JP2006260520A - Image processor, image processing method, and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor capable of improving display image quality, by performing contour correction processing suitable for each of a still image area and a moving image area. <P>SOLUTION: A contour width of a contour part in an input image is detected (31), the amount of magnification control for specifying for every pixel, the interpolation magnification of interpolation pixels to correct the contour part of the input image is generated, based on the contour width (33), between each frame variation of the input image is obtained for each pixel (10), and pixel data of the interpolation pixels is calculated by interpolation operation, using the conversion magnification obtained through adjustment of the magnification control amount according to the variation amount (34). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus and method for correcting a contour of a digital image to a desired sharpness, and an image display apparatus using the image processing apparatus.

  As an image processing method for correcting the contour portion of an image to increase the sharpness, there is one disclosed in the following cited document. The image processing method disclosed in the cited document 1 calculates an absolute value of a differential value of an input image signal and an average value of the absolute value, obtains a difference value obtained by subtracting the average value from the calculated absolute value, The image enlargement / reduction ratio is controlled in accordance with the difference value. In this way, by controlling the enlargement / reduction ratio of the image according to the change of the image signal, it is possible to use the image enlargement / reduction circuit to make the rising and falling edges sharp and to increase the sharpness of the image. it can.

The image processing method disclosed in the cited document 2 generates a control amount based on a high frequency component of an image signal when converting the number of pixels of an input image, and uses this control amount in an interpolation filter for pixel number conversion. Controls the interpolation phase. In this way, by controlling the interpolation phase based on the high frequency component of the image, it is possible to make the change in the contour portion of the image steep and increase the sharpness of the image.
JP 2002-16820 A JP 2000-101870 A

In the conventional image processing method disclosed in the above cited document, the sharpness of the contour is improved based on the amount of the high frequency component of the image. There is a problem that the sharpness is difficult to be improved in the contour portion where the difference is small. Also, since the same processing is performed in the moving image area and the still image area, if sharpness improvement is performed in accordance with the still image area, the moving image area lacks sharpness, and if the contour improvement is performed in accordance with the moving image area, the still image There is a problem in that the sharpness is too strong in the part and the image becomes unnatural.
Furthermore, there is a problem that flicker is emphasized more in an image including flicker by increasing the sharpness of the outline.

The present invention has been made to solve the above-described problems, and image processing that can improve the display image quality by performing contour correction processing suitable for each of a still image region and a moving image region. An object is to provide an apparatus.
It is another object of the present invention to provide an image processing apparatus capable of improving the sharpness of an outline without enhancing flicker.

An image processing apparatus according to the present invention is an image processing apparatus that corrects a contour portion of an input image,
Magnification control for detecting the contour width of the contour portion in the input image and generating a magnification control amount for designating the interpolation magnification of the interpolation pixel for correcting the contour portion of the input image for each pixel based on the contour width A quantity generating means;
A magnification generating means for obtaining a change amount between the input image and an image one frame before the input image for each pixel, adjusting the magnification control amount according to the change amount, and generating a conversion magnification;
Interpolation calculation means for calculating pixel data of the interpolation pixel by interpolation calculation using the conversion magnification and outputting image data in which the contour portion is corrected is provided.

An image processing method according to the present invention is an image processing method for correcting a contour portion of an input image,
Detecting a contour width of a contour portion in the input image, and generating a magnification control amount for designating, for each pixel, an interpolation magnification of an interpolation pixel for correcting the contour portion of the input image based on the contour width;
Obtaining a change amount between the input image and the image one frame before the input image for each pixel, adjusting the magnification control amount according to the change amount, and generating a conversion magnification;
Calculating pixel data of the interpolated pixel by an interpolation operation using the conversion magnification, and outputting image data in which the contour portion is corrected.

  The image processing apparatus according to the present invention generates a magnification control amount for designating, for each pixel, an interpolation magnification of an interpolation pixel for correcting the contour portion based on the contour width, and according to a change amount between one frame of the input image. Since the pixel data of the interpolation pixel is calculated using the conversion magnification obtained by adjusting the magnification control amount, by making the contour portion in the moving image area steeper in the image in which the moving image area and the still image area are mixed, The blur of the image in the moving image area can be improved, and a clearer image can be obtained.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing an embodiment of an image display apparatus provided with an image processing apparatus according to the present invention. The image display apparatus shown in FIG. 1 includes a reception unit 1, an image processing unit 2, an output synchronization signal generation unit 7, a transmission unit 8, and a display unit 9. The image processing unit 2 includes a conversion unit 3, a storage unit 4, a contour correction unit 5, a conversion unit 6, and a comparison determination unit 10.

  The receiving unit 1 receives an image signal Di and a synchronization signal Si input from the outside, converts them into digital image data Da, and outputs them together with the synchronization signal Sa. The receiving unit 1 is configured by an A / D converter when the image signal Di is an analog signal. Further, when the image signal Di is a serial digital signal or a parallel digital signal, the image signal Di is configured by a receiver corresponding to the format of the input image signal, and includes a receiver such as a tuner as appropriate.

  The image data Da may be composed of R, G, B3 primary color data or luminance component and color component data. Here, the R, G, B3 primary color data is used. The description will be made assuming that it is configured.

The image data Da and the synchronization signal Sa output from the reception unit 1 are input to the conversion unit 3 of the image processing unit 2. Further, the synchronization signal Sa is also input to the output synchronization signal generator 7.
The conversion unit 3 converts image data Da composed of color data of R, G, B3 primary colors into luminance data DY and color difference data DCr, DCb, and delays the synchronization signal Sa by a time necessary for conversion of the image data Da. Then, the delayed synchronization signal DS is output. The luminance data DY, the color difference data DCr and DCb, and the synchronization signal DS output from the conversion unit 3 are sent to the storage unit 4.

  The storage unit 4 temporarily stores the luminance data DY and the color difference data DCr and DCb output from the conversion unit 3. The storage unit 4 is a frame frequency conversion memory that converts an image signal output from a PC (personal computer) or a device having a different frame frequency, such as a television, to a fixed frame frequency (for example, 60 Hz), or an image for one screen. A frame memory used as a frame buffer for holding data is provided, and luminance data DY and color difference data DCr, DCb are stored in the frame memory.

  The output synchronization signal generation unit 7 generates a synchronization signal QS indicating the timing for reading the luminance data DY and the color difference data DCr and DCb stored in the storage unit 4 and outputs the synchronization signal QS to the storage unit 4. Here, the output synchronization signal generation unit 7 is different from the synchronization signal Sa when performing frame frequency conversion in the frame memory of the storage unit 4, that is, when outputting image data having a frame frequency different from the image data Da from the storage unit 4. A period synchronization signal QS is generated. When the frame frequency is not converted in the storage unit 4, the synchronization signal QS and the synchronization signal Sa are equal.

  The storage unit 4 reads the luminance data DY and the color difference data DCr and DCb based on the synchronization signal QS from the output synchronization signal generation unit 7, and the timing-adjusted luminance data QY and color difference data QCr and QCb to the contour correction unit 5. Output. The storage unit 4 also outputs the luminance data RY one frame before the luminance data QY to the comparison determination unit 10.

  The comparison determination unit 10 detects a change in luminance level between frames in each pixel by calculating a difference between the luminance data QY read from the storage unit 4 and the luminance data RY of the previous frame for each pixel. The comparison determination unit 10 generates an image processing adjustment coefficient QF for adjusting the contour correction amount in the subsequent contour correction unit 5 based on the luminance level change between frames, and outputs the image processing adjustment coefficient QF to the contour correction unit 5.

  The contour correction unit 5 performs contour correction processing on the luminance data QY output from the storage unit 4 based on the image processing adjustment coefficient QF output from the comparison determination unit 10, and uses the luminance data ZYa corrected in contour as color difference data. It outputs to the conversion part 6 with QCr and QCb.

  The conversion unit 6 converts the luminance data ZYa and the color difference data QCr, QCb into image data Qb in a format that can be displayed by the display unit 9 and outputs the image data Qb to the transmission unit 8. Specifically, image data composed of luminance data and color difference data is converted into image data composed of color data of three primary colors of R, G, and B. This is not the case when the data format receivable by the display unit 9 is other than the image data composed of the three primary color data, and the conversion unit 6 converts the data into an appropriate format.

  The display unit 9 is configured by a display device such as a liquid crystal panel, a plasma panel, a CRT, or an organic EL, and displays the image data Qc output from the transmission unit 8 at the timing indicated by the synchronization signal Sc.

  FIG. 2 is a block diagram showing a detailed internal configuration of the image processing unit 2 shown in FIG. As shown in FIG. 2, the storage unit 4 includes a frame memory 13 and a frame memory control unit 11. As described above, the frame memory 13 is used as a frame frequency conversion memory or a frame buffer for holding image data for at least one screen, and is a frame memory provided for a general image display device. Can be used.

  FIG. 3 is a block diagram showing an internal configuration of the frame memory control unit 11 shown in FIG. As shown in FIG. 3, the frame memory control unit 11 includes a write control unit 14 and a read control unit 19. The write control unit 14 includes line buffers 15, 16, and 17 and a write address control unit 18, and the read control unit 19 includes line buffers 20, 21, 22, and 23, and a read address control unit 24.

Hereinafter, the operation of the image processing unit 2 will be described in detail.
As shown in FIG. 2, the conversion unit 3 converts the image data Da into luminance data DY and color difference data DCr and DCb, and outputs them to the frame memory control unit 11 of the storage unit 4. At the same time, the conversion unit 3 delays the synchronization signal Sa by a time necessary for the conversion process of the image data Da, and outputs the delayed synchronization signal DS to the frame memory control unit 11.

  As shown in FIG. 3, the luminance data DY and the color difference data DCr and DCb input to the frame memory control unit 11 are input to the line buffers 15, 16 and 17 of the write control unit 14, respectively. The write address control unit 18 generates a write address WA for writing the luminance data DY and the color difference data DCr and DCb input to the line buffers 15, 16, and 17 into the frame memory 13 based on the synchronization signal DS. Luminance data DY and color difference data DCr and DCb read from the line buffers 15, 16, and 17 are written in the frame memory 13 as image data WD corresponding to the write address WA.

  On the other hand, the read address control unit 24 sets the read address RA for reading the luminance data DY and the color difference signals DCr and DCb written in the frame memory 13 based on the synchronization signal QS output from the output synchronization signal generation unit 7. Generate and output. The frame memory 13 outputs the data RD read based on the read address RA to the line buffers 20, 21, 22 and 23. The line buffers 20, 21, and 22 output the brightness data QY and the color difference data QCr and QCb that have been adjusted in timing to the contour correction unit 5.

  As shown in FIG. 2, the luminance data QY input to the contour correction unit 5 is input to the vertical contour correction unit 12. The vertical contour correction unit 12 performs vertical contour correction processing on the luminance data QY and outputs luminance component data ZYa after contour correction to the conversion unit 6 (details of the contour correction processing will be described later). Here, when the contour correction process in the vertical direction is performed, a delay corresponding to a predetermined number of lines occurs between the corrected luminance data ZYa and the corrected luminance data QY. If the number of delay lines is k lines, a delay corresponding to k lines also occurs between the luminance data QY and the color difference data QCr, QCb. Therefore, the frame memory control unit 11 delays and outputs the color difference data QCr, QCb by k lines so that the corrected luminance data ZYa and the color difference data QCr, QCb are input to the conversion unit 6 in synchronization. Specifically, the read address control unit 24 of the frame memory control unit 11 generates the read address RA so that the color difference data QCr and QCb are read with a delay of k lines with respect to the luminance data QY.

