JP2005192005A - Interpolation signal processing circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an interpolation signal processing circuit which changes the number of pixels of an image or the number of scanning lines while maintaining high frequency components of the image. <P>SOLUTION: The interpolation signal processing circuit is characterized by providing a slanting correlation judgment part 8 which detects combination of real pixels with the highest correlation among combinations of two actual pixels located in the vertical direction or the slanting direction of the image centering around a correlation judgment phase on an intermediate line located in between first and second mutually adjacent scanning lines, an interpolation control part 10 which determines an interpolation direction on the basis of the combination of the real pixels detected by the slanting correlation judgment part 8, reference pixel generation parts 11, 12 which output pixel values of reference pixels using the two actual pixels located in the interpolation direction to an interpolation phase on the first and second scanning lines as the reference pixels and an interpolation pixel generation part 13 which calculates a pixel value of an interpolation pixel by performing weighting relevant to distance between the reference pixel and the interpolation phase to the pixel values of the reference pixel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an interpolation signal processing circuit that changes the number of pixels or the number of scanning lines of an image.

  Various formats such as HDTV (High Definition Television) having a pixel count of (1920 × 1080) are adopted for television video signals. In recent years, plasma display devices and liquid crystal display devices have been used as display devices for displaying reception screens such as television broadcasts, and the pixel arrangement on the display screen is determined for these plasma display devices and liquid crystal display devices. ing. In such a display device, in order to project the video signal on the display screen, the video signal needs to be subjected to interpolation signal processing with the number of pixels or the number of scanning lines suitable for the display device.

  Therefore, when the above interpolated signal processing is required in an I / P conversion system that converts an input interlaced scanning video signal into a progressive scanning video signal and outputs it, first, the interlaced scanning video signal is converted into a progressive scanning video signal. Scanning video signals are sequentially scanned and converted, and the progressive scanning video signals are subjected to scaling processing. This conventional interpolation signal processing method will be described with reference to FIG. In FIG. 13, a case where the interpolation pixel P is interpolated between the scanning lines L1 and L2 in which the actual pixels (pixels constituting the image (original image) before the interpolation signal processing) are arranged adjacent to each other in the horizontal direction will be described. To do. In FIG. 13, the color assigned to each pixel indicates the pixel value of each pixel. Note that the pixel value is a data value representing the brightness and color density of the pixel. In FIG. 13, a pixel having a lower lightness has a black color and a pixel having a higher lightness has a white color.

  First, the progressive scan conversion performed prior to the scaling process will be described with reference to FIGS. 13 (a) and 13 (b). Here, as a sequential scanning conversion technique, a technique using correlation in an oblique direction (for example, see Patent Document 1) will be described as an example. This sequential scan conversion is performed by interpolating pixels at the same horizontal position as the actual pixels in the intermediate line M located between the two adjacent scan lines L1 and L2.

  When generating the pixel m0, a direction having a high correlation between the two pixels is determined among the vertical direction and the diagonal direction of the image centered on the pixel m0. For example, as shown in FIG. 13A, a combination of pixels (A1, B5) (A2, B4) (A3, B3) (A4, B2) (A5) facing the pixel m0 as the center in the scanning lines L1, L2. , B1), the absolute value of the pixel value difference is compared, and the direction in which the combination of the pixels with the smallest difference is opposed is determined as the direction with high correlation. Here, as a result of the correlation determination, it is determined that the combination of the pixels (A2, B4) has the highest correlation. Then, the average of the pixel values of the two pixels (A2, B4) determined to have the highest correlation is calculated, and this average value is set as the pixel value of the pixel m0.

  Also in the case of generating the pixel m1, as in the case of the pixel m0, a direction in which the correlation between the two pixels is high is determined among the vertical direction and the diagonal direction of the image centered on the pixel m1. For example, as shown in FIG. 13B, combinations (A2, B6) (A3, B5) (A4, B4) (A5, B3) (A2 and B6) of the scanning lines L1 and L2 facing each other with the interpolation pixel m1 as the center. The absolute values of the pixel value differences are compared with A6, B2), and the direction in which the combination of the pixels with the smallest difference is opposed is determined as the direction with high correlation. Here, as a result of the correlation determination, it is determined that the combination of the pixels (A3, B5) has the highest correlation. Then, the average of the pixel values of the two pixels (A3, B5) determined to have the highest correlation is calculated, and this average value is set as the pixel value of the pixel m1. By performing the processing described above for other pixels on the intermediate line M, the scan conversion is performed sequentially.

  Next, scaling processing performed after the sequential scan conversion will be described with reference to FIG. First, on the interpolation line N passing through the interpolation point P, the pixel is interpolated at the same horizontal position as the pixels m0 and m1.

  When the pixel p0 is generated, a value corresponding to the distance between the pixel A3 and the pixel p0 and the distance between the pixel m0 and the pixel p0 is used as a coefficient, and the coefficient is weighted to the pixel value of the pixel A3 and the pixel m0. Thus, the weighted average of the pixel values of the pixel A3 and the pixel m0 is calculated. That is, the weighted average of the pixel values of the pixel A3 and the pixel m0 is calculated by the following formula (1), and this weighted average value is set as the pixel value of the pixel p0. Here, kv1 is the distance between the pixel A3 and the pixel p0, and kv2 is the distance between the pixel m0 and the pixel p0.

p0 = (kv2 × A3 + kv1 × m0) / (kv1 + kv2) (1)
Also in the case of generating the pixel p1, similarly to the pixel p0, a value corresponding to the distance between the pixel A4 and the pixel p1 and the distance between the pixel m1 and the pixel p1 is used as a coefficient, and the coefficient is set between the pixel A4 and the pixel m1. By weighting the pixel values, a weighted average of the pixel values of the pixel A4 and the pixel m1 is calculated. That is, the weighted average of the pixel values of the pixel A4 and the pixel m1 is calculated by the following equation (2), and this weighted average value is set as the pixel value of the pixel p1. Here, kv3 is the distance between the pixel A4 and the pixel p1, and kv4 is the distance between the pixel m1 and the pixel p1.

p1 = (kv4 × A4 + kv3 × m1) / (kv3 + kv4) (2)
Subsequently, the interpolation point P is interpolated according to the horizontal phase from the pixels p0 and p1. A value corresponding to the distance between the pixel p0 and the pixel P and the distance between the pixel p1 and the pixel P is used as a coefficient, and the coefficient is weighted to the pixel value between the pixel p0 and the pixel p1, thereby the pixel p0 and the pixel p1. The weighted average of the pixel values of is calculated. That is, the weighted average of the pixel values of the pixel p0 and the pixel p1 is calculated by the following equation (3), and this weighted average value is set as the pixel value of the pixel P. Here, kh1 is the distance between the pixel p0 and the pixel P, and kh2 is the distance between the pixel p1 and the pixel P.

P = (kh2 × p0 + kh1 × p1) / (kh1 + kh2) (3)
The scaling process is performed by performing the above-described process on other interpolation points on the interpolation line N. Then, the number of pixels or the number of scanning lines of the image is changed by interpolating the interpolation pixels P generated by the scaling processing between the actual pixels in the original image.
JP-A-2-213289 (page 3, FIG. 2)

  In the above-described conventional interpolation signal processing method, vertical and diagonal correlations are determined for pixels located on the intermediate line M, and scanning conversion is sequentially performed. However, in the subsequent scaling process, the interpolated pixel P is generated by sequentially interpolating the pixels in the vertical direction and the horizontal direction regardless of the correlation between the interpolated pixel P and other pixels. For this reason, an image is clearly divided into a high brightness area and a low brightness area with the connection between the pixel A3 and the pixel B5 (connection between the pixel A2 and the pixel B4) shown in FIG. When the interpolation signal processing is performed by the conventional interpolation signal processing method, as shown in FIG. 13C, pixels P having intermediate brightness (displayed in gray) are interpolated at the boundary of the region, and the boundary of the region is It becomes an ambiguous image.

  As described above, in the conventional interpolation signal processing method, the interpolation pixel P is generated regardless of the correlation between the interpolation pixel P and other pixels, so that the high-frequency component of the image is lost and the image quality of the image is deteriorated. Was regarded as a problem.

  The present invention has been made from the above background, and an object thereof is to provide an interpolation signal processing circuit that changes the number of pixels or the number of scanning lines of an image while maintaining a high-frequency component of the image.

  In order to achieve the above object, an interpolation signal processing circuit according to the present invention includes a plurality of scanning lines arranged in parallel at regular intervals in the vertical direction, and a plurality of actual lines on each of the plurality of scanning lines. In the image in which the pixels are arranged, the combination of the real pixels having the highest correlation among the combinations of the real pixels positioned in the vertical direction or the diagonal direction of the image with at least one correlation determination phase adjacent to the interpolation phase as a center. An oblique correlation determination unit that detects each correlation determination phase, an interpolation direction determination unit that determines an interpolation direction based on a combination of the actual pixels detected by the oblique correlation determination unit, and the interpolation direction with respect to the interpolation phase A reference pixel output means for outputting a pixel value of the reference pixel using at least two pixels located in the reference pixel, and a pixel of the reference pixel from the reference pixel output means Interpolated pixel generating means for calculating the pixel value of the interpolated pixel in the interpolated phase by performing weighting related to the distance between the reference pixel and the interpolated phase on the pixel value of the reference pixel. It is characterized by that.

  Further, the interpolation signal processing circuit according to the present invention is an image in which a plurality of scanning lines are arranged in parallel at regular intervals in the vertical direction, and a plurality of actual pixels are arranged on each of the plurality of scanning lines. And at least two real pixels positioned in the vertical direction or diagonal direction of the image with the correlation determination phase on the intermediate line positioned between the first and second scanning lines facing each other at regular intervals as the center. Among the combinations, an oblique correlation determination unit that detects a combination of real pixels having the highest correlation, an interpolation direction determination unit that determines an interpolation direction based on the combination of the actual pixels detected by the oblique correlation determination unit, and the first An actual pixel positioned in the interpolation direction with respect to the interpolation phase on one scanning line is set as a first reference pixel, and the interpolation pixel is set in the interpolation direction with respect to the interpolation phase on the second scanning line. A reference pixel output means for outputting the pixel values of the first and second reference pixels, and a pixel of the first and second reference pixels from the reference pixel output means. A value is input, and weighting related to the distance between the first and second reference pixels and the interpolation phase is performed on the pixel value of the first and second reference pixels, so that the interpolation pixel of the interpolation phase in the interpolation phase is obtained. Interpolation pixel generation means for calculating pixel values is provided.

  Furthermore, the interpolation signal processing circuit according to the present invention is an image in which a plurality of scanning lines are arranged in parallel at regular intervals in the vertical direction, and a plurality of actual pixels are arranged on each of the plurality of scanning lines. And at least two points positioned in the vertical direction or the diagonal direction of the image with the first correlation determination phase on the intermediate line positioned in the middle of the first and second scanning lines facing each other at a constant interval. A first diagonal correlation determination unit that detects a combination of real pixels having the highest correlation among the combinations of real pixels, and an interpolation direction that determines an interpolation direction based on the combination of the real pixels detected by the diagonal correlation determination unit And calculating a pixel value of a first reference pixel located in the interpolation direction with respect to an interpolation phase on the first scanning line using a pixel value of an actual pixel, and determining the pixel value on the second scanning line. The pixel value of the second reference pixel located in the interpolation direction with respect to the interpolation phase is calculated using the pixel value of the actual pixel, and the pixel value of the first and second reference pixels is output. Pixel values of the first and second reference pixels are input from the pixel output means and the reference pixel output means, and weighting related to the distance between the first and second reference pixels and the interpolation phase is set to the first value. Interpolation pixel generation means for calculating the pixel value of the interpolation pixel in the interpolation phase by performing the processing on the pixel values of the first and second reference pixels is provided.

  According to the present invention, it is possible to provide an interpolation signal processing circuit that changes the number of pixels or the number of scanning lines of an image while maintaining a high-frequency component of the image.

(First embodiment)
A first embodiment of an interpolation signal processing circuit and an interpolation signal processing method according to the present invention will be described below with reference to FIGS.

  First, the configuration of the interpolation signal processing circuit according to this embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram illustrating a configuration of an interpolation signal processing circuit according to the present embodiment.

  As shown in FIG. 1, the interpolation signal processing circuit according to this embodiment includes an input signal generation unit 101, an interpolation signal generation unit 102, and a display signal generation unit 103.

  The input signal generation unit 101 receives an input video signal A, a horizontal synchronization signal H, and a vertical synchronization signal V from input terminals 104, 105, and 106, and interpolates an image data string according to the horizontal synchronization signal H and the vertical synchronization signal V. The signal is output to the signal generator 102. Here, the input video signal A is an array of pixel values of real pixels (pixels constituting the original image) having adjacent pixel positions in the original image (image before the interpolation signal processing). Note that the pixel value is a data value representing the brightness of the pixel and the shade of the color, and the image data string is an array of pixel values of actual pixels whose pixel positions are adjacent in the horizontal direction in the original image.

  The interpolation signal generation unit 102 receives the image data string from the input signal generation unit 101. Using this image data string, the interpolation signal generation unit 102 arranges a plurality of scanning lines in parallel at regular intervals in the vertical direction, and arranges a plurality of actual pixels on each of the plurality of scanning lines. Among the combinations of real pixels located in the vertical direction or the diagonal direction of the image with at least one correlation determination phase adjacent to the interpolation phase as the center, for each correlation determination phase To detect. The interpolation signal generation unit 102 determines an interpolation direction based on the detected combination of real pixels, and generates at least two pixels located in the interpolation direction with respect to the interpolation phase as reference pixels (interpolation pixels). Therefore, the pixel value of the reference pixel is output as a pixel whose pixel value is referred to).

  The display signal generation unit 103 receives the pixel value of the reference pixel from the interpolation signal generation unit 102, and performs weighting related to the distance between the reference pixel and the interpolation phase on the pixel value of the reference pixel, so that the pixel of the interpolation pixel Calculate the value. Here, the interpolation phase is a pixel position of an interpolation pixel (a pixel generated by interpolation), and the interpolation direction is a direction in which a reference pixel is located with respect to the interpolation phase.

  Further, the display signal generation unit 103 outputs the display video signal D from the output terminal 107 by outputting the pixel value of the interpolation pixel or the actual pixel in accordance with the horizontal synchronization signal H and the vertical synchronization signal V. The display video signal D is obtained by arranging pixel values of pixels whose pixel positions are adjacent in an image after interpolation signal processing (an image in which interpolation pixels are interpolated in the original image).

  As described above, the interpolation signal processing circuit according to this embodiment illustrated in FIG. 1 detects a direction having a high correlation with respect to the correlation determination phase as an interpolation direction, and refers to a pixel located in the interpolation direction with respect to the interpolation phase. Interpolated pixels are generated as pixels. For this reason, the interpolation signal processing circuit according to the present embodiment can change the number of pixels or the number of scanning lines of the image while maintaining the high-frequency component of the image.

  Further, the interpolation signal processing circuit according to the present embodiment generates an interpolation pixel by performing weighting related to the distance between the reference pixel and the interpolation phase on the pixel value of the reference pixel. For this reason, the interpolation signal processing circuit according to the present embodiment can convert an image into an arbitrary number of pixels or scanning lines.

  Next, a specific configuration of the interpolation signal processing circuit according to the present embodiment will be described with reference to FIG. FIG. 2 is a circuit diagram illustrating a circuit configuration of the interpolation signal processing circuit according to the present embodiment.

  First, a specific configuration of the input signal generation unit 101 will be described. As shown in FIG. 2, the input signal generation unit 101 includes a field memory control unit 1, a field memory 2, a line memory control unit 3, and line memories 4 and 5.

  The field memory control unit 1 receives a horizontal synchronization signal H from an input terminal 105 and a vertical synchronization signal V from an input terminal 106. The field memory control unit 1 outputs a control signal to the field memory 2 based on the horizontal synchronization signal H and the vertical synchronization signal V. The field memory 2 holds the input video signal A input from the input terminal 104 for each field or frame by a predetermined method based on the control signal from the field memory control unit 1.

  The line memory control unit 3 receives a horizontal synchronization signal H from the input terminal 105 and a vertical synchronization signal V from the input terminal 106. The line memory control unit 3 outputs a control signal to the line memories 4 and 5 based on the horizontal synchronizing signal H and the vertical synchronizing signal V. The line memory 4 is an image on a predetermined scanning line L1 (first scanning line) in the original image in the input video signal A held in the field memory 2 based on a control signal from the line memory control unit 3. Holds the data column. Further, the line memory 5 is based on the control signal from the line memory control unit 3 and the scanning line L2 (second scanning line) adjacent to the scanning line L1 in the input video signal A held in the field memory 2. Holds the upper image data string. That is, the line memories 4 and 5 store image data strings on the two scanning lines L1 and L2 that face each other at the predetermined interval in an image in which a plurality of scanning lines are arranged in parallel in the vertical direction at predetermined intervals. Hold.

  Next, a specific configuration of the interpolation signal generation unit 102 will be described. As shown in FIG. 2, the interpolation signal generation unit 102 includes registers 6 a to e and 7 a to e, an oblique correlation determination unit 8, an interpolation phase generation unit 9, an interpolation control unit 10, and reference pixel output units 11 and 12. ing.

  The registers 6a to 6e are D-type flip-flops with enable, and holding and updating of output data of each flip-flop are controlled by controlling these enables. The registers 6a to 6e form a delay circuit corresponding to the number of taps (the number of actual pixels whose pixel values are referred to in the diagonal correlation determination), and sequentially delay the image data string input from the line memory 4. To do. Thus, the registers 6a to 6e hold pixel values of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L1, and the pixel values of these real pixels are stored in the diagonal correlation determination unit 8 and the reference pixel. It is output to the output unit 11.

  The registers 7a to 7e are D-type flip-flops with enable in the same manner as the registers 6a to 6e, and holding and updating the output data of each flip-flop are controlled by controlling these enables. The registers 7a to 7e form a delay circuit corresponding to the number of taps, and sequentially delay the image data string input from the line memory 5. Thereby, the registers 7a to e hold the pixel values of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L2, and the pixel values of these real pixels are output to the diagonal correlation determination unit 8 and the reference pixel output. Is output to the unit 12.

  Further, the actual pixels held in the registers 6a to 7e and 7a to 7e are at the same horizontal position at the same tap position. For example, real pixels whose pixel values are held in the registers 6a and 7a are in the same horizontal position in the original image, and real pixels whose pixel values are held in the registers 6b and 7b are in the same horizontal position in the original image. Is in position.

  The diagonal correlation determination unit 8 receives the pixel values of the actual pixels on the scanning line from the registers 6a to 7e and 7a to e, and is the same as the actual pixel on the intermediate line M (a line located between the scanning lines L1 and L2). A combination of real pixels having the highest correlation is detected from a combination of two real pixels located in the vertical direction or diagonal direction of the image with the correlation determination phase at the horizontal position as the center, and this detection result is used as a correlation determination result. Output to the interpolation controller 10.

  The interpolation phase generation unit 9 receives the horizontal synchronization signal H and the vertical synchronization signal V, and based on the horizontal synchronization signal H and the vertical synchronization signal V, the horizontal phase information (the pixel position in the horizontal direction of the interpolation pixel) and the vertical phase information. (Pixel position in the vertical direction of the interpolation pixel) is generated and output to the interpolation control unit 10.

  The interpolation control unit 10 receives the correlation determination result, the horizontal phase information, and the vertical phase information from the oblique correlation determination unit 8 and determines the interpolation direction based on the combination of actual pixels detected by the oblique correlation determination unit 8. A horizontal phase coefficient signal and a vertical phase coefficient signal are generated. The horizontal phase coefficient signal is output to the reference pixel output units 11 and 12.

  The reference pixel output units 11 and 12 are actual pixels located in the interpolation direction detected by the diagonal correlation determination unit 8 with respect to the interpolation phase on the scanning line L1 based on the horizontal phase coefficient signal input from the interpolation control unit 10. Is the first reference pixel, and the actual pixel located in the interpolation direction with respect to the interpolation phase on the scanning line L2 is the second reference pixel, and the pixel values of the first and second reference pixels are output.

  Next, a specific configuration of the display signal generation unit 103 will be described. As shown in FIG. 2, the display signal generation unit 103 includes an interpolation pixel generation unit 13, a line memory control unit 14, and a line memory 15.

  The interpolation pixel generation unit 13 receives the vertical phase coefficient signal from the interpolation control unit 10 and the pixel values of the first and second reference pixels from the reference pixel output units 11 and 12. Then, the interpolation pixel generation unit 13 performs the weighting related to the distance between the first and second reference pixels and the interpolation phase on the pixel values of the first and second reference pixels to thereby obtain the pixel value of the interpolation pixel. Is calculated.

  The line memory control unit 14 receives the horizontal synchronization signal H, the vertical synchronization signal V, the horizontal phase information, and the vertical phase information, and outputs a control signal to the line memory 15 based on these signals. Based on the line memory control unit 14, the line memory 15 holds pixel values of interpolation pixels or actual pixels, and outputs these pixel values in the order required for the display video signal D.

  Next, the operation of the interpolation signal processing circuit according to this embodiment shown in FIG. 2 will be described with reference to FIG. FIG. 3 is an explanatory diagram illustrating an interpolation signal processing method performed by the interpolation signal processing circuit according to the present embodiment. In FIG. 3, a case where the original image is expanded four times in the vertical direction by interpolating interpolation pixels in the interpolation lines N1, N2, and N3 between the scanning lines L1 and L2 will be described. Further, in FIG. 3, the color given to each pixel indicates the pixel value of each pixel. A pixel having a lower brightness has a black color, and a pixel having a higher brightness has a white color.

