Visual processing device, visual processing method, program, display device, and integrated circuit

• US 7,894,684 B2
• Filed: 03/27/2007
• Issued: 02/22/2011
• Est. Priority Date: 04/19/2006
• Status: Expired due to Fees

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Monobe, Yusuke, Ito, Takeshi, Yamashita, Haruo
• Primary Examiner(s): Le; Vu
• Assistant Examiner(s): Allison; Andrae S
• Application Number:
  US12/297,403
• Publication Number:
  US 20090097775A1
• Time in Patent Office: 1,428 Days
• Field of Search: 382/165, 382/167, 382/190, 382/199, 382/219, 382/220, 382/250, 382251-252, 382255-256, 382260-266, 348/607, 348/610, 348/615, 348/622, 348/625, 348/627, 358/3.26, 358/3.27, 358/532, 358/537, 358/540, 358/463, 358/464
• US Class Current: 382/254
• CPC Class Codes: G06T 2207/20012 Locally adaptive
• CPC Class Codes: G06T 2207/20021 Dividing image into blocks, subimages or windows
• CPC Class Codes: G06T 2207/20192 Edge enhancement; Edge preservation
• CPC Class Codes: G06T 5/94 based on local image properties, e.g. for local contrast enhancement
• CPC Class Codes: H04N 1/4092 Edge or detail enhancement
• CPC Class Codes: H04N 5/142 Edging; Contouring
• CPC Class Codes: H04N 5/20 Circuitry for controlling amplitude response

Abstract

In order to inhibit artifacts (even when a special image has been input) a visual processing device is provided with a spatial processing portion extracting surrounding image information US from an input image signal IS, and a special image detection portion outputting a special image effect adjustment signal DS according to a degree of a statistical bias of the image signal IS. The visual processing device also includes a continuous changing portion outputting an effect adjustment signal MOD in which the special image effect adjustment signal DS is continuously changed between frames, an effect adjustment portion outputting a synthesized signal MUS in which the effect of the visual processing differs depending on the effect adjustment signal MOD, and a visual processing portion outputting a processed signal OS obtained by visually processing the image signal IS based on the image signal IS and the synthesized signal MUS.

Claims

1. A visual processing device, comprising:

a surrounding image information extraction portion operable to extract, from a pixel group of a pixel area surrounding a target pixel of an input image, surrounding image information including luminance information of the pixel group;

a visual processing portion operable to (i) receive a pixel value of the target pixel, (ii) receive the surrounding image information, (iii) obtain a converted pixel value by converting the pixel value of the target pixel according to a conversion characteristic, such that, for a specific pixel value of the target pixel, the converted pixel value of the specific pixel value of the target pixel monotonically decreases as a value of the surrounding image information increases, and (iv) output an output image including a group of converted target pixels, each target pixel of the group of converted target pixels having the converted pixel value;

a special image detection portion operable to detect a change in gradation in a predetermined area included in the input image, and output one of (i) an effect adjustment signal that reduces an effect of the visual processing performed by the visual processing portion in the predetermined area as a ratio of (a) part regions of the predetermined area in which the gradation changes, to (b) the predetermined area decreases, and (ii) an effect adjustment signal that reduces the effect of the visual processing performed by the visual processing portion in the predetermined area as a ratio of (c) part regions of the predetermined area in which the gradation does not change, to (d) the predetermined area increases is higher; and

an effect adjustment portion operable to control the effect of the visual processing with respect to the input image, in accordance with the output effect adjustment signal.

5. The visual processing device according to claim 1,

wherein the output effect adjustment signal reduces the effect of the visual processing as a value of the output effect adjustment signal decreases,

wherein the special image detection portion, when a gradation change region percentage, which is a percentage of regions of the predetermined area in which the gradation changes, is smaller than a first value, sets a signal level of the output effect adjustment signal to a value that is smaller than a first effect adjustment signal level threshold;

wherein the special image detection portion, when the gradation change region percentage is equal to or greater than the first value and is smaller than a second value, which is greater than the first value, sets the signal level of the output effect adjustment signal to a larger value, the larger a value of the gradation change region percentage; and

wherein the special image detection portion, when the gradation change region percentage is equal to or greater than the second value, sets the gradation change region percentage to a larger value than a second effect adjustment signal level threshold, which is a larger value than the first effect adjustment signal level threshold.