  FIG. 4 is a diagram showing luminance data RY, QY and color difference data QCr, QCb output from the frame memory control unit 11 in one line cycle, and luminance data ZYa after contour correction output from the vertical contour correction unit 12. is there. In FIG. 4, QSh indicates one line period. As shown in FIG. 4, the color difference data QCr and Qcb are read out with a delay of the line period k necessary for the contour correction unit 5 to perform the contour correction processing with respect to the luminance data QY.

  As described above, the image data is converted into the luminance data DY and the color difference data DCr and DCb and written into the frame memory 13, the luminance data of the necessary number of lines is read out and the contour correction processing is performed. By reading data with a delay of the number of lines necessary for the correction process, it is possible to reduce the line memory necessary for adjusting the timing of the color difference data. Further, the capacity of the frame memory 13 is reduced and the bus bandwidth between the frame memory 13 and the frame memory control unit 11 is saved as compared with the case where the contour correction processing is performed on the R, G, B color data. be able to.

  FIG. 5 is a diagram showing luminance data RY and QY and color difference data QCr and QCb output from the frame memory control unit 11 in one frame period, and luminance data ZYa after contour correction output from the vertical contour correction unit 12. is there. In FIG. 5, QSv indicates one frame period. As shown in FIG. 5, the luminance data RY is read with a delay of one frame period with respect to the luminance data QY.

  The luminance data QY and RY output from the frame memory control unit 11 are input to the comparison determination unit 10 as shown in FIG. The comparison / determination unit 10 calculates a difference between the luminance data QY and the luminance data RY of the previous frame for each pixel, thereby obtaining an inter-frame luminance difference | QY−RY | indicating the luminance change of the image. The value of the inter-frame luminance difference | QY−RY | is small in the still image region where the image motion is small and is large in the moving image region where the image motion is large. The comparison determination unit 10 generates an image processing adjustment coefficient QF for adjusting the contour correction amount in the contour correction unit 5 for each pixel data of the luminance data QY based on the inter-frame luminance difference | QY−RY |.

  FIG. 6 is a diagram illustrating an example of the relationship between the inter-frame luminance difference | QY−RY | and the image processing adjustment coefficient QF. The horizontal axis of FIG. 6 indicates the inter-frame luminance difference | QY-RY | of the input image, and the vertical axis indicates the image processing adjustment coefficient QF. The comparison determination unit 10 compares the inter-frame luminance difference | QY−RY | with a predetermined threshold value Fm, the region A where | QY−RY | ≦ Fs is a still image region, and the region where | QY−RY |> Fs. B is determined as a moving image area, an image processing adjustment coefficient in the area A is QF = QFs, and an image processing adjustment coefficient in the area B is QF = QFm (where QFs <QFm).

FIG. 7 is a diagram illustrating another example of the relationship between the inter-frame luminance difference | QY−RY | and the image processing adjustment coefficient QF. According to the characteristics shown in FIG. 7, the comparison / determination unit 10 compares the inter-frame luminance difference | QY−RY | with predetermined threshold values Fl and Fh, and determines the region A where | QY−RY | ≦ Fl as a still image region. , Fl <| QY−RY | ≦ Fh is determined as an intermediate region, and region B where Fh <| QY−RY | is determined as a moving image region, and an image processing adjustment coefficient in region A is QF = QFs, region B Let Fs <QF <QFm for the image processing adjustment coefficient in Q, and QF = QFm for the image processing adjustment coefficient in region B.
As shown in FIG. 7, the value of the image processing adjustment coefficient QF is small in the still image area and large in the moving image area. According to the characteristics shown in FIG. 7, since the image processing adjustment coefficient QF can be continuously changed according to the inter-frame luminance difference | QY-RY |, the inter-frame luminance difference | QY-RY due to the influence of noise or the like. Even when | varies, the value of the image processing adjustment coefficient QF can be stably output.

The image processing adjustment coefficient QF generated by the comparison determination unit 10 is input to the contour correction unit 5. Here, the operation of the image processing adjustment coefficient QF in the contour correction process will be described.
FIG. 8 is a diagram illustrating an example of a moving image. In FIG. 8, a region indicated by S is a still image region where no image change occurs between frames, and a region indicated by M is a moving image region where an image changes between frames. In an image in which a moving image region and a still image region are mixed as shown in FIG. 8, the moving image region appears more blurred than the still image region, so it is desirable to increase the sharpness of the contour portion. As shown in FIGS. 6 and 7, since the value of the image processing adjustment coefficient QF is small in the still image area and large in the moving image area, the contour correction processing increases the sharpness of the contour portion according to the value of the image processing adjustment coefficient QF. By performing the above, the sharpness of the contour portion is more emphasized in the moving image region where the blurring occurs, so that a clearer moving image can be obtained.

Hereinafter, the configuration and operation of the contour correction unit 5 will be described in detail. As shown in FIG. 2, the luminance data QY input to the contour correction unit 5 is input to the vertical contour correction unit 12.
FIG. 9 is a block diagram showing an internal configuration of the vertical contour correction unit 12. The vertical contour correcting unit 12 includes line delays 25 and 28 and a contour width correcting unit 26. The contour width correction unit 26 includes a contour width detection unit 31, a magnification control amount generation unit 32, a multiplier 320, a magnification generation unit 33, and an interpolation calculation unit 34.

The line delay 25 outputs luminance data QYa having the number of pixels necessary for the contour width correction process in the vertical direction in the contour width correction unit 31. When the contour width correction process is performed using 11 pixels arranged in the vertical direction, the luminance data QYa is composed of 11 pixel data.
FIG. 10 is a timing chart of the luminance data QY delayed by the line delay 25, and shows a case where the number of pixels of the luminance data QYa is 2ka + 1. As shown in FIG. 10, the line delay 25 delays luminance data QY for 2 ka + 1 lines, and outputs luminance data QYa for 2 ka + 1 pixels arranged in the vertical direction by simultaneously reading one pixel from each line. The luminance data QYa is input to the contour width detector 31 and the interpolation calculator 34.
The line delay 28 outputs the image processing adjustment coefficient QF1 corresponding to each pixel data of the luminance data QYa output by the line delay 25 by delaying the image processing adjustment coefficient QF.

  FIG. 11 is a diagram for explaining the contour width correction processing in the contour width correction unit 26. FIG. 11A shows the contour width Wa and the reference position PM detected by the contour width detector 31. The detected contour width Wa and reference position PM are input to the magnification control amount generation unit 32.

  The magnification control amount generation unit 32 outputs a magnification control amount ZC used for contour width correction based on the detected contour width Wa and the reference position PM. FIG. 11B shows the magnification control amount. The magnification control amount ZC is a control amount for designating the interpolation magnification (interpolation density) of each pixel for each pixel when obtaining the pixel for correcting the contour by interpolation calculation described later, and is shown in FIG. Thus, the contour front part b and the contour rear part c are positive, the contour center part c is negative, the other parts are zero, and the sum in the contour part is zero. The magnification control amount ZC is input to the multiplier 320 together with the image processing adjustment coefficient QF1 output by the line delay 28.

  The multiplier 320 outputs the adjusted magnification control amount ZFC by adding the image processing adjustment coefficient QF1 to the magnification control amount ZC. FIG. 11C is a diagram showing the magnification control amount ZCF adjusted by the image processing adjustment coefficient QF1. The magnification control amount ZFC shown in FIG. 11C changes according to the value of the image processing coefficient QF1. That is, the magnification control amount ZFC has a large amplitude in a moving image region where the image change is large.

  The magnification generation unit 33 generates a conversion magnification Z by superimposing a magnification control amount ZCF on a preset reference conversion magnification Z0 of the entire image. FIG. 11D shows the conversion magnification Z. The conversion magnification Z is larger than the reference conversion magnification Z0 at the contour front part b and the contour rear part d, and smaller than the reference conversion magnification Z0 at the contour center part c, and the average of the conversion magnifications Z is equal to the reference conversion magnification Z0. When this reference magnification is Z0> 1, enlargement processing for increasing the number of pixels is performed in the contour width correction processing, and when Z0 <1, reduction processing for reducing the number of pixels is performed. When the reference conversion magnification is set to Z0 = 1, only the contour correction process is performed.

The interpolation calculation unit 34 calculates pixel data of an interpolation pixel for correcting the contour portion by performing an interpolation calculation process on the luminance data QYa based on the conversion magnification Z. During the interpolation calculation process, the interpolation density is high at the contour front portion b and the contour rear portion d where the conversion magnification Z is larger than the reference conversion magnification Z0, and the interpolation density is high at the contour central portion c where the conversion magnification Z is smaller than the reference magnification Z0. Lower. That is, enlargement processing for relatively increasing the number of pixels is performed at the front contour portion b and the rear contour portion d, and reduction processing for relatively decreasing the number of pixels is performed at the contour center portion c.
FIG. 11E is a diagram showing luminance data ZYa that has undergone pixel number conversion and contour width correction based on the conversion magnification Z shown in FIG. By reducing the image at the contour center portion c and enlarging the image at the contour front portion b and the contour rear portion d, the contour width is reduced as shown in FIG. The sharpness of the image can be improved.

  Here, the magnification control amount ZC generated based on the contour width Wa is generated such that the sum in the periods b, c, and d becomes zero. That is, if the areas of the hatched portions in FIG. 11B are Sb, Sc, and Sd, respectively, they are generated so that Sb + Sd = Sc. For this reason, although the conversion magnification Z varies locally, the conversion magnification Z0 in the entire image is equal to the reference conversion magnification Z0. In this way, by generating the magnification control amount ZC so that the total sum of the conversion magnifications Z becomes equal to the reference conversion 0, the contour width can be corrected without causing an image shift in the contour portion.

  FIG. 12 is a diagram illustrating a difference in contour correction amount between a still image region and a moving image region. 12A shows luminance data QYa, FIG. 12B shows conversion magnification Z, and FIG. 12C shows luminance data ZYa after contour correction. In FIG. 12B, the solid line indicates the conversion magnification Z in the moving image area, and the broken line indicates the conversion magnification Z in the still image area. In FIG. 12C, the solid line indicates the luminance data ZYa after contour correction in the moving image region, and the broken line indicates the luminance data ZYa after contour correction in the still image region.

  In the moving image area, the value of the image processing adjustment coefficient QF1 integrated with the magnification control amount ZC is larger than that in the still image area. Therefore, as shown in FIG. The moving image area (solid line) is larger than the broken line). That is, the reduction ratio at the contour center portion c increases, and the image enlargement ratio at the contour front portion b and the contour rear portion d increases. For this reason, as shown in FIG. 12C, the contour width Wc of the luminance data ZYa after contour correction in the moving image region is narrower than the contour width Wb in the still image region, and the sharpness is increased. Thereby, the blur of the image generated in the moving image area can be improved.

  As described above, the image processing apparatus according to the present invention adjusts the sharpness of the contour portion according to the luminance change between frames, so that the contour portion in the moving image region in an image in which the moving image region and the still image region are mixed. By making the image sharper, blurring of the image in the moving image region can be improved and a clearer image can be obtained.

  FIG. 13 is a block diagram showing another configuration of the vertical contour correction unit 12. The vertical contour correcting unit 12 illustrated in FIG. 13 includes line delays 27 and 29 and a contour emphasizing unit 30 subsequent to the contour width correcting unit 12. The contour emphasizing unit 30 performs contour emphasis processing described later on the luminance data ZYa after contour width correction output by the contour width correcting unit 30. The contour enhancement unit 30 includes a contour detection unit 35, an enhancement amount generation unit 36, a multiplier 360, and an enhancement amount addition unit 37.

The luminance data ZYa output from the contour width correction unit 26 is input to the line delay 27. The line delay 27 outputs luminance data QYb having the number of pixels necessary for the contour enhancement processing in the contour enhancement unit 30. When the contour enhancement process is performed using five pixels arranged in the vertical direction, the luminance data QYb is composed of luminance data for five pixels.
FIG. 14 is a timing chart of the luminance data ZYa delayed by the line delay B27, and shows a case where the number of pixels of the luminance data QYb is 2 kb + 1. As shown in FIG. 14, the line delay 27 delays the luminance data ZYa for 2 kb + 1 lines, and outputs luminance data QYb for 2 kb + 1 pixels arranged in the vertical direction by simultaneously reading out one pixel from each line. The luminance data QYb is input to the contour detection unit 35 and the enhancement amount addition unit 37.
The line delay 29 delays the image processing adjustment coefficient QF1 output by the line delay 28, thereby outputting the image processing adjustment coefficient QF2 corresponding to each pixel data of the luminance data QYb.

  The contour detection unit 35 detects a change in luminance in the corrected contour width by performing a differential operation such as a second derivative on the luminance data QYb, and uses the detection result as the contour detection data R for the enhancement amount generation unit 36. Output to. The enhancement amount generator 36 generates an enhancement amount SH for enhancing the contour of the luminance data QYb based on the contour detection data R, and outputs the enhancement amount SH to the multiplier 360. The multiplier 360 outputs the enhancement amount SHF obtained by multiplying the enhancement amount SH by the image processing adjustment coefficient QF2 to the enhancement amount addition unit 37. The enhancement amount adding unit 37 enhances the contour of the image data QYb by adding the enhancement amount SHF to the luminance data QYb.

FIG. 15 is a diagram for explaining the contour emphasis processing in the contour emphasizing unit 30.
FIG. 15A shows the luminance data QYb before the edge enhancement process. In FIG. 15A, the solid line indicates the luminance data QYb in the moving image area, and the broken line indicates the luminance data QYb in the still image area. Here, each of the luminance data QYb shown in FIG. 15A corresponds to the luminance data ZYa shown in FIG.
FIG. 15B shows the enhancement amount SH generated based on the luminance data QYb shown in FIG. In FIG. 15B, the solid line indicates the enhancement amount SH generated for the luminance data QYb in the moving image region, and the broken line indicates the enhancement amount SH generated for the luminance data QYb in the still image region.
FIG. 15C shows an enhancement amount SHF obtained by multiplying the enhancement amount SH shown in FIG. 15B by the image processing adjustment coefficient QF2. In FIG. 15C, the solid line indicates the enhancement amount SHF in the moving image region, and the broken line indicates the enhancement amount SHF in the still image region.
FIG. 15 (d) shows luminance data ZYb after edge enhancement obtained by adding the enhancement amount SHF shown in FIG. 15 (c) to the luminance data QYb shown in FIG. 15 (a). In FIG. 15D, the solid line indicates the luminance data ZYb in the moving image area, and the broken line indicates the luminance data ZYb in the still image area.

  As shown in FIG. 15B, the enhancement amount SH generated for the luminance data QYb in the moving image region is narrower than the enhancement amount SH in the still image region. In addition, as shown in FIG. 15C, the amplitude of the enhancement amount SHF in the moving image region can be increased by multiplying the enhancement amount SH by the image processing adjustment coefficient QF2. As a result, as shown in FIG. 15D, sharper overshoot and undershoot are added before and after the contour portion in the moving image region, so that the sharpness of the moving image region can be increased.

  Since the processing in the contour width correcting unit 26 and the contour emphasizing unit 30 requires k + kb line periods, the frame memory control unit 11 (FIG. 2) determines the luminance data ZYb and color difference data QCr, QCb after contour emphasis. Are output with a delay of k + kb lines with respect to the luminance data QY.

  As described above, undershoot and overshoot (enhancement amount SH) are generated by performing operations such as secondary differentiation on the luminance data with the reduced width of the contour portion, and the image processing adjustment coefficient QF is added to the enhancement amount SH. By adding the enhancement amount SHF multiplied by ## EQU1 ## before and after the contour portion, an image in which a moving image region and a still image region are mixed can be made clearer.

FIG. 16 is a block diagram showing a modification of the vertical contour correcting unit 12 shown in FIG. The vertical contour correction unit 12 shown in FIG. 16 includes a coefficient correction unit 38 following the line delay 29, and the image processing adjustment coefficient QFa is input to the line delay 28.
FIG. 17 is a diagram illustrating the relationship between the inter-frame luminance difference | QY−RY | and the image processing adjustment coefficient QFa. As shown in FIG. 17, the image processing adjustment coefficient QFa is QFa = QFm in the region A, QFs <QFa <QFm in the region B, and QY = QFs in the region C. That is, the image processing adjustment coefficient QFa is large in the still image region and small in the moving image region.
In the contour width correction unit 26 shown in FIG. 16, contour width correction processing using the image processing adjustment coefficient QFa having the characteristics shown in FIG. 17 is performed.

  The line delay 28 outputs the image processing adjustment coefficient QFa1 corresponding to each pixel data of the luminance data QYa output by the line delay 25 by delaying the image processing adjustment coefficient QFa for a predetermined period. The line delay 29 delays the image processing adjustment coefficient QFa1 output by the line delay 28, thereby outputting an image processing adjustment coefficient QFa2 corresponding to each pixel data of the luminance data QYb. The coefficient correction unit 38 performs a predetermined filtering process on the image processing adjustment coefficient QFa2, thereby converting the characteristics of the image processing adjustment coefficient QFa2 and outputs a new image processing adjustment coefficient QFb.

FIG. 18 is a diagram illustrating the relationship between the inter-frame luminance difference | QY−RY | and the image processing adjustment coefficient QFb. As shown in FIG. 18, the image processing adjustment coefficient QFb is QFa = QFs in the region A, QFs <QFa <QFm in the region B, and QY = QFs in the region C. That is, the image processing adjustment coefficient QFb is large in the moving image area and small in the still image area.
In the contour emphasizing unit 30 shown in FIG. 16, the contour emphasizing process using the image processing adjustment coefficient QFb having the characteristics shown in FIG. 18 is performed.

FIG. 19 is a diagram for explaining the contour correction processing in the vertical contour correcting unit 12 shown in FIG.
FIG. 19A is a diagram showing the luminance data QYa before performing the contour correction process.
FIG. 19B is a diagram showing luminance data QYb subjected to contour width correction. In FIG. 19B, the solid line indicates the luminance data QYb in the moving image area, and the broken line indicates the luminance data QYb in the still image area.
FIG. 19C shows the enhancement amount SH generated based on the luminance data QYb shown in FIG. In FIG. 19C, the solid line indicates the enhancement amount SH generated for the luminance data QYb in the moving image region, and the broken line indicates the enhancement amount SH generated for the luminance data QYb in the still image region.
FIG. 19D shows an enhancement amount SHF obtained by multiplying the enhancement amount SH shown in FIG. 19C by the image processing adjustment coefficient QFb. In FIG. 19D, the solid line indicates the enhancement amount SHF in the moving image region, and the broken line indicates the enhancement amount SHF in the still image region.
FIG. 19 (e) shows luminance data ZYb after edge enhancement obtained by adding the enhancement amount SHF shown in FIG. 19 (d) to the luminance data QYb shown in FIG. 19 (b). In FIG. 19 (e), the solid line indicates the luminance data QYb in the moving image area, and the broken line indicates the luminance data ZYb in the still image area.

  In the contour width correction unit 26 shown in FIG. 16, the contour width correction amount is adjusted using the image processing adjustment coefficient QFa shown in FIG. 17, so the contour width correction amount in the moving image region is larger than that in the still image region. Small. For this reason, as shown in FIG. 19B, the contour width Wc of the luminance data ZYa after the contour width correction in the moving image region is wider than the contour width Wb in the still image region. For this reason, as shown in FIG. 19C, the width of the enhancement amount SH generated with respect to the luminance data QYb of the contour portion in the moving image region becomes thick. By multiplying the enhancement amount shown in FIG. 19C by the image processing adjustment coefficient QFb shown in FIG. 18, the amplitude of the enhancement amount SHF in the moving image region can be further increased. As a result, as shown in FIG. 19E, overshoot and undershoot with a larger width and a larger amplitude are added before and after the contour portion in the moving image area.

  In moving images that move very quickly, it may be possible to improve the sharpness of the image more effectively by adding a sharper edge to the contour portion than increasing the amount of contour width correction. In the contour correction unit 26 shown in FIG. 16, the amount of correction of the contour width in the moving image region is reduced and the amount of enhancement of the contour is increased. In addition, since a thick and clear edge is obtained, the sharpness of the contour can be effectively improved even in a moving image with very fast movement.

Embodiment 2. FIG.
FIG. 20 is a block diagram illustrating another configuration of the image processing unit 2. The image processing unit 2 illustrated in FIG. 20 includes a horizontal contour correcting unit 38 following the vertical contour correcting unit 12. The horizontal contour correction unit 38 performs horizontal contour correction processing on the luminance data ZYb output from the vertical contour correction unit 12 and outputs luminance data ZYe.
As the vertical contour correcting unit 12 shown in FIG. 20, any of the configurations of FIGS. 9, 13, and 16 may be used. The image processing adjustment coefficient QF used in the vertical contour correcting unit 12 is sent to the horizontal contour correcting unit 38 together with the luminance data ZYb.

  FIG. 21 is a block diagram showing an internal configuration of the horizontal contour correction unit 34. The horizontal contour correction unit 34 illustrated in FIG. 21 includes pixel delays 39 and 40, coefficient correction units 41 and 42, a contour width correction unit 26, and a contour enhancement unit 30. The configurations and operations of the contour width correction unit 26 and the contour enhancement unit 30 are the same as those of the contour width correction unit 26 and the contour enhancement unit 30 in the vertical contour correction unit 12 shown in FIG.

  The pixel delay 39 receives luminance data ZYb sequentially output from the vertical contour correction unit 12 and outputs luminance data QYc of the number of pixels necessary for the horizontal contour width correction processing in the contour width correction unit 26. FIG. 22 is a schematic diagram showing the luminance data QYc output from the pixel delay 39, and shows a case where the number of pixels of the luminance data QYc is 2ma + 1. As shown in FIG. 22, the pixel delay 39 outputs luminance data QYc composed of a plurality of pixel data arranged in the horizontal direction. When the contour width correction is performed using 11 pixels arranged in the horizontal direction, the luminance data QYc is composed of 11 pixel data.