  First, by sequentially delaying the image data string input from the line memory 4, the registers 6a to 6e have pixel values A1, A2, and A3 of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L1. , A4, A5. Further, by sequentially delaying the image data string input from the line memory 5, the registers 7a to 7e allow the pixel values B1, B2, and B3 of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L2. , B4, B5.

  Then, the diagonal correlation determination unit 8 includes a combination of two actual pixels located in the vertical direction or the diagonal direction of the image with the correlation determination phase M3 at the same horizontal position as the actual pixels A3 and B3 in the intermediate line M as the center. The combination of real pixels having the highest correlation is detected. For example, as shown in FIG. 3A, combinations (A1, B5) (A2, B4) (A3, B3) (A4, B2) (A1, B5) of the scanning pixels L1, L2 facing each other with the pixel M3 as the center. The absolute value of the difference between the pixel values is compared with A5, B1), and the direction in which the combination of pixels with the smallest difference is opposed is determined as the direction with high correlation. Here, it is assumed that, as a result of this correlation determination, the combination of pixels (A1, B5) is determined to have the highest correlation.

  The determination result of the diagonal correlation determination unit 8 is input to the interpolation control unit 10. Then, the interpolation control unit 10 faces the two real pixels (A1, B5) that are determined to have the highest correlation based on the correlation determination result of the diagonal correlation determination unit 8, the horizontal phase information, and the vertical phase information. Is determined as an interpolation direction, and a horizontal phase coefficient signal and a vertical phase coefficient signal indicating the interpolation direction are output.

  Based on the horizontal phase coefficient signal input from the interpolation control unit 10, the reference pixel output units 11 and 12 interpolate with respect to the interpolation phase P on the scanning lines L 1 and L 2 as shown in FIG. The pixel values of two real pixels (A2, B6) located in the same direction as the direction in which the two real pixels (A1, B5) face each other are output to the interpolation pixel generation unit 13.

  The interpolation pixel generation unit 13 receives pixel values of two real pixels (A2, B6) from the horizontal interpolation phase generation units 11 and 12, and performs weighting related to the distance between the two real pixels and the interpolation phase P. The pixel value of the interpolation pixel is calculated by performing the calculation on the pixel values of two pixels (A2, B6). That is, when the distance between the actual pixel and the interpolation phase P is long, the coefficient value is decreased. Conversely, when the distance between the actual pixel and the interpolation phase P is short, the coefficient value is increased and the coefficients are The weighted average of the pixel values of the actual pixels is calculated by weighting the pixel values of the pixels. For example, the weighted average of the pixel values of the real pixel A2 and the real pixel B6 is calculated by the following formula (4), and this weighted average value is used as the pixel value of the interpolation pixel. Here, kv1 is the distance between the actual pixel A2 and the interpolation phase P, and kv2 is the distance between the actual pixel B6 and the interpolation phase P.

P = (kv2 × A2 + kv1 × B6) / (kv1 + kv2) (4)
By performing the above-described processing for other interpolation points on the interpolation lines N1, N2, and N3, an image obtained by expanding the original image four times in the vertical direction as shown in FIG. 3C is obtained. It is done.

  The image subjected to the interpolation signal processing by the interpolation signal processing circuit according to the present embodiment shown in FIG. 3C has a connection between the real pixel A3 and the real pixel B7 (connection between the real pixel A2 and the real pixel B6). The boundary is clearly divided into a high brightness area and a low brightness area, and the high frequency components of the original image are not lost. Thus, according to the interpolation signal processing circuit according to the present embodiment, it is possible to change the number of pixels or the number of scanning lines of the image while maintaining the high-frequency component of the image.

  Subsequently, an interpolation signal processing method according to the present embodiment will be described with reference to FIG. FIG. 4 is a flowchart illustrating the procedure of the interpolation signal processing method according to the present embodiment. The interpolation signal processing method according to this embodiment can be implemented by the interpolation signal processing circuit according to this embodiment described above. Therefore, here, a case where the interpolation signal processing circuit according to this embodiment is implemented will be described.

  First, the pixel values of actual pixels are read from the field memory 2 and the line memories 4 and 5, and the image data strings on the scanning lines L1 and L2 held in the registers 6a to 7e and 7a to e are updated (S11). Next, diagonal correlation determination is performed by the diagonal correlation determination unit 8 using the image data sequences held in the registers 6a to 7e and 7a to 7e (S12). In this step S12, among the combinations of two real pixels located in the vertical direction or diagonal direction of the image with the correlation determination phase at the same horizontal position as the real pixels in the intermediate line M as the center, A combination of pixels is detected.

  Next, an interpolation direction is determined based on a combination of real pixels having the highest correlation detected in step S12 (S13). In step S13, the direction in which the two real pixels detected in step S12 face each other is determined as the interpolation direction. Then, the pixel value of the interpolation pixel is obtained by performing weighting related to the distance between the reference pixel and the interpolation phase on the pixel value of the reference pixel, using the two real pixels positioned in the interpolation direction with respect to the interpolation phase as reference pixels. Is generated (S14).

  If the process for one screen is not completed after the interpolation pixel generation process in step S14 is completed, the process returns to step 11 and the processes from steps S11 to S14 described above until the process for one screen is completed. Is repeated (S15).

  The interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment described above determine a direction with high correlation around the correlation determination phase at the same horizontal position as the actual pixel on the intermediate line M, and set the interpolation phase to the interpolation phase. On the other hand, an interpolation pixel is generated using two actual pixels located in a direction with high correlation as reference pixels. For this reason, the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment can change the number of pixels or the number of scanning lines of the image while maintaining the high-frequency component of the image.

  Further, the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment use two actual pixels as reference pixels, and perform weighting related to the distance between the reference pixels and the interpolation phase on the pixel values of the reference pixels. Thus, the pixel value of the interpolation pixel is calculated. For this reason, the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment can convert an image into an arbitrary number of pixels or scanning lines.

  In the description of the interpolation signal processing circuit according to the present embodiment, specific circuit configurations of the input signal generation unit 101, the interpolation signal generation unit 102, and the display signal generation unit 103 are shown. It is not restricted to what was shown in the present Example.

  In addition, all the components (the input signal generation unit 101, the interpolation signal generation unit 102, and the display signal generation unit 103) in the interpolation signal processing circuit according to the present embodiment may be provided on the same semiconductor chip. Some or all of these may be provided independently of other components.

  Furthermore, in the interpolation signal processing method according to the present embodiment, the case where the interpolation signal processing circuit according to the present embodiment is implemented has been described as an example. The present invention is not limited to the interpolation signal processing circuit according to the present embodiment.

  Furthermore, in the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment, the highest correlation among the combinations of two real pixels located in the vertical direction or the diagonal direction of the image with the correlation determination phase as the center. Although the diagonal correlation determination is performed by detecting the combination of pixels, the number of actual pixels used for the diagonal correlation determination is not limited to two. The same effect as that of the present embodiment can also be obtained by using three or more real pixels for the diagonal correlation determination.

(Second embodiment)
Hereinafter, a second embodiment of the interpolation signal processing circuit and the interpolation signal processing method according to the present invention will be described with reference to FIGS. The interpolation signal processing circuit according to this embodiment is obtained by changing the circuit configurations of the interpolation signal processing circuit 102 and the display signal generation circuit 103 in the interpolation signal processing circuit according to the first embodiment shown in FIG. .

  First, the configuration of the interpolation signal processing circuit according to the present embodiment will be described with reference to FIG. FIG. 5 is a circuit diagram showing a configuration of the interpolation signal processing circuit according to the present embodiment. Here, portions common to those described in the first embodiment with reference to FIG. 2 are denoted by the same reference numerals as those in FIG. 2, and description thereof is omitted.

  As shown in FIG. 5, the oblique signal generation unit 102 includes registers 6 a to e, 7 a to e, 16, an oblique correlation determination unit 8, an interpolation phase generation unit 9, an interpolation control unit 17, and reference pixel output units 18 and 19. It has.

  As described in the first embodiment, the diagonal correlation determination unit 8 has two real pixels located in the vertical direction or diagonal direction of the image with the correlation determination phase at the same horizontal position as the real pixel in the intermediate line M as the center. Among these combinations, a combination of two real pixels having the highest correlation is detected, and this detection result is output to the interpolation control unit 10 as a correlation determination result.

  The register 16 receives the correlation determination result from the diagonal correlation determination unit 8 and holds the correlation determination result. By this register 16, the correlation determination result output from the diagonal correlation determination unit 8 is delayed by one stage and input to the interpolation control unit 17.

  The interpolation control unit 17 receives the correlation determination result from the diagonal correlation determination unit 8 and the register 16. That is, the correlation control unit 17 receives two correlation determination results successively performed by the diagonal correlation determination unit 8. Then, the interpolation control unit 17 determines an interpolation direction based on a combination of two sets of two real pixels indicated by these two correlation determination results, and based on the horizontal phase information and the vertical phase information, A vertical phase coefficient signal is generated. The horizontal phase coefficient signal is output to the reference pixel output units 18 and 19.

  The reference pixel output units 18 and 19 are first reference pixels located in the interpolation direction determined by the interpolation control unit 17 with respect to the interpolation phase on the scanning line L1 based on the horizontal phase coefficient signal from the interpolation control unit 10. Is calculated using the pixel value of the actual pixel, and the pixel value of the second reference pixel located in the interpolation direction with respect to the interpolation phase on the scanning line L2 is calculated using the pixel value of the actual pixel. The pixel values of the first and second reference pixels are output.

  Next, a specific configuration of the display signal generation unit 103 will be described. As shown in FIG. 5, the display signal generation unit 103 includes an interpolation pixel generation unit 20, a line memory control unit 14, and a line memory 15.

  The interpolation pixel generation unit 20 receives the vertical phase coefficient signal from the interpolation control unit 17 and receives the pixel values of the first and second reference pixels from the reference pixel output units 18 and 19. The pixel value of the interpolation pixel is calculated by performing weighting related to the distance between the reference pixel and the interpolation phase on the pixel values of the first and second reference pixels.

  Next, the operation of the interpolation signal processing circuit according to this embodiment shown in FIG. 5 will be described with reference to FIGS. 6 and 7 are explanatory diagrams illustrating an interpolation signal processing method performed by the interpolation signal processing circuit according to the present embodiment. 6 and 7, the interpolation image is interpolated to the interpolation lines N1, N2, and N3 between the scanning lines L1 and L2, so that the original image is expanded four times in the vertical direction and twice in the horizontal direction. The case where it does is demonstrated. 6 and FIG. 7, the color given to each pixel indicates the pixel value of each pixel. A pixel with lower brightness has a black color, and a pixel with higher brightness has a white color.

