JP2009105990A - Block noise detector and detection method, and block noise eliminating device and eliminating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a block noise detector with a comparatively simplified structure that determines a block boundary (BLB) to be an edge even if signal fluctuation is great at only one side of the block boundary (BLB). <P>SOLUTION: The block noise detector includes a spatial difference comparator (101) to output a spatial difference comparison determination signal (SDJ) based on results of the comparison of a plurality of adjacent spatial differences obtained by calculating spatial differences between adjacent pixels according to an inputted video signal (Va), a phase accumulator (102) to output accumulated value signals (CAV0-CAV7) by counting the spatial difference comparison determination signal (SDJ) for each phase, and a maximum accumulated phase detector (103) to output a phase corresponding to the maximum accumulated value signal (MAS) of the accumulated value signal whose value is the maximum as the maximum accumulated phase signal (MAS). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a video signal processing technique for block noise generated when a video signal is divided into a plurality of blocks and then encoded, transmitted or recorded, and decoded.

  In the conventional block distortion detection device, the block edge determination circuit constituting the block distortion detection device determines an edge when the luminance signal difference value of interest is larger than the average coefficient multiple of the luminance signal difference values around the left and right sides. Was. In addition, the block boundary is specified at the timing when the boundary specifying means constituting the block distortion detection device is synchronized with the vertical synchronization signal (for example, Patent Document 1).

Republished patent WO2005 / 004489 (page 6, line 4 to line 11, FIGS. 1 to 3)

  In the conventional block distortion detection device, when the edge is determined, the signal difference value of interest and the signal difference values around the left and right sides thereof are compared simultaneously on the left and right. For example, the signal change is small on the right side of the block boundary and the left side When the signal change is large, the block boundary is not determined as an edge.

  Further, in the conventional block distortion detection device, the block boundary is specified at the timing synchronized with the vertical synchronization signal, and therefore the block boundary for one frame is specified. For this reason, there has been a problem that the number of bits of the edge number counter constituting the block distortion detection device becomes large and the circuit scale of the block distortion detection device becomes large. Furthermore, in order to specify a block boundary for one frame, when configuring a block distortion removal apparatus using a block distortion detection apparatus, in order to perform block distortion removal processing based on the block distortion detection result, There was a problem of requiring a memory circuit.

  The present invention has been made to solve the above-described problems. Even when the signal change is large only on one side of the block boundary, the block boundary can be determined as an edge, and the circuit scale is small. However, an object of the present invention is to realize a block noise detection device with high detection accuracy.

The block noise detection device of the present invention is
A block noise detection device that receives an input video signal, detects a block boundary, and outputs the block boundary,
A spatial difference calculation unit that calculates and outputs a spatial difference between adjacent pixels with respect to the input video signal, and a spatial difference obtained by comparing the spatial difference of interest and the spatial difference between the left and right sides separately from the left and right. A spatial difference comparison unit including a spatial difference comparison determination unit that outputs a comparison determination signal;
A phase provided with a plurality of counters that counts the spatial difference comparison determination signal for each phase and outputs a count value corresponding to each phase as a cumulative value signal at a timing synchronized with the horizontal synchronization signal of the input video signal Cumulative part,
A cumulative value signal having a maximum value among the plurality of cumulative value signals is output as a maximum cumulative value signal, and a phase corresponding to the cumulative value signal having the maximum value is set as a maximum cumulative phase signal. A maximum cumulative phase detector with a maximum cumulative value detector for output,
Based on the maximum accumulated phase signal, a detected block phase signal indicating the position of the detected block boundary is output.

  According to the present invention, in the spatial difference comparison determination, the horizontal difference signal is compared with the spatial difference of interest and the left and right peripheral spatial differences separately, and when the detection block phase signal is output. The block boundary is detected as an edge even when the signal change is large only on one side of the block boundary by performing block noise detection for each line constituting one frame. Even if the scale is small, a block noise detection device with high detection accuracy can be realized.

It is a block diagram which shows the block noise detection apparatus 100 which is Embodiment 1 of this invention. 3 is a block diagram showing a spatial difference comparison unit 101 that constitutes the block noise detection apparatus 100. FIG. (A) thru | or (c) are time charts which show operation | movement of the spatial difference comparison part 101 which comprises the block noise detection apparatus 100. FIG. (A) thru | or (c) are time charts which show operation | movement of the spatial difference comparison part 101 which comprises the block noise detection apparatus 100. FIG. 2 is a block diagram showing a phase accumulating unit 102 constituting the block noise detecting apparatus 100. FIG. (A) thru | or (j) are time charts which show operation | movement of the phase accumulation part 102 which comprises the block noise detection apparatus 100. FIG. FIG. 3 is a block diagram showing a maximum accumulation phase detection unit 103 constituting the block noise detection device 100. It is a block diagram which shows the block noise removal apparatus 200 comprised using the block noise detection apparatus 100 of Embodiment 1. FIG. It is a block diagram which shows the horizontal smoothing part 203 which comprises the block noise removal apparatus 200. FIG. (A) thru | or (e) are time charts which show operation | movement of the horizontal smoothing part 203 which comprises the block noise removal apparatus 200. FIG. It is a block diagram which shows an example of the smoothing process part 233 of FIG. It is a block diagram which shows the block noise detection apparatus 300 which is Embodiment 2 of this invention. FIG. 4 is a block diagram showing a phase mutual determination unit 104 constituting the block noise detection device 300. (A) thru | or (k) are time charts which show operation | movement of the phase mutual determination part 104 which comprises the block noise detection apparatus 300. FIG. It is a block diagram which shows the block noise removal apparatus 400 comprised using the block noise detection apparatus 300 of Embodiment 2. FIG. It is a block diagram which shows the block noise detection apparatus 500 which is Embodiment 3 of this invention. It is a block diagram which shows the block noise detection apparatus 600 which is Embodiment 4 of this invention. It is a block diagram which shows the block noise detection apparatus 700 which is Embodiment 5 of this invention. 5 is a block diagram showing a color difference signal horizontal smoothing unit 701 constituting the block noise detection device 700. FIG. FIG. 20 is a block diagram illustrating an example of a color difference signal smoothing processing unit 702 in FIG. 19. (A) thru | or (d) are time charts which show operation | movement of the smoothing process part 233 and the color difference signal smoothing process part 702. FIG. It is a block diagram which shows the block noise detection apparatus 800 which is Embodiment 6 of this invention.

