Patent ID: 6882752

Claim:
An image compression and expansion apparatus, comprising: a reduced image generating processor that generates, based on original image data arranged in a first matrix comprised of a plurality of pixels, reduced image data arranged in a second matrix comprised of a smaller number of pixels than said first matrix; a reduced image recording processor that records said reduced image data in a recording medium; an orthogonal transforming processor that reads said reduced image data from said recording medium and applies an orthogonal transformation to obtain orthogonal transformation coefficients arranged in said second matrix; and an expanded image generating processor that applies an inverse orthogonal transformation to all of said orthogonal transformation coefficients to obtain expanded image data arranged in a third matrix having a greater number of pixels than said second matrix, wherein said reduced image generating processor obtains an average value of a predetermined number of pixel values included in said first matrix, and sets said average value as one pixel value corresponding to a predetermined number of pixels included in said second matrix.