  First, by sequentially delaying the image data string input from the line memory 4, the registers 6a to 6e have pixel values A1, A2, and A3 of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L1. , A4, A5. Further, by sequentially delaying the image data string input from the line memory 5, the registers 7a to 7e allow the pixel values B1, B2, and B3 of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L2. , B4, B5.

  The diagonal correlation determination unit 8 is positioned in the vertical direction or the diagonal direction of the image with the correlation determination phase M3 (first correlation determination phase) at the same horizontal position as the actual pixels A3 and B3 in the intermediate line M as the center. Among the real pixel combinations of the points, the real pixel combination having the highest correlation is detected. For example, as shown in FIG. 6A, combinations (A1, B5) (A2, B4) (A3, B3) (A4, B2) (A2 and B4) of the actual pixels facing the pixel M3 as the center in the scanning lines L1 and L2. The absolute value of the difference between the pixel values is compared with A5, B1), and the direction in which the combination of the real pixels with the smallest difference is opposed is determined as the direction with high correlation. Here, it is assumed that, as a result of this correlation determination, it is determined that the combination of real pixels (A1, B5) has the highest correlation. The result of the correlation determination with the correlation determination phase M3 as the center is held in the register 16.

  Next, the registers 6a to 6e delay the image data sequence by one pixel, so that the pixel values A2, A3, A4, A5, A6 of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L1. Hold. Further, the registers 7a to 7e delay the image data sequence by one pixel, thereby obtaining the pixel values B2, B3, B4, B5, and B6 of the five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L2. Hold.

  The diagonal correlation determination unit 8 is positioned in the vertical direction or the diagonal direction of the image with the correlation determination phase M4 (second correlation determination phase) at the same horizontal position as the actual pixels A4 and B4 in the intermediate line M as the center. Among the real pixel combinations of the points, the real pixel combination having the highest correlation is detected. For example, as shown in FIG. 6B, combinations (A2, B6) (A3, B5) (A4, B4) (A5, B3) (A2 and B6) of the scanning pixels L1 and L2 facing each other with the pixel M4 as the center. The absolute value of the difference between the pixel values is compared with A6, B2), and the direction in which the combination of the real pixels with the smallest difference is opposed is determined as the direction with high correlation. Here, it is assumed that, as a result of this correlation determination, the combination of real pixels (A2, B6) is determined to have the highest correlation. The correlation determination result of the diagonal correlation determination unit 8 is input to the interpolation control unit 17.

  Next, the interpolation control unit 17 calculates the interpolation direction with respect to the interpolation phase from the combination (A1, B5) (A2, B6) of the two real pixels indicated by the correlation determination result input from the oblique correlation determination unit 8 and the register 16. To decide. Here, since the direction in which (A1, B5) faces is the same as the direction in which (A2, B6) faces, the direction in which (A1, B5) faces (the direction in which (A2, B6) faces) Determine the interpolation direction. Then, the interpolation control unit 17 generates a horizontal phase coefficient signal and a vertical phase coefficient signal indicating the determination result of the interpolation direction based on the horizontal phase information and the vertical phase information.

  Next, as shown in FIG. 7A, the reference pixel output units 18 and 19 based on the horizontal phase coefficient signal from the interpolation control unit 17 perform an interpolation direction (with respect to the interpolation phase P on the scanning line L1). The pixel value of the first reference pixel p0 located in the real pixel two points (the same direction as the direction in which the two pixels A1 and B5 face each other) is calculated using the pixel value of the real pixel, and the interpolation phase P is calculated on the scanning line L2. The pixel value of the second reference pixel p1 positioned in the interpolation direction is calculated using the pixel value of the actual pixel. For example, when generating the first reference pixel p0 located on the scanning line L1, the average of the pixel values of the real pixel A2 and the real pixel A3 adjacent to the first reference pixel p0 in the horizontal direction is calculated. This average value is set as the pixel value of the generated pixel p0. Also in the case of generating the second reference pixel p1 located on the scanning line L2, similarly to the first reference pixel p0, the real pixel B6 and the real pixel B7 that are adjacent to the second reference pixel p1 in the horizontal direction. The average of the pixel values is calculated, and this average value is set as the pixel value of the second reference pixel p1. Then, the reference pixel output units 18 and 19 output the pixel values of the first reference pixel p0 and the second reference pixel p1 to the interpolation pixel generation unit 20.

  The interpolation pixel generation unit 20 receives the pixel values of the first reference pixel p0 and the second reference pixel p1 from the reference pixel output units 18 and 19, and interpolates with the first and second reference pixels p0 and p1. By performing weighting related to the distance to the phase P on the pixel values of the first and second reference pixels p0 and p1, the pixel value of the interpolation pixel is calculated. That is, when the distance between the reference pixel and the interpolation phase P is long, the coefficient value is decreased. Conversely, when the distance between the reference pixel and the interpolation phase P is short, the coefficient value is increased and A weighted average of the pixel values of the reference pixels is calculated by weighting the pixel values of the first and second reference pixels p0 and p1. For example, the weighted average of the pixel values of the first reference pixel p0 and the second reference pixel p1 is calculated by the following equation (5), and this weighted average value is used as the pixel value of the interpolation pixel. Here, kv3 is the distance between the first reference pixel p0 and the interpolation phase P, and kv4 is the distance between the second reference pixel p1 and the interpolation phase P.

P = (kv4 × p0 + kv3 × p1) / (kv3 + kv4) (5)
By performing the processing described above for other interpolation points on the interpolation lines N1, N2, and N3, the original image is quadrupled in the vertical direction and 2 in the horizontal direction as shown in FIG. 7B. A double-stretched image is obtained. The interpolated pixels interpolated between the actual pixels on the scanning line L1 and the actual pixels on the scanning line L2 are the first and second reference values of the two actual pixels on the scanning lines L1 and L2. It is generated as the pixel value of the pixel. For example, the interpolation pixel on the connection between the real pixel A1 and the real pixel B5 uses the pixel value of the real pixel A1 as the pixel value of the first reference pixel, and the pixel value of the real pixel B5 as the pixel value of the second reference pixel. Is generated as The interpolation pixel on the connection between the real pixel A3 and the real pixel B7 uses the pixel value of the real pixel A3 as the pixel value of the first reference pixel, and the pixel value of the real pixel B7 as the pixel value of the second reference pixel. Is generated as

  In the image subjected to the interpolation signal processing by the interpolation signal processing circuit according to the present embodiment shown in FIG. 7B, the connection between the real pixel A3 and the real pixel B7 (connection between the real pixel A2 and the real pixel B6) is obtained. The boundary is clearly divided into a high brightness area and a low brightness area, and the high frequency components of the original image are not lost. Thus, according to the interpolation signal processing circuit according to the present embodiment, the number of pixels or the number of scanning lines of the image can be changed while maintaining the high-frequency component of the original image.

  Next, an interpolation signal processing method according to the present embodiment will be described with reference to FIG. FIG. 8 is a flowchart illustrating the procedure of the interpolation signal processing method according to the present embodiment. The interpolation signal processing method according to this embodiment can be implemented by the interpolation signal processing circuit according to this embodiment described above. Therefore, here, a case where the interpolation signal processing circuit according to this embodiment is implemented will be described.

  First, the pixel values of actual pixels are read from the field memory 2 and the line memories 4 and 5, and the image data strings on the scanning lines L1 and L2 held in the registers 6a to 7e and 7a to e are updated (S21). Next, the first diagonal correlation determination is performed by the diagonal correlation determination unit 8 using the image data sequences held in the registers 6a to 7e and 7a to 7e (S22). In this step S22, a combination of two real pixels positioned in the vertical direction or diagonal direction of the image with the correlation determination phase (first correlation determination phase) at the same horizontal position as the actual pixel in the intermediate line M as the center. Among them, a combination of real pixels having the highest correlation is detected.

  Next, the image data sequence on the scanning lines L1 and L2 held in the registers 6a to 7e and 7a to 7e is updated by one pixel (S23). Then, the second diagonal correlation determination is performed by the diagonal correlation determination unit 8 using the image data sequences held in the registers 6a to 7e and 7a to 7e (S24). In this step S24, two points located in the vertical direction or the diagonal direction of the image centered on the correlation determination phase (second correlation determination phase) horizontally adjacent to the first correlation determination phase in the intermediate line M. Among the combinations of pixels, the combination of real pixels having the highest correlation is detected.

  Next, the interpolation direction for the interpolation phase is determined based on the combination of the two sets of real pixels detected in step S22 and step S24 (S25). Then, the pixel values of the first and second reference pixels positioned with respect to the interpolation phase in the interpolation direction determined in step S25 are calculated using the pixel values of the actual pixels (S26). Then, the pixel value of the interpolation pixel is generated by performing weighting related to the distance between the first and second reference pixels and the interpolation phase on the pixel value of the first and second reference pixels (S27).

  If the process for one screen is not completed after the interpolation pixel generation process in step S27 is completed, the process returns to step 21 and the processes from steps S21 to S27 described above until the process for one screen is completed. Is repeated (S28).

  The interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment described above, after determining the direction of high correlation around the two correlation determination phase points at the same horizontal position as the actual pixel on the intermediate line M, Two reference pixels positioned with respect to the interpolation phase in the direction of high correlation are generated using the pixel values of the actual pixels, and the interpolation pixels are generated using the pixel values of the generated two reference pixels. . For this reason, even when there are no actual pixels in the interpolation direction with respect to the interpolation phase on the scanning lines L1 and L2, the number of pixels or the number of scanning lines of the image can be changed while maintaining the high-frequency component of the image.

  In addition, the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment perform two oblique correlation determinations using the two pixels on the intermediate line M as the correlation determination phase, and result of the two oblique correlation determinations. Is used to determine the interpolation direction. For this reason, the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment can prevent erroneous detection of the correlation determination and accurately perform the interpolation signal processing.

  In the description of the interpolation signal processing circuit according to the present embodiment, specific circuit configurations of the input signal generation unit 101, the interpolation signal generation unit 102, and the display signal generation unit 103 are shown, but the same as in the first embodiment. These circuit configurations are not limited to those shown in this embodiment.

  Also, each component (input signal generation unit 101, interpolation signal generation unit 102, and display signal generation unit 103) in the interpolation signal processing circuit according to the present embodiment is the same semiconductor chip as in the first embodiment. Or a part or all of these may be provided independently of other components.

  Furthermore, in the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment, two oblique correlation determinations are performed with the correlation determination phase at two points on the intermediate line M as the center. The diagonal correlation determination is not necessarily an essential process. Only one diagonal correlation determination around the correlation determination phase at one point on the intermediate line M may be performed. That is, the interpolation direction may be determined using only the correlation determination result directly input from the oblique correlation determination unit 8 to the interpolation control unit 17 without using the correlation determination result held in the register 16. In this case as well, the number of pixels or scanning of the image is maintained while maintaining the high-frequency component of the original image, as in the case where the two diagonal correlation determinations are performed with the correlation determination phase at two points on the intermediate line M as the center. The number of lines can be changed.