  Hereinafter, a block noise detection device of the present invention and a block noise removal device including the block noise detection device will be described. The block noise detection apparatus of the present invention is for detecting block noise in a video signal compressed and expanded in units of a predetermined rectangular block. In the example described in detail below, the horizontal size of a block is 8. Assume that it is a pixel.

Embodiment 1 FIG.
FIG. 1 shows a block noise detection apparatus 100 according to Embodiment 1 of the present invention. The illustrated block noise detection apparatus 100 includes a spatial difference comparison unit 101, a phase accumulation unit 102, a maximum accumulation phase detection unit 103, and a control unit 109.

  The input video signal Va is supplied to the spatial difference comparison unit 101. At this time, the control unit 109 extracts the horizontal synchronization signal Hsync from the input video signal Va and supplies it to the phase accumulation unit 102.

  Further, in the control unit 109, a pixel clock CLKH having a period equal to the pixel sampling period is generated in synchronization with the horizontal synchronization signal Hsync and supplied to the phase accumulating unit 102.

  The control unit 109 also extracts the vertical synchronization signal Vsync, and the vertical synchronization signal Vsync and the horizontal synchronization signal Hsync are also used for control of the spatial difference comparison unit 101 and the maximum accumulation time phase detection unit 103, but the details are as follows. Omitted.

  The spatial difference comparison unit 101 calculates a spatial difference of the input video signal Va that has been input, compares the calculated spatial difference with a plurality of adjacent spatial differences, and determines the determination result as a spatial difference comparison determination signal SDJ. To the phase accumulating unit 102.

The phase accumulating unit 102 receives the input spatial difference comparison determination signal SDJ for each phase in the spatial direction (that is, eight phases having eight consecutive pixels that match the horizontal block size as one cycle. (According to each of the 8 phases).
Eight accumulated value signals CAV0 to CAV7 are output to the maximum accumulation phase detection unit 103 at a timing synchronized with the horizontal synchronization signal Hsync extracted from the input video signal Va.

  The maximum accumulation phase detection unit 103 detects the phase corresponding to the maximum value among the eight input accumulated value signals CAV0 to CAV7 (the phase when the accumulated value signal is maximized) as the block phase. Output as signal DBP. The detection of the phase corresponding to the maximum value of the accumulated value signals CAV0 to CAV7 and the output of the detection block phase signal DBP are performed for each line.

  FIG. 2 shows an example of the spatial difference comparison unit 101 constituting the block noise detection apparatus 100. The illustrated space difference comparison unit 101 includes a space difference calculation unit 111, an adjacent space difference holding output unit 112, and a space difference comparison determination unit 113.

  The spatial difference calculation unit 111 calculates the absolute value of the gradation difference between adjacent pixels for the input video signal Va input, and outputs the gradation difference to the adjacent spatial difference holding output unit 112 as a spatial difference signal SPD. To do. For example, as shown in FIG. 3A, in an input video signal Va having a gradation distribution having a block boundary BLB, adjacent pixels as shown in FIG. 3B with respect to the gradations of the pixels p0 and p1. The absolute value G0 of the tone difference between them is calculated and output as a spatial difference. Similarly, the absolute value of the gradation difference between adjacent pixels is calculated between other pixels.

  The adjacent spatial difference holding / outputting unit 112 holds the input spatial difference signal SPD by a plurality of flip-flops and outputs nine adjacent spatial difference signals G1 to G9 to the spatial difference comparison / determination unit 113. .

The spatial difference comparison / determination unit 113 has the fifth spatial difference signal value G5 out of the nine adjacent spatial difference signals G1 to G9 that are input, and all the four spatial difference signal values G1 to G1 that are the first to fourth. If it is larger than either G4 or any of the fourth to ninth spatial difference signal values G6 to G9, “1” is output as the spatial difference comparison determination signal SDJ. When the above condition is not satisfied, “0” is output as the spatial difference comparison determination signal SDJ. For example, in the spatial difference signal SDJ shown in FIG. 3B, since the spatial difference values G1 to G9 satisfy both the following expressions (1) and (2), as shown in FIG. “1” is output as the difference comparison determination signal SDJ.
G5> MAX (G1, G2, G3, G4) (1)
G5> MAX (G6, G7, G8, G9) (2)

  Similarly, as shown in FIG. 4A, the spatial difference calculation unit 111 outputs the spatial difference signal SPD shown in FIG. 4B with respect to the input video signal Va having a gradation distribution having the block boundary BLB. Then, the spatial difference comparison / determination unit 113 outputs a spatial difference comparison / determination signal SDJ shown in FIG. 4 (c) in response to the spatial difference signal SPD shown in FIG. 4 (b). At this time, in the spatial difference SPD shown in FIG. 4B, the spatial difference values G1 to G9 do not satisfy the expression (1), but satisfy the expression (2). Therefore, as shown in FIG. “1” is output as the difference comparison determination signal SDJ.

  In FIG. 4C, the spatial difference comparison determination signal SDJ is “1” at the pixel positions p6 and p14 of the phase PH6 that is the phase of the block boundary BLB, but also at the pixel positions p4 and p15 of a phase other than the block boundary BLB. The spatial difference comparison determination signal SDJ is “1”. However, while the spatial difference comparison determination signal SDJ is always “1” at the pixel position of the phase PH6, the spatial difference comparison determination signal SDJ is sometimes “1” at the pixel positions of other phases, and is often “0”. It is. Therefore, of the eight accumulated value signals CAV0 to CAV7 output from the phase accumulating unit 102, the phase when the accumulated value signal becomes the maximum is the phase of the block boundary BLB.

  FIG. 5 shows an example of the phase accumulating unit 102 constituting the block noise detecting apparatus 100. The illustrated phase accumulation unit 102 includes a phase number output unit 121, a spatial difference comparison determination signal distribution unit 122, and eight counters 1230 to 1237.

  The phase number output unit 121 operates in synchronization with the horizontal synchronization signal Hsync, detects the phase by counting the pixel clock CLKH, and generates the phase number signal PNS for sequentially specifying the phases PH0 to PH7. It outputs to the part 122.

  For example, the phase number output unit 121 assumes that the phase PH is a specific phase, for example, PH0, when the horizontal synchronization signal Hsync is received, and a value (number indicating the phase every time one pixel clock CLKH is input thereafter. ) Is incremented by 1 and when the maximum value PH7 is reached, the initial value PH0 is restored, and the same processing is repeated thereafter.

