Apparatus for encoding a video signal using feature point based motion estimation
First Claim
1. An apparatus, for use in a motion-compensated video signal encoder, for determining a predicted current frame based on a current frame and a previous frame of a digital video signal, comprising:
- region detection means for calculating a difference between the current frame and the previous frame and for detecting a processing region encompassing a moving object from the previous frame based on the calculated difference to generate region information representing the detected processing region, wherein the processing region has a plurality of image blocks contained in the previous frame and the image blocks are determined by using the calculated difference, wherein said region detection means includes;
means for calculating the difference between the current and the previous frames on a pixel-by-pixel basis to generate a frame difference signal wherein the frame difference signal includes N×
M blocks, each block having P×
Q pixel difference values and N, M, P and Q are positive integers;
means for absolutizing the frame difference signal to generate an absolutized frame difference signal;
means for comparing the absolutized frame difference signal with a predetermined value to convert the absolutized frame difference signal into a converted frame difference signal, wherein, when a pixel difference value of the absolutized frame difference signal is smaller than the predetermined value, "0" is assigned as the pixel difference value and, otherwise, "1" is assigned as the pixel difference value;
means for counting the number of "1"'"'"'s contained in each block of the converted frame difference signal; and
means for comparing the counted number for each block with a predetermined number to generate the region information having sequentially arranged N×
M block representative values, wherein, when the counted number for a block is smaller than the predetermined value, "0" is assigned as a block representative value of the region information and, otherwise, "1" is assigned as the block representative value;
feature point selection means for selecting a number of pixels from the pixels contained in the detected processing region as feature points based on the region information;
first motion vector detection means for detecting a first set of motion vectors between the current and the previous frames, each of the first set of motion vectors representing a motion for each of the feature points;
second motion vector detection means for producing a second set of motion vectors for all of the pixels contained in the current frame by using the first set of motion vectors; and
motion compensation means for assigning the value of each of the pixels in the previous frame, said each of the pixels corresponding to one of the pixels in the current frame through one of the second set of motion vectors, as the value of said one of the pixels in the current frame, to thereby determine the predicted current frame.
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Accused Products
Abstract
A motion-compensated video signal encoder has a circuit for determining a predicted current frame based on a current frame and a previous frame of a digital video signal. The circuit includes a region detection circuit for detecting a processing region encompassing a moving object from the previous frame based on a difference between the current and the previous frames to generate region information representing the detected processing region. Therefore, a number of pixels is selected from the pixels contained in the detected processing region as feature points based on the region information. A first set of motion vectors between the current and the previous frames, each of the first set of motion vectors representing a motion for each of the selected pixels is then detected. The first set of motion vectors is used for predicting the predicted current frame and transmitted as a set of motion vectors of the video signal together with the region information.
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Citations
15 Claims
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1. An apparatus, for use in a motion-compensated video signal encoder, for determining a predicted current frame based on a current frame and a previous frame of a digital video signal, comprising:
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region detection means for calculating a difference between the current frame and the previous frame and for detecting a processing region encompassing a moving object from the previous frame based on the calculated difference to generate region information representing the detected processing region, wherein the processing region has a plurality of image blocks contained in the previous frame and the image blocks are determined by using the calculated difference, wherein said region detection means includes; means for calculating the difference between the current and the previous frames on a pixel-by-pixel basis to generate a frame difference signal wherein the frame difference signal includes N×
M blocks, each block having P×
Q pixel difference values and N, M, P and Q are positive integers;means for absolutizing the frame difference signal to generate an absolutized frame difference signal; means for comparing the absolutized frame difference signal with a predetermined value to convert the absolutized frame difference signal into a converted frame difference signal, wherein, when a pixel difference value of the absolutized frame difference signal is smaller than the predetermined value, "0" is assigned as the pixel difference value and, otherwise, "1" is assigned as the pixel difference value; means for counting the number of "1"'"'"'s contained in each block of the converted frame difference signal; and means for comparing the counted number for each block with a predetermined number to generate the region information having sequentially arranged N×
M block representative values, wherein, when the counted number for a block is smaller than the predetermined value, "0" is assigned as a block representative value of the region information and, otherwise, "1" is assigned as the block representative value;feature point selection means for selecting a number of pixels from the pixels contained in the detected processing region as feature points based on the region information; first motion vector detection means for detecting a first set of motion vectors between the current and the previous frames, each of the first set of motion vectors representing a motion for each of the feature points; second motion vector detection means for producing a second set of motion vectors for all of the pixels contained in the current frame by using the first set of motion vectors; and motion compensation means for assigning the value of each of the pixels in the previous frame, said each of the pixels corresponding to one of the pixels in the current frame through one of the second set of motion vectors, as the value of said one of the pixels in the current frame, to thereby determine the predicted current frame. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A video signal encoding apparatus for reducing a transmission rate of a digital video signal, said digital video signal having a plurality of frames including a current frame and a previous frame, comprising:
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memory means for storing the previous frame of the digital video signal; region detection means for calculating a difference between the current frame and the previous frame and for detecting a processing region encompassing a moving object from the previous frame based on the calculated difference to generate region information representing the detected processing region, wherein the processing region has a plurality of image blocks contained in the previous frame and the image blocks are determined by using the calculated difference, wherein said region detection means includes; means for calculating the difference between the current and the previous frames on a pixel-by-pixel basis to generate a second frame difference signal wherein the second frame difference signal includes N×
M blocks, each block having P×
Q pixel difference values and N, M, P and Q are positive integers;means for absolutizing the second frame difference signal to generate an absolutized frame difference signal; means for comparing the absolutized frame difference signal with a predetermined value to convert the absolutized frame difference signal into a converted frame difference signal, wherein, when a pixel difference value of the absolutized frame difference signal is smaller than the predetermined value, "0" is assigned as the pixel difference value and, otherwise, "1" is assigned as the pixel difference value; means for counting the number of "1"'"'"'s contained in each block of the converted frame difference signal; and means for comparing the counted number for each block with a predetermined number to generate the region information having sequentially arranged N×
M block representative values, wherein, when the counted number for a block is smaller than the predetermined value, "0" is assigned as a block representative value of the region information and, otherwise, "1" is assigned as the block representative value;feature point selection means for selecting a number of pixels from the pixels contained in the detected processing region as feature points based on the region information; first motion vector detection means for detecting a first set of motion vectors between the current and the previous frames, each of the first set of motion vectors representing a motion for each of the selected pixels; second motion vector detection means for producing a second set of motion vectors for all of the pixels contained in the current frame by using the first set of motion vectors; motion compensation means for assigning the value of each of the pixels in the previous frame, said each of the pixels corresponding to one of the pixels in the current frame through one of the second set of motion vectors, as the value of said one of the pixels in the current frame, to thereby determine the predicted current frame; and coding means for encoding a difference signal representing a difference between the current frame and the predicted current frame, the first set of motion vectors and the region information to thereby generate the digital video signal. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification