Motion estimation and compensation method and device adaptive to change in illumination

A motion estimation device comprising:

• a pattern block generating unit generating a current frame pattern block of a current frame block and reference frame pattern blocks of a reference frame block;
• a motion vector determining unit calculating the sum of absolute differences (SAD) of candidate pattern blocks corresponding to the current frame pattern block among the reference frame pattern blocks and determining each candidate pattern block corresponding to the SAD satisfying a predetermined condition among the calculated SAD as a motion vector;
• a motion compensation unit generating a residual signal using a difference signal between the candidate pattern block corresponding to the motion vector and the current frame pattern block;
• and
• an adding unit adding flag information indicating the addition of a mean pixel value applied to an encoded current frame block and identification information on an encoding mode as header information corresponding to the encoded current frame block;
• wherein the addition of a mean pixel value to be applied to the current frame block is identified by the flag information,
• wherein the pattern block generating unit:
• calculates a mean brightness value of the current frame block and a mean brightness value of the reference frame block;
• generates the current frame pattern block by subtracting the mean brightness value of the current frame block from brightness values of the current frame block;
• and
• generates the reference frame pattern blocks by subtracting the mean brightness value of the reference frame block from brightness values of the reference frame block.

A motion estimation method comprising the steps of:

• (a) generating a current frame pattern block for a current frame block and a reference frame pattern block for a reference frame block;
• (b) calculating the sum of absolute differences (SAD) for candidate pattern blocks corresponding to the current frame pattern block among reference frame pattern blocks and determining each candidate pattern block corresponding to the SAD satisfying a predetermined condition among the calculated SAD as a motion vector;
• (c) encoding the current frame block, by generating a residual signal using a difference signal between the candidate pattern block corresponding to the motion vector and the current frame pattern block then performing discrete cosine transform and quantization to the residual signal with a predetermined encoding mode;
• and
• (d) adding flag information indicating whether a mean pixel value of the encoded current frame block is included and identification information on the encoding mode to the encoded current frame block as header information,
• wherein whether the mean pixel value of the current frame block is included is identified by the flag information,
• wherein step (a) includes the steps of:
• calculating a mean brightness value of the current frame block and a mean brightness value of the reference frame block;
• and
• generating the current frame pattern block by subtracting the mean brightness value of the current frame block from brightness values of the current frame block and generating the reference frame pattern blocks by subtracting the mean brightness value of the reference frame block from brightness values of the reference frame block.

A motion estimation device comprising:

• a pattern block generating unit generating a current frame pattern block for a current frame block and reference frame pattern blocks for a reference frame block;
• a motion vector determining unit calculating the sum of absolute differences (SAD) for candidate pattern blocks corresponding to the current frame pattern block among the reference frame pattern blocks and determining each candidate pattern block corresponding to the SAD satisfying a predetermined condition among the calculated SAD as a motion vector;
• a motion compensation unit generating a residual signal using a difference signal between the candidate pattern block corresponding to the motion vector and the current frame pattern block;
• and
• an adding unit adding flag information indicating whether a mean pixel value of an encoded current frame block is included and identification information on an encoding mode to the encoded current frame block as header information,
• wherein whether the mean pixel value of the current frame block is included is identified by the flag information,
• wherein the pattern block generating unit:
• calculates a mean brightness value of the current frame block and a mean brightness value of the reference frame block;
• generates the current frame pattern block by subtracting the mean brightness value of the current frame block from brightness values of the current frame block;
• and
• generates the reference frame pattern blocks by subtracting the mean brightness value of the reference frame block from brightness values of the reference frame block.