  Furthermore, in the interpolation signal processing method according to this embodiment, the case where the interpolation signal processing circuit according to this embodiment is used has been described as an example. However, as in the first embodiment, the interpolation signal according to this embodiment is described. The circuit that performs the processing method is not limited to the interpolation signal processing circuit according to the present embodiment.

  Furthermore, in the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment, the highest correlation among the combinations of two real pixels located in the vertical direction or the diagonal direction of the image with the correlation determination phase as the center. Although the diagonal correlation determination is performed by detecting the combination of pixels, the number of actual pixels used for the diagonal correlation determination is not limited to two as in the first embodiment. The same effect as that of the present embodiment can also be obtained by using three or more real pixels for the diagonal correlation determination.

(Third embodiment)
Hereinafter, a third embodiment of the interpolation signal processing circuit and the interpolation signal processing method according to the present invention will be described with reference to FIGS. Note that the interpolation signal processing circuit according to this embodiment is obtained by changing the circuit configuration of the input signal generation unit 101 and the interpolation signal processing circuit 102 in the interpolation signal processing circuit according to the second embodiment shown in FIG. is there.

  First, the configuration of the interpolation signal processing circuit according to this embodiment will be described with reference to FIG. FIG. 9 is a circuit diagram illustrating a configuration of the interpolation signal processing circuit according to the present embodiment. Here, portions common to those described in the first embodiment with reference to FIG. 2 are denoted by the same reference numerals as those in FIG. 2, and description thereof is omitted.

  First, a specific configuration of the input signal generation unit 101 will be described. As shown in FIG. 9, the input signal generation unit 101 includes a field memory control unit 1, a field memory 2, a line memory control unit 3, and line memories 4, 5, 21, and 22.

  The line memory 21 is on the scanning line L3 adjacent to the scanning line L1 on the side opposite to the scanning line L2 in the input video signal A held in the field memory 2 based on the control signal from the line memory control unit 3. Holds the image data string. Further, the line memory 22 is based on the control signal from the line memory control unit 3 and the scanning line L4 adjacent to the scanning line L2 on the side opposite to the scanning line L1 in the input video signal A held in the field memory 2. Holds the upper image data string. That is, the line memories 4, 5, 21, 22 have four scanning lines L 1, L 2 arranged at regular intervals in an image in which a plurality of scanning lines are arranged parallel to the vertical direction at regular intervals. , L3 and L4 are held.

  Next, a specific configuration of the interpolation signal generation unit 102 will be described. As shown in FIG. 9, the interpolation signal generation unit 102 includes registers 6 a to e, 7 a to e, 16, 23 a to e, 24 a to e, 25 and 26, oblique correlation determination units 8, 27 and 28, and interpolation phase generation. 9, the interpolation control unit 29, and the reference pixel output units 18 and 19.

  The registers 23a to 23e are D-type flip-flops with enable, and holding and updating of output data of each flip-flop are controlled by controlling these enables. The registers 23a to 23e form a delay circuit corresponding to the number of taps, and sequentially delay the image data string input from the line memory 21. As a result, the register 23a-e holds pixel values of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L3, and the pixel values of these real pixels are output to the diagonal correlation determination unit 27. The

  The registers 24a to 24e are D-type flip-flops with enable in the same manner as the registers 23a to 23e, and holding and updating of output data of each flip-flop are controlled by controlling these enables. The registers 24 a to 24 e form a delay circuit corresponding to the number of taps, and sequentially delay the image data string input from the line memory 22. As a result, the register 24a-e holds the pixel values of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L4, and the pixel values of these real pixels are output to the diagonal correlation determination unit 28. .

  Further, the actual pixels held in the registers 6a to e, 7a to e, 23a to e, and 24a to e are at the same horizontal position at the same tap position. For example, real pixels whose pixel values are held in the registers 6a, 7a, 23a, and 24a are in the same horizontal position in the original image, and real pixels whose pixel values are held in the registers 6b, 7b, 23b, and 24b Are in the same horizontal position in the original image.

  The oblique correlation determination unit 27 receives pixel values of actual pixels on the scanning lines L2 and L3 from the registers 7a to e and 23a to e, and stores the pixel values in the register 6c (pixels in the registers 6a to e). The pixel value is held in the register 6c and the two real pixels located in the vertical direction or the diagonal direction of the image centering on the five real pixels on the scanning line L1 on which the value is held. Among the combinations with actual pixels, the combination of actual pixels with the highest correlation is detected, and this detection result is output to the interpolation control unit 29 as a correlation determination result.

  The register 25 receives the correlation determination result from the diagonal correlation determination unit 27 and holds the correlation determination result. By this register 25, the correlation determination result output from the diagonal correlation determination unit 27 is delayed by one stage and input to the interpolation control unit 29.

  The oblique correlation determination unit 28 receives the pixel values of the actual pixels on the scanning lines L1 and L4 from the registers 6a to e and 24a to e, and stores the pixel values in the register 7c (pixels in the registers 7a to e). The pixel value is held in the register 7c and the two real pixels located in the vertical direction or the diagonal direction of the image centering on the five real pixels on the scanning line L2 on which the value is held. Among the combinations with actual pixels, the combination of actual pixels with the highest correlation is detected, and this detection result is output to the interpolation control unit 29 as a correlation determination result.

  The register 26 receives the correlation determination result from the diagonal correlation determination unit 28 and holds the correlation determination result. By this register 26, the correlation determination result output from the oblique correlation determination unit 27 is delayed by one stage and input to the interpolation control unit 29.

  The interpolation control unit 29 receives correlation determination results from the diagonal correlation determination units 8, 27, and 28 and the registers 16, 25, and 26. That is, the correlation control unit 29 receives six correlation determination results continuously performed by the diagonal correlation determination units 8, 27, and 28. Then, the interpolation control unit 29 determines the interpolation direction based on the combination of the six sets of real pixels indicated by these six correlation determination results, and the horizontal phase coefficient signal and the vertical phase based on the horizontal phase information and the vertical phase information. A coefficient signal is generated. The horizontal phase coefficient signal is output to the reference pixel output units 18 and 19.

  Next, the operation of the interpolation signal processing circuit according to this embodiment shown in FIG. 9 will be described with reference to FIG. 10 and 11 are explanatory diagrams illustrating an interpolation signal processing method performed by the interpolation signal processing circuit according to the present embodiment. 10 and 11, the interpolation image is interpolated to the interpolation lines N1, N2, and N3 between the scanning lines L1 and L2, so that the original image is expanded four times in the vertical direction and twice in the horizontal direction. The case where it does is demonstrated. 10 and 11, the color given to each pixel indicates the pixel value of each pixel, and a pixel having a lower brightness has a black color, and a pixel having a higher brightness has a white color.

  First, by sequentially delaying the image data string input from the line memory 4, the registers 6a to 6e have pixel values A1, A2, and A3 of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L1. , A4, A5. Further, by sequentially delaying the image data string input from the line memory 5, the registers 7a to 7e allow the pixel values B1, B2, and B3 of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L2. , B4, B5. Furthermore, by sequentially delaying the image data string input from the line memory 21, the registers 23a to 23e allow the pixel values C1, C2, and C3 of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L3. , C4, C5. Furthermore, by sequentially delaying the image data sequence input from the line memory 22, the registers 24 a to 24 e allow the pixel values D 1, D 2, and 5 pixel values D 1, D 2, and 5 adjacent pixel positions in the horizontal direction on the scanning line L 4. Holds D3, D4, and D5.

  The diagonal correlation determination unit 8 is positioned in the vertical direction or the diagonal direction of the image with the correlation determination phase M3 (first correlation determination phase) at the same horizontal position as the actual pixels A3 and B3 in the intermediate line M as the center. Among the real pixel combinations of the points, the real pixel combination having the highest correlation is detected. For example, as shown in FIG. 10A, a combination of real pixels (A1, B5) (A2, B4) (A3, B3) (A4, B2) (with the pixel M3 as the center in the scanning lines L1, L2 ( The absolute value of the difference between the pixel values is compared with A5, B1), and the direction in which the combination of the pixels with the smallest difference is opposed is determined as the direction with high correlation. Here, it is assumed that, as a result of the correlation determination, it is determined that the combination of the pixels (A5, B1) has the highest correlation. The result of the correlation determination with the correlation determination phase M3 as the center is held in the register 16. Here, the inclination of the connection between the actual pixel A5 and the actual pixel B1 is defined as an inclination kM3.

  In addition, the diagonal correlation determination unit 27 is a combination of two real pixels and the real pixel A3 positioned in the vertical direction or the diagonal direction of the image with the real pixel A3 (second correlation determination phase) on the scanning line L1 as the center. Among them, a combination of real pixels having the highest correlation is detected. For example, as shown in FIG. 10B, a combination (C1, A3, B5) (C2, A3) of two real pixels A3 that are opposed to each other with the real pixel A3 as the center on the scanning lines L2, L3. , B4) (C3, A3, B3) (C4, A3, B2) (C5, A3, B1), the absolute value of the difference between the actual pixel value on the scanning line L2 and the actual pixel A3 and the scan The absolute value of the difference between the pixel values of the real pixel on the line L3 and the real pixel A3 is added and compared, and the direction in which the combination of the real pixels with the smallest sum is opposed is determined as the direction with high correlation. To do. That is, for the combination of real pixels (C1, A3, B5), the absolute value of the difference between the pixel values of the pixel C1 and the pixel A3 is calculated, and further, the difference between the pixel values of the pixel B5 and the pixel A3 is calculated. Calculate the absolute value and add these values together. Then, the same calculation as that performed for the real pixel combination (C1, A3, B5) is performed on the other real pixel combinations (C2, A3, B4) (C3, A3, B3) (C4, A3, B2). ) (C5, A3, B1), and the values obtained as a result are compared. Here, it is assumed that, as a result of this correlation determination, it is determined that the combination of pixels (C1, A3, B5) has the highest correlation. The result of the correlation determination with the actual pixel A3 as the center is held in the register 25. Here, the inclination of the connection between the actual pixel C1 and the actual pixel B5 is defined as an inclination kA3.