  The coefficient correction unit 41 outputs an image processing adjustment coefficient QFc for adjusting the correction amount of the contour width in the horizontal direction by performing a predetermined filtering process on the image processing adjustment coefficient QF input from the vertical contour correction unit 12. To do.

  The luminance data QYc for 2ma + 1 pixels output from the pixel delay 39 is sent to the contour width correction unit 26. The contour width correction unit 26 corrects the horizontal contour width by performing the same processing as the vertical contour width correction processing described above on the horizontal luminance data QYc using the image processing adjustment coefficient QFc. The luminance data ZYc thus output is output.

The brightness data ZYc after the contour width correction output by the contour width correction unit 26 is input to the pixel delay 40. The pixel delay 40 outputs luminance data QYd having the number of pixels necessary for the contour enhancement processing in the contour enhancement unit 30. FIG. 23 is a schematic diagram showing QYd data output from the pixel delay B40, and shows a case where the number of pixels of the luminance data ZYc is 2 mb + 1. As shown in FIG. 23, the pixel delay 40 outputs luminance data QYd composed of a plurality of pixel data arranged in the horizontal direction. When the contour emphasis process is performed using five pixels arranged in the horizontal direction, the luminance data QYd is composed of five pixel data.
The coefficient correction unit 42 performs a predetermined filtering process on the image processing adjustment coefficient QFc output from the coefficient correction unit 41 to output an image processing adjustment coefficient QFd for adjusting the amount of enhancement of the contour in the horizontal direction.

The luminance data QYd for 2 mb + 1 pixel output from the pixel delay 40 is sent to the contour emphasizing unit 30. The contour emphasizing unit 30 uses the image processing adjustment coefficient QFd output from the coefficient correcting unit 42 to perform horizontal processing on the luminance data QYd in the horizontal direction by performing processing similar to the above-described contour emphasizing processing in the vertical direction. Luminance data ZYd whose contour is emphasized in the direction is output.
Note that the contour correction in the vertical direction may be performed after performing the contour correction in the horizontal direction, or the contour correction in the vertical direction and the horizontal direction may be performed simultaneously. Further, the circuit size may be reduced by configuring the horizontal contour correcting unit 38 only by the contour width correcting unit 26 or the contour emphasizing unit 30.

As described above, since the image processing apparatus according to the present embodiment performs the contour correction processing described in the first embodiment in the horizontal and vertical directions, the image blur in the moving image area is excessively and insufficiently horizontal and vertical. The image can be improved and a clearer image can be obtained.
Note that the image processing adjustment coefficients QFc and QFd used in the contour width correcting unit 26 and the contour emphasizing unit 30 of the horizontal direction contour correcting unit 38 are appropriately adjusted to adjust the contour width in the vertical and horizontal directions and before and after the contour portion. The size of the overshoot and undershoot added to can be adjusted adaptively.

Embodiment 3 FIG.
FIG. 24 is a block diagram illustrating another configuration of the image processing unit 2. The frame memory control unit 11 in the image processing unit 2 shown in FIG. 24 further outputs the luminance data SY after two frames of the luminance data RY (after one frame of the luminance data QY). The luminance data SY is sent to the comparison determination unit 10 together with the luminance data RY. Other configurations are the same as those of the image processing unit 2 shown in FIG.

  FIG. 25 is a block diagram showing an internal configuration of the frame memory control unit 11 in the image processing unit 2 shown in FIG. As shown in FIG. 25, the frame memory control unit 11 further includes a line buffer 42 that outputs luminance data SY read from the frame memory 13. Other configurations are the same as those of the frame memory control unit 11 shown in FIG.

FIG. 26 shows luminance data SY, QY, RY and color difference data QCr, QCb output from the frame memory control unit 11 in one frame period, and luminance data ZYb after contour correction output from the vertical contour correction unit 12. FIG. In FIG. 26, QSv indicates one frame period. As shown in FIG. 26, the luminance data RY and SY have a phase difference of one frame before and after the luminance data QY.
FIG. 27 is a diagram showing luminance data QY and color difference data QCr, QCb output from the frame memory control unit 11 in one line cycle, and luminance data ZYb after contour correction output from the vertical contour correction unit 12. In FIG. 27, QSh indicates one line period. As shown in FIG. 27, the color difference data QCr and Qcb are read out with a delay of the line period k necessary for the contour correction unit 5 to perform the contour correction processing with respect to the luminance data QY.

FIG. 28 is a block diagram illustrating an internal configuration of the comparison determination unit 10. 28 includes a moving image still image determination unit 43, a flicker determination unit 44, and a coefficient correction unit 45. The moving image still image determination unit 43 generates an image processing adjustment coefficient QF based on the luminance data QY and the inter-frame luminance difference | QY−RY | obtained from the luminance data RY of the previous frame, and supplies the coefficient correction unit 45 with the image processing adjustment coefficient QF. Output. The moving image still image determination unit 43 outputs the moving image detection flag H = 1 when the inter-frame luminance difference | QY−RY | exceeds a predetermined value. On the other hand, when the inter-frame luminance difference | QY−RY | is equal to or smaller than a predetermined value, a moving image detection flag H = 0 indicating that the luminance data QY represents a still image area is output. The moving image detection flag H is sent to the flicker determination unit 44.
Note that the relationship between the image processing adjustment coefficient QF output by the still image determination unit 43 and the inter-frame luminance difference | QY-RY | is the same as that shown in FIG.

  The flicker determination unit 44 calculates a difference between the luminance data RY and the luminance data SY after two frames for each pixel, thereby obtaining an inter-frame luminance difference | QY−SY | indicating a luminance change between the three frames. The flicker determination unit 33 detects a flicker component included in the luminance data QY based on the inter-frame luminance difference | QY-SY | and the moving image detection flag H, and generates a flicker adjustment coefficient QG.

  FIG. 29 is a diagram for explaining a flicker detection method in the flicker determination unit 44. FIG. 29A shows changes in the luminance data RY, QY, SY when the luminance data QY represents a moving image area. When the luminance data QY represents a moving image area, the two inter-frame luminance differences | QY−RY | and | QY−SY | are both large values as shown in FIG. FIG. 29B shows changes in the luminance data RY, QY, SY when the luminance data QY includes a flicker component. When the luminance data QY includes a flicker component, the inter-frame luminance difference | QY-RY | is a large value, whereas the inter-frame luminance difference | QY-SY | is 0 or a very small value. Here, when the inter-frame luminance difference | QY−RY | exceeds a predetermined value, the moving image detection flag is H = 1, so that the moving image detection flag H = 1 and the inter-frame luminance difference | QY−RY | When the value is 0 or a very small value, it is determined that the luminance data QY includes a flicker component.

  The flicker determination unit 44 determines whether or not the luminance data QY includes flicker based on the value of the moving image detection flag H output from the moving image still image determination unit 43 and the magnitude of the inter-frame luminance difference | RY-SY |. The flicker adjustment coefficient QG is output based on the determination result. When the moving image detection flag H = 0, that is, when the luminance data QY represents a still image region, the flicker determination unit 44 outputs the flicker adjustment coefficient QG as 1. On the other hand, when the moving image detection flag H = 1, that is, when the luminance data QY represents a moving image area, the flicker detection unit 44 outputs the flicker adjustment coefficient QG based on the magnitude of the inter-frame luminance difference | RY-SY |. To do.

FIG. 30 is a diagram illustrating a relationship between the flicker adjustment coefficient QG and the inter-frame luminance difference | RY−SY |. In FIG. 30, the horizontal axis represents the reciprocal of the inter-frame luminance difference | RY-SY |, and the vertical axis represents the magnitude of the flicker adjustment coefficient QG. In FIG. 30, a region A (region where RY−SY | is large) having a small reciprocal of the inter-frame luminance difference | RY−SY | is a moving image region, and a region C having a large reciprocal of the inter-frame luminance difference | RY−SY | (A region where | RY-SY | is small) is a flicker generation region, and an intermediate region between the moving image region and the flicker generation region is a region B.
As shown in FIG. 30, the flicker adjustment coefficient QG has a large value (QG = QGm) in the moving image region (region A) and a small value (QG = QGf) in the flicker generation region (region C). In the intermediate area (area B), the flicker adjustment coefficients Qf and Qm in the moving image area and the flicker occurrence area are intermediate values (QGf <QF <QGf).
The coefficient correction unit 45 integrates the image processing adjustment coefficient QF output from the moving image still image determination unit 43 and the flicker adjustment coefficient QG output from the flicker determination unit 44 to generate a new image processing adjustment coefficient QFG. .

When the luminance data QY represents a still image area (when the moving image detection flag is H = 0), the flicker adjustment coefficient is QG = 1, so that the image processing adjustment coefficient QFG is the area A (still image shown in FIG. Image processing adjustment coefficient QF = QFs in the region).
When the inter-frame luminance difference | QY−RY | exceeds a predetermined value (when the moving image detection flag is H = 1), as shown in FIG. 7, the image processing adjustment coefficient QF is QFm in the region B (moving region). (QFm> QFs). On the other hand, the flicker adjustment coefficient QG is small in the flicker occurrence region (region C) and large in the moving image region (region A) as shown in FIG. Therefore, the image processing adjustment coefficient QFC in the flicker occurrence area becomes a value obtained by reducing the image processing adjustment coefficient QF = QFm in the area C (moving area) shown in FIG. 7, and the image processing adjusting coefficient QFC in the area A (moving area). Is equal to or larger than the image processing adjustment coefficient QF = QFm.

FIG. 31 is a diagram showing a difference in contour correction amount depending on the presence or absence of flicker. FIGS. 31A, 31B, and 31C show luminance data QYa, conversion magnification Z, and luminance data ZYa after contour correction. In FIG. 31B, the solid line indicates the conversion magnification Z in the moving image area, and the broken line indicates the conversion magnification Z in the flicker occurrence area. In FIG. 31C, the solid line indicates the luminance data ZYa after contour correction in the moving image region, and the broken line indicates the luminance data ZYa after contour correction in the flicker occurrence region.
In the flicker occurrence region, the value of the image processing adjustment coefficient QFG integrated with the magnification control amount ZC is smaller than that of the moving image region not including flicker. Therefore, as shown in FIG. It becomes smaller in the flicker occurrence area. For this reason, as shown in FIG. 31C, the contour width Wb of the luminance data ZYa after contour correction in the flicker occurrence region is wider than the contour width Wc in the moving image region not including flicker, and the sharpness is lowered. . That is, in the flicker occurrence region, it is possible to prevent the flicker from being emphasized by increasing the sharpness of the contour portion.

  As described above, according to the image processing apparatus of the present embodiment, flicker is detected based on the inter-frame luminance difference | QY−RY |, | RY−SY |, and the contour correction amount in the flicker occurrence region is suppressed. Therefore, the sharpness of the moving image region can be increased without enhancing the flicker component.