  The spatial difference comparison determination signal allocating unit 122 distributes the input spatial difference comparison determination signal SDJ to the counters 1230 to 1237 in accordance with the phase indicated by the input phase number signal PNS. Specifically, when the phase number signal PNS indicates a certain phase PHn (0 ≦ n ≦ 7), the nth spatial difference comparison determination signal SDJ is provided corresponding to the nth counter 123n (phase PHn). Output to the counter 123n).

  For example, when the spatial difference comparison determination signal SDJ is as shown in FIG. 6A and the phase number signal PNS is as shown in FIG. 6B, the spatial difference comparison determination signal SDJ at the position of the pixel p6 is “ 1 ”, and the phase number signal PNS indicates the phase PH6 at the position of the pixel p6. Therefore, as shown in FIGS. 6C to 6J, the counter 1236 corresponding to the phase PH6 has a space. “1” is output as the difference comparison determination signal SDJ.

  The counters 1230 to 1237 cumulatively add the spatial difference comparison determination signal SDJ input via the spatial difference comparison determination signal allocating unit 122, and the horizontal synchronization signal Hsync with the accumulated value for one line as the accumulated value signals CAV0 to CAV7. Output at the timing synchronized with.

  For example, when the number of pixels for one line is L, as shown in FIGS. 6C to 6J, a signal representing an accumulated value at the (L-1) th pixel p (L-1). Are output as accumulated value signals CAV0 to CAV7.

  FIG. 7 shows an example of the maximum accumulation phase detection unit 103 constituting the block noise detection apparatus 100. The illustrated maximum accumulation phase detection unit 103 includes a maximum accumulation value detection unit 131.

  The maximum cumulative value detection unit 131 compares the values of the eight input cumulative value signals CAV0 to CAV7, outputs the maximum cumulative value signal as the maximum cumulative value signal MAS, and accumulates the maximum value. A signal representing the phase (PHm) corresponding to the value signal (CAVm) is output as the maximum accumulated phase signal MAP. The process of outputting the cumulative value signal having the maximum value among the cumulative value signals CAV0 to CAV7 as the maximum cumulative value signal MAS, and the phase (PHm) corresponding to the cumulative value signal (CAVm) having the maximum value The process of outputting the signal representing the maximum accumulated phase signal MAP is performed for each line.

  In the first embodiment, the maximum accumulation phase signal MAP output from the maximum accumulation value detection unit 131 is used as the detection block phase signal DBP.

  FIG. 8 shows a block noise removing apparatus 200 configured using the block noise detecting apparatus 100 according to the first embodiment. The illustrated block noise removal apparatus 200 includes a horizontal block noise detection apparatus 201, a line memory 202, and a horizontal smoothing unit 203.

  The horizontal block noise detection device 201 has the same configuration as the block noise detection device 100 shown in FIG. 1, and outputs a detection block phase signal DBP to the horizontal smoothing unit 203 with respect to the input video signal Va. .

  The line memory 202 holds the input video signal Va for one line, and then outputs it to the horizontal smoothing unit 203 as a one-line delayed input video signal Vb.

  The horizontal smoothing unit 203 smoothes the input one-line delayed input video signal Vb at the phase specified by the detection block phase signal DBP of the line, and then outputs it as an output video signal Vd.

  FIG. 9 shows an example of the horizontal smoothing unit 203 constituting the block noise removing apparatus 200. The illustrated horizontal smoothing unit 203 includes a phase number output unit 231, a number comparison unit 232, a smoothing processing unit 233, and a selector 234.

  The phase number output unit 231 is the same as the phase number output unit 121 shown in FIG. 5, and receives the horizontal synchronization signal Hsync and the pixel clock CLKH output from the control unit 109 of the horizontal block noise detection device 201, and receives the horizontal number. By operating in synchronization with the synchronization signal Hsync and counting the pixel clock CLKH, the phase number signal PMS for sequentially specifying the phases PH0 to PH7 is output to the number comparison unit 232.

  The number comparison unit 232 compares the input phase number signal PMS with the input detection block phase signal DBP, and outputs a smoothing determination signal FPJ to the selector 234 according to the comparison result. Specifically, the detected block phase signal DBP indicates a certain phase PHn (0 ≦ n ≦ 7), and the phase PHn indicated by the phase number signal PNS is from phase (n−2) to phase (n + 1). In any case, “1” is output to the selector 234 as the smoothing process determination signal FPJ, and “0” is output to the selector 234 as the smoothing process determination signal FPJ when the above conditions are not satisfied. To do.

  For example, when the phase number signal PMS is as shown in FIG. 10A and the detection block phase signal DBP indicates the phase PH6 (n = 6), (n−2) = 4, (n + 1) ) = 7, and the phase number signal PMS indicates the phases PH4 to PH7 at the positions of the pixels p4 to p7. Therefore, as shown in FIG. “1” is output as the FPJ, and “0” is output as the smoothing process determination signal FPJ in the other pixels.

  The smoothing processing unit 233 performs a smoothing process on the input 1-line delayed input video signal Vb and outputs the smoothed output signal Vf to the selector 234.

  For example, when the one-line delayed input video signal Vb is as shown in FIG. 10C and has a block boundary BLB, the smoothed output signal Vf shown in FIG. Is output.

  FIG. 11 shows a configuration example of the smoothing processing unit 233. The illustrated smoothing processing unit 233 includes delay circuits 240g, 240h, 240i, and 240j, and an average value calculation unit 241.

  The delay circuit 240g gives a delay of one pixel sampling (delay of one pixel clock CLKH cycle) to the input one-line delayed input video signal Vb, and sends it to the delay circuit 240h as a one-pixel delayed input video signal Vg. Output. The delay circuit 240h gives a delay of one pixel sampling to the input one-pixel delayed input video signal Vg, and outputs it to the delay circuit 240i as a two-pixel delayed input video signal Vh. The delay circuit 240i gives a delay of one pixel sampling to the input two-pixel delayed input video signal Yh, and outputs it to the delay circuit 240j as a three-pixel delayed input video signal Vi. The delay circuit 240j gives a delay of one pixel sampling to the input 2-pixel delayed input video signal Vi, and outputs it to the average value calculation unit 241 as a 4-pixel delayed input video signal Yj.