  Further, the diagonal correlation determination unit 28 combines the real pixel B3 with the two actual pixels positioned in the vertical direction or the diagonal direction of the image with the real pixel B3 (third correlation determination phase) on the scanning line L2 as the center. Among them, a combination of real pixels having the highest correlation is detected. For example, as shown in FIG. 11A, a combination (A1, B3, D5) (A2, B3, D4) of two real pixels B3 facing each other with the pixel B3 as the center in the scanning lines L1, L4. ) (A3, B3, D3) (A4, B3, D2) (A5, B3, D1) With respect to (A5, B3, D1), the absolute value of the pixel value difference between the actual pixel on the scanning line L1 and the actual pixel B3 and the scanning line L4 The absolute values of the difference between the pixel values of the real pixel and the real pixel B3 are added together and compared, and the direction in which the combination of the real pixels having the smallest sum is opposed is determined as the direction with high correlation. Here, it is assumed that, as a result of this correlation determination, it is determined that the combination of pixels (A2, B3, D4) has the highest correlation. The result of the correlation determination with the actual pixel B3 as the center is held in the register 26. Here, the inclination of the connection between the actual pixel A2 and the actual pixel D4 is defined as an inclination kB3.

  Next, the registers 6a to 6e delay the image data sequence by one pixel, so that the pixel values A2, A3, A4, A5, A6 of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L1. Hold. Further, the registers 7a to 7e delay the image data sequence by one pixel, thereby obtaining the pixel values B2, B3, B4, B5, and B6 of the five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L2. Hold. Further, the registers 23a to 23e delay the image data sequence by one pixel, thereby obtaining pixel values C2, C3, C4, C5, and C6 of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L3. Hold. Furthermore, the registers 24a to 24e delay the image data sequence by one pixel, so that the pixel values D2, D3, D4, D5, D6 of five real pixels whose pixel positions are adjacent in the horizontal direction on the scanning line L4. Hold.

  Then, the diagonal correlation determination unit 8 is located in the vertical direction or the diagonal direction of the image around the correlation determination phase M4 (fourth correlation determination phase) at the same horizontal position as the actual pixels A4 and B4 in the intermediate line M. Of the combination of two pixels, two real pixels having the highest correlation are detected. For example, the pixel value difference with respect to the combination (A2, B6) (A3, B5) (A4, B4) (A5, B3) (A6, B2) of the opposing pixels centering on the pixel M4 in the scanning lines L1, L2. Are compared, and the direction in which the combination of pixels having the smallest difference is opposed is determined as the direction with high correlation. Here, it is assumed that, as a result of this correlation determination, it is determined that the combination of pixels (A3, B5) has the highest correlation. The correlation determination result of the diagonal correlation determination unit 8 is output to the interpolation control unit 29. Here, the inclination of the connection between the actual pixel A3 and the actual pixel B5 is defined as an inclination kM4.

  In addition, the diagonal correlation determination unit 27 is a combination of two real pixels and the real pixel A4 positioned in the vertical direction or the diagonal direction of the image with the real pixel A4 (fifth correlation determination phase) on the scanning line L1 as the center. Among them, a combination of real pixels having the highest correlation is detected. For example, a combination (C2, A4, B6) (C3, A4, B5) (C4, A4, B4) (C2, A4, B6) of two real pixels and the real pixel A4 facing each other about the real pixel A4 in the scanning lines L2, L3 ( C5, A4, B3) (C6, A4, B2), the absolute value of the difference in pixel value between the actual pixel on the scanning line L2 and the actual pixel A4, the actual pixel on the scanning line L3, and the actual pixel A4 The absolute values of the pixel value differences are added and compared, and the direction in which the combination of the real pixels having the smallest added value is opposed is determined as the direction with high correlation. Here, it is assumed that, as a result of the correlation determination, it is determined that the combination of pixels (C2, A4, B6) has the highest correlation. The result of the correlation determination with the actual pixel A4 as the center is output to the interpolation control unit 29. Here, the inclination of the connection between the actual pixel C2 and the actual pixel B6 is defined as an inclination kA4.

  Further, the diagonal correlation determination unit 28 combines the real pixel B4 with the two real pixels located in the vertical direction or the diagonal direction of the image with the real pixel B4 (sixth correlation determination phase) on the scanning line L2 as the center. Among them, a combination of real pixels having the highest correlation is detected. For example, combinations (A2, B4, D6) (A3, B4, D5) (A4, B4, D4) (A5) of two real pixels and the actual pixel B4 facing each other with the pixel B4 as the center in the scanning lines L1, L4 , B4, D3) (A6, B4, D2), the absolute value of the difference in pixel value between the actual pixel on the scanning line L1 and the actual pixel B4 and the actual pixel on the scanning line L4 and the actual pixel B4 The absolute values of the pixel value differences are added together and compared, and the direction in which the combination of the real pixels having the smallest added value is opposite is determined as the direction with high correlation. Here, it is assumed that, as a result of this correlation determination, the combination of pixels (A3, B4, D5) is determined to have the highest correlation. The result of the correlation determination with the actual pixel B4 as the center is output to the interpolation control unit 29. Here, the inclination of the connection between the actual pixel A3 and the actual pixel D5 is defined as an inclination kB4.

  Next, the interpolation control unit 29 combines the real pixels (A5, B1) (C1, A3, B5) indicated by the correlation determination results input from the diagonal correlation determination units 8, 27, 28 and the registers 16, 25, 26. From (A2, B3, D4) (A3, B5) (C2, A4, B6) (A3, B4, D5), the interpolation direction for the interpolation phase is determined. First, out of the correlation determination results input from the diagonal correlation determination units 8, 27, and 28 and the registers 16, 25, and 26, the correlation determination result that is most suspected of being a false detection is excluded. For example, as shown in FIG. 11 (b), the determination result having the largest absolute value of the difference from the average value of the gradients among the gradients kM3, kA3, kB3, kM4, kA4, and kB4 is detected and eliminated. . Here, since the absolute value of the difference between the gradient kM3 and the average value is the largest, the determination result for the correlation determination phase M3 is excluded. Then, weights related to the distances between the correlation determination phases A3, B3, M4, A4, and B4 and the interpolation phase P are applied to the gradients kM3, kA3, kB3, kM4, kA4, and kB4. calculate. For example, the weighted average of the slope is calculated by the following equation (6), and the calculated weighted average value is set as the slope K in the interpolation direction. Here, mA3, mB3, mM4, mA4, and mB4 are weighting coefficients based on the relative positional relationship between the interpolation phase P and the pixels A3, B3, M4, A4, and B4.

K = (mA3 * kA3 + mB3 * kB3 + mM4 * kM4 + mA4 * kA4 + mB4 * kB4) / (mA3 + mB3 + mM4 + mA4 + mB4) (6)
Next, the reference pixel output units 18 and 19 are based on the horizontal phase coefficient signal from the interpolation control unit 29, and the first reference pixel is positioned on the scanning line L1 in the interpolation direction with the inclination K with respect to the interpolation phase P. The pixel value of p0 is calculated using the pixel value of the actual pixel, and the pixel value of the second reference pixel p1 located in the interpolation direction with the inclination K with respect to the interpolation phase P on the scanning line L2 is calculated as the pixel value of the actual pixel. Calculate using. For example, as shown in FIG. 11B, when generating the first reference pixel p0 located on the scanning line L1, weighting related to the distance between the real pixels A2 and A3 and the first reference pixel p0. Is applied to the pixel values of the real pixel A2 and the real pixel A3, thereby calculating a weighted average of the pixel values of the real pixel A2 and the real pixel A3. That is, when the distance between the actual pixel and the interpolation phase P is long, the coefficient value is decreased. Conversely, when the distance between the actual pixel and the interpolation phase P is short, the coefficient value is increased and the coefficients are A weighted average of the pixel values of the actual pixels is calculated by weighting the pixel values of the pixel A2 and the actual pixel A3. For example, a weighted average of pixel values of the real pixel A2 and the real pixel A3 is calculated by the following formula (7), and this weighted average value is set as the pixel value of the first reference pixel p0. Here, kh1 is the distance between the real pixel A2 and the first reference pixel p0, and kh2 is the distance between the real pixel A3 and the first reference pixel p0.

p0 = (kh2 × A2 + kh1 × A3) / (kh1 + kh2) (7)
Further, when generating the second reference pixel p1 located on the scanning line L2, weighting related to the distance between the real pixels B3 and B4 and the second reference pixel p1 is set between the real pixel B3 and the real pixel B4. By performing on the pixel value, a weighted average of the pixel values of the actual pixel B3 and the actual pixel B4 is calculated. That is, when the distance between the actual pixel and the interpolation phase P is long, the coefficient value is decreased. Conversely, when the distance between the actual pixel and the interpolation phase P is short, the coefficient value is increased and the coefficients are The weighted average of the pixel values of the actual pixels is calculated by weighting the pixel values of the pixels B3 and B4. For example, a weighted average of pixel values of the real pixel B3 and the real pixel B4 is calculated by the following formula (8), and this weighted average value is set as the pixel value of the second reference pixel p1. Here, kh3 is the distance between the actual pixel B3 and the second reference pixel p1, and kh4 is the distance between the actual pixel B4 and the second reference pixel p1.

p1 = (kh4 × B3 + kh3 × B4) / (kh3 + kh4) (8)
Then, the interpolation pixel generation unit 20 receives the pixel values of the first reference pixel p0 and the second reference pixel p1 from the reference pixel output units 18 and 19, and the first and second reference pixels p0 and p1. The pixel value of the interpolation pixel is calculated by weighting the pixel values of the first and second reference pixels p0 and p1 in relation to the distance between the interpolation pixel P and the interpolation phase P.

  By performing the above-described processing on other interpolation points on the interpolation lines N1, N2, and N3, an image obtained by expanding the original image four times in the vertical direction and twice in the horizontal direction can be obtained.

  Subsequently, an interpolation signal processing method according to the present embodiment will be described with reference to FIG. FIG. 12 is a flowchart illustrating the procedure of the interpolation signal processing method according to the present embodiment. The interpolation signal processing method according to this embodiment can be implemented by the interpolation signal processing circuit according to this embodiment described above. Therefore, here, a case where the interpolation signal processing circuit according to this embodiment is implemented will be described.

  First, the pixel values of the actual pixels are read from the field memory 2 and the line memories 4, 5, 21, and 22, and the scanning lines L1, L2, and the like held in the registers 6a to e, 7a to e, 23a to e, and 24a to e, The image data strings on L3 and L4 are updated (S31). Next, the first diagonal correlation determination is performed by the diagonal correlation determination unit 8 using the image data sequences held in the registers 6a to 7e and 7a to 7e (S32). In this step S32, a combination of two actual pixels located in the vertical direction or diagonal direction of the image with the correlation determination phase (first correlation determination phase) at the same horizontal position as the actual pixel in the intermediate line M as the center. Among them, a combination of real pixels having the highest correlation is detected.

  Next, the second diagonal correlation determination is performed by the diagonal correlation determination unit 27 using the image data strings held in the registers 23a to e and 7a to e (S33). In this step S33, two points located in the vertical direction or diagonal direction of the image centering on the correlation determination phase (second correlation determination phase) at the same horizontal position as the first correlation determination phase on the scanning line L3. Among the combinations of real pixels and real pixels located in the second correlation determination phase, the combination of real pixels having the highest correlation is detected.

