Patent ID: 8554004

Claim:
A data transform apparatus for orthogonally transforming a plurality of blocks of image data, the blocks represented by a preset number of pixels, to encode the image data, the apparatus comprising: a storage unit which stores image data to be orthogonally transformed; an access unit which reads each block from said storage unit; a first transforming unit which receives and orthogonally transforms the block in the image data that has been stored in said storage unit and read out via said access unit, and for calculates and outputs only one direct current (DC) component; a selection unit which selects and outputs one of: the block read out via said access unit, and data of DC components from said first transforming unit that are equal in number to pixels included in the block; a second transforming unit which orthogonally transforms data, output from said selection unit, that are equal in number to pixels included in the block, and outputs one of: one DC component and a plurality of alternative current (AC) components; and a control unit which controls said access unit, said selection unit, and said second transforming unit to execute one of a first setting of causing said selection unit to select a DC component from said first transforming unit, and said second transforming unit to output one DC component obtained by orthogonal transform, a second setting of causing said selection unit to select a DC component from said first transforming unit, and said second transforming unit to output a plurality of AC components obtained by orthogonal transform, and a third setting of causing said selection unit to select a block of image data read via said access unit, and said second transforming unit to output a plurality of AC components obtained by orthogonal transform.