Embodiment 4 FIG.
FIG. 32 is a block diagram showing a configuration of the frame memory control unit 11 in the fourth embodiment, and shows another configuration of the frame memory control unit 11 in the image processing apparatus 2 shown in FIG.
The frame memory control unit 11 includes a write control unit 14 and a read control unit 19. The write control unit 14 includes encoding units 46, 47 and 48, buffers 49, 50 and 51, and a write address control unit 52. The read control unit 19 includes buffers 53, 54, 55 and 56, and a decoding unit 57. , 58, 59 and 60, and a read address control unit 61.

  The luminance data DY and the color difference data DCr and DCb input to the frame memory control unit 11 are input to the encoding units 46, 47 and 48 of the write control unit 14, respectively.

  The encoding unit 46 outputs the encoded luminance data EY corresponding to the luminance data DY to the buffer 49 by encoding the input luminance data DY. For coding the luminance data DY, block coding such as FBTC (Fixed Block Truncation Coding) or GBTC (Generalized Block Truncation Coding) can be used. Also, encoding methods for still images such as two-dimensional discrete cosine transform coding such as JPEG (Joint Photographic Experts Group), predictive coding such as JPEG-LS (Joint Photographic Experts Group-Lossless), and coding using wavelet transform such as JPEG2000. Any can be used. Note that such a still image encoding method is applied even to lossy encoding in which luminance data DY before encoding and encoded luminance data after decoding, which will be described later, do not completely match. It is possible.

  Similarly, the encoding units 47 and 48 encode the input color difference data DCr and DCb, thereby buffering the encoded color difference data ECr and ECb corresponding to the color difference data DCr and DCb, respectively. Respectively.

  The write address control unit 52 generates a write address WA for writing the encoded luminance data EY and the encoded color difference data ECr and ECb input to the buffers 49, 50 and 51 to the frame memory 13 based on the synchronization signal DS. To do. The encoded luminance data EY and the encoded color difference data ECr and ECb read from the buffers 49, 50 and 51 are written into the frame memory as write data WD corresponding to the write address WA.

  Here, the output synchronization signal generation unit 7 performs the conversion of the frame frequency in the frame memory of the storage unit 4, that is, when the image data having a frame frequency different from the image data Da is output from the storage unit 4, A synchronization signal QS having a different period is generated. When the frame frequency is not converted in the storage unit 4, the synchronization signal QS and the synchronization signal Sa are equal. (See Figure 2)

The read address control unit 61 reads out the encoded luminance data EY and the encoded color difference data ECr and ECb written in the frame memory 13 based on the synchronization signal QS output from the output synchronization signal generation unit 7. Generate RA.
The frame memory 13 outputs data RD read based on the read address RA to the buffers 53, 54, 55, and 56. The buffers 53, 54, and 55 output the encoded luminance data EY1 and the encoded color difference data ECr1 and ECb1, and are input to the decoding units 57, 58, and 59, respectively. Further, the buffer 56 outputs encoded luminance data EY2 delayed by one frame period from the encoded luminance data EY1 output from the buffer 53, and the encoded luminance data EY2 is input to the decoding unit 60.

The decoding unit 57 decodes the encoded luminance data EY1 output from the buffer 53, and outputs luminance data QY corresponding to the input luminance data DY. Similarly, the decoding units 58 and 59 decode the encoded color difference data ECr and ECb output from the buffers 54 and 55, so that the color difference data QCr corresponding to each of the input color difference data DCr and DCb QCb is output. The output luminance data QY and color difference data QCr, QCb are input to the contour correction unit 5.
In addition, the decoding unit 60 decodes the encoded luminance data EY2 from the buffer 56, thereby outputting luminance data RY delayed by one frame from the luminance data QY.
The luminance data QY and RY are input to the comparison determination unit 10.

  As shown in FIG. 2, the luminance data QY input to the contour correction unit 5 is input to the vertical contour correction unit 12. As described in the first embodiment, when the vertical contour correction unit 12 performs the contour correction process in the vertical direction on the luminance data QY and outputs the luminance data ZYa after the contour correction, the corrected luminance data ZYa is output. And a delay of a predetermined number of lines occurs between the luminance data QY before correction. If the number of delay lines is k lines, a delay corresponding to k lines also occurs between the luminance data QY and the color difference data QCr, QCb. Therefore, the frame memory control unit 11 delays and outputs the color difference data QCr, QCb by k lines so that the corrected luminance data ZYa and the color difference data QCr, QCb are input to the conversion unit 6 in synchronization. Specifically, the read address control unit 24 of the frame memory control unit 11 generates the read address RA so that the color difference data QCr and QCb are read with a delay of k lines with respect to the luminance data QY.

  FIG. 4 is a diagram showing luminance data RY, QY and color difference data QCr, QCb output from the frame memory control unit 11 in one line cycle, and luminance data ZYa after contour correction output from the vertical contour correction unit 12. is there. In FIG. 4, QSh indicates one line period. As shown in FIG. 4, the color difference data QCr and Qcb are read out with a delay of the line period k necessary for the contour correction unit 5 to perform the contour correction processing with respect to the luminance data QY.

  FIG. 5 is a diagram showing luminance data RY and QY and color difference data QCr and QCb output from the frame memory control unit 11 in one frame period, and luminance data ZYa after contour correction output from the vertical contour correction unit 12. is there. In FIG. 5, QSv indicates one frame period. As shown in FIG. 5, the luminance data RY is read with a delay of one frame period with respect to the luminance data QY.

  The luminance data QY and RY output from the frame memory control unit 11 are input to the comparison determination unit 10 as shown in FIG. The comparison / determination unit 10 determines a moving image / still image based on the luminance data QY and the luminance data RY one frame before, and generates an image processing adjustment coefficient QF from the determination result. The image processing adjustment coefficient QF is input to the contour correction unit 5. The contour correction unit 5 performs contour correction processing based on the image processing adjustment coefficient QF and outputs luminance data ZYa whose contour has been corrected.

  Since the contour correction unit 5, the comparison determination unit 10, and the conversion units 3 and 6 are the same as those already described in the first embodiment, detailed description thereof is omitted.

As described above, the image data is converted into the luminance data DY and the color difference data DCr and DCb and written in the frame memory 13, the luminance data of the necessary number of lines is read out and the contour correction processing is performed. By reading data with a delay of the number of lines necessary for the correction process, it is possible to reduce the line memory necessary for adjusting the timing of the color difference data.
Further, when image data is written to or read from the frame memory 13, the image data is encoded, and then the encoded image data is written to the frame memory 13, and the image data encoded from the frame memory 13 is encoded. Therefore, as the coding rate (data compression rate) of the encoded image data is increased, the capacity of the frame memory 13 for storing the encoded image data can be reduced, and the frame The bus bandwidth between the memory 13 and the frame memory control unit 11 can be saved.

  FIG. 33 is a block diagram illustrating another configuration of the frame memory control unit 11 according to the fourth embodiment. 33 includes an encoding unit 47, 48, buffers 49, 50, 51, a write address control unit 52, buffers 53, 54, 55, 56, a decoding unit 58, 59, and a read address control. The unit 61 is configured.

The frame memory control unit 11 shown in FIG. 33 performs the encoding process before writing to the frame memory 13 and the decoding process after reading on the color difference data DCr and DCb, and on the luminance data DY. Not performed.
The luminance data DY input to the frame memory control unit 11 is input to the buffer 49, and the color difference data DCr and DCb are input to the encoding units 47 and 48, respectively. The encoding units 47 and 48 encode the color difference data DCr and DCb and output the encoded color difference data ECr and ECb, respectively. The encoded color difference data ECr and ECb are input to the buffers 50 and 51, respectively.

  The write address control unit 52 writes the luminance data DY input to the buffer 49 and the encoded color difference data ECr and ECb input to the buffers 50 and 51 to the frame memory 13 based on the synchronization signal DS. Generate WA. The luminance data DY and the encoded color difference data ECr and ECb read from the buffers 49, 50 and 51 are written into the frame memory as write data WD corresponding to the write address WA.

  On the other hand, the read address control unit 61 reads the luminance data DY and the encoded color difference data ECr and ECb written in the frame memory 13 based on the synchronization signal QS output from the output synchronization signal generation unit 7. Generate RA. The frame memory 13 outputs data RD read based on the read address RA to the buffers 53, 54, 55, and 56. The buffer 53 outputs luminance data QY. The buffers 54 and 55 output the encoded color difference data ECr1 and ECb1, and are input to the decoding units 58 and 59, respectively. The buffer 56 outputs luminance data RY delayed by one frame period from the luminance data QY output from the buffer 53.

  The decoding units 58 and 59 output the color difference data QCr and QCb corresponding to the input color difference data DCr and DCb by decoding the encoded color difference data ECr and ECb output from the buffers 54 and 55, respectively. To do. The output luminance data QY and color difference data QCr, QCb are input to the contour correction unit 5.

  Since the timing relationship between the luminance data QY, RY and the color difference data QCr, QCb is the same as that already described with reference to FIGS. 4 and 5 in the fourth embodiment, description thereof is omitted here.

  With regard to the color difference data, the encoded color difference data is stored in the frame memory 13, so that the memory capacity of the frame memory 13 can be reduced.

When lossy encoding is used as an encoding method, an error occurs between image data before encoding and image data that has undergone encoding and decoding. In the configuration example shown in FIG. 33, the color difference data outputs QCr and QCb that have undergone the encoding process and the decoding process may cause an error between the original color difference data DCr and DCb. On the other hand, since the luminance data DY is not subjected to the encoding process and the decoding process, there is no error between the input luminance data DY and the output luminance data QY, RY.
Generally, human visual sensitivity to color difference data is lower than that of luminance data. Therefore, even if an error occurs in the color difference data due to the encoding process and the decoding process, no error occurs in the luminance data. Adverse effects can be suppressed.

Embodiment 5. FIG.
FIG. 34 is a block diagram showing the configuration of the frame memory 11 in the fifth embodiment. This shows another configuration of the frame memory control unit 11 in the image processing apparatus 2 shown in FIG.
The frame memory control unit 11 shown in FIG. 34 includes a write control unit 14 and a read control unit 19. The write control unit 14 has the same configuration as that shown in FIG. The read control unit 19 further includes a buffer 62 and a decoding unit 63 in addition to the configuration shown in FIG.

  Since the write control unit 14 is the same as the configuration shown in FIG. 32 in the fourth embodiment, a detailed description of the operation is omitted. Further, the synchronization signal QS generated by the output synchronization signal generation unit 7 is the same as the content described in the fourth embodiment, and thus the description thereof is omitted.

As for the read control unit 19, the read address control unit 61, based on the synchronization signal QS output from the output synchronization signal generation unit 7, encodes the encoded luminance data EY and the encoded color difference data ECr written in the frame memory 13. A read address RA for reading ECb is generated.
The frame memory 13 outputs data RD read based on the read address RA to the buffers 53, 54, 55, 56 and 62. The buffers 53, 54, and 55 output the encoded luminance data EY1 and the encoded color difference data ECr1 and ECb1, and are input to the decoding units 57, 58, and 59, respectively. Further, the buffer 56 outputs encoded luminance data EY2 delayed by one frame period from the encoded luminance data EY1 output from the buffer 53, and the encoded luminance data EY2 is input to the encoding unit 60.
Further, the buffer 62 outputs encoded luminance data EY0 that is one frame period earlier than the encoded luminance data EY1, and is input to the decoding unit 63.

