LOCAL CORRECTION APPARATUS FOR A COLOR PREVIEWER

• US 3,848,856 A
• Filed: 10/01/1973
• Issued: 11/19/1974
• Est. Priority Date: 10/01/1973
• Status: Expired due to Term

• Current Assignee: Nicholas J. Reeber, St. John, Karl M.
• Original Assignee: Nicholas J. Reeber, St. John, Karl M.
• Inventors: Reeber, Nicholas J., St. John, Karl M.
• Primary Examiner(s): Murray, Richard
• Application Number:
  US05/402,234
• Time in Patent Office: 414 Days
• Field of Search: 178/5.2A 358/76
• US Class Current: 358/527
• CPC Class Codes: H04N 1/622 with simulation on a subsidiary picture reproducer

Abstract

Disclosed is apparatus for use in a color previewer for simulating a graphic arts process, which enables the operator of the previewer to select a local area of a simulated reproduction and adjust the component color content of the selected area. In one embodiment of the invention the adjustment simulates hand etching of the selected local area on half-tone color separation transparencies. The apparatus may include circuits for measuring the component color content of the selected local area and thereby provide a calibration for the subsequent etching operation.

Claims

1. In a graphic arts color previewer wherein a set of color component signals are developed by successively scanning elemental areas of an input image, said signals being individually representative of corresponding elemental areas of color separations in the actual graphic arts process being previewed, and wherein said color component signals are processed to provide on a display a preview image simulating a color reproduction of said input image, apparatus for adjusting the color content of a selected local area of said preview image, comprising:

means for generating a series of pulse-type signals in synchronism with the scanning of said input image, the number of pulses, pulse duration and time of occurrence of said pulsetype signals in said series being selected to define a series of time intervals corresponding to a local area of said preview image; and

means responsive to saiD pulse-type signals for adjusting the color content of at least one of said color component signals during said time intervals defined by said pulse-type signals to form a locally corrected color component signal;

thereby causing an adjustment in the color content of said selected local area in said preview image.

2. In a graphic arts color previewer wherein a set of color component signals are developed by successively scanning elemental areas of an input image, said signals being individually representative of corresponding elemental areas of color separations in the actual graphic arts process being previewed, and wherein said color component signals are processed to provide on a display a preview image simulating a color reproduction of said input image, apparatus for adjusting the color content of a selected local area of said preview image, comprising:

means for generating a series of pulse-type signals in synchronism with the scanning of said input image, the number of pulses, pulse duration and time of occurrence of said pulse-type signals in said series being selected to define a series of time intervals corresponding to a local area of said preview image;

means responsive to said pulse-type signals for generating an adjustable correction signal during said time intervals defined by said pulse-type signals; and

means for combining said correction signal with at least one of said color component signals to form a locally corrected color component signal, thereby causing an adjustment in the color content of said selected local area in said preview image.

3. Apparatus as specified in claim 2, wherein the time of occurrence of said pulse-type signals is adjustable, thereby permitting the selection of a local area at a different location in said preview image.

4. Apparatus as specified in claim 3, wherein the number of pulses and pulse duration of said pulse-type signals is adjustable, thereby permitting different size local areas to be selected.

5. Apparatus as specified in claim 2, wherein said correction signal is adjustable in amplitude.

6. Apparatus as specified in claim 5, wherein said correction signal comprises a series of constant voltage pulses.

7. Apparatus as specified in claim 2, wherein said means for combining comprises means for adding said correction signal and at least one of said color component signals.

8. Apparatus as specified in claim 2, wherein said input image is scanned by a raster scanner and wherein said pulse-type signals are generated during a selected identical portion of each of a selected set of adjacent line scans of said raster.

9. Apparatus as specified in claim 2, which additionally includes means for measuring the color content of that portion of said locally corrected color component signal corresponding to said selected local area.

10. Apparatus as specified in claim 2, which additionally includes means responsive to said pulse-type signals for generating a corresponding set of signals appropriate for causing a visual indication on said displayed preview image corresponding to said selected local area.

11. In a graphic arts color previewer, wherein a set of color component signals are developed by successively scanning elemental areas of an input image, said signals being individually representative of corresponding elemental areas of color separations in the actual graphic arts process being previewed, and wherein said color component signals are processed to provide on a display a preview image simulating a color reproduction of said input image, apparatus for adjusting the color content of a selected local area of said preview image, comprising:

means for generating a series of pulse-type signals in synchronism with the scanning of said input image, the number of pulses, pulse duration and time of occurrence of said pulse-type signals in said series being selected to define a series of time intervals corresponding to a local area of said preview image;

means responsivE to said pulse-type signals for generating a plurality of individually adjustable correction signals, one for each of said color component signals, during said time intervals defined by said pulse-type signals; and

means for combining each of said correction signals with a corresponding one of said color component signals to form a locally corrected color component signal, thereby causing an adjustment in the color content of said selected local area of said preview image.

12. In a graphic arts color previewer, wherein a set of four color component signals are developed by raster scanning an input image, said signals being individually representative of corresponding elemental areas of color separations in the actual graphic arts process being previewed, and wherein said color component signals are processed to provide on a display a preview image simulating a color reproduction of said input image, apparatus for adjusting the color content of a selected local area of said preview image, comprising:

means for generating a series of pulse-type signals in synchronism with said raster scanning of said input image, said pulse-type signals occurring during a selected identical portion of each of a selected set of adjacent line scans of said raster, the number of pulses, pulse duration and time of occurrence of said pulse-type signals in said series being adjustable, and defining a series of time intervals corresponding to a selected local area of said preview image;

means responsive to said pulse-type signals for generating four individually adjustable, constant voltage correction signals during said time intervals defined by said pulse-type signals; and

means for individually adding each of said correction signals and a corresponding one of said color component signals to form a set of locally corrected color component signals;

thereby causing an adjustment in the color content of said selected local area in said preview image.

13. Apparatus as specified in claim 12, which additionally includes means for measuring the color content of that portion of said locally corrected color component signal corresponding to said selected local area.

14. Apparatus as specified in claim 12, which additionally includes means responsive to said pulse-type signals for generating a corresponding set of signals appropriate for causing a visual indication on said displayed preview image corresponding to said selected local area.