6. The visual processing device according to claim 1, wherein the special image detection portion detects the change in gradation by detecting an edge component in the predetermined area included in the input mage.

7. The visual processing device according to claim 1, wherein the special image detection portion detects the change in gradation by detecting a degree of flatness in the predetermined area included in the input image.

8. The visual processing device according to claim 7, wherein the special image detection portion detects the degree of flatness based on a length of successive and analogous pixels.

9. The visual processing device according to claim 6, wherein the special image detection portion detects a percentage of regions of the predetermined area in which the gradation changes based on an edge pixel number, which is a number of pixels that make up the edge component.

10. The visual processing device according to claim 9, wherein the special image detection portion detects the percentage of regions of the predetermined area in which the gradation changes based on an edge pixel ratio, which is a percentage of the number of pixels that make up the edge component of a number of pixels that make up the predetermined area included in the input image.

11. The visual processing device according to claim 10,

wherein the output effect adjustment signal reduces the effect of the visual processing as a value of the output effect adjustment signal decreases, and

wherein the special image detection portion outputs an output value of the output effect adjustment signal as a value that is equal to or greater than a first threshold, when the edge pixel ratio is 20 or more percent.

12. The visual processing device according to claim 1, wherein the special image detection portion detects a percentage of regions of the predetermined area in which the gradation changes based on a number of high frequency blocks, which are blocks that include high frequency components, which are present in the predetermined area included in the input image.

13. The visual processing device according to claim 1, wherein the special image detection portion detects a percentage of regions of the predetermined area in which the gradation changes based on a high frequency block ratio, which is a percentage of a number of high frequency blocks out of a total number of blocks, which are present in the predetermined area included in the input image.

14. The visual processing device according to claim 8, wherein

wherein the special image detection portion includes:

an analogous luminance detection portion operable to detect an analogous pixel having a difference in luminance with an adjacent pixel in the predetermined area included in the input image that is less than or equal to a predetermined value;

a length detection portion operable to detect the length of successive and analogous pixels; and

a mean length calculation portion operable to calculate a mean length by averaging a plurality of lengths detected by the length detection portion, and

wherein the special image detection portion outputs the output effect adjustment signal according to the mean length.

16. The visual processing device according to claim 1,

wherein, when the input image is a frame image, the special image detection portion detects a percentage of part regions of the predetermined area in which the gradation changes from a frame image, which is one or more prior to a frame image that makes up the input image, and

wherein, when the input image is a field image, the special image detection portion detects a percentage of part regions of the predetermined area in which the gradation changes from a field image, which is one or more prior to a field image that makes up the input image.

17. The visual processing device according to claim 16, further comprising a sequentially changing portion operable to continuously change the output effect adjustment signal,

wherein the sequentially changing portion changes the output effect adjustment signal sequentially among frames when the output effect adjustment signal is output for each frame, or changes the output effect adjustment signal sequentially among fields when the output effect adjustment signal is output for each field.

18. A display device, comprising:

a data reception portion operable to receive image data that haste been transmitted or broadcast;

a decoding portion operable to decode the received image data that have been received into video data;

the visual processing device according to claim 1 performing the visual processing with respect to the video data decoded from the received image data by the decoding portion and outputting an output signal obtained by performing the visual processing; and

a display portion operable to display the output signal obtained by performing the visual processing.

