Machine for transmitting colour images - renders colour image into colour source image data and compresses data before transmitting compressed image data

Patent Assignee: HEWLETT-PACKARD CO (HEWP )

Inventor: BERETTA G; BHASKARAN V; KONSTANTINIDES K; NATARAJAN B K

Number of Countries: 004 Number of Patents: 002

Patent Family:

Patent No	Kind	Date	Week
EP 735772	A2	19961002	199644 B
JP 8274998	A	19961018	199701

Local Applications (No Type Date): EP 96103596 A 19960307; JP 9687081 A
19960318
Priority Applications (No Type Date): US 95411380 A 19950327
Abstract (Basic): EP 735772 A
The device for transmitting colour images forms a quantization table which is particularly well adapted for colour facsimile application. Three terms used in the table are selected. One gives perceptual lossless quantization, another is a bit rate term that produces a value that equals a predetermined size, whilst the third is a suprathreshold term which produces a perceptually lossy compression but where the loss does not impact the visual quality of the image.

The selection of the suprathreshold term involves selecting a set of target images, where each target image includes one or more image elements such as text. These image elements are then analysed to identify those that are critical for visual quality. The suprathreshold term is then selected in order to give a larger weight to the table elements that correspond to the critical image elements only.

ADVANTAGE - Particularly well adapted to colour facsimile applications. Compatible with any JPEG compliant decompression engine in use.