pixel area specifying means for specifying a plurality of peripheral pixel areas including at least a plurality of real pixels, which are areas not surrounding the target pixel and arranged in a circle at substantially equal distances from the target pixel; Total calculation means for calculating for each pixel area the total pixel information of the pixels included in the central pixel area and the plurality of peripheral pixel areas specified by the area specifying means, and each pixel area calculated by the total calculation means total each, and total based on the positional relationship of each pixel region was made to detect the strongest direction of the correlation comprises determining the interpolation direction determination hand stage a direction the detected as the interpolation direction,
The interpolation value calculating means detects the pixel interpolation direction for each pixel of interest determined to be a pixel of a pattern other than a complex pattern, a corner pattern, a vertical line pattern, and a flat pattern in the pixel feature determination device. based on the detected interpolation direction in the apparatus, image-containing interpolator you and calculates the interpolated value from the real pixels on the interpolation direction. The pixel interpolating device according to claim 14 or 15 , comprising inter-frame interpolation of a pixel signal determined not to move in an interlaced scanning video signal, and moving in an interlaced scanning video signal. A video signal processing apparatus, wherein the determined pixel signal is interpolated by the pixel interpolator to convert an interlaced scanning video signal into a progressive scanning video signal.

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