Automatic day-night television surveillance system

• US 3,891,795 A
• Filed: 04/11/1974
• Issued: 06/24/1975
• Est. Priority Date: 04/11/1974
• Status: Expired due to Term

• Current Assignee: Edward H. Pignone, Quentin S. Johnson
• Original Assignee: Edward H. Pignone, Quentin S. Johnson
• Inventors: Johnson, Quentin S., Pignone, Edward H.
• Primary Examiner(s): Murray, Richard
• Application Number:
  US05/460,089
• Time in Patent Office: 439 Days
• Field of Search: 178/7.2,DIG.29,DIG.21,DIG.38
• US Class Current: 348/143
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

An automatic day-night, closed circuit, remotely controlled television surveillance system employing a daylight vidicon or orthicon television camera. The camera is automatically and selectively placed in optical alignment with either a day-viewing optical system or a night-viewing optical system by a photocell, switching relay, rotary solenoid arrangement operating to position a rotatable mirror which, in conjunction with a pair of fixed mirrors and field lenses, directs the viewed scene image to the camera from one of the optical systems as a function of average scene illumination.

Claims

1. A closed circuit television surveillance system for nightviewing at scene illumination levels as low as 10 5 ft-candles and day-viewing at scene illumination levels as high as 104 ftcandles, capable of automatically switching between a nightviewing mode and a day-viewing mode, and having a single daylight television camera receiving a scene image along a viewing axis, comprising:

a night-viewing optical system including an image intensifier and a first objective lens disposed at one end oF said image intensifier for receiving and transmitting the image along a first optical axis;

a day-viewing optical system including, in optical alignment, a second objective lens and a field lens for receiving and transmitting the image along a second optical axis;

aligning means for automatically and selectively placing one or the other of said optical systems in optical alignment with the viewing axis of the daylight television camera depending upon the average scene illumination level thereby to adapt the system for day or night viewing; and

means for supplying power to said image intensifier and said aligning means.

2. The closed circuit television surveillance system as defined in claim 1, wherein said aligning means comprises:

a rotatable mirror positioned to intersect the viewing axis of the daylight television camera;

a first mirror disposed behind said night-viewing optical system, said first mirror intersecting the first optical axis at an angle of 45*;

a first relay lens disposed between said first mirror and said rotatable mirror for receiving the image reflected by said first mirror and transmitting the image to said rotatable mirror;

a second mirror disposed behind said day-viewing optical system, said second mirror intersecting the second optical axis at an angle of 45*;

a second relay lens disposed between said second mirror and said rotatable mirror for receiving the image transmitted by said day-viewing optical system and reflected by said second mirror and transmitting the image to said rotatable mirror; and

means operatively connected to said rotatable mirror for automatically and selectively rotating said rotatable mirror to reflect the image transmitted by one of said optical systems to the television camera depending upon the average scene illumination level.

3. The closed circuit, television surveillance system as defined in claim 2, wherein said automatic and selective rotating means comprises:

a photosensitive element for sensing an average scene illumination level and generating a control signal;

stop means for limiting rotation of said rotatable mirror between a first position and a second position;

a solenoid operatively connected to said rotatable mirror for rotating said mirror between said first position wherein the image received by said first relay lens is reflected to the television camera and said second position wherein said image received by said second relay lens is reflected to the television camera; and

a switching relay electrically connected to said photosensitive element, said solenoid, and said power supply means whereby said rotary mirror is placed in said first position when the average scene illumination level is less than or equal to 0.20 ft-lamberts and in said second position when the average scene illumination is greater than or equal to 0.50 ft-lamberts, said rotatable mirror staying in said second position until the average scene illumination level is again less than or equal to 0.20 ft-lamberts.

4. The closed circuit television surveillance system as defined by claim 3, further comprising:

a micro switch electrically connected to said image intensifier and said power supply means; and

means connected to said rotatable mirror for activating said micro switch when said mirror is in said first position whereby the image intensifier is operative only when the surveillance system is in the night-viewing mode.

5. A closed circuit television surveillance system for night-viewing at scene illumination levels as low as 10 5 ft-candles and day-viewing at scene illumination levels as high as 104 ft-candles, capable of automatically switching between a night-viewing mode and a day-viewing mode, comprising:

a housing defining a support chamber, said housing having formed in one wall thereof a first opening, a second opening, and a third opening;

a daylight television camera for receiving an Image along a viewing axis, said viewing axis extending from said camera objective in a direction opposite from said housing wall having said first, said second, and said third openings;

a night-viewing optical system including an image intensifier in optical alignment with an objective lens, said objective lens supported in said first opening formed in the wall of said housing, said night-viewing optical system receiving and transmitting an image along a first optical axis which is parallel to the viewing axis of said camera objective;

a day-viewing optical system including an objective lens in optical alignment with a field lens, said objective lens supported in said second opening formed in said housing, said day-viewing optical system receiving and transmitting an image along a second optical axis which is parallel to said viewing axis of said camera objective;

a first mirror supported in said housing behind said night-viewing optical system and intersecting said first optical axis at an angle of 45*;

a first relay lens supported in said housing for receiving and transmitting the image reflected by said first mirror;

a second mirror supported in said housing behind said day-viewing optical system and intersecting said second optical axis at an angle of 45*;

a second relay lens supported in said housing for receiving and transmitting the image reflected by said second mirror;

means mounted within said housing for automatically and selectively aligning the television camera objective with one of said relay lenses depending upon the average scene illumination level viewed to thereby adapt the system for day or night viewing; and

means for supplying power to said image intensifier and said aligning means.

6. A closed circuit, television surveillance system as defined in claim 5 wherein said aligning means comprises:

a photosensitive element for sensing an average scene illumination level and generating a control signal, said photosensitive element supported in said third opening formed in the wall of said housing;

a mirror rotatably mounted in said housing said rotatable mirror intersecting the viewing axis of the camera objective;

stop means for limiting rotation of said rotatable mirror between a first position and a second position;

a solenoid operatively connected to said rotatable mirror serving to rotate said mirror between a first position wherein the image transmitted by said first relay lens is reflected to said camera objective and a second position wherein said image transmitted by said second relay lens is reflected to said camera objective; and

a switching relay electrically connected to said photosensitive element, said rotary solenoid and said power supply means whereby said rotary mirror is placed in said first position when the average scene illumination level is less than or equal to 0.20 ft-lamberts and in said second position when the average scene illumination level is greater than or equal to 0.50 ft-lamberts, said rotatable mirror staying in said second position until the average scene illumination level is again less than or equal to 0.20 ft-lamberts.

7. The closed circuit television surveillance system as defined in claim 6, further comprising:

a micro switch electrically connected to said image intesifier and said power supply means; and

means connected to said rotatable mirror for activating said micro switch when said mirror is in said first position whereby said image intensifier is operative only when the television surveillance system is in the night-viewing mode.

8. The closed circuit television surveillance system as defined in claim 7, wherein said first and second objective lenses have a 24* field of view.

9. The closed circuit television surveillance system as defined in claim 7, further comprising:

means connected to said housing for tilting said housing through a tilt angle of 90* and sweeping saId housing through an azimuth angle of 180*.

10. The closed circuit television surveillance system as defined in claim 9, wherein said first and second objective lenses have 14* field of view.