Image coding method and apparatus
First Claim
Patent Images
1. An image coding method for coding a moving picture, comprising:
- a first step of detecting a motion vector for a current image to be coded using a reference image;
a second step of performing motion compensation to the reference image using the motion vector; and
a third step of coding, using orthogonal transformation, quantization and variable-length coding, a difference between the current image and the motion-compensated reference image and producing coded data,wherein the first step includes;
performing a first search by matching between the current image and the reference image;
determining whether a motion vector is detected in the first search; and
performing, only when no motion vector is detected in the first search,wavelet transform to both of the current image and the reference image, and then matching between size-reduced images generated by the wavelet transform to each other to perform a second search.
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Abstract
A motion detection block includes a wavelet transform section which receives a current image I1 and a reference image I2 as inputs. The motion detection section detects a motion vector using size-reduced images RI1 and RI2 generated by transform in the wavelet transform section. Thus, the search range of a motion vector can be apparently extended at the same processing amount.
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Citations
16 Claims
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1. An image coding method for coding a moving picture, comprising:
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a first step of detecting a motion vector for a current image to be coded using a reference image; a second step of performing motion compensation to the reference image using the motion vector; and a third step of coding, using orthogonal transformation, quantization and variable-length coding, a difference between the current image and the motion-compensated reference image and producing coded data, wherein the first step includes; performing a first search by matching between the current image and the reference image; determining whether a motion vector is detected in the first search; and performing, only when no motion vector is detected in the first search, wavelet transform to both of the current image and the reference image, and then matching between size-reduced images generated by the wavelet transform to each other to perform a second search. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 16)
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11. An image coding apparatus for coding a moving picture, comprising:
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a detection block for detecting a motion vector for a current image to be coded using a reference image; a motion compensation section for performing motion compensation to the reference image using the motion vector detected by the motion detection block; a coding block for coding, using orthogonal transformation, quantization and variable-length coding, a difference between the current image and the motion-compensated reference image and producing coded data; and a microcomputer for determining whether motion vector detection using size-reduced images is needed, wherein the motion detection block includes; a first wavelet transform section for performing a first wavelet transform to the current image to generate a first size-reduced image; and a second wavelet transform for performing a second wavelet transform which is substantially the same as the first wavelet transform to the reference image to generate a second size-reduced image, and the motion detection block is so configured to be able to detect a motion vector for the first size-reduced image by referring to the second size-reduced image. - View Dependent Claims (12, 13, 14, 15)
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Specification