IMAGE COMPRESSING APPARATUS AND IMAGE READING APPARATUS INCLUDING THE SAME, IMAGE PROCESSING APPARATUS INCLUDING IMAGE COMPRESSING APPARATUS AND IMAGE FORMING APPARATUS INCLUDING THE SAME, IMAGE COMPRESSION PROCESSING METHOD, COMPUTER PROGRAM THEREOF, AND RECORDING MEDIUM

An image compressing apparatus and method are provided that execute an appropriate JPEG compression process in accordance with a document type of image data to realize maintenance of good image quality and improvement of a compression rate at the same time. Document image data input from an image input apparatus are converted into digital signals by an image compressing apparatus and delivered to a JPEG compression section and a document discrimination section. The document discrimination section discriminates a document type for each page and the parameter setting section calculates optimum compression parameters (a quantization table and a subsampling) in accordance with a document discrimination signal from the document discrimination section. The JPEG compression section executes the JPEG compression process with the use of the parameters from the parameter setting section to output a JPEG code along with encoded data.