US 6,191,827 B1Granted

Electronic keystone correction for electronic devices with a visual display

AssigneeOplus Technologies Ltd.

InventorsYosef Segman, Gady Yearim, Avy Strominger

Life of this patent

Estimating the term…

Loading patent…

Abstract

A method of electronic Keystone correction for electronic devices having visual displays which exhibit optical distortion on the display screen. The corrective method is based on computation and electronic (physical) manipulation of the pixels of a visual display screen grid, and features the principle steps of: 1) characterization of the size of an input image, 2) determination of the number of generated pixels in the output image, 3) determination of the real position of each pixel in the output image by performing an electronic distortion to the input image opposite to the optical distortion of the input image, 4) interpolation of the output value of all color components of each pixel of the input image, 5) correction of (non-uniform) edge effects at both ends of each line of pixels, 6) transmission of the output corrected image to the electronic display device, individually, pixel by pixel, or as complete set of corrected pixels of the image, and 7) display of the perfected corrected optical image. The method of this invention solves at least two universally known optical distortion problems involving trapezoidal distortion and computerized diagonal line drawing. Moreover, the method of this invention is applicable to real time domain of operation of electronic devices with visual displays.

A method for correcting an optical distortion of an image on a visual display screen, the steps of the method being performed by a data processor, the method comprising the steps of:

(a) receiving an input image featuring pixels;
(b) determining a distortion mode of said input image;
(c) determining a number of said pixels in said input image;
(d) determining a number of horizontal lines of said pixels in each group of said horizontal lines of said pixels in said input image;
(e) determining a number of said groups of said horizontal lines of said pixels in said input image;
(f) determining a number of output pixels of each said horizontal line in a corrected output image;
(g) determining a plurality of positions of said pixels of said input image;
(h) performing an opposite electronic distortion to the optical distortion of said input image, comprising the steps of:
(i) calculating a horizontal position of each of a plurality of first generated said output pixels in grid space of said input image, said horizontal position of each of said plurality of said horizontal positions located between first said input pixel of each said horizontal line and second said input pixel of each said horizontal line in said grid space of said input image, said calculating performed according to said distortion mode of said input image, using a LineCounter;
and
(ii) calculating said plurality of said horizontal positions of remaining said output pixels in said grid space of said input image, said calculating performed according to said distortion mode of said input image, using a GroupCounter;
(i) determining said plurality of positions of said output pixels of said opposite electronic distortion to the optical distortion of said input image;
(j) determining a plurality of values of said output pixels of said opposite electronic distortion to the optical distortion of said input image to form said corrected output image;
(k) correcting a plurality of edge effects in said horizontal lines of said plurality of said output pixels of said corrected output image to form a straight diagonal line along each of two sides of said corrected output image;
(l) transmitting said plurality of said output pixels of said corrected output image to a visual display device;
and
(m) displaying said corrected output image on the visual display screen.

14 more elements

Abstract

Claims15