TELEVISION SYSTEMS

• US 3,833,760 A
• Filed: 02/27/1973
• Issued: 09/03/1974
• Est. Priority Date: 02/27/1973
• Status: Expired due to Term

• Current Assignee: John Edward Tickle
• Original Assignee: John Edward Tickle
• Inventors: Tickle, John Edward
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US05/336,374
• Time in Patent Office: 553 Days
• Field of Search: 178/6.8,DIG.6,DIG.35
• US Class Current: 348/584
• CPC Class Codes: H04N 5/272 Means for inserting a foreground image in a background image, i.e. inlay, outlay

Abstract

A television system for producing overlay effects by replacing part of a background image by an overlay image includes a detector operable to detect the presence or absence of the overlay image during a predetermined scan line. The detector output is connected to control means operable to move the overlay image vertically to the desired position.

Claims

1. A television system for producing overlay effects by replacing part of a background image by an overlay image, which includes detector means operable to detect the presence or absence of the overlay image during a predetermined scan line of the television picture, and control means responsive to the output from the detector means to change the vertical position of the overlay image in the required direction.

2. A system as claimed in claim 1 in which the detector means includes a bistable device which is set to one of its two stable states at the beginning of the predetermined scan line and to the other of its two stable states by the presence of an overlay image during that scan line, and gating means responsive to the output of the bistable device to apply a signal to the gating means only when the overlay image is absent during said predetermined scan line.

3. A system as claimed in claim 1 in which the control means includes a correction counter to which the output of the detector means is applied and shift voltage control means responsive to the state of the correction counter to develop an appropriate shift voltage operable to vary the vertical position of the overlay image.

4. A system as claimed in claim 3 in which the shift voltage control means includes combining means for combining the shift voltage generated therein with any existing shift voltage applied to the overlay image.

5. A system as claimed in claim 3 in which the correction counter is operable to count the number of scan lines between the actual position of the overlay image and said predetermined scan line.