  Next, a third diagonal correlation determination is performed by the diagonal correlation determination unit 28 using the image data sequences held in the registers 6a to e and 24a to e (S34). In step S34, the image is positioned in the vertical direction or oblique direction of the image with the correlation determination phase (third correlation determination phase) at the same horizontal position as the first and second correlation determination phases on the scanning line L4. Among the combinations of the two real pixels and the real pixels located in the third correlation determination phase, the combination of the real pixels having the highest correlation is detected.

  Next, the image data sequence on the scanning lines L1, L2, L3, and L4 held in the registers 6a to 7e, 7a to e, 23a to e, and 24a to e is updated by one pixel (S35). Then, a fourth diagonal correlation determination is performed by the diagonal correlation determination unit 8 using the image data sequences held in the registers 6a to 7e and 7a to 7e (S36). In this step S36, two points located in the vertical direction or the diagonal direction of the image centered on the correlation determination phase (fourth correlation determination phase) horizontally adjacent to the first correlation determination phase in the intermediate line M. Among the combinations of pixels, the combination of real pixels having the highest correlation is detected.

  Next, a fifth diagonal correlation determination is performed by the diagonal correlation determination unit 27 using the image data sequences held in the registers 23a to e and 7a to e (S37). In this step S37, two points located in the vertical direction or the oblique direction of the image centering on the correlation determination phase (fifth correlation determination phase) at the same horizontal position as the fourth correlation determination phase in the scanning line L3. Among the combinations of real pixels and real pixels located in the fifth correlation determination phase, the combination of real pixels having the highest correlation is detected.

  Next, a sixth diagonal correlation determination is performed by the diagonal correlation determination unit 28 using the image data sequences held in the registers 6a to e and 24a to e (S38). In this step S38, the image is positioned in the vertical direction or diagonal direction of the image with the correlation determination phase (sixth correlation determination phase) at the same horizontal position as the fourth and fifth correlation determination phases on the scanning line L4. Among the combinations of the two real pixels and the real pixels located in the sixth correlation determination phase, the combination of the real pixels having the highest correlation is detected.

  Next, the interpolation direction for the interpolation phase is determined based on the combination of the six real pixels detected in steps S32, S33, S34, S36, S37, and S38 (S39). Then, two reference pixels located with respect to the interpolation phase in the interpolation direction determined in step S39 are calculated using the pixel values of the actual pixels (S310). Then, the pixel value of the interpolation pixel is generated by performing weighting related to the distance between the two reference pixels and the interpolation phase on the pixel value of the two reference pixels (S311).

  If the process for one screen is not completed after the interpolation pixel generation process in step S311 is completed, the process returns to step 31 and the processes from steps S31 to S311 described above until the process for one screen is completed. Is repeated (S312).

  The interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment described above perform the correlation determination using the two pixels on the intermediate line M and the four actual pixels on the scanning line as the correlation determination phase. The interpolation direction is determined from the determination result. For this reason, the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment can prevent erroneous detection of the correlation determination and accurately perform the interpolation signal processing.

  In addition, the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment can obtain the same effects as those of the first and second examples in other effects.

  In the description of the interpolation signal processing circuit according to the present embodiment, specific circuit configurations of the input signal generation unit 101, the interpolation signal generation unit 102, and the display signal generation unit 103 are shown. Like the embodiment, these circuit configurations are not limited to those shown in this embodiment.

  Also, each component (input signal generation unit 101, interpolation signal generation unit 102, and display signal generation unit 103) in the interpolation signal processing circuit according to this embodiment is the same as in the first and second embodiments. The semiconductor chip may be provided, or a part or all of these may be provided independently of other components.

  Furthermore, in the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment, six diagonal operations are performed with two pixels on the intermediate line M and four actual pixels on the scanning lines L1 and L2 as correlation determination phases. Although the correlation determination is performed, the six diagonal correlation determinations are not necessarily essential processes. Three oblique correlation determinations may be performed using one pixel on the intermediate line M and two actual pixels on the scanning lines L1 and L2 as the correlation determination phase. That is, without using the correlation determination results held by the registers 16, 25, and 26, the interpolation direction is determined using only the correlation determination results directly input from the diagonal correlation determination units 8, 27, and 28 to the interpolation control unit 29. It doesn't matter. In this case as well, the high frequency of the original image is the same as in the case of performing six diagonal correlation determinations using the two pixels on the intermediate line M and the four actual pixels on the scanning lines L1 and L2 as the correlation determination phase. The number of pixels or the number of scanning lines of the image can be changed while maintaining the components. However, in order to detect erroneous detection of correlation determination with higher accuracy, it is desirable to determine the interpolation direction from a larger number of correlation determination results.

  Furthermore, in the interpolated signal processing circuit according to the present embodiment, among the correlation determination results input from the diagonal correlation determination units 8, 27, and 28 and the registers 16, 25, and 26, the correlation determination that is most suspected of being a false detection. Although the result is excluded, this process is not necessarily an essential process.

  Furthermore, in the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment, the interpolation direction is determined in accordance with the distance between the correlation determination phase and the interpolation phase. Not limited. For example, a combination of two real pixels that indicate the same direction among the six combinations of two real pixels detected by the diagonal correlation determination units 8, 27, and 28 is detected, and the two detected real pixels The direction in which the two face each other may be the interpolation direction.

  Furthermore, in the interpolation signal processing method according to this embodiment, the case where the interpolation signal processing circuit according to this embodiment is used has been described as an example. However, like the first and second embodiments, The circuit that performs the interpolation signal processing method is not limited to the interpolation signal processing circuit according to the present embodiment.

  Furthermore, in the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment, when the correlation determination phase is located on the intermediate line M, two points located in the vertical direction or the oblique direction of the image with the correlation determination phase as the center. The diagonal correlation determination is performed by detecting the combination of the actual pixels having the highest correlation among the actual pixel combinations. However, as in the first and second embodiments, the actual pixel used for the diagonal correlation determination is determined. The number is not limited to two. The same effect as that of the present embodiment can also be obtained by using three or more real pixels for the diagonal correlation determination.

  Furthermore, in the interpolation signal processing circuit and the interpolation signal processing method according to the present embodiment, when the correlation determination phase is located on the scanning lines L1 and L2, three real pixels (up and down direction of the image centering on the correlation determination phase). Alternatively, the diagonal correlation determination is performed by detecting the combination of the real pixels having the highest correlation among the combinations of the two real pixels positioned in the diagonal direction and the actual pixels positioned in the correlation determination phase. The number of actual pixels used for the diagonal correlation determination is not limited to three points. This embodiment can also be implemented by using four or more pixels (three or more actual pixels located in the vertical direction or diagonal direction of the image and the actual pixels located in the correlation determination phase) centered on the correlation determination phase for the diagonal correlation determination. The same effect as the example can be obtained.

  The present invention can be variously modified without departing from the scope of the invention in the implementation stage.

  For example, in the embodiment of the present invention, the case where the correlation determination phase is located on any of the first scan line, the second scan line, or the intermediate line is shown. It is not limited to these. The correlation determination phase is not limited to the position of the correlation determination phase as long as the correlation determination phase is adjacent to the interpolation phase and a plurality of actual pixels are positioned in the vertical direction or the oblique direction of the image with the correlation determination phase as the center. The same effect as the embodiment can be obtained.

  As described above, the features of the interpolation signal processing circuit according to the present invention are summarized as follows.

  In the interpolation signal processing circuit according to the present invention, a plurality of scanning lines are arranged in parallel at regular intervals with respect to the vertical direction, and in an image in which a plurality of actual pixels are arranged on each of the plurality of scanning lines, A combination of real pixels having the highest correlation is detected for each correlation determination phase among combinations of real pixels positioned in the vertical direction or the diagonal direction of the image with at least one correlation determination phase adjacent to the interpolation phase as a center. An oblique correlation determining means; an interpolation direction determining means for determining an interpolation direction based on a combination of the actual pixels detected by the oblique correlation determining means; and at least two pixels located in the interpolation direction with respect to the interpolation phase. And a reference pixel output means for outputting a pixel value of the reference pixel, and a pixel value of the reference pixel is input from the reference pixel output means. By performing the weighting associated with the distance between the interpolation phase to the pixel values of the reference pixels, and characterized by including an interpolation pixel generating means for calculating a pixel value of the interpolation pixel in the interpolation phase.

  Further, the interpolation signal processing circuit according to the present invention is an image in which a plurality of scanning lines are arranged in parallel at regular intervals in the vertical direction, and a plurality of actual pixels are arranged on each of the plurality of scanning lines. And at least two real pixels positioned in the vertical direction or diagonal direction of the image with the correlation determination phase on the intermediate line positioned between the first and second scanning lines facing each other at regular intervals as the center. Among the combinations, an oblique correlation determination unit that detects a combination of real pixels having the highest correlation, an interpolation direction determination unit that determines an interpolation direction based on the combination of the actual pixels detected by the oblique correlation determination unit, and the first An actual pixel positioned in the interpolation direction with respect to the interpolation phase on one scanning line is set as a first reference pixel, and the interpolation pixel is set in the interpolation direction with respect to the interpolation phase on the second scanning line. A reference pixel output means for outputting the pixel values of the first and second reference pixels, and a pixel of the first and second reference pixels from the reference pixel output means. A value is input, and weighting related to the distance between the first and second reference pixels and the interpolation phase is performed on the pixel value of the first and second reference pixels, so that the interpolation pixel of the interpolation phase in the interpolation phase is obtained. Interpolation pixel generation means for calculating pixel values is provided.

  Furthermore, the interpolation signal processing circuit according to the present invention is an image in which a plurality of scanning lines are arranged in parallel at regular intervals in the vertical direction, and a plurality of actual pixels are arranged on each of the plurality of scanning lines. And at least two points positioned in the vertical direction or the diagonal direction of the image with the first correlation determination phase on the intermediate line positioned in the middle of the first and second scanning lines facing each other at a constant interval. A first diagonal correlation determination unit that detects a combination of real pixels having the highest correlation among the combinations of real pixels, and an interpolation direction that determines an interpolation direction based on the combination of the real pixels detected by the diagonal correlation determination unit And calculating a pixel value of a first reference pixel located in the interpolation direction with respect to an interpolation phase on the first scanning line using a pixel value of an actual pixel, and determining the pixel value on the second scanning line. The pixel value of the second reference pixel located in the interpolation direction with respect to the interpolation phase is calculated using the pixel value of the actual pixel, and the pixel value of the first and second reference pixels is output. Pixel values of the first and second reference pixels are input from the pixel output means and the reference pixel output means, and weighting related to the distance between the first and second reference pixels and the interpolation phase is set to the first value. Interpolation pixel generation means for calculating the pixel value of the interpolation pixel in the interpolation phase by performing the processing on the pixel values of the first and second reference pixels is provided.