The decoding units 57, 58 and 59 decode the encoded luminance data EY1 and the encoded color difference data ECr1 and ECb1, thereby outputting luminance data QY and color difference data QCr and QCb corresponding to the input image data. Similarly, the decoding units 60 and 63 decode the encoded luminance data EY2 and EY0, respectively, thereby outputting luminance data RY delayed by one frame and luminance data SY one frame earlier than the luminance data QY.
The luminance data QY is input to the contour correction unit 5 and the comparison determination unit 10, and the color difference data QCr and QCb are input to the contour correction unit 5. Further, the luminance data RY and SY are input to the comparison determination unit 10.

As shown in FIG. 26, the luminance data RY and SY have a phase difference of one frame before and after the luminance data QY. Further, as shown in FIG. 27, the color difference data QCr and QCb are read out with respect to the luminance data QY with a delay of a line period k necessary for the contour correction unit 5 to perform the contour correction processing.
Since the details of the relationship between the luminance data QY, RY, SY, and the color difference data QCr, QCb are the same as those already described in the third embodiment, the description thereof is omitted here.

The comparison determination unit 10 detects the presence or absence of flicker based on the input luminance data QY, RY, and SY, and generates an image processing adjustment coefficient QFG that works to suppress the contour correction amount in the flicker generation region. The image processing adjustment coefficient QFG is input to the contour correction unit 5.
The contour correction unit 5 performs contour correction processing on the luminance data QY based on the image processing adjustment coefficient QFG, and outputs contour corrected luminance data ZYa.
Since the operations of the comparison determination unit 10 and the contour correction unit 5 have already been described in the third embodiment and the first embodiment, detailed description thereof is omitted here.

  Flicker is detected based on the inter-frame luminance difference | QY−RY | and | RY−SY |, and the amount of contour correction in the flicker occurrence area can be suppressed. Therefore, the sharpness of the moving image area is enhanced without enhancing the flicker component. be able to.

  Further, when image data is written to or read from the frame memory 13, the image data is encoded, and then the encoded image data is written to the frame memory 13, and the image data encoded from the frame memory 13 is encoded. Therefore, as the coding rate (data compression rate) of the encoded image data is increased, the capacity of the frame memory 13 for storing the encoded image data can be reduced, and the frame The bus bandwidth between the memory 13 and the frame memory control unit 11 can be saved.

  Also, as shown in FIG. 35, encoding processing and decoding processing when writing and reading image data to and from the frame memory 13 are performed for the color difference data DCr and DCb, but not for the luminance data DY. The frame memory control unit 11 may be configured. FIG. 35 is a block diagram illustrating another configuration example of the frame memory control unit 11 according to the fifth embodiment.

  In FIG. 35, the luminance data DY is directly input to the buffer 49 without going through the encoding unit. The color difference data DCr and DCb are encoded by the encoding units 47 and 48, respectively, and the encoded color difference data ECr and ECb are input to the buffers 50 and 51, respectively. Uncoded luminance data DY and encoded color difference data ECr read from the buffers 49, 50 and 51 are written in the frame memory 13 as write data WD.

Next, the luminance data DY and the encoded color difference data ECr and ECb written in the frame memory 13 are read as read data RD and input to the buffers 52, 53, 54, 55 and 62. The buffer 52 outputs luminance data QY, and the buffers 55 and 62 output luminance data RY delayed by one frame with respect to the luminance data QY and luminance data SY that is one frame earlier.
The buffers 54 and 55 output the encoded color difference data ECr1 and ECb1 of the same frame as the luminance data QY to the decoding units 58 and 59, respectively. In the decoding units 58 and 59, the encoded color difference data ECr1 and ECb1 are decoded, and the decoded color difference data QCr and QCb are output.

Encoded by writing encoded color difference data and non-encoded luminance data to the frame memory 13, reading encoded color difference data and luminance data from the frame memory 13, and decoding the encoded color difference data. As the coding rate (data compression rate) of the color difference data is increased, the capacity of the frame memory 13 can be reduced and the bus band between the frame memory 13 and the frame memory control unit 11 can be saved.
In addition, since color difference data with low human visual sensitivity is encoded and decoded, even if the encoding method is irreversible encoding, the difference between the color difference data before and after encoding is determined. Deterioration of an image due to an error that occurs can be suppressed.

Embodiment 6 FIG.
FIG. 36 is a block diagram showing the configuration of the frame memory control unit 11 in the sixth embodiment, and shows another configuration of the frame memory control unit 11 in the image processing apparatus 2 shown in FIG.
The frame memory control unit 11 includes a write control unit 14 and a read control unit 19. The write control unit 14 includes an encoding unit 46, buffers 49, 50 and 51, and a write address control unit 52. The read control unit 19 includes buffers 54, 55 and 56, a decoding unit 60, and a read address control unit 61. Consists of.

The operation will be described.
The luminance data DY input to the frame memory control unit 11 is input to the encoding unit 46 and also output as luminance data QY via the read control unit 19. The encoding unit 46 encodes the luminance data DY, and outputs the encoded luminance data EY corresponding to the luminance data DY to the buffer 49.
The color difference data DCr and DCb input to the frame memory control unit 11 are input to the buffers 50 and 51.

  Based on the synchronization signal DS, the write address control unit 52 writes the coded luminance data EY input to the buffer 49 and the color difference data DCr and DCb input to the buffers 50 and 51 to the frame memory WA. Is generated. The encoded luminance data EY and the color difference data DCr and DCb read from the buffers 49, 50 and 51 are written in the frame memory 13 as write data WD corresponding to the write address WA.

  Here, the output synchronization signal generation unit 7 does not perform frame frequency conversion in the frame memory 13 of the storage unit 4 and generates a synchronization signal QS synchronized with the synchronization signal Sa (ie, DS).

Based on the synchronization signal QS output from the output synchronization signal generation unit 7, the read address control unit 61 sets a read address RA for reading the encoded luminance data EY and the color difference data DCr and DCb written in the frame memory 13. appear.
The frame memory 13 outputs the data RD read based on the read address RA to the buffers 54, 55, and 56. The buffers 54 and 55 output the color difference data QCr and QCb. Further, the buffer 56 outputs the luminance data QY, that is, the encoded luminance data EY1 delayed by one frame from the input luminance data DY. The encoded luminance data EY1 output from the buffer 56 is input to the decoding unit 60, and the decoding unit 60 decodes the encoded luminance data EY1 to output luminance data RY. The luminance data RY is delayed by one frame from the luminance data QY.
Luminance data QY and color difference data QCr, QCb are input to the contour correction unit 5, and luminance data QY and RY are input to the comparison determination unit 10.

  As shown in FIG. 2, the luminance data QY input to the contour correction unit 5 is input to the vertical contour correction unit 12. As already described in the first embodiment, when the vertical contour correction unit 12 performs the contour correction process in the vertical direction on the luminance data QY and outputs the luminance data ZYa after the contour correction, the corrected luminance data A delay corresponding to a predetermined number of lines occurs between ZYa and luminance data QY before correction. If the number of delay lines is k lines, a delay corresponding to k lines also occurs between the luminance data QY and the color difference data QCr, QCb. Therefore, the frame memory control unit 11 outputs the color difference data QCr and QCb with a delay of k lines so that the corrected luminance data ZYa and the color difference data QCr and QCb are input to the conversion unit 6 in synchronization. . Specifically, the read address control unit 24 of the frame memory control unit 11 sets the read address RA so that the color difference data QCr and QCb are read with a delay of k lines with respect to the luminance data QY (that is, the input luminance data DY). Generate.

  FIG. 37 shows luminance data DY, color difference data DCr and DCb input to the frame memory control unit 11, luminance data RY, QY and color difference data QCr, QCb output from the frame memory control unit in one line cycle, and vertical contours. It is a figure which shows the luminance data ZYa after the outline correction output from the correction | amendment part 12. FIG. In FIG. 37, DSh and QSh indicate one line period, and the output horizontal synchronizing signal QSh is synchronized with the input horizontal synchronizing signal QSh. As shown in FIG. 37, the color difference data QCr and Qcb are read out with a delay of the line period k required for the contour correction unit 5 to perform the contour correction processing with respect to the luminance data QY. The input luminance data DY and the output luminance data QY and RY indicate the same line position n, whereas the output color difference data QCr and QCb are line positions nk.

  FIG. 38 is a diagram showing luminance data RY and QY and color difference data QCr and QCb output from the frame memory control unit 11 in one frame period, and luminance data ZYa after contour correction output from the vertical contour correction unit 12. is there. In FIG. 38, DSv and QSv indicate one frame period, and the output vertical synchronization QSv is synchronized with the input vertical synchronization DSv. As shown in FIG. 38, the luminance data RY is read with a delay of one frame period with respect to the luminance data QY.

  The luminance data QY and RY output from the frame memory control unit 11 are input to the comparison determination unit 10 as shown in FIG. The comparison / determination unit 10 determines a moving image / still image based on the luminance data QY and the luminance data RY one frame before, and generates an image processing adjustment coefficient QF from the determination result. The image processing adjustment coefficient QF is input to the contour correction unit 5. The contour correction unit 5 performs contour correction processing based on the image processing adjustment coefficient QF and outputs luminance data ZYa whose contour has been corrected.

  Since the contour correction unit 5, the comparison determination unit 10, and the conversion units 3 and 6 are the same as those already described in the first embodiment, detailed description thereof is omitted.

In this way, the encoded luminance data EY and color difference data DCr, DCb are written into the frame memory 13, the contour correction processing is performed on the input luminance data DY (= QY), and the color difference data QCr, QCb are contoured. By reading data with a delay of the number of lines necessary for the correction process, it is possible to reduce the line memory necessary for adjusting the timing of the color difference data.
Furthermore, after the luminance data DY is encoded, the encoded luminance data EY is written into the frame memory 13, and the encoded luminance data EY1 is read out from the frame memory 13 and then decoded. As the coding rate (data compression rate) of the luminance data is increased, the capacity of the frame memory 13 for storing the coded luminance data EY can be reduced, and the bus bandwidth between the frame memory 13 and the frame memory control unit 11 Can be saved.

  Further, the frame memory control unit 11 may perform encoding processing and decoding processing for writing and reading image data to and from the frame memory 13 for the color difference data DCr and DCb in addition to the luminance data DY. . FIG. 39 is a block diagram showing another configuration of the frame memory control unit 11 in the sixth embodiment. The configuration shown in FIG. 39 further includes encoding units 47 and 48 and decoding units 58 and 59 with respect to the configuration shown in FIG.

  The encoding units 47 and 48 output the encoded color difference data ECr0 and ECb0 corresponding to the color difference data DCr and DCb to the buffers 50 and 51, respectively, by encoding the input color difference data DCr and DCb. The coded color difference data ECr0 and ECb0 read from the buffers 50 and 51 are written in the frame memory 13. The coded color difference data ECr0 and ECb0 written in the frame memory 13 are read out and input to the buffers 54 and 55. The buffers 54 and 55 output the encoded color difference data ECr0 and ECb0 to the decoding units 58 and 59, respectively. The decoding units 58 and 59 decode the encoded color difference data ECr0 and ECb0 and output the decoded color difference data QCr and QCb, respectively. The color difference data QCr and QCb are read out with respect to the luminance data QY after being delayed by a line period k necessary for the contour correction unit 5 to perform the contour correction processing. The other parts are the same as those already described.

