Color display using auxiliary memory for color information

• US 4,206,457 A
• Filed: 12/27/1977
• Issued: 06/03/1980
• Est. Priority Date: 12/27/1977
• Status: Expired due to Term

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: RCA Corporation
• Inventors: Weisbecker, Joseph A., Baltzer, Philip K.
• Primary Examiner(s): Trafton, David L.
• Application Number:
  US05/864,765
• Time in Patent Office: 889 Days
• Field of Search: 340/324 AD, 340/701, 340/703
• US Class Current: 345/549
• CPC Class Codes: G09G 5/024 using colour registers, e.g. to control background, foreground, surface filling G09G5/06 takes precedence

Abstract

Method and circuit for controlling the color of dot elements in a raster scan display having a data memory for storing the state (on or off) of dot elements which are mapped onto the raster scan display and a smaller auxiliary memory for storing color information. The color information stored in a location of the auxiliary memory specifies the color of a plurality of contiguous dot elements so that the auxiliary memory can be much smaller than the data memory. The contiguous dot elements whose color is specified by a location in the auxiliary memory form a block which can be arranged so that the address bits to the auxiliary memory form a proper subset of the address bits to the data memory.

Claims

1. A method for displaying information in color on a raster scan medium comprising the steps of:

supplying, under programmable control, luminance data to be displayed as an array of dot elements arranged in successive horizontal lines with each horizontal line being comprised of a series of successive groups of N dot elements;

mapping each successive dot element of each group of dot elements one at a time on the raster scan medium with some dot elements having luminance and some dot elements not having luminance in accordance with said luminance data; and

providing color data, under programmable control, representative of the color of dot elements having luminance in two or more groups of N dot elements with each group of N dot elements being positioned in successive horizontal lines to form subarrays which begin and end at corresponding positions on said successive horizontal lines.

2. The method as claimed in claim 1, where said supplying step includes the steps of:

storing the luminance data under said programmable control as binary information, one bit corresponding to each dot element in the display; and

retrieving the luminance data in sequence; and

wherein said providing step includes the steps of;

storing the color data as groups of bits for each subarray, a bit of a group corresponding to the red, blue and green components of the color of the dots of the subarray; and

retrieving the color data for a subarray simultaneously with the retrieving of the luminance data corresponding to the dot elements within the subarray.

3. The method claimed in claim 2 including the steps of:

supplying background data to be displayed in the absence of dot elements; and

gating said color data, under said programmable control, as color signals to the raster scan medium when the programmable luminance data indicate a dot element is to be displayed and said background data as color signals to the raster scan medium when the luminance indicates no dot element is to be displayed.

4. A system for programmably controlling the color of a raster scan display means which maps dot elements derived from a digital memory onto the raster in successive horizontal lines with each line being formed by successively mapping the dot elements, one by one, and comprising in combination:

programmable control means;

programmable data storage means responsive to said programmable control means for storing at locations therein bits corresponding to the luminance information of each dot element to be displayed;

auxiliary storage means having fewer storage locations than said data storage means and responsive to said programmable control means for storing at each location therein chroma information indicative of the color in which a plurality of contiguous dot elements forming a block of at least two rows of dot elements high and less than a full line in length, is to be displayed;

synchronizing means including addressing means coupled to said data storage means and said auxiliary storage means for providing synchronization signals to the raster scan display means and for extracting in proper relation with said synchronization signals the bits from said data storage means and the chroma information from said auxiliary storage means;

said addressing means comprising a first plurality of addressing signal means for specifying the location in said data storage means from which said luminance information is to be retrieved and for mapping said dot elements on the scan display means in successive rows with each row of dot elements comprising a plurality of groups of N dot elements;

said addressing means further comprising a second plurality of addressing signal means for specifying the location from which said chroma information is to be received, said second plurality of addressing means corresponding to a proper subset of said first plurality of addressing signal means; and

said second plurality of addressing signal means controlling the color of a group of N dot elements in each of two or more adjacent rows of dot elements with each group of N dot elements beginning and ending at corresponding horizontal coordinates in said rows of dot elements.

5. A system as in claim 4 further comprising:

color select means for supplying signals indicative of a background color; and

gating means responsive to said luminance information for gating said chroma information to said raster scan display means from said auxiliary storage means when said luminance information has one binary value and for gating the signals from said color select means when said luminance information has the other binary value.