  The average value calculation unit 241 receives the 1-line delayed input video signal Vb, the 1-pixel delayed input video signal Vg, the 2-pixel delayed input video signal Vh, the 3-pixel delayed input video signal Vi, and the 4-pixel delayed input video signal Vj. An average value is calculated and output as a smoothed output signal Vf. The average value calculated by the average value generation unit 241 may be a simple average value or a weighted average value.

  The selector 234 selects either the input smoothed output signal Vf or the input one-line delayed input video signal Vb according to the input smoothing processing determination signal FPJ, and outputs it as the output video signal Vd. To do. Specifically, when the smoothing process determination signal FPJ is “1”, the smoothed output signal Vf is selected and output as the output video signal Vd, and when the smoothing process determination signal FPJ is “0”. Selects one line delayed input video signal Vb and outputs it as an output video signal.

  For example, in the operations shown in FIGS. 10A to 10E, the smoothing determination signal FPJ is “1” at the positions of the pixels p4 to p7 as shown in FIG. As shown in FIG. 10E, the smoothed output signal Vf shown in FIG. 10D is output as the output video signal Vd at the positions of these pixels. On the other hand, since the smoothing process determination signal FPJ is “0” at the positions of the pixels other than the pixels p4 to p7, the output video signal Vd is shown in FIG. A one-line delayed input video signal Vb is output.

  As described above, in the spatial difference comparison determination, the input video signal is compared when the spatial difference of interest and the spatial difference between the left and right sides thereof are compared separately on the left and right sides, and the detection block phase signal DBP is output. A block noise detection device with high detection accuracy can be realized even if the circuit scale is small by outputting at a timing synchronized with the horizontal synchronization signal Hsync separated from Va and performing block noise detection for each line constituting one frame. be able to.

  In the above description, the number of the counters 1230 to 1237 constituting the block noise detection device 100 is eight in correspondence with the horizontal block size being eight pixels, but the block size is eight. Even if it is not, the number of counters (equivalent to 1230 to 1237) is provided accordingly, and the number of values that the phase number signals PNS and PMS can take is changed accordingly, so that the block size can be changed. A corresponding block noise detection device (or block noise removal device) can be configured.

Embodiment 2. FIG.
FIG. 12 shows a block noise detection apparatus 300 according to the second embodiment of the present invention. 12, the same reference numerals as those in FIG. 1 denote the same or similar components and signals, and the description of these components and signals is omitted. The block noise detection apparatus 300 shown in the figure is generally the same as the block noise detection apparatus shown in FIG. 1, but is different in that a phase mutual determination unit 104 is added. The phase mutual determination unit 104 is provided on the output side of the maximum cumulative phase detection unit 103, and the maximum cumulative phase signal MAP output from the maximum cumulative phase detection unit 103 is supplied to the phase mutual determination unit 104.

  In the block noise detection device 300 of FIG. 12, the control unit 109 extracts the horizontal synchronization signal Hsync as well as the vertical synchronization signal Vsync from the input video signal Va, and extracts the extracted horizontal synchronization signal Hsync and vertical synchronization signal Vsync. Is supplied to the phase mutual determination unit 104.

  The phase mutual determination unit 104 stores eight input maximum accumulated phase signals MAP for each of eight consecutive lines, compares them with each other, and the eight maximum accumulated phase signals MAP match each other. When this occurs, the maximum accumulated phase signal MAP is output as the detection block phase signal DBP.

  FIG. 13 shows an example of the phase mutual determination unit 104. The illustrated phase mutual determination unit 104 includes a line number output unit 141, a phase signal distribution unit 142, and a phase signal comparison determination unit 143.

  The line number output unit 141 operates in synchronization with the vertical synchronization signal Vsync and counts the horizontal synchronization signal Hsync, thereby outputting the line number signal LNS for sequentially specifying the line numbers PV0 to PV7 to the phase signal distribution unit 142. To do.

  The phase signal allocating unit 142 converts the input maximum accumulated phase signal MAP from any one of the line numbers PV0 to PV7 according to the line number indicated by the input line number signal LNS. A signal (any one of MAP0 to MAP7) is output to the phase signal comparison / determination unit 143. Specifically, when the line number signal LNS indicates a certain line number PVn (0 ≦ n ≦ 7), the maximum accumulation phase signal MAP is output as the line maximum accumulation phase signal MAPn in the nth line. .

  For example, when the maximum accumulated phase signal MAP is as shown in FIG. 14A and the line number signal LNS is as shown in FIG. 14B, the maximum accumulated phase signal MAP is at the position of the line L0. Since the line number signal LNS indicates “PH6” and the line number PV0, a signal indicating “PH6” is output as the line maximum accumulated phase signal MAP0 as shown in FIG.

  The phase signal comparison / determination unit 143 compares the inputted line maximum accumulated phase signals MAP0 to MAP7, and when the eight line maximum accumulated phase signals MAP0 to MAP7 coincide with each other, the line maximum accumulated phase signals MAP0 to MAP0. A signal having a value equal to MAP7 is output as the detection block phase signal DBP, and when they do not match, nothing is output as the detection block phase signal DBP.

  For example, in the operations shown in FIGS. 14A to 14K, since the values of the line maximum accumulated phase signals MAP0 to MAP7 all coincide with “PH6” at the position of the line L7, the detected block phase signal A signal representing “PH6” is output as DBP. This detection block phase signal DBP is the same in the same screen (field to frame), and all the values of the phase signal MAP0 to MAP7 at the time of the maximum line accumulation next match different values (values other than “PH6” in the above example). Until the same value ("PH6").

  In the example shown in FIGS. 14A to 14K, the value of the line maximum accumulated phase signal MAP0 is “PH0” at the position of the line L8 next to the line L7. Although the condition that the values of MAP0 to MAP7 coincide with each other is not satisfied, once the above condition is satisfied, the values of the phase signals MAP0 to MAP7 at the time of maximum line accumulation are all “PH6” on the screen. The detection block phase signal DBP representing “PH6” continues to be output until it matches a value other than “”. For example, if the values of the phase signals MAP0 to MAP7 at the time of maximum line accumulation all coincide with “PH2”, then the detection block phase signal DBP representing “PH2” is continuously output.

  FIG. 15 shows a block noise removing apparatus 400 configured using the block noise detecting apparatus 300 of the second embodiment. The illustrated block noise removal apparatus 400 includes a horizontal block noise detection apparatus 401, a line memory 204, and a horizontal smoothing unit 203. The horizontal smoothing unit 203 has the same configuration as that shown in FIG. 8, and a description thereof will be omitted.