  Furthermore, the interpolation signal processing circuit according to the present invention includes at least two points located in the vertical direction or the oblique direction of the image with the second correlation determination phase adjacent to the first correlation determination phase as a center on the intermediate line. A second diagonal correlation determination unit that detects a combination of real pixels having the highest correlation among the real pixel combinations, and the interpolation direction determination unit detects the first diagonal correlation determination unit detected by the first diagonal correlation determination unit. The interpolation direction is determined based on the combination of real pixels and the combination of real pixels detected by the second oblique correlation determination unit.

  Furthermore, the interpolation signal processing circuit according to the present invention is configured such that the image is vertically or obliquely centered on a third correlation determination phase at the same horizontal position as the first correlation determination phase on the first scanning line. A third diagonal correlation determining means for detecting a combination of real pixels having the highest correlation among the combinations of at least two real pixels positioned at the third position and real pixels positioned in the third correlation determination phase; At least two real pixels positioned in the vertical direction or the diagonal direction of the image with the fourth correlation determination phase at the same horizontal position as the first and third correlation determination phases on the two scanning lines; and And a fourth diagonal correlation determining means for detecting a combination of real pixels having the highest correlation among combinations with real pixels located in the fourth correlation determination phase, Determining the interpolation direction based on the combination of real pixels detected by the first diagonal correlation determination unit and the combination of real pixels detected by the third and fourth diagonal correlation determination units. It is a feature.

  Furthermore, the interpolation signal processing circuit according to the present invention includes at least two points located in the vertical direction or the oblique direction of the image with the second correlation determination phase adjacent to the first correlation determination phase as a center on the intermediate line. A second diagonal correlation determination unit that detects a combination of real pixels having the highest correlation among the actual pixel combinations; and a second diagonal correlation determination unit that is in the same horizontal position as the second correlation determination phase on the first scanning line. An actual pixel having the highest correlation among the combinations of at least two real pixels located in the vertical direction or diagonal direction of the image centering on the correlation determination phase of 5 and the real pixels located in the fifth correlation determination phase And a sixth correlation determination position at the same horizontal position as the second and fifth correlation determination phases on the second scanning line. The combination of real pixels having the highest correlation among the combinations of at least two real pixels located in the vertical direction or oblique direction of the image with respect to the center and real pixels located in the sixth correlation determination phase is detected. And a sixth diagonal correlation determination unit, wherein the interpolation direction determination unit detects the actual detected by the first correlation determination unit, the third diagonal correlation determination unit, and the fourth diagonal correlation determination unit. The interpolation direction is determined based on a combination of pixels and a combination of the real pixels detected by the second diagonal correlation determination unit, the fifth diagonal correlation determination unit, and the sixth diagonal correlation determination unit. It is a feature.

1 is a schematic diagram showing the configuration of an interpolation signal processing circuit according to a first embodiment of the present invention. 1 is a circuit diagram showing a configuration of an interpolation signal processing circuit according to a first embodiment of the present invention. Explanatory drawing which shows the interpolation signal processing method which the interpolation signal processing circuit based on 1st Example of this invention performs. The flowchart which shows the procedure of the interpolation signal processing method which concerns on 1st Example of this invention. The circuit diagram which shows the structure of the interpolation signal processing circuit which concerns on 2nd Example of this invention. The 1st explanatory view which shows the interpolation signal processing method which the interpolation signal processing circuit concerning the 2nd example of the present invention performs. The 2nd explanatory view showing the interpolation signal processing method which the interpolation signal processing circuit concerning the 2nd example of the present invention performs. The flowchart which shows the procedure of the interpolation signal processing method which concerns on 2nd Example of this invention. The circuit diagram which shows the structure of the interpolation signal processing circuit which concerns on 3rd Example of this invention. The 1st explanatory view showing the interpolation signal processing method which the interpolation signal processing circuit concerning the 3rd example of the present invention performs. The 2nd explanatory view showing the interpolation signal processing method which the interpolation signal processing circuit concerning the 3rd example of the present invention performs. The flowchart which shows the procedure of the interpolation signal processing method which concerns on 3rd Example of this invention. Explanatory drawing which shows the conventional interpolation signal processing method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Field memory control part 2 ... Field memory 3, 14 ... Line memory control part 4, 5, 15, 21, 22 ... Line memory 6a-e, 7a-e, 16, 23a-e, 24a-e, 25, 26: Registers 8, 27, 28 ... Oblique correlation determination unit 9: Interpolation phase generation units 10, 17, 29 ... Interpolation control units 11, 12, 18, 19 ... Reference pixel output units 13, 20 ... Interpolation pixel generation unit 101 ... Input signal generation unit 102 ... interpolation signal generation unit 103 ... display signal generation units 104 to 106 ... input terminal 107 ... output terminal

Claims (6)

Correlation of at least one point adjacent to the interpolation phase in an image in which a plurality of scanning lines are arranged in parallel at regular intervals with respect to the vertical direction and a plurality of actual pixels are arranged on each of the plurality of scanning lines. An oblique correlation determination unit that detects, for each correlation determination phase, a combination of real pixels having the highest correlation among the combinations of actual pixels positioned in the vertical direction or the diagonal direction of the image with the determination phase as a center;
Interpolation direction determining means for determining an interpolation direction based on the combination of the real pixels detected by the oblique correlation determining means;
A reference pixel output means for outputting a pixel value of the reference pixel using at least two pixels located in the interpolation direction with respect to the interpolation phase as reference pixels;
The pixel value of the reference pixel is input from the reference pixel output means, and the pixel value of the interpolation pixel in the interpolation phase is obtained by weighting the pixel value of the reference pixel with respect to the distance between the reference pixel and the interpolation phase. An interpolation signal processing circuit comprising interpolation pixel generation means for calculating a value. In an image in which a plurality of scanning lines are arranged in parallel at regular intervals with respect to the vertical direction, and a plurality of real pixels are arranged on each of the plurality of scanning lines, the first and A combination of real pixels having the highest correlation among a combination of at least two real pixels located in the vertical direction or diagonal direction of the image with the correlation determination phase on the intermediate line located in the middle of the second scanning line as the center An oblique correlation determination means for detecting
Interpolation direction determining means for determining an interpolation direction based on the combination of the real pixels detected by the oblique correlation determining means;
An actual pixel located in the interpolation direction with respect to the interpolation phase on the first scanning line is defined as a first reference pixel, and an actual pixel located in the interpolation direction with respect to the interpolation phase on the second scanning line Reference pixel output means for outputting the pixel values of the first and second reference pixels as a second reference pixel;
Pixel values of the first and second reference pixels are input from the reference pixel output means, and weights related to the distances between the first and second reference pixels and the interpolation phase are set to the first and second reference pixels. An interpolation signal processing circuit comprising: interpolation pixel generation means for calculating a pixel value of an interpolation pixel in the interpolation phase by being performed on a pixel value of a reference pixel. In an image in which a plurality of scanning lines are arranged in parallel at regular intervals with respect to the vertical direction, and a plurality of real pixels are arranged on each of the plurality of scanning lines, the first and Of the combinations of at least two real pixels located in the vertical direction or diagonal direction of the image with the first correlation determination phase on the intermediate line located in the middle of the second scanning line as the center, the highest correlation is obtained. First oblique correlation determination means for detecting a combination of pixels;
Interpolation direction determining means for determining an interpolation direction based on the combination of the real pixels detected by the oblique correlation determining means;
A pixel value of a first reference pixel located in the interpolation direction with respect to an interpolation phase on the first scanning line is calculated using a pixel value of an actual pixel, and the interpolation phase on the second scanning line is calculated with respect to the interpolation phase. Calculating a pixel value of a second reference pixel located in the interpolation direction using a pixel value of an actual pixel, and outputting a pixel value of the first and second reference pixels;
Pixel values of the first and second reference pixels are input from the reference pixel output means, and weights related to the distances between the first and second reference pixels and the interpolation phase are set to the first and second reference pixels. An interpolation signal processing circuit comprising: interpolation pixel generation means for calculating a pixel value of an interpolation pixel in the interpolation phase by being performed on a pixel value of a reference pixel. Among the combinations of at least two real pixels located in the vertical direction or the oblique direction of the image with the second correlation determination phase adjacent to the first correlation determination phase as the center on the intermediate line, the highest correlation is obtained. A second oblique correlation determination unit for detecting a combination of real pixels;
The interpolation direction determination unit determines the interpolation direction based on the combination of the real pixels detected by the second diagonal correlation determination unit and the combination of the real pixels detected by the first diagonal correlation determination unit. The interpolated signal processing circuit according to claim 3. On the first scanning line, at least two real pixels positioned in the vertical direction or the diagonal direction of the image with the third correlation determination phase at the same horizontal position as the first correlation determination phase as the center, and the first 3rd diagonal correlation determination means which detects the combination of the real pixel with the highest correlation among the combinations with the real pixel located in 3 correlation determination phases;
On the second scanning line, at least two actual pixels positioned in the vertical direction or the diagonal direction of the image with the fourth correlation determination phase being at the same horizontal position as the first and third correlation determination phases. And a fourth diagonal correlation determination means for detecting a combination of real pixels having the highest correlation among the combinations of real pixels located in the fourth correlation determination phase,
The interpolation direction determining means is based on the combination of the real pixels detected by the first diagonal correlation determination means and the interpolation direction based on the combination of the real pixels detected by the third and fourth diagonal correlation determination means. The interpolation signal processing circuit according to claim 3, wherein the interpolation signal processing circuit is determined. Among the combinations of at least two real pixels located in the vertical direction or the oblique direction of the image with the second correlation determination phase adjacent to the first correlation determination phase as the center on the intermediate line, the highest correlation is obtained. Second oblique correlation determination means for detecting a combination of real pixels;
On the first scanning line, at least two real pixels positioned in the vertical direction or diagonal direction of the image with the fifth correlation determination phase at the same horizontal position as the second correlation determination phase as the center, and the first 5th diagonal correlation determination means which detects the combination of the real pixel with the highest correlation among the combinations with the real pixel located in the correlation determination phase of 5;
On the second scanning line, at least two real pixels positioned in the vertical direction or the diagonal direction of the image with the sixth correlation determination phase being at the same horizontal position as the second and fifth correlation determination phases. And a sixth diagonal correlation determination means for detecting a combination of real pixels having the highest correlation among the combinations of real pixels located in the sixth correlation determination phase,
The interpolation direction determination means includes the second diagonal correlation determination means together with the combination of the real pixels detected by the first correlation determination means, the third diagonal correlation determination means, and the fourth diagonal correlation determination means. 6. The interpolation signal processing circuit according to claim 5, wherein the interpolation direction is determined based on a combination of the real pixels detected by the fifth diagonal correlation determination unit and the sixth diagonal correlation determination unit.

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