Method and apparatus for calibrating a pipelined color processing device

• US 5,296,935 A
• Filed: 09/27/1991
• Issued: 03/22/1994
• Est. Priority Date: 02/05/1990
• Status: Expired due to Fees

• Current Assignee: Creoscitex Corporation Limited (Creo Products Incorporated)
• Original Assignee: Scitex Corporation Ltd. (Suny Cellular Communication Ltd.)
• Inventors: Bresler, Yoav
• Primary Examiner(s): Coles, Sr., Edward L.
• Assistant Examiner(s): Jackson, Jill
• Application Number:
  US07/766,765
• Time in Patent Office: 907 Days
• Field of Search: 358/406, 358/75, 358/80, 395/131, 382/17
• US Class Current: 358/406
• CPC Class Codes: G06F 17/15 Correlation function computation including computation of convolution operations arithmetic circuits for sum of products per se, e.g. multiply-accumulators G06F7/5443; digital filters, e.g. FIR, IIR, adaptive filters H03H17/00
• CPC Class Codes: G06K 15/02 using printers
• CPC Class Codes: G06K 2215/0037 depending on an output condition, e.g. size, resolution
• CPC Class Codes: G06K 2215/0094 Colour printing
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: H04N 1/52 Circuits or arrangements for halftone screening
• CPC Class Codes: H04N 1/6033 using test pattern analysis H04N1/6055 takes precedence

Abstract

A method and apparatus for adapting a digital representation of a first color image for output representation by an output device having spatial and color characteristics are disclosed. The apparatus includes apparatus for modifying the spatial characteristics of the digital representation of the first color image and the color characteristics of the first color image to correspond to the spatial and color characteristics of the output device such that, in an output representation, the color characteristics of the first color image would be substantially preserved. The method includes the step of modifying the spatial characteristics of the digital representation of the first color image and the color characteristics of the first color image to correspond to the spatial and color characteristics of the output device such that, in an output representation, the color characteristics of the first color image would be substantially preserved.

Claims

1. A method for calibrating a color pipeline including at least one initial color processing unit, an intermediate color processing unit and a final color processing unit, the method comprising the steps of:

comparing a first output representation of a first reference color image to a first target representation thereof and calibrating the final color processing unit in accordance with the comparison;

processing a second input representation of a second reference color image using a pipeline comprising the intermediate color processing unit and the calibrated final color processing unit, thereby to define a second output representation of the second reference color image;

comparing the second output representation to a second target representation of the second reference color image and calibrating the intermediate color processing unit in accordance with the comparison;

processing a third input representation of a third reference color image using a pipeline comprising the calibrated intermediate and final color processing units, thereby to define a third output representation of the third reference color image; and

comparing the third output representation to a third target representation of the third reference color image and calibrating at least one of the uncalibrated initial color processing units in accordance with the comparison.

2. A method according to claim 1 and also comprising the step of processing a first input representation of a first reference color image using the final color processing unit, thereby to generate the first output representation.

4. A method according to claim 1 wherein the final color processing unit comprises a calibratable subunit and a color output device downstream thereof.

5. A method according to claim 1 wherein the reference color processing device comprises a color output system.

3. Apparatus for calibrating a color processing pipeline including at least one initial color processing unit, an intermediate color processing unit and a final color processing unit, the apparatus comprising:

a comparison unit operative to generate first, second and third comparison outputs by respectively comparing first, second and third output representations of first, second and third reference color images, respectively, to first, second and third target representations of the first, second nd third reference color images, respectively, the first output representation being generated by processing a first input representation of the first reference color image using the final color processing unit; and

a calibration unit operative to calibrate the final color processing unit in accordance with the first comparison output, to subsequently calibrate the intermediate color processing unit in accordance with the second comparison output, and to subsequently calibrate an initial color processing unit in accordance with the third calibration output,

wherein the second output representation is generated by processing a second input representation of the second reference color image using the calibrated final color processing unit, and

the third output representation is generated by processing a third input representation of the third reference color image using a pipeline comprising the calibrated intermediate and final color processing units.