2. A visual processing device, comprising:

a surrounding image information extraction portion operable to extract, from a pixel group of a pixel area surrounding a target pixel of an input image, surrounding image information including luminance information of the pixel group;

an effect adjustment portion operable to generate synthesized surrounding image information obtained by synthesizing a pixel value of the target pixel and the surrounding image information, and operable output the synthesized surrounding image information to a visual processing portion;

the visual processing portion operable to (i) receive the pixel value of the target pixel, (ii) receive the synthesized surrounding image information, (iii) obtain a converted pixel value by converting the pixel value of the target pixel according to a conversion characteristic, such that, for a specific pixel value of the target pixel, the converted pixel value of the specific pixel value of the target pixel monotonically decreases as a value of the synthesized surrounding image information increases, and (iv) output an output image including a group of converted target pixels, each target pixel of the group of converted target pixels having the converted pixel value; and

a special image detection portion operable to detect a change in gradation in a predetermined area included in the input image, and output one of (i) an effect adjustment signal that reduces an effect of the visual processing performed by the visual processing portion in the predetermined area as a ratio of (a) part regions of the predetermined area in which the gradation changes, to (b) the predetermined area decreases, and (ii) an effect adjustment signal that reduces the effect of the visual processing performed by the visual processing portion in the predetermined area as a ratio of (c) part regions of the predetermined area in which the gradation does not change, to (d) the predetermined area increases

wherein the effect adjustment portion synthesizes the pixel value of the target pixel and the surrounding image information with a higher ratio for the pixel value of the target pixel as the output effect adjustment signal reduces the effect of the visual processing.

3. A visual processing device, comprising:

a surrounding image information extraction portion operable to extract, from a pixel group of a pixel area surrounding a target pixel of an input image, surrounding image information including luminance information of the pixel group;

a visual processing portion operable to (i) receive a pixel value of the target pixel, (ii) receive the surrounding image information, (iii) obtain a converted pixel value by converting the pixel value of the target pixel according to a conversion characteristic, such that, for a specific pixel value of the target pixel, the converted pixel value of the specific pixel value of the target pixel monotonically decreases as a value of the surrounding image information increases, and (iv) output an output image including a group of converted target pixels, each target pixel of the group of converted target pixels having the converted pixel value;

a special image detection portion operable to detect a change in gradation in a predetermined area included in the input image, and output one of (i) an effect adjustment signal that reduces an effect of the visual processing performed by the visual processing portion in the predetermined area as a ratio of (a) part regions of the predetermined area in which the gradation changes, to (b) the predetermined area decreases, and (ii) an effect adjustment signal that reduces the effect of the visual processing performed by the visual processing portion in the predetermined area as a ratio of (c) part regions of the predetermined area in which the gradation does not change, to (d) the predetermined area increases; and

an effect adjustment portion operable to synthesize the input image and the output image to output a synthesized output image with a higher ratio for the input image as the output effect adjustment signal reduces the effect of the visual processing.

4. A visual processing device, comprising:

a surrounding image information extraction portion operable to extract, from a pixel group of a pixel area surrounding a target pixel of an input image, surrounding image information including luminance information of the pixel group;

a visual processing portion operable to (i) receive a pixel value of the target pixel, (ii) receive the surrounding image information, (iii) obtain a converted pixel value by converting the pixel value of the target pixel according to a conversion characteristic, such that, for a specific pixel value of the target pixel, the converted pixel value of the specific pixel value of the target pixel monotonically decreases as a value of the surrounding image information increases, and (iv) output an output image including a group of converted target pixels, each target pixel of the group of converted target pixels having the converted pixel value;

a special image detection portion operable to detect a change in gradation in a predetermined area included in the input image, and output one of (i) an effect adjustment signal that reduces an effect of the visual processing performed by the visual processing portion in the predetermined area as a ratio of (a) part regions of the predetermined area in which the gradation changes, to (b) the predetermined area decreases, and (ii) an effect adjustment signal that reduces the effect of the visual processing performed by the visual processing portion in the predetermined area as a ratio of (c) part regions of the predetermined area in which the gradation does not change, to (d) the predetermined area increases; and

an effect adjustment portion operable to decrease a degree of the monotonical decrease caused by the conversion characteristic as the output effect adjustment signal reduces the effect of the visual processing.