  The horizontal block noise detection device 401 has the same configuration as the block noise detection device 300 shown in FIG. 12, and outputs a detection block phase signal DBP to the horizontal smoothing unit 203 with respect to the input video signal Va. .

  The line memory 204 holds the inputted input video signal Va for 8 lines, and then outputs it to the horizontal smoothing unit 203 as an 8-line delayed input video signal Vc.

  The operation of the horizontal smoothing unit 203 is the same as described with reference to FIG. However, in FIG. 8, a difference is that an 8-line delayed input video signal Vc is input while a 1-line delayed input video signal Vb is input. The 8-line delayed input video signal Vc is input instead of the 1-line delayed input video signal Vb in the phase mutual determination unit 104 in the block noise detection device 401 based on the data for 8 lines. This is because the signal DBP is generated, and the timing is adjusted to this.

  As described above, when the eight maximum accumulated phase signals MAP0 to MAP7 obtained from eight consecutive lines coincide with each other, the detection block phase signal DBP is output, thereby preventing erroneous detection of block noise. Can do.

  In the above description, the number of maximum cumulative phase signals MAP0 to MAP7 to be compared is eight. However, the number may be two or more, and the larger the number, the more effective for preventing false detection. On the other hand, the time required for the processing becomes long and the scale of the hardware used for the processing becomes large.

Embodiment 3 FIG.
FIG. 16 shows a block noise detecting apparatus 500 according to the third embodiment of the present invention. In FIG. 16, the same reference numerals as those in FIG. 1 denote the same or similar components and signals, and description of these components and signals is omitted. The block noise detection device 500 shown in the figure is generally the same as the block noise detection device shown in FIG. 1 except that a phase threshold value determination unit 105 is added. The phase threshold determination unit 105 is provided on the output side of the maximum accumulation phase detection unit 103, and the maximum accumulation value signal MAS and the maximum accumulation phase signal MAP output from the maximum accumulation phase detection unit 103 are the phase threshold determination unit. 105.

  The phase threshold determination unit 105 compares the input maximum accumulated value signal MAS with the threshold, and outputs the maximum accumulated phase signal MAP as the detection block phase signal DBP only when the maximum accumulated value signal MAS is larger.

  As described above, by outputting the maximum cumulative phase signal MAP as the detection block phase signal DBP only when the maximum cumulative value signal MAS is larger than the threshold value, a square or the like generated in a part of the screen is erroneously detected as block noise. Detection can be prevented.

  The block noise detection apparatus 500 shown in FIG. 16 can be used as the horizontal block noise detection apparatus 201 shown in FIG. 8 instead of the block noise detection apparatus 100 shown in FIG. .

Embodiment 4 FIG.
FIG. 17 shows a block noise removing apparatus 600 according to Embodiment 4 of the present invention. The block noise removing device 600 shown in the figure includes a signal separating unit 601, a horizontal block noise detecting device 201, a luminance signal line memory 202Y, a blue color difference signal line memory 202CB, a red color difference signal line memory 202CR, and a luminance signal horizontal smoothing. , A blue difference signal horizontal smoothing unit 203CB, and a red difference signal horizontal smoothing unit 203CR. The present embodiment is used when the input video signal Va is composed of three video signals of the input luminance signal Ya, the input blue difference signal CBa, and the input blue difference signal CRa.
The signal separation unit 601 separates the input video signal Va into an input luminance signal Ya, an input blue color difference signal CBa, and an input blue color difference signal CRa.

  The horizontal block noise detection apparatus 201 has the same configuration as that shown in FIG. 8, and receives the input luminance signal Ya constituting the input video signal Va, detects block noise in the input luminance signal Ya, and detects it. The block phase signal DBP is output to the luminance signal horizontal smoothing unit 203Y, the blue color difference signal horizontal smoothing unit 203CB, and the red color difference signal smoothing unit 203CR.

  The luminance signal line memory 202Y has the same configuration as the line memory 202 shown in FIG. 8, and after the input luminance signal Ya is input instead of the input video signal Va, the input luminance signal Ya is held for one line. The 1-line delayed input luminance signal Yb is output to the luminance signal horizontal smoothing unit 203Y.

  The blue color difference signal line memory 202CB has the same configuration as the line memory 202 shown in FIG. 8, and instead of the input video signal Va, the input blue color difference signal CBa is inputted, and the input blue color difference signal CBa is supplied for one line. After being held, it is output to the blue difference signal horizontal smoothing unit 203CB as a one-line delayed input blue difference signal CBb.

  The red color difference signal line memory 202CR has the same configuration as the line memory 202 shown in FIG. 8, and instead of the input video signal Va, an input red color difference signal CRa is inputted, and the input red color difference signal CRa is divided into one line. After being held, it is output to the red color difference signal horizontal smoothing unit 203CR as a one-line delayed input red color difference signal CRb.

  The luminance signal horizontal smoothing unit 203Y has the same configuration as the horizontal smoothing unit 203 shown in FIG. 8, and instead of the one-line delayed input video signal Vb, the one-line delayed input luminance signal Yb is input. The line delay input luminance signal Yb is smoothed at a phase specified by the detection block phase signal DBP of the line, and then output as an output luminance signal Yd.

  The blue difference signal horizontal smoothing unit 203CB has the same configuration as the horizontal smoothing unit 203 shown in FIG. 8, and instead of the one line delayed input video signal Vb, the one line delayed input blue difference signal CBb is input. The one-line delayed input blue color difference signal CBb is smoothed at a phase specified by the detection block phase signal DBP of the line, and then output as an output blue color difference signal CBd.

  The red difference signal horizontal smoothing unit 203CR has the same configuration as the horizontal smoothing unit 203 shown in FIG. 8, and instead of the one line delayed input video signal Vb, the one line delayed input red difference signal CBb is input. The one-line delayed input red color difference signal CRb is smoothed at a phase specified by the detection block phase signal DBP of the line, and then output as an output red color difference signal CRd.

  As described above, by performing smoothing processing on all three video signals of the input luminance signal Ya, the input blue difference signal CBa, and the input blue difference signal CRa constituting the input video signal Va, a red or blue screen is displayed. Block noise generated in the above can be removed.

