Display processor system and method

• US 4,531,160 A
• Filed: 05/03/1983
• Issued: 07/23/1985
• Est. Priority Date: 05/03/1983
• Status: Expired due to Fees

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Itek Corp (Northrop Grumman Corporation)
• Inventors: Ehn, Dennis C.
• Primary Examiner(s): Martin, John C.
• Assistant Examiner(s): Toth, E. Anne
• Application Number:
  US06/491,129
• Time in Patent Office: 812 Days
• Field of Search: 358/230, 358/240, 358/283, 358/298, 340/728, 340/793, 315/169.1, 315/169.3, 315/169.4
• US Class Current: 348/798
• CPC Class Codes: G09G 3/2051 with use of a spatial dither pattern

Abstract

A technique for reproducing an image in a set of grey scale steps is disclosed including: providing a plurality of superpixels for providing an output representative of an image; providing a set of threshold levels for each pixel in a superpixel, which set is different from each of the sets of threshold levels of the other pixels in that superpixel and different from the set of greyscale steps; identifying the position of a given pixel in a superpixel and designating a particular set of threshold levels corresponding to the position of that given pixel; comparing the output of the given pixel with its particular set of threshold levels; and indicating the greyscale step in the set of greyscale steps in response to the output of the given pixel equal to or in excess of at least one of the threshold levels in the set of threshold levels corresponding to that pixel position.

Claims

1. A display processor system for reproducing an image in a set of more than two greyscale steps comprising:

a plurality of superpixels each including a number of pixels for providing an output representative of an incident image portion;

means for providing a set of threshold levels for each pixel in a superpixel, which set is different from each of the sets of threshold levels of the other pixels in that superpixel and different from the set of greyscale steps;

means for identifying the position of a given pixel in a superpixel and designating the particular set of threshold levels corresponding to the position of that given pixel;

means for comparing the output of the given pixel with said particular set of threshold levels; and

means, responsive to said means for comparing, for indicating a greyscale step in said set of more than two greyscale steps in response to an output from said given pixel equal to or in excess of at least one of said threshold levels in the set of threshold levels corresponding to that pixel position.

2. The display processor system of claim 1 in which the set of threshold levels is the same for each pixel in the same location in each superpixel.

3. The display processor system of claim 1 in which all the threshold levels of all the sets in a superpixel constitute a field of uniform increments.

4. The display processor system of claim 3 in which all the threshold levels constituting the field of uniform increments are non-uniformly distributed in the pixels of a superpixel.

5. A method for reproducing an image in a set of more than two greyscale steps comprising:

providing a set of threshold levels for each pixel in a superpixel of an imaging device, which set is different from each of the sets of threshold levels of the other pixels in that superpixel and different from the set of greyscale steps;

identifying the position of a given pixel in a superpixel and designating the particular set of threshold levels corresponding to the position of that given pixel;

comparing the output of the given pixel with its particular set of threshold levels; and

indicating a greyscale step in the set of more than two greyscale steps in response to an input to said given pixel equal to or in excess of at least one of said threshold levels in the set of threshold levels corresponding to that pixel position.