Temporal Video Filtering
First Claim
1. A method for temporal filtering, comprising:
- determining a difference between a first frame pixel and a second frame pixel;
if the difference is within a first range of thresholds, adding a first offset to the first frame pixel to form a filtered frame pixel;
if the difference is not within the first range of thresholds, and the difference is within a second range of thresholds, adding a second offset to the first frame pixel to form the filtered frame pixel; and
if the difference is not within the first range of thresholds and the difference is not within the second range of thresholds, adding a value approximately equal to the difference to the first frame pixel to form the filtered frame pixel.
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Abstract
In various embodiments, temporal filtering may be used to reduce noise over time in a series of video frames. A temporal filter may use previous filtered frames to reduce the noise in a current frame. For example, a temporal filter may filter noise in still parts of an image more strongly than in moving parts of the image. In some embodiments, a temporal filter requiring less processing power may include a method for detecting motion between a set of pixels and applying the temporal filter based on the detected motion. For example, if substantial motion is not detected, the temporal filter for the block of pixels may be stronger (i.e., reduce more noise) than the temporal filter applied to a block of pixels for which substantial motion has been detected.
55 Citations
21 Claims
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1. A method for temporal filtering, comprising:
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determining a difference between a first frame pixel and a second frame pixel;
if the difference is within a first range of thresholds, adding a first offset to the first frame pixel to form a filtered frame pixel;
if the difference is not within the first range of thresholds, and the difference is within a second range of thresholds, adding a second offset to the first frame pixel to form the filtered frame pixel; and
if the difference is not within the first range of thresholds and the difference is not within the second range of thresholds, adding a value approximately equal to the difference to the first frame pixel to form the filtered frame pixel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for temporal filtering, comprising:
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determining differences between each of at least two first frame pixels and two corresponding second frame pixels and adding the differences to produce a resultant;
if the resultant is within a resultant range of thresholds, applying a filter to a selected first frame pixel of the at least two first frame pixels; and
if the resultant is not within the resultant range of thresholds, not applying the filter to the corresponding second frame pixels. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A video conferencing system, comprising:
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a video display;
a video codec coupled to the video display, wherein the video codec is configured to send/receive video frames to/from a remote video conferencing system; and
wherein the video codec comprises a processor and memory;
wherein the memory is configured to store program instructions executable by the processor to;
determine a difference between a first frame pixel and a second frame pixel;
if the difference is within a first range of thresholds, add a first offset to the first frame pixel to form a filtered frame pixel;
if the difference is not within the first range of thresholds, and the difference is within a second range of thresholds, add a second offset to the first frame pixel to form the filtered frame pixel; and
if the difference is not within the first range of thresholds and the difference is not within the second range of thresholds, using a pixel value approximately equal to the corresponding second frame pixel for the filtered frame pixel. - View Dependent Claims (18, 19, 20, 21)
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Specification