15. A visual processing device, comprising:

a surrounding image information extraction portion operable to extract, from a pixel group of a pixel area surrounding a target pixel of an input image, surrounding image information including luminance information of the pixel group;

a visual processing portion operable to (i) receive a pixel value of the target pixel, (ii) receive the surrounding image information, (iii) obtain a converted pixel value by converting the pixel value of the target pixel according to a conversion characteristic, such that, for a specific pixel value of the target pixel, the converted pixel value of the specific pixel value of the target pixel monotonically decreases as a value of the surrounding image information increases, and (iv) output an output image including a group of converted target pixels, each target pixel of the group of converted target pixels having the converted pixel value;

a special image detection portion operable to detect a change in gradation in a predetermined region included in a reduced image obtained by reducing a predetermined area included in the input image, and output one of (i) an effect adjustment signal that reduces an effect of the visual processing performed by the visual processing portion in the predetermined area as a ratio of (a) part regions of the predetermined area in which the gradation changes, to (b) the predetermined area decreases, and (ii) an effect adjustment signal that reduces the effect of the visual processing performed by the visual processing portion in the predetermined area as a ratio of (c) part regions of the predetermined area in which the gradation does not change, to (d) the predetermined area increases; and

an effect adjustment portion operable to control the effect of the visual processing with respect to the input image, in accordance with the output effect adjustment signal.

19. A visual processing method, comprising:

a surrounding image information extraction step of extracting, from a pixel group of a pixel area surrounding a target pixel of an input image, surrounding image information including luminance information of the pixel group;

a visual processing step of (i) receiving a pixel value of the target pixel, (ii) receiving the surrounding image information, (iii) obtaining a converted pixel value by converting the pixel value of the target pixel according to a conversion characteristic, such that, for a specific pixel value of the target pixel, the converted pixel value of the specific pixel value of the target pixel monotonically decreases as a value of the surrounding image information increases, and (iv) outputting an output image including a group of converted target pixels, each target pixel of the group of converted target pixels having the converted pixel value;

a special image detection step of detecting a change in gradation in a predetermined area included in the input image, and outputting one of (i) an effect adjustment signal that reduces an effect of the visual processing performed by the visual processing step in the predetermined area as a ratio of (a) part regions of the predetermined area in which the gradation changes, to (b) the predetermined area decreases, and (ii) an effect adjustment signal that reduces the effect of the visual processing performed by the visual processing step in the predetermined area as a ratio of (c) part regions of the predetermined area in which the gradation does not change, to (d) the predetermined area increases; and

an effect adjustment step of controlling the effect of the visual processing with respect to the input image, in accordance with the output effect adjustment signal.

23. A non-transitory computer-readable storage medium having a program stored thereon, the program causing a computer to execute the visual processing method according to claim 19.

27. An integrated circuit executing the visual processing method according to claim 19.

31. An image display device comprising the integrated circuit according to claim 27.

20. A visual processing method, comprising:

a surrounding image information extraction step of extracting, from a pixel group of a pixel area surrounding a target pixel of an input image, surrounding image information including luminance information of the pixel group;

an effect adjustment step of generating synthesized surrounding image information obtained by synthesizing a pixel value of the target pixel and the surrounding image information, and outputting the synthesized surrounding image info information to a visual processing step;

the visual processing step of (i) receiving the pixel value of the target pixel, (ii) receiving the synthesized surrounding image information, (iii) obtaining a converted pixel value by converting the pixel value of the target pixel according to a conversion characteristic, such that, for a specific pixel value of the target pixel, the converted pixel value of the specific pixel value of the target pixel monotonically decreases as a value of the synthesized surrounding image information increases, and (iv) outputting an output image including a group of converted target pixels, each target pixel of the group of converted target pixels having the converted pixel value; and

