Color motion artifact detection and processing apparatus compatible with video coding standards
First Claim
1. A method for detecting a color-motion artifact in a block of a video frame, the method comprising:
- computing a motion-compensated color-difference value associated with the block;
determining an activity level associated with the block, wherein the activity level is indicative of a smoothness of transitions in pixel values disposed in the block;
selecting a threshold value based on the activity level and a target bit rate associated with the block; and
identifying the block as containing a color motion artifact if the motion-compensated color-distance value associated with the block is one of greater than and equal to the threshold value.
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Abstract
To detect color motion artifacts in a video frame, a motion-compensated color-distance value is compared against a threshold value. If the motion-compensated color-distance value is greater than or equal to the threshold value, color-motion artifacts are detected. The motion-compensated color-distance value is a sum of absolute values of the differences between corresponding pixel values of the video frame and a reference frame. To detect color motion artifacts in a video frame, in another embodiment, luminance and chrominance components of the intra-frame activity levels are compared against luminance and chrominance components of the inter-frame activity levels. If any of the components of the inter-frame activity levels is greater than the corresponding components of the intra-frame activity levels, color-motion artifacts are detected. To reduce color-motion artifacts, either a smaller quantization scale or intra-frame encoding is used to encode the data.
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Citations
21 Claims
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1. A method for detecting a color-motion artifact in a block of a video frame, the method comprising:
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computing a motion-compensated color-difference value associated with the block; determining an activity level associated with the block, wherein the activity level is indicative of a smoothness of transitions in pixel values disposed in the block; selecting a threshold value based on the activity level and a target bit rate associated with the block; and identifying the block as containing a color motion artifact if the motion-compensated color-distance value associated with the block is one of greater than and equal to the threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus adapted to detect a color-motion artifact in a block of a video frame, the apparatus comprising:
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a first module for computing a motion-compensated color-difference value associated with the block; a second module for determining an activity level associated with the block, wherein the activity level is indicative of a smoothness of transitions in pixel values disposed in the block; a third module for selecting a threshold value based on the activity level and a target bit rate associated with the block; and a fourth module for identifying the block as containing a color motion artifact if the motion-compensated color-distance value computed for the block is one of greater than and equal to a the threshold value. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for detecting a color-motion artifact in a block of a video frame, the method comprising:
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computing a motion-compensated color-difference value associated with the block; selecting a threshold value based on a target bit rate associated with the block, wherein the threshold value is inversely proportional to the target bit rate; and identifying the block as containing a color motion artifact if the motion-compensated color-distance value associated with the block is one of greater than and equal to the threshold value.
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21. A method for detecting a color-motion artifact in a block of a video frame, the method comprising:
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computing a motion-compensated color-difference value associated with the block; and identifying the block as containing a color motion artifact if the motion-compensated color-distance value associated with the block is one of greater than and equal to the threshold value; wherein the motion-compensated color-difference value is defined by a luminance coefficient multiplied by a sum of absolute values of differences of corresponding luminance component values of similarly located pixels of the block and an associated block of a reference frame, and a chrominance coefficient multiplied by a sum of absolute values of differences of corresponding chrominance component values of similarly located pixels of the block and the associated block of the reference frame.
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Specification