Patent ID: 7050644

Claim:
A method for coding input image data in a predetermined signal format, comprising: dividing said image data into block units; and carrying out orthogonal transformation in said block units at a time when data output value X 0 +X 1 and data output value X 0 −X 1 are generated from two data input values X 0 and X 1 by at least a function of said orthogonal transform transformation, said orthogonal transformation comprising the following steps: setting said X 0 value in a register A and setting said X 1 value in a register B; subtracting said X 1 value from said X 0 value to obtain a new X 0 value and storing said new X 0 value in register A; shifting said X 1 value used as a binary number by one bit to a MSB side to obtain a new X 1 value and storing said new X 1 value in register B; adding said new X 0 value to said new X 1 value to obtain a further new X 1 value and outputting said further new X 1 value as a sum of said new X 0 value and said new X 1 value.