DISTORTION CORRECTION SYSTEM

• US 3,723,805 A
• Filed: 05/12/1971
• Issued: 03/27/1973
• Est. Priority Date: 05/12/1971
• Status: Expired due to Term

• Current Assignee: Douglas W. Holbrook, Theodore J. Scarpino
• Original Assignee: Douglas W. Holbrook, Theodore J. Scarpino
• Inventors: Scarpino, Theodore J., Holbrook, Douglas W.
• Primary Examiner(s): Sebastian, Leland A.
• Application Number:
  US05/142,706
• Time in Patent Office: 685 Days
• Field of Search: 178/6.8,7.85,7.88 315/23,24,27GD
• US Class Current: 315/370
• CPC Class Codes: H04N 3/2335 with calculating means

Abstract

Combinational distortion correction in a cathode ray tube (CRT) head-up display is accomplished for both optical distortion and CRT distortion by electronically predistorting the displays that appear on the face of the CRT. The corrections are performed in one step by the implementation of a complete mathematical model describing the combinational distortion patterns. The corrections to the vertical and horizontal CRT deflection voltages are represented as combinations of a plurality of transformation functions which are electronically mechanized by a straight line segment approximation technique where the slope and segment lengths are controlled by diode segment generators.

Claims

1. An opto-electronic system for producing a display corresponding to a set of input signals, comprising:

optical means with inherent optical distortion for projecting a replica of an image;

CRT means having inherent CRT distortion operatively aligned with said optical means for producing the image; and

signal conditioning means operatively connected to said CRT means and having horizontal and vertical input terminals for receiving corresponding input signals designated respectively Vx and Vy, the input signals being corrected in accordance with a least square mathematical model describing the combined effect of CRT and optical distortion, for electronically compensating the input signals to provide a deflection output to said CRT means corrected for both CRT and optical distortion, said signal conditioning means having a first plurality of function generators operatively receiving Vx and a second plurality of function generators operatively receiVing Vy, and means for combining the outputs of said function generators according to the mathematical model to provide the corrected deflection outputs to said CRT means.

2. An opto-electronic system according to claim 1 further comprising:

each of said first and second plurality of function generators having a discrete line segment generator circuit.

3. An opto-electronic system according to claim 1 further comprising:

said first plurality of function generators including at least five generators producing outputs f1, f3, f5, g2 and g4 respectively, said second plurality of function generators including at least five generators producing outputs f2, f4, g1, g3 and g5 respectively, and said combining means including means for combining said function generator outputs to produce the corrected outputs to said CRT means according to the equations;

Vx'"'"''"'"' f1 + f2f3 + f4f5, and Vy'"'"''"'"' g1 + g2g3 + g4g5, where Vx'"'"''"'"' and Vy'"'"''"'"' represent the corrected deflection outputs to said CRT means.

4. An opto-electronic system according to claim 1 further comprising:

said function generators having means for producing respective ones of the following functions;

f1 a1 + a2x + a3x3 + a4x5 + a5x7 f2 a12y + a13y3 f3 a6x + a7x3 + a8x5 f4 a14y2 f5 a9x + a10x3 + a11x5 g1 b1 + b2y + b3y2 + b4y3 + b5y4 g2 b13x2 g3 b6 + b7y + b8y2 + b9y3 g4 b14x4 g5 b10 + b11y + b12y3, where x is proportional to Vx and y is proportional to Vy, all ai and bi being constants.