Patent Number: 6,167,091

Title: Image data encoding apparatus

Abstract: An image data encoding apparatus performs a two-step process to expand and compress digital image data. The apparatus includes a transform unit for performing orthogonal transform of the image data in a block-by-block manner and generating transform coefficient data. In the first step of the encoding step, a quantizer quantizes the transform coefficient data using a first quantization coefficient to generate first code data. A coefficient operation unit receives the first code data and computes a second quantization coefficient for determining an optimal compression rate of the image data. In the second step of the encoding process, the quantizer receives the second quantization coefficient and quantizes the transform coefficient data to generate second code data. The transform coefficient data is stored in a memory. By optimally compressing the image data, a high image data compression rate is achieved, which allows a greater number of compressed images to be stored. Also, by pipelining the encoding and decoding processes, image processing time is decreased.

Inventors: Okada; Masaki (Kasugai, JP), Fukuoka; Tomohiro (Kasugai, JP)

Assignee: Fujitsu Limited

International Classification: H04N 7/30 (20060101); H04N 7/26 (20060101); H04N 007/12 ()

Expiration Date: 12/26/2017