Method and apparatus for determining offset values using human visual characteristics

A video encoding apparatus comprising:

• an encoder configured to encode a current image;
• a decoder configured to decode the encoded current image to produce a restored image of the current image;
• an offset determiner configured to divide the current image into a plurality of blocks, determine a category of pixels in each of the plurality of blocks based on values of neighboring pixels, and determine an offset value for pixels belonging to the category;
• and
• an offset adjuster configured to adjust the offset value based on characteristics of the category and a background pixel value of each of the pixels,
• wherein the offset value is an average of differences between values of original images and restored images of pixels belonging to one category, and
• wherein the background pixel value is an average of values of pixels in a background pixel block to which the pixels belong among background pixel blocks divided to calculate a background pixel value.

A video decoding apparatus comprising:

• decoder configured to decode an encoded current image to produce a restored image of the current image;
• and
• an offset applier configured to decode an encoded offset value and apply the decoded offset value to the restored image,
• wherein an offset value for pixels belonging to a category is determined by dividing the current image into a plurality of blocks and determining a category of pixels in each of the plurality of blocks based on values of neighboring pixels,
• wherein the offset value is adjusted based on characteristics of the category and a background pixel value of each of the pixels,
• wherein the offset value is an average of differences between values of original images and restored images of pixels belonging to one category, and
• wherein the background pixel value is an average of values of pixels in a background pixel block to which the pixels belong among background pixel blocks divided to calculate a background pixel value.

A video decoding method, the method comprising:

• decoding an encoded current image to produce a restored image of the current image;
• and
• decoding an encoded offset value and applying the decoded offset value to the restored image,
• wherein the offset value is determined for pixels belonging to a category by dividing the current image into a plurality of blocks and determining the category of pixels in each of the plurality of blocks based on values of neighboring pixels, and
• wherein the offset value is adjusted based on characteristics of the category and a background pixel value of each of the pixels.