  Since the luminance data DY and the color difference data DCr and DCb are encoded, the encoded luminance data EY0 is written to the frame memory 13, and the encoded luminance data EY1 is read from the frame memory 13 and then decoded. As the coding rate (data compression rate) of the encoded luminance data and color difference data is increased, the capacity of the frame memory 13 for storing the encoded luminance data EY0, color difference data ECr0, ECb0 can be reduced, and the frame The bus bandwidth between the memory 13 and the frame memory control unit 11 can be saved.

Embodiment 7 FIG.
FIG. 40 is a block diagram illustrating a configuration of the image processing unit 2 according to the seventh embodiment. In the configuration shown in FIG. 40, compared with the configuration shown in FIG. 2, the frame memory control unit 11 outputs luminance data QY1 and QY2, the luminance data QY1 is input to the contour correction unit 5, and the luminance data QY2 is compared and determined. The difference is that it is input to the unit 10. Luminance data QY1 is luminance data that has not undergone encoding and decoding, and luminance data QY2 is luminance data that has undergone encoding and decoding. (Details will be described later)

  FIG. 41 is a block diagram showing a configuration of the frame memory control unit 11 in the image processing apparatus 2 shown in FIG. The frame memory control unit 11 shown in FIG. 41 further includes a decoding unit 57 in the read control unit in addition to the configuration shown in FIG.

The input luminance data DY is input to the encoding unit 46 and also output as luminance data QY1 via the read control unit 19. The encoding unit 46 encodes the luminance data DY to output encoded luminance data EY0 corresponding to the luminance data DY. The encoded luminance data EY0 is input to the buffer 49 and the decoding unit 57. The decoding unit 57 decodes the encoded luminance data EY0, thereby outputting luminance data QY2 of the same frame and the same line as the luminance data QY1. The frame memory control unit 11 outputs luminance data RY with one frame delay from the color difference data QCr and QCb and the luminance data QY1 and QY2. The readout timing of the luminance data QY1 and QY2 is the same as the luminance data QY in FIGS. 37 and 38 in the sixth embodiment.
The other parts are the same as those already described in the sixth embodiment, and thus the description thereof is omitted here.
The luminance data QY1 and the color difference data QCr and QCb are input to the contour correction unit 5, and the luminance data QY2 and the luminance data RY with one frame delay are input to the comparison determination unit 10.

The luminance data QY1 has not undergone encoding and decoding processing, the luminance data QY2 has undergone encoding and decoding processing, and the luminance data QY1 and QY2 are different in this respect. For example, when the encoding method is lossy encoding in which the luminance data DY before encoding and the luminance data QY2 after decoding do not completely match, an error occurs between the luminance data DY and QY2.
The comparison determination unit 10 performs moving image still image determination based on the difference in luminance data between two consecutive frames, and operates to control the correction amount of the contour correction unit 5.
If the comparison / determination process in the comparison / determination unit 10 is performed based on the luminance data RY that has been encoded and decoded and the luminance data QY1 that has not been encoded, the encoding / decoding is performed even for a still image. Due to an error that occurs between the luminance data QY1 that has not passed through and the luminance data RY that has passed through, the still image portion may be determined as a moving image.

  On the other hand, when the comparison determination process is performed based on the encoded luminance data RY and QY2, the luminance data RY and QY2 similarly cause an error with respect to the input luminance data. Since errors occurring in QY2 are equal, they are canceled out, and a more accurate determination can be made. In addition, since the contour correction process is performed on the luminance data QY1 that has not been encoded and decoded, the image quality can be improved.

Embodiment 8 FIG.
FIG. 42 is a block diagram illustrating a configuration of the frame memory control unit 11 according to the eighth embodiment. This shows another configuration of the frame memory control unit 11 in the image processing apparatus 2 shown in FIG.
The frame memory control unit 11 shown in FIG. 42 includes a buffer 62 and a decoding unit 63 in addition to the configuration shown in FIG. 36, and can output luminance data QY, RY, and SY for three consecutive frames. It is what I did.

  Since the operation of the write control unit 14 and the synchronization signal QS generated by the output synchronization signal generation unit 7 are the same as those described in the sixth embodiment, detailed description of the operation is omitted.

Based on the synchronization signal QS output from the output synchronization signal generation unit 7, the read address control unit 61 sets a read address RA for reading the encoded luminance data EY and the color difference data DCr and DCb written in the frame memory 13. appear.
The frame memory 13 outputs data RD read based on the read address RA to the buffers 54, 55, 56, and 62. The buffers 54 and 55 output the color difference data QCr and QCb. Further, the buffer 56 outputs the luminance data QY, that is, the encoded luminance data EY1 delayed by one frame from the input luminance data DY to the decoding unit 60. The buffer 62 outputs the encoded luminance data EY2 delayed by two frames from the luminance data QY to the decoding unit 63. The decoding unit 60 outputs luminance data RY by decoding the encoded luminance data EY1, and the decoding unit 63 outputs decoded luminance data SY by decoding the encoded luminance data EY2. Here, the luminance data RY is delayed by one frame from the luminance data QY, and the luminance data SY is delayed by two frames from the luminance data QY.
Luminance data QY and color difference data QCr, QCb are input to the contour correction unit 5, and luminance data QY, RY, and SY are input to the comparison determination unit 10.

  Similarly to the description so far, the frame memory control unit 11 is configured so that the brightness data ZYa after contour correction in which a delay of k lines has occurred and the color difference data QCr and QCb are input to the conversion unit 6 in synchronization. The color difference data QCr and QCb are delayed by k lines and output. Specifically, the read address control unit 24 of the frame memory control unit 11 sets the read address RA so that the color difference data QCr and QCb are read with a delay of k lines with respect to the luminance data QY (that is, the input luminance data DY). Generate.

  43 shows luminance data DY, color difference data DCr and DCb input to the frame memory control unit 11, luminance data SY, RY, QY and color difference data QCr, QCb output from the frame memory control unit in one line cycle, and It is a figure which shows the brightness | luminance data ZYa after the outline correction | amendment output from the vertical outline correction | amendment part 12. FIG. In FIG. 43, DSh and QSh indicate one line period, and the output horizontal synchronization signal QSh is synchronized with the input horizontal synchronization signal QSh. As shown in FIG. 43, the color difference data QCr and Qcb are read out with a delay of the line period k necessary for the contour correcting unit 5 to perform the contour correcting process with respect to the luminance data QY. The input luminance data DY and the output luminance data QY, RY, and SY indicate the same line position n, whereas the output color difference data QCr and QCb are line positions nk.

  FIG. 44 shows luminance data SY, RY, QY and color difference data QCr, QCb output from the frame memory control unit 11 in one frame period, and luminance data ZYa after contour correction output from the vertical contour correction unit 12. FIG. In FIG. 44, DSv and QSv indicate one frame period, and the output vertical synchronization QSv is synchronized with the input vertical synchronization DSv. As shown in FIG. 44, the luminance data RY is read with a delay of one frame period with respect to the luminance data QY, and the luminance data SY is read with a delay of two frame periods with respect to the luminance data QY.

  The comparison determination unit 10 detects the presence / absence of flicker based on the input luminance data QY, luminance data RY one frame before, and luminance data SY two frames before, and suppresses the contour correction amount in the flicker occurrence region. The image processing adjustment coefficient QFG that works as described above is generated, and the image processing adjustment coefficient QFG is input to the contour correction unit 5.

FIG. 45 is a block diagram illustrating an internal configuration of the comparison / determination unit 10 according to the eighth embodiment. The comparison determination unit 10 illustrated in FIG. 45 includes a moving image still image determination unit 43, a flicker determination unit 44, and a coefficient correction unit 45. The moving image still image determination unit 43 generates an image processing adjustment coefficient QF based on the luminance data QY and the inter-frame luminance difference | QY−RY | obtained from the luminance data RY one frame before, and supplies the coefficient correction unit 45 with the image processing adjustment coefficient QF. Output. The moving image still image determination unit 43 outputs a moving image detection flag H = 1 when the inter-frame luminance difference | QY−RY | exceeds a predetermined value. On the other hand, when the inter-frame luminance difference | QY−RY | is equal to or smaller than a predetermined value, a moving image detection flag H = 0 indicating that the luminance data QY represents a still image area is output. The moving image detection flag H is sent to the flicker determination unit 44.
The relationship between the image processing adjustment coefficient QF output from the still image determination unit 43 and the inter-frame luminance difference | QY−RY | is the same as that shown in FIG.

  The flicker determination unit 44 calculates a difference between the luminance data QY and the luminance data SY two frames before for each pixel, thereby obtaining an inter-frame luminance difference | QY−SY | indicating a luminance change between the three frames. The flicker determination unit 33 detects a flicker component included in the luminance data QY based on the inter-frame luminance difference | QY−SY | and the moving image detection flag H, and generates a flicker adjustment coefficient QG.

  FIG. 46 is a diagram for explaining a flicker detection method in the flicker determination unit 44. FIG. 46A shows changes in the luminance data RY, QY, SY when the luminance data QY represents a moving image area. When the luminance data QY represents a moving image area, the two inter-frame luminance differences | QY−RY | and | QY−SY | are both large values as shown in FIG. FIG. 29B shows changes in the luminance data RY, QY, SY when the luminance data QY includes a flicker component. When the luminance data QY includes a flicker component, the inter-frame luminance difference | QY−RY | is a large value, whereas the inter-frame luminance difference | QY−SY | is 0 or a very small value. Here, when the inter-frame luminance difference | QY−RY | exceeds a predetermined value, the moving image detection flag is H = 1, so that the moving image detection flag H = 1 and the inter-frame luminance difference | QY−RY | When the value is 0 or a very small value, it is determined that the luminance data QY includes a flicker component.

  The flicker determination unit 44 determines whether the luminance data QY includes flicker based on the value of the moving image detection flag H output from the moving image still image determination unit 43 and the magnitude of the inter-frame luminance difference | QY−SY |. The flicker adjustment coefficient QG is output based on the determination result. When the moving image detection flag H = 0, that is, when the luminance data QY represents a still image region, the flicker determination unit 44 outputs the flicker adjustment coefficient QG as 1. Conversely, when the moving image detection flag H = 1, that is, when the luminance data QY represents a moving image region, the flicker detection unit 44 outputs the flicker adjustment coefficient QG based on the magnitude of the inter-frame luminance difference | QY−SY |. To do.

FIG. 47 is a diagram showing the relationship between the flicker adjustment coefficient QG and the inter-frame luminance difference | QY−SY |. In FIG. 30, the horizontal axis represents the reciprocal of the inter-frame luminance difference | QY-SY |, and the vertical axis represents the magnitude of the flicker adjustment coefficient QG. In FIG. 47, a region A in which the reciprocal of the inter-frame luminance difference | QY−SY | is small (region where | QY−SY | is large) is a moving image region, and a region C in which the reciprocal of the inter-frame luminance difference | QY−SY | (A region where | QY−SY | is small) is a flicker generation region, and an intermediate region between the moving image region and the flicker generation region is a region B.
As shown in FIG. 47, the flicker adjustment coefficient QG has a large value (QG = QGm) in the moving image region (region A) and a small value (QG = QGf) in the flicker generation region (region C). In the intermediate area (area B), the flicker adjustment coefficients Qf and Qm are intermediate between the moving image area and the flicker occurrence area (QGf <QF <QGf).
The coefficient correction unit 45 integrates the image processing adjustment coefficient QF output from the moving image still image determination unit 43 and the flicker adjustment coefficient QG output from the flicker determination unit 44 to generate a new image processing adjustment coefficient QFG. .

