TELEVISION CAMERA GEOMETRIC DISTORTION CORRECTION SYSTEM

• US 3,757,161 A
• Filed: 09/03/1970
• Issued: 09/04/1973
• Est. Priority Date: 09/03/1970
• Status: Expired due to Term

• Current Assignee: Donald D. Kline
• Original Assignee: Donald D. Kline
• Inventors: Kline, Donald D.
• Primary Examiner(s): Quarforth, Carl D.
• Assistant Examiner(s): Potenza, J. M.
• Application Number:
  US05/069,293
• Time in Patent Office: 1,097 Days
• Field of Search: 315/276D,27TD,28,29,10,24,22
• US Class Current: 315/276
• CPC Class Codes: H04N 3/2335 with calculating means

Abstract

A geometric distortion correction system for a television camera in which a suitable combination of sawtooth and parabolic wave forms at the horizontal and vertical repetition rates are applied to one of the grids of the camera tube. These wave forms may be regarded as functioning to increase or decrease the deflection sensitivity of the camera tube in synchronism with the scanning thereof, so that the application of conventional linear wave forms to the deflection coils of the camera tube will result in a non-linear scan which, in turn, corrects for the geometric distortion of the camera tube. Preferably, the sawtooth and parabolic wave forms are applied to the focus or G3 grid of the camera tube, the amplitudes and polarities of the wave forms being determined by the nature of the geometric distortion to be corrected for.

Claims

1. A method for correcting geometric distortion in the camera tube of a television camera comprising the steps of generating sawtooth wave form signals at the horizontal and vertical repetition rates, generating parabolic wave form signals at the horizontal and vertical repetition rates, applying said sawtooth and parabolic wave form signals to at least one of the grids of said camera tube and adjusting the amplitudes and polarities of the applied parabolic and sawtooth wave forms to substantially correct for the geometric distortion of said camera tube.

2. The method according to claim 1 wherein the step of generating parabolic wave form signals comprises integrating said sawtooth wave form signals.

3. The method according to claim 1 wherein the step of applying comprises coupling said sawtooth and parabolic wave form signals with opposite polarities to the G3 and G4 grids of said camera tube.

4. The method for correcting geometric distortion in the camera tubes of a color television camera comprising the steps of generating sawtooth wave form signals at the horizontal and vertical repetition rates, generating parabolic wave form signals at the horizontal and vertical repetition rates, applying said sawtooth and parabolic wave form signals to at least one of the grids of each of said camera tubes and adjusting the amplitudes and polarities of the parabolic and sawtooth wave forms applied to each of said camera tubes independently to substantially correct for the geometric distortion of said camera tubes.

5. The method according to claim 4 wherein the step of generating parabolic wave form signals comprises integrating said sawtooth wave form signals.

6. The method according to claim 4 wherein the step of applying comprises coupling said sawtooth and parabolic wave form signals with opposite polarities to the G3 and G4 grids of each of said camera tubes.