Production of composite images

• US 4,202,008 A
• Filed: 03/29/1977
• Issued: 05/06/1980
• Est. Priority Date: 03/29/1976
• Status: Expired due to Term

• Current Assignee: Evershed Power-Optics Limited
• Original Assignee: Evershed Power-Optics Limited
• Inventors: King, Reginald
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Psitos, Aristotelis M.
• Application Number:
  US05/782,579
• Time in Patent Office: 1,134 Days
• Field of Search: 358/22, 358/181, 358/185, 358/183, 358/104, 352/38, 352/49, 352/47, 352/85, 352/88, 40/606, 40/624
• US Class Current: 348/587
• CPC Class Codes: H04N 9/75 Chroma key

Abstract

To permit panning and tilting of the foreground camera when composite images are being produced by the color separation overlay or chroma-key technique, signals representing the panning and tilting motions of the foreground camera are used to control the movement of the background image in front of the background camera in two mutually perpendicular directions.

Claims

1. A method for producing composite images in which a foreground camera views a subject in front of a colored screen, a background camera views an image of a background scene, and a mixing circuit derives from the foreground and background cameras a composite signal which represents the foreground subject but in which the background signal is substituted for the foreground camera signal whenever the latter represents said colored screen, the method further comprising the steps of:

generating signals responsive to panning and tilting movements of the foreground camera, said signals representing the extend of such movements; and

mounting an opaque picture constituting the background image on a support so as to be viewed directly by the back-ground camera and moving said picture in first and second mutually perpendicular directions in a plane perpendicular to the optical axis of the background camera in response to said signals generated in response to panning and tilting movements so that the image provided by the background camera appears to move in a direction opposite to the direction of panning or tilting movement of the foreground camera, said opaque picture being larger than the shot viewed by said background camera.

2. A method for producing composite images in which a foreground camera views a subject in front of a colored screen, a background camera views an image of a background scene, and a mixing circuit derives from the foreground and background cameras a composite signal which represents the foreground subject but in which the background signal is substituted for the foreground camera signal whenever the latter represents said said colored screen, the method further comprising the steps of:

generating signals responsive to panning and tilting movements of the foreground camera, said signals representing the extent of such movements;

projecting the background image onto a screen which is viewed by the background camera from a background picture, transparency or film, the projected image being larger than the shot viewed by the background camera; and

positioning the background image in relation to the background camera in first and second mutually perpendicular directions in a plane perpendicular to the optical axis of the background camera in response to said panning and tilting signals, respectively, while maintaining the background camera stationary so that the image provided by the background camera appears to move in a direction opposite to the direction of panning or tilting movement of the foreground camera.

3. A method in accordance with claim 2, including panning and tilting a projector which projects the said image onto the screen in response to the said panning and tilting signals, respectively.

4. Apparatus for generating a composite image, comprising:

a screen of a predetermined color;

a foreground television camera for viewing a foreground subject in front of the said screen;

a background television camera;

means for presenting an image of a background scene to the background camera;

mixing means for mixing the signals from the foreground and background cameras in such a manner that the foreground camera signal is present in the output of the mixing means whenever the foreground subject is represented by the signal from the foreground camera and the background signal is present in the output of the mixing means whenever the output of the foreground camera represents the colored screen;

a pan and tilt transmitter connected to the foreground camera for deriving electric signals representing panning and tilting movement of the foreground camera;

and means for moving the background image relative to the background camera in accordance with the said pan and tilt signals in two mutually perpendicular directions in a plane perpendicular to the optical axis of the background camera in such a manner that in the output signal from the mixing means the background appears to move in a direction opposite to the direction of panning or tilting of the foreground camera, wherein said background image moving means comprises a first frame mounted on a support for movement relative to the support in one of two mutually perpendicular directions, a second frame mounted on the first frame for movement with respect to the first frame in the other of the said mutually perpendicular directions, the second frame having means for receiving a background picture, said background picture being larger than the shot viewed by said background camera.

5. Apparatus in accordance with claim 4, in which the background image moving means includes two signal generators respectively generating signals representing the position of the said second frame in the said two mutually perpendicular directions, the apparatus further comprising, in a coupling between the foreground camera signal generators and the said support unit, a servo loop responsive to command signals originating at the foreground camera signal generators and also responsive to the position signals from the signal generators of the background image moving means.

6. Apparatus for generating a composite image, comprising:

a screen of a predetermined color;

a foreground television camera for viewing a foreground subject in front of the said screen;

a background television camera;

means for presenting an image of a background scene to the background camera;

mixing means for mixing the signals from the foreground and background cameras in such a manner that the foreground camera signal is present in the output of the mixing means whenever the foreground subject is represented by the signal from the foreground camera and the background signal is present in the output of the mixing means whenever the output of the foreground camera represents the colored screen;

a pan and tilt transmitter connected to the foreground camera for deriving electric signals representing panning and tilting movement of the foreground camera;

and means for moving the background image relative to the background camera in accordance with the said pan and tilt signals in two mutually perpendicular directions in a plane perpendicular to the optical axis of the background camera in such a manner that in the output signal from the mixing means the background appears to move in a direction opposite to the direction of panning or tilting of the foreground camera, wherein said background image moving means comprises a projector and a background screen and means for moving the projector relative to the background screen in panning and tilting directions, the projected background image being larger than the shot viewed by the background camera.

7. Apparatus in accordance with claim 6, in which the background image moving means includes two signal generators respectively generating signals representing the position of the projector in pan and tilt, the apparatus including in a coupling between the foreground camera signal generators and the said background image moving means a servo loop responsive to command signals originating at the foreground camera signal generators and to position signals from the projector pan and tilt signal generators.