Embodiment 5 FIG.
FIG. 18 shows a block noise removing apparatus 700 according to the fifth embodiment of the present invention. The block noise removing device 700 shown in the figure includes a signal separating unit 602, a horizontal block noise detecting device 201, a luminance signal line memory 202Y, a color difference signal 202C, a luminance signal horizontal smoothing unit 203Y, and a color difference signal horizontal smoothing unit. 701. In the present embodiment, the input video signal Va is composed of two video signals of an input luminance signal Ya and an input color difference signal Ca. The input color difference signal Ca is a data string configured such that data representing a blue color difference signal component and data representing a red color difference signal component appear alternately for each pixel. The horizontal block noise detection device 201, the luminance signal line memory 202Y, and the luminance signal horizontal smoothing unit 203Y have the same configuration as that shown in FIG.

  The signal separation unit 602 separates the input video signal Va into an input luminance signal Ya and an input color difference signal Ca.

  The color difference signal line memory 202C has the same configuration as that of the line memory 202 shown in FIG. 8. After the input color difference signal Ca is input instead of the input video signal Va, the input color difference signal Ca is held for one line. 1 line delayed input color difference signal Cb is output to the color difference signal horizontal smoothing unit 701.

  The chrominance signal horizontal smoothing unit 701 smoothes the input one-line delayed input chrominance signal Cb at a phase specified by the detection block phase signal DBP of the line, and then outputs it as an output blue difference signal Cd.

  FIG. 19 shows a color difference signal horizontal smoothing unit 701 constituting the block noise removing device 700. The illustrated color difference signal horizontal smoothing unit 701 includes a phase number output unit 231, a number comparison unit 232, a color difference signal smoothing processing unit 702, and a selector 234. The phase number output unit 231, the number comparison unit 232, and the selector 234 have the same configuration as that shown in FIG. 9 and will not be described.

  The color difference signal smoothing processing unit 702 smoothes the input 1-line delayed input color difference signal Cb and outputs the smoothed output signal Cf to the selector 234. The input color difference signal Ca is a signal in which the blue color difference signal and the red color difference signal are alternately arranged for each pixel as described above, and the 1-line delayed input color difference signal Cb is the same. It is configured.

  FIG. 20 shows a configuration example of the color difference signal smoothing processing unit 702 constituting the color difference signal horizontal smoothing unit 701. The illustrated color difference signal smoothing processing unit 702 includes delay circuits 240g, 240h, 240i, and 240j, and a color difference signal average value calculation unit 703. The delay circuits 240g, 240h, 240i, and 240j have the same configuration as that shown in FIG. However, instead of the one-line delayed video signal Vb, the one-line delayed input color difference signal Cb is input, and the one-pixel delayed input color difference signal Cg, the two-pixel delayed input color difference signal Ch, the three-pixel delayed input color difference signal Ci, and the four pixels, respectively. The delayed input color difference signal Cj is output.

  The color difference signal average value calculation unit 703 calculates an average value of the input 1-line delayed input color difference signal Cb, the 2-pixel delayed input color difference signal Ch, and the 4-pixel delayed input color difference signal Cj, and outputs it as a smoothed output signal Cf. To do. The calculation of the average value may be a simple average value calculation or a weighted average calculation.

  The luminance signal horizontal smoothing unit 203Y and the color difference signal horizontal smoothing unit 701 having the above configuration example perform operations as shown in FIG.

  21A shows the gradations of the pixels p0, p1, p2,... Sequentially supplied as the one-line delayed input luminance signal Yb by reference characters Y0, Y1, Y2,.

  Similarly, FIG. 21C shows the gradations of the pixels p0, p1, p2,... Sequentially supplied as the one-line delayed input color difference signal Cb by reference numerals CB0, CB1, CB2,.

  As shown in FIG. 21A, the luminance signal horizontal smoothing unit 203Y receives the pixel p2 and the pixel p2 at the timing when the luminance gradation Y4 of the pixel p4 is input to the delay circuit 240g as the one-line delayed input luminance signal Yb. The average gray level Yave2 of the luminance gray levels Y0 to Y4 of the surrounding pixels p0, p1, p3, and p4 is output as a smoothed output signal Yf as shown in FIG.

  In addition, as shown in FIG. 21C, the color difference signal horizontal smoothing unit 701 has a timing at which the red color difference gradation CB4 of the pixel p4 is input to the delay circuit 240g as the one-line delayed input color difference signal Cb. The gray level CBave2 of the average value of the red differences CB0, CB2, and CB4 of the pixel p2 and the surrounding pixels p0 and p4 is output as a smoothed output color difference signal Cf, as shown in FIG. At the timing when the blue difference gray level CR5 of the pixel p5 is input to the delay circuit 240g, the average gray level CRave3 of the red difference gray levels CR1, CR3, and CR5 of the pixel p3 and the surrounding pixels p1 and p5 is As shown in FIG. 21D, a smoothed output color difference signal Cf is output.

  In this way, the color difference signal average value calculation unit 703 alternately outputs the average value of the blue color difference gradation and the average value of the red color difference gradation for each pixel.

  As described above, the smoothing process is performed on the input video signal Va composed of the two video signals including the input luminance signal Ya and the input color difference signal Ca, thereby making it possible to perform horizontal smoothing as compared with the fourth embodiment. It is possible to reduce the number of conversion units from three to two, and the scale of the block noise removing apparatus 700 can be reduced to two thirds.

Embodiment 6 FIG.
FIG. 22 shows a block noise removing apparatus 800 according to the sixth embodiment of the present invention. The block noise removing device 800 shown in the figure includes a signal separating unit 601, a luminance signal block noise removing device 800Y, a blue color difference signal block noise removing device 800CB, and a red color difference signal block noise removing device 800CR.

  The signal separation unit 601 separates the input video signal Va into an input luminance signal Ya, an input blue color difference signal CBa, and an input blue color difference signal CRa.

  The luminance signal block noise removing device 800Y includes a luminance signal horizontal block noise detecting device 201Y, a luminance signal line memory 202Y, and a luminance signal horizontal smoothing unit 203Y.

  The blue color difference signal block noise removing device 800CB includes a blue color difference signal horizontal block noise detecting device 201CB, a blue color difference signal line memory 202CB, and a blue color difference signal horizontal smoothing unit 203CB.

  The red color difference signal block noise removing device 800CR includes a red color difference signal horizontal block noise detecting device 201CR, a red color difference line memory 202CR, and a red color difference signal horizontal smoothing unit 203CR.