When the luminance data QY represents a still image area (when the moving image detection flag is H = 0), the flicker adjustment coefficient is QG = 1, so that the image processing adjustment coefficient QFG is the area A (still image shown in FIG. Image processing adjustment coefficient QF = QFs in the region).
When the inter-frame luminance difference | QY−RY | exceeds a predetermined value (when the moving image detection flag is H = 1), as shown in FIG. 7, the image processing adjustment coefficient QF is QFm in the region B (moving region). (QFm> QFs). On the other hand, the flicker adjustment coefficient QG is small in the flicker occurrence region (region C) and large in the moving image region (region A) as shown in FIG. Therefore, the image processing adjustment coefficient QFC in the flicker occurrence area is a value obtained by reducing the image processing adjustment coefficient QF = QFm in the area C (moving area) shown in FIG. 7, and the image processing adjustment coefficient QFC in the area A (moving area). Is equal to or larger than the image processing adjustment coefficient QF = QFm.

FIG. 31 is a diagram showing a difference in contour correction amount depending on the presence or absence of flicker. FIGS. 31A, 31B, and 31C show luminance data QYa, conversion magnification Z, and luminance data ZYa after contour correction. In FIG. 31B, the solid line indicates the conversion magnification Z in the moving image area, and the broken line indicates the conversion magnification Z in the flicker occurrence area. In FIG. 31C, the solid line indicates the luminance data ZYa after contour correction in the moving image region, and the broken line indicates the luminance data ZYa after contour correction in the flicker occurrence region.
In the flicker occurrence region, the value of the image processing adjustment coefficient QFG integrated with the magnification control amount ZC is smaller than that of the moving image region not including flicker. Therefore, as shown in FIG. It becomes smaller in the flicker occurrence area. For this reason, as shown in FIG. 31C, the contour width Wb of the luminance data ZYa after contour correction in the flicker occurrence region is wider than the contour width Wc in the moving image region not including flicker, and the sharpness is lowered. . That is, in the flicker occurrence region, it is possible to prevent the flicker from being emphasized by increasing the sharpness of the contour portion.

  As described above, according to the image processing apparatus according to the present embodiment, flicker is detected based on the inter-frame luminance difference | QY-RY |, | QY-SY |, and the contour correction amount in the flicker occurrence region is suppressed. Therefore, the sharpness of the moving image region can be increased without enhancing the flicker component.

Further, the frame memory control unit 11 writes the encoded luminance data EY and color difference data DCr and DCb to the frame memory 13, performs contour correction processing on the input luminance data DY (= QY), and performs color difference data QCr. , QCb can be read out with a delay corresponding to the number of lines necessary for the contour correction process, thereby reducing the line memory required for timing adjustment of the color difference data.
Furthermore, after the luminance data DY is encoded, the encoded luminance data EY is written into the frame memory 13, and the encoded luminance data EY1 is read out from the frame memory 13 and then decoded. As the coding rate (data compression rate) of the luminance data is increased, the capacity of the frame memory 13 for storing the coded luminance data EY can be reduced, and the bus bandwidth between the frame memory 13 and the frame memory control unit 11 is reduced. Can be saved.

The contour correction unit 5 performs contour correction processing on the luminance data QY based on the image processing adjustment coefficient QFG, and outputs contour corrected luminance data ZYa.
Since the operations of the comparison determination unit 10 and the contour correction unit 5 have already been described in the third embodiment and the first embodiment, detailed description thereof is omitted here.

1 is a block diagram showing an embodiment of an image processing apparatus according to the present invention. It is a block diagram which shows the internal structure of an image process part. It is a block diagram which shows the internal structure of a frame memory control part. It is a figure which shows the read-out timing of a frame memory. It is a figure which shows the read-out timing of a frame memory. It is a figure which shows an example of the characteristic of an image processing adjustment coefficient. It is a figure which shows an example of the characteristic of an image processing adjustment coefficient. It is a figure which shows an example of a moving image. It is a block diagram which shows the internal structure of a vertical outline correction | amendment part. It is a figure which shows the operation | movement of a line delay. It is a figure for demonstrating an outline width correction process. It is a figure for demonstrating the outline width correction process in a moving image area | region and a still image area | region. It is a block diagram which shows the internal structure of a vertical outline correction | amendment part. It is a figure which shows the operation | movement of a line delay. It is a figure for demonstrating an outline emphasis process. It is a block diagram which shows the internal structure of a vertical outline correction | amendment part. It is a figure which shows an example of the characteristic of an image processing adjustment coefficient. It is a figure which shows an example of the characteristic of an image processing adjustment coefficient. It is a figure for demonstrating an outline correction process. It is a block diagram which shows the internal structure of an image process part. It is a block diagram which shows the internal structure of a horizontal outline correction | amendment part. It is a figure which shows the operation | movement of a pixel delay. It is a figure which shows the operation | movement of a pixel delay. It is a block diagram which shows the internal structure of an image process part. It is a block diagram which shows the internal structure of a frame memory control part. It is a figure which shows the read-out timing of a frame memory. It is a figure which shows the read-out timing of a frame memory. It is a block diagram which shows the internal structure of a comparison determination part. It is a figure for demonstrating the detection method of a flicker. It is a figure which shows the characteristic of a flicker adjustment coefficient. It is a figure for demonstrating the outline correction process in a moving image area | region and a flicker generation | occurrence | production area | region. It is a block diagram which shows the structure of the frame memory control part in Embodiment 4 of this invention. It is a block diagram which shows another structure of the frame memory control part in Embodiment 4 of this invention. It is a block diagram which shows the structure of the frame memory control part in Embodiment 5 of this invention. It is a block diagram which shows another structure of the frame memory control part in Embodiment 5 of this invention. It is a block diagram which shows the structure of the frame memory control part in Embodiment 6 of this invention. It is a figure which shows the write-in / read-out timing of a frame memory. It is a figure which shows the write-in / read-out timing of a frame memory. It is a block diagram which shows another structure of the frame memory control part in Embodiment 6 of this invention. It is a block diagram which shows the structure of the image process part in Embodiment 7 of this invention. It is a block diagram which shows the structure of the frame memory control part in Embodiment 7 of this invention. It is a block diagram which shows the structure of the frame memory control part in Embodiment 8 of this invention. It is a figure which shows the write-in / read-out timing of a frame memory. It is a figure which shows the write-in / read-out timing of a frame memory. FIG. 20 is a block diagram illustrating an internal configuration of a comparison / determination unit according to Embodiment 8. It is a figure for demonstrating the detection method of a flicker. It is a figure which shows the characteristic of a flicker adjustment coefficient.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reception part, 2 Image processing part, 3 Conversion part, 4 Storage part, 5 Contour correction part, 6 Conversion part, 7 Output synchronous signal generation part, 8 Transmission part, 9 Display part, 10 Comparison determination part, 11 Frame memory control Unit, 12 vertical contour correction unit, 13 frame memory, 46 to 48 encoding unit, 49 to 51 buffer, 52 write address control unit, 53 to 56 buffer, 57 to 60 decoding unit, 61 read address control unit, 62 buffer 63 Decoding unit.

Claims (13)

An image processing apparatus for correcting a contour portion of an input image,
Magnification control amount generation that detects the contour width of the contour portion in the input image and generates a magnification control amount that specifies the interpolation magnification of the interpolation pixel for correcting the contour portion of the input image for each pixel based on the contour width Means,
A comparison means for obtaining, for each pixel, the amount of change between the input image and the image one frame before the input image;
A magnification generation means for adjusting the magnification control amount according to the amount of change and generating a conversion magnification;
An image processing apparatus comprising: interpolation calculation means for calculating pixel data of the interpolation pixel by interpolation calculation using the conversion magnification and outputting image data in which a contour portion is corrected. The comparison means is
Encoding means for encoding input image data;
Memory means for delaying the encoded image data;
Decoding means for decoding encoded image data read from the memory means;
The image processing apparatus according to claim 1, further comprising:   The magnification control amount generation means generates the magnification control amount so that the sum of the image data is positive at the front of the contour, negative at the center of the contour, and positive at the rear of the contour, and the total sum is 0. The image processing apparatus according to claim 1, wherein the conversion magnification is generated by being superimposed on a reference conversion magnification that indicates an enlargement or reduction ratio. An enhancement amount calculating means for detecting a high frequency component of the image data in which the contour portion is corrected, and calculating an enhancement amount for enhancing the contour portion of the image data based on the detected high frequency component;
The image processing apparatus according to any one of claims 1 to 3, further comprising contour enhancement means for enhancing the contour portion of the image data by adding the enhancement amount to the image data obtained by correcting the contour portion. Image processing device.   The image processing apparatus according to claim 4, wherein the enhancement amount is adjusted based on a change amount between the input image and an image one frame before the input image. Flicker determination means for obtaining a change amount between the input image and an image of a frame before and after the input image and detecting a flicker occurrence area included in the input image based on the change amount;
6. The image processing apparatus according to claim 1, wherein the magnification control amount is limited in the flicker occurrence region.   An image display device comprising the image processing device according to claim 1. An image processing method for correcting a contour portion of an input image,
Detecting a contour width of a contour portion in the input image, and generating a magnification control amount for designating, for each pixel, an interpolation magnification of an interpolation pixel for correcting the contour portion of the input image based on the contour width;
A comparison step for obtaining, for each pixel, a change amount between the input image and an image one frame before the input image;
Adjusting the magnification control amount according to the amount of change and generating a conversion magnification;
An image processing method comprising: calculating pixel data of the interpolated pixel by an interpolation operation using the conversion magnification and outputting image data in which a contour portion is corrected. The comparison process is
Encoding input image data;
Delaying the encoded image data;
The image processing method according to claim 8, further comprising a step of decoding the delayed encoded image data.   The magnification control amount is generated so that the front of the contour is positive, negative at the center of the contour, positive at the rear of the contour, and the total sum is 0. 10. The image processing method according to claim 8, wherein the conversion magnification is generated by superimposing the conversion magnification. Detecting a high frequency component of the image data in which the contour portion is corrected, and calculating an enhancement amount for enhancing the contour portion of the image data based on the detected high frequency component;
The image processing according to claim 8, further comprising: a step of enhancing the contour portion of the image data by adding the enhancement amount to the image data obtained by correcting the contour portion. Method.   The image processing method according to claim 11, wherein the enhancement amount is adjusted based on a change amount between the input image and an image one frame before the input image. A step of obtaining a change amount between the input image and an image of a frame before and after the input image, and detecting a flicker occurrence region included in the input image based on the change amount;
The image processing method according to claim 8, wherein the magnification control amount is limited in the flicker occurrence region.

Images