Image signal processing device

An image signal processing device, comprising:

• orthogonal transformation means for applying an orthogonal transformation to original image data comprising at least one image component to obtain orthogonal transformation coefficients corresponding to predetermined spatial frequencies for each image component, said original image data comprising a first, a second, and a third image component;
• quantization means for quantizing said orthogonal transformation coefficients, comprising quantization tables including quantization coefficients to obtain quantized orthogonal transformation coefficients;
• first inverse quantization means for inversely quantizing said quantized orthogonal transformation coefficients to obtain restored orthogonal transformation coefficients;
• error data producing means for obtaining quantized error data of a difference between said restored orthogonal transformation coefficients and said orthogonal transformation coefficients for each image component;
• encoding means for encoding said quantized error component and said quantized orthogonal transformation coefficients to form a compressed image data;
• error data synthesizing means for arranging said quantized error data into unit data of a fixed length for each same spatial frequency of components so as to synthesize a fourth component, said encoding means encodes said fourth component and said quantized orthogonal transformation coefficients to form compressed image data;
• and
• recording means for recording said compressed image data to a recording medium.