  This embodiment is used when the input video signal Va is composed of three video signals of the input luminance signal Ya, the input blue difference signal CBa, and the input blue difference signal CRa.

  The luminance signal line memory 202Y, the blue color difference signal line memory 202CB, and the red color difference signal line memory 202CR have the same configurations as those shown in FIG.

  The horizontal block noise detection device 201Y has the same configuration as that shown in FIG. 17, and receives the input luminance signal Ya constituting the input video signal Va, detects block noise in the input luminance signal Ya, and detects it. The block phase signal DBP is output to the luminance signal horizontal smoothing unit 203Y.

  The blue difference signal horizontal block noise detection device 201CB has the same configuration as that shown in FIG. 8, and receives the input blue difference signal CBa constituting the input video signal Va as an input, and block noise in the input blue difference signal CBa. And the detected block phase signal DBP_CB is output to the blue color difference signal horizontal smoothing unit 203CB.

  The horizontal block noise detection device 201CR has the same configuration as that shown in FIG. 8, and receives the input red color difference signal CRa constituting the input video signal Va and detects block noise in the input red color difference signal CRa. The detection block phase signal DBP_CR is output to the red-difference horizontal smoothing unit 203CR.

  The luminance signal horizontal smoothing unit 203Y, the blue color difference signal horizontal smoothing unit 203CB, and the red color difference signal horizontal smoothing unit 203CR have the same configurations as those shown in FIG. To do. However, the blue difference signal horizontal smoothing unit 203CB operates in response to the horizontal synchronization signal Hsync_CB and the pixel clock signal CLKH_CB output from the blue difference signal horizontal block noise detection device 201CB, and the red difference signal horizontal smoothing unit 203CR is red. It operates in response to the horizontal synchronization signal Hsync_CR and the pixel clock signal CLKH_CR output from the difference signal horizontal block noise detector 201CR.

  As described above, the horizontal block noise detection devices 201Y, 201CB, and 201CR are respectively applied to the three video signals of the input luminance signal Ya, the input blue difference signal CBa, and the input red difference signal CRa that constitute the input video signal Va. By providing, even when the gradation of the input luminance signal Ya is constant and block noise occurs in at least one of the input blue color difference signal CBa and the input red color difference signal CRa, the block noise can be removed.

  With this configuration, block-like color noise generated on a blue or red screen, such as a blue sky or a sunset sky, can be removed.

  100, 300, 500 Block noise detection device, 101 Spatial difference comparison unit, 102 Phase accumulation unit, 103 Maximum accumulated phase detection unit, 104 Phase mutual judgment unit, 105 Phase threshold judgment unit, 111 Spatial difference calculation unit, 112 Adjacent space Difference holding output unit, 113 Spatial difference comparison / determination unit, 121, 231 Phase number output unit, 122 Spatial difference comparison / determination signal distribution unit, 1230-1237 counter, 131 Maximum accumulated value detection unit, 141 Line number output unit, 142 Phase Signal distribution unit, 143 Phase signal comparison / determination unit, 200, 400, 600, 700, 800 Block noise removal device, 201, 401 Horizontal block noise detection device, 201Y Luminance signal horizontal block noise detection device, 201CB Blue difference signal horizontal block Noise detection 201CR red difference signal horizontal block noise detection device, 201CB blue difference signal horizontal block noise detection device, 202 1 line memory, 202Y luminance signal 1 line memory, 202CB blue difference signal 1 line memory, 202CR red difference signal 1 line memory, 202C color difference signal 1 line memory, 203 horizontal smoothing unit, 203Y luminance signal horizontal smoothing unit, 203CB blue difference signal horizontal smoothing unit, 203CR red difference signal horizontal smoothing unit, 204 line memory, 232 number comparison unit, 233 smoothing Conversion processing unit, 234 selector, 240g, 240h, 240i, 240j delay circuit, 241 average value calculation unit, 701 color difference signal horizontal smoothing unit, 702 color difference signal smoothing processing unit, 703 color difference signal average value calculation unit.

Claims (16)

