Display system with luminance calculation

• US 4,952,917 A
• Filed: 01/14/1988
• Issued: 08/28/1990
• Est. Priority Date: 01/19/1987
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yabuuchi, Shigeru
• Primary Examiner(s): Oberley, Alvin
• Assistant Examiner(s): HJERPE, RICHARD A
• Application Number:
  US07/143,956
• Time in Patent Office: 957 Days
• Field of Search: 340/701, 340/703, 358/31, 358/39, 358/161, 358/168, 358/219
• US Class Current: 345/690
• CPC Class Codes: G09G 1/06 using single beam tubes G09G1/26, G09G1/28 take precedence, e.g. three-dimensional or perspective representation, rotation or translation of display pattern, hidden lines, shadows G09G1/28 takes precedence; stereoscopic TV-systems, details thereof H04N13/00; oscilloscopes for three-dimensional representation G01R13/206; vectorscopes G01R13/208
• CPC Class Codes: G09G 5/10 Intensity circuits

Abstract

A display system calculates the value of luminance of a screen of a display unit for each display frame and dynamically controls the luminance of the display screen on the basis of the calculated luminance value while taking the surrounding brightness, thereby providing a display appearance easiest to see.

Claims

1. A display system comprising:

image displaying means for displaying a predetermined image on a screen by a raster scan;

image data generating means or generating predetermined image data to be displayed by said image displaying means;

storing means fore storing information representative of said predetermined image data generated by said image data generating means; and

image designating means for supplying said information stored in said storing means to said image displaying means in synchronism with said raster scan, said image designating means including luminance calculating means for calculating a value of luminance in accordance with contents of said information stored in said storing means and luminance controlling means for controlling luminance of said screen of said image displaying means in response to said calculated luminance value;

wherein said luminance calculating means adds luminance data to a sum of previous luminance data each time information for a pixel of said screen is read from said storing means, thereby calculating luminance of the screen for one image to be displayed by said image displaying means.

2. A display system according to claim 1, wherein said image designating means includes a color look-up table in which the values of luminance for respective pixels are stored.

3. A display system according to claim 2 wherein said luminance calculating means calculates the luminance I_p for each pixel of information in accordance with an equation of

4. A display system according to claim 1, wherein said luminance controlling means includes a reference table which indicates a control condition of luminance of an image to be displayed.

5. A display system according to claim 4, wherein said luminance controlling means detects the brightness of an interior of a room in which said image displaying means is placed, and establishes a luminance control condition on the basis of the value of the detected brightness.

6. A display system comprising:

image displaying means for displaying a predetermined image on a screen by a raster scan;

image data generating means for generating predetermined image data to be displayed by said image displaying means;

storing means for storing information representative of said predetermined image data generated by said image data generating means; and

image designating means for supplying said information stored in said storing means to said image displaying means in synchronism with said raster scan, said image designating means including luminance calculating means for calculating a value of luminance in accordance with contents of said information stored in said storing means and luminance controlling means for controlling luminance of said screen of said image displaying means in response to said calculated luminance value;

wherein said luminance calculating means divides the screen of said image displaying means into a character region and a figure region, designated foreground and background colors of each of said character and figure regions, and determines the luminance of the display screen in accordance with an equation of (luminance of display screen)=(number of characters to be displayed)×

(luminance of foreground color of characters+luminance of background color of characters)+(luminance of background color of figure region).

7. A display system according to claim 6, wherein said luminance controlling means includes a reference table which indicates a control condition of luminance of an image to be displayed.

8. A display system comprising;

a display unit for displaying display data;

a display processor for generating display data to be displayed on a screen of said display unit;

storing means for storing the display data to be displayed on the screen of said display unit;

means for reading the display stored in said storing means in synchronism with a raster scan of said display unit to display the display data on the screen of said display unit;

means for calculating a value of luminance of said display data stored in said storing means and displayed on the screen of said display unit; and

means for dynamically controlling the luminance of the display screen on the basis of the value of luminance determined by said calculating means;

wherein said means for calculating adds luminance doa to a sum of previous luminance doa each time display data displayed on said screen is read from said storing means by said means for reading, thereby calculating luminance of said screen for one image to be displayed by said display unit.

9. A display system according to claim 8, furthe comprising:

a color look-up table connected between said storing means and said reading means, for converting said display data stored in said storing means to color display data which is supplied to said reading means, said look up table has stored therein quantities of primary red, green and blue colors representative of a color and an amount of luminance when the color is lightened on said display unit.

10. A display system according to claim 8, comprising a detector for detecting brightness of an interior of a room, and means applied with the detected value of brightness detected by said detector and a value of luminance of the screen of said display unit calculated by said calculating means, for controlling a luminance signal for said display unit.

11. A display system according to claim 8, further comprising:

means for establishing a control condition for dynamically controlling the luminance of the screen of said display unit, said established control condition being referred to by said dynamically controlling means.