05283671 is referenced by 54 patents and cites 8 patents.

A printing system is disclosed. The system includes a scanner which produces an RGB signal corresponding to a scanned image. The RGB signal is compressed in accordance with a tone curve which is built in reliance upon input provided by the user. The resultant compressed RGB signal is conveyed to a computer. The RGB signal may be modified by a number of interface controls. The RGB signal is driven through a separation engine to produce individual CMYK signals. The separation engine relies upon the interface controls in converting the signal. Image sharpening, or unsharp masking, is performed on resultant CMYK signals to produce a sharp printed image. The image sharpening procedure includes sharpening pixels, calculating T-sums for pixels, calculating gradients for pixels, and smoothing pixels in response to the T-sums and gradient calculations. The resultant CMYK signals may be exported for further data processing, such as integration with text, or they may be sent to a printer to produce high-quality prints.

Title
Method and apparatus for converting RGB digital data to optimized CMYK digital data
Application Number
7/658188
Publication Number
5283671
Application Date
February 20, 1991
Publication Date
February 1, 1994
Inventor
Charlie Fenton
141 Winfield St., San Francisco, 94110
CA, US
Bradley A Silen
8 Buckeye Way, Kentfield, 94904
CA, US
David Alexander
19 NeDean Ave, Normanhurst
AU
Andrew Cunningham
66 Whale Beach Rd., Avalone
AU
John R Stewart
1/80 Woodland St., Balgowlah Heights
AU
Agent
Flehr Hohbach Test Albritton & Herbert
IPC
H04N 1/46
View Original Source