A block noise detection device that receives an input video signal, detects a block boundary, and outputs the block boundary,
A spatial difference calculation unit that calculates and outputs a spatial difference between adjacent pixels with respect to the input video signal, and a spatial difference obtained by comparing the spatial difference of interest and the spatial difference between the left and right sides separately from the left and right. A spatial difference comparison unit including a spatial difference comparison determination unit that outputs a comparison determination signal;
A phase provided with a plurality of counters that counts the spatial difference comparison determination signal for each phase and outputs a count value corresponding to each phase as a cumulative value signal at a timing synchronized with the horizontal synchronization signal of the input video signal Cumulative part,
A cumulative value signal having a maximum value among the plurality of cumulative value signals is output as a maximum cumulative value signal, and a phase corresponding to the cumulative value signal having the maximum value is set as a maximum cumulative phase signal. A maximum cumulative phase detector with a maximum cumulative value detector for output,
A block noise detection device that outputs a detection block phase signal indicating a position of a detected block boundary based on the maximum cumulative phase signal. The spatial difference comparison / determination unit is configured such that the spatial difference of interest is greater than any of the predetermined number of spatial differences located on the left side thereof, or greater than any of the predetermined number of spatial differences located on the right side thereof. The block noise detection apparatus according to claim 1, wherein the spatial difference comparison determination signal is output based on the determination result.   The block noise detection device according to claim 1, wherein the maximum cumulative phase signal is output as the detection block phase signal.   The block noise detection apparatus according to claim 1, wherein the number of the counters is equal to the number of pixels representing a block size.   The block noise detection apparatus according to claim 4, wherein the block size is eight.   A phase signal that receives the maximum accumulated phase signal, compares the plurality of maximum accumulated phase signals respectively obtained from a plurality of continuous lines, and outputs the detected block phase signal when all coincide with each other The block noise detection apparatus according to claim 1, further comprising a phase mutual determination unit including a comparison determination unit. A phase threshold determination unit that compares the maximum cumulative value signal with a threshold and outputs the maximum cumulative phase signal as a detection block phase signal only when the maximum cumulative value signal is larger, is further characterized in that,
The block noise detection device according to claim 1. A block noise detection method for receiving an input video signal and detecting and outputting a block boundary,
For the input video signal, calculate the spatial difference between adjacent pixels,
From the result of comparing the spatial difference of interest and the spatial difference around the left and right separately, output a spatial difference comparison determination signal,
The spatial difference comparison determination signal is counted for each phase, and the count value corresponding to each phase is output as a cumulative value signal at a timing synchronized with the horizontal synchronization signal of the input video signal,
The phase corresponding to the cumulative value signal having the maximum value among the plurality of cumulative value signals is output as the maximum cumulative phase signal,
A block noise detection method for outputting a signal indicating the position of a detected block boundary as a detection block phase signal based on the maximum cumulative phase signal. From the result of determining whether the spatial difference of interest is greater than any of the predetermined number of spatial differences located on the left side or greater than any of the predetermined number of spatial differences located on the right side thereof The block noise detection method according to claim 8, wherein the spatial difference comparison determination signal is output. The block noise detection method according to claim 8 or 9, wherein a plurality of the maximum accumulated phase signals respectively obtained from a plurality of continuous lines are compared, and a detection block phase signal is output when all coincide with each other. . The block noise detection method according to claim 8 or 9, wherein the maximum cumulative value signal is compared with a threshold value, and the maximum cumulative phase signal is output as a detection block phase signal only when the maximum cumulative value signal is larger. A block noise detection device according to any one of claims 1 to 7,
A smoothing processing unit that smoothes the input video signal and outputs the smoothed video output signal; a phase corresponding to the detection block phase signal among the input video signal and the smoothed output signal; and A horizontal smoothing unit including a selector that outputs the smoothed output signal as a phase within a predetermined range before and after that and the input video signal as an output video signal in another phase. Noise removal device. Block noise is detected by the block noise detection method according to any one of claims 8 to 11,
The input video signal is smoothed and output as a smoothed output signal.
Of the input video signal and the smoothed output signal, the smoothed output signal is output in the phase corresponding to the maximum accumulated phase signal and the phase within a predetermined range before and after the phase, and the input video signal is output in the other phases. Block noise removal method to output as video signal. A block noise removing device comprising: the block noise detecting device according to claim 1; a luminance signal horizontal smoothing unit; a blue difference signal horizontal smoothing unit; and a red difference signal horizontal smoothing unit. There,
As the input video signal, an input luminance signal, an input blue difference signal and an input red difference signal are input,
The block noise detection device outputs the detection block phase signal based on the input luminance signal,
The luminance signal horizontal smoothing unit performs a smoothing process on the input luminance signal and outputs the smoothed luminance output signal, and among the input luminance signal and the smoothed luminance output signal, A selector that outputs the smoothed luminance output signal in a phase corresponding to the detection block phase signal and a phase within a predetermined range before and after the phase, and a selector that outputs the input luminance signal as an output luminance signal in other phases;
The blue difference signal horizontal smoothing unit smoothes the input blue difference signal and outputs the smoothed blue difference output signal as a smoothed blue difference output signal; the input blue difference signal and the smoothed blue difference Among the output signals, the smoothed blue difference output signal is output as the output blue difference signal at the phase corresponding to the detection block phase signal and the phase within the predetermined range before and after the phase, and the input blue difference signal at the other phase. With a selector,
The red color difference signal horizontal smoothing unit smoothes the input red color difference signal and outputs it as a smoothed red color difference output signal; the input red color difference signal and the smoothed red color difference Among the output signals, the smoothed red color difference output signal is output as the output red color difference signal at the phase corresponding to the detection block phase signal and the phase within the predetermined range before and after the phase, and the input red color difference signal is output at the other phase A block noise removing device comprising: a selector. A block noise removing device comprising the block noise detecting device according to any one of claims 1 to 7, a luminance signal horizontal smoothing unit, and a color difference signal horizontal smoothing unit,
As the input video signal, a signal including an input luminance signal and an input color difference signal is input,
The block noise detection device detects block noise based on the input luminance signal, and outputs the detection block phase signal,
The luminance signal horizontal smoothing unit performs a smoothing process on the input luminance signal and outputs the smoothed luminance output signal, and among the input luminance signal and the smoothed luminance output signal, A selector that outputs the smoothed luminance output signal in a phase corresponding to the detection block phase signal and a phase within a predetermined range before and after the phase, and a selector that outputs the input luminance signal as an output luminance signal in other phases;
A smoothing processing unit that performs a smoothing process on the input color difference signal constituting the input video signal and outputs the smoothed color difference output signal;
The color difference signal horizontal smoothing unit smoothes the input color difference signal and outputs a smoothed color difference output signal, and among the input color difference signal and the smoothed color difference output signal, A selector that outputs the smoothed chrominance output signal as the output chrominance signal at the phase corresponding to the detection block phase signal and the phase within a predetermined range before and after the phase; Block noise elimination device. A block noise removing device comprising a luminance signal block noise removing device, a blue color difference signal block noise removing device, and a red color difference signal block noise removing device,
As the input video signal, an input luminance signal, an input blue difference signal, and an input red difference signal are input,
8. The block noise detecting device according to claim 1 and a horizontal smoothing each of the luminance signal block noise removing device, the blue color difference signal block noise removing device, and the red color difference signal block noise removing device. With
The block noise detection device of the luminance signal block noise removal device outputs the detection block phase signal based on the input luminance signal,
The horizontal smoothing unit of the luminance signal block noise removing device smoothes the input luminance signal and outputs the smoothed luminance output signal, and the input luminance signal and the smoothing. Among the luminance output signals, the smoothed luminance output signal is different in the phase corresponding to the detected block phase signal output by the block noise detecting device of the luminance signal block noise removing device and the phase within a predetermined range before and after the phase. A selector that outputs the input luminance signal as an output luminance signal in the phase of
The horizontal smoothing unit of the blue difference signal block noise removing device smoothes the input blue difference signal and outputs the smoothed blue difference output signal, and the input blue difference signal. Among the smoothed blue difference output signals and the phase corresponding to the detected block phase signal output by the block noise detecting device of the blue difference signal block noise removing device and the phase within a predetermined range before and after the phase. A blue difference output signal, and a selector that outputs the input blue difference signal as an output blue difference signal in other phases;
The horizontal smoothing unit of the red difference signal block noise removing device smoothes the input red difference signal and outputs it as a smoothed blue difference output signal; and the input red difference signal Among the smoothed red color difference output signals and the phase corresponding to the detected block phase signal output by the block noise detection device of the red color difference signal block noise removing device and the phase within a predetermined range before and after the phase. A block noise removing apparatus comprising: a selector that outputs a red color difference output signal as an output red color difference signal at another phase.

Images