a special image detection step of detecting a change in gradation in a predetermined area included in the input image, and outputting one of (i) an effect adjustment signal that reduces an effect of the visual processing performed by the visual processing step in the predetermined area as a ratio of (a) part regions of the predetermined area in which the gradation changes, to (b) the predetermined area decreases, and (ii) an effect adjustment signal that reduces the effect of the visual processing performed by the visual processing step in the predetermined area as a ratio of (c) part regions of the predetermined area in which the gradation does not change, to (d) the predetermined area increases,

wherein, in the effect adjustment step, the pixel value of the target pixel and the surrounding image information are synthesized with a higher ratio for the pixel value of the target pixel as the output effect adjustment signal reduces the effect of the visual processing.

24. A non-transitory computer-readable storage medium having a program stored thereon, the program causing a computer to execute the visual processing method according to claim 20.

28. An integrated circuit executing the visual processing method according to claim 20.

21. A visual processing method, comprising:

a surrounding image information extraction step of extracting, from a pixel group of a pixel area surrounding a target pixel of an input image, surrounding image information including luminance information of the pixel group;

a visual processing step of (i) receiving a pixel value of the target pixel, (ii) receiving the surrounding image information, (iii) obtaining a converted pixel value by converting the pixel value of the target pixel according to a conversion characteristic, such that, for a specific pixel value of the target pixel, the converted pixel value of the specific pixel value of the target pixel monotonically decreases as a value of the surrounding image information increases, and (iv) outputting an output image including a group of converted target pixels, each target pixel of the group of converted target pixels having the converted pixel value;

a special image detection step of detecting a change in gradation in a predetermined area included in the input image, and outputting one of (i) an effect adjustment signal that reduces an effect of the visual processing performed in the visual processing step in the predetermined area as a ratio of (a) part regions of the predetermined area in which the gradation changes, to (b) the predetermined area decreases, and (ii) an effect adjustment signal that reduces the effect of the visual processing performed by the visual processing step in the predetermined area as a ratio of (c) part regions of the predetermined area in which the gradation does not change, to (d) the predetermined area increases; and

an effect adjustment step of synthesizing the input image and the output image to output a synthesized output image with a higher ratio for the input image as the output effect adjustment signal reduces the effect of the visual processing.

25. A non-transitory computer-readable storage medium having a program stored thereon, the program causing a computer to execute the visual processing method according to claim 21.

29. An integrated circuit executing the visual processing method according to claim 21.

22. A visual processing method, comprising:

a surrounding image information extraction step of extracting, from a pixel group of a pixel area surrounding a target pixel of an input image, surrounding image information including luminance information of the pixel group;

a visual processing step of (i) receiving a pixel value of the target pixel, (ii) receiving the surrounding image information, (iii) obtaining a converted pixel value by converting the pixel value of the target pixel according to a conversion characteristic, such that, for a specific pixel value of the target pixel, the converted pixel value of the specific pixel value of the target pixel monotonically decreases as a value of the surrounding image information increases, and (iv) outputting an output image including a group of converted target pixels, each target pixel of the group of converted target pixels having the converted pixel value;

a special image detection step of detecting a change in gradation in a predetermined area included in the input image, and outputting one of (i) an effect adjustment signal that reduces an effect of the visual processing performed by the visual processing step in the predetermined area as a ratio of (a) part regions of the predetermined area in which the gradation changes, to (b) the predetermined area decreases, and (ii) an effect adjustment signal that reduces the effect of the visual processing performed by the visual processing step in the predetermined area as a ratio of (c) part regions of the predetermined area in which the gradation does not change, to (d) the predetermined area increases; and

an effect adjustment step of decreasing a degree of the monotonical monotonically decrease caused bythe conversion characteristic as the output effect adjustment signal reduces the effect of the visual processing.

26. A non-transitory computer-readable storage medium having a program stored thereon, the program causing a computer to execute the visual processing method according to claim 22.

30. An integrated circuit executing the visual processing method according to claim 22.