Infrared camera

• US 6,353,223 B1
• Filed: 08/16/1999
• Issued: 03/05/2002
• Est. Priority Date: 09/10/1998
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Ookawa, Norio
• Primary Examiner(s): Hannaher, Constantine
• Assistant Examiner(s): GAGLIARDI, ALBERT J
• Application Number:
  US09/374,506
• Time in Patent Office: 932 Days
• Field of Search: 250/330, 250/332, 250/252.1, 250/339.02, 250/339.03, 250/339.04, 250/339.08, 250/341.5
• US Class Current: 250/330
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 5/064 Ambient temperature sensor; Housing temperature sensor; Constructional details thereof
• CPC Class Codes: G01J 5/53 Reference sources, e.g. standard lamps; Black bodies
• CPC Class Codes: G01J 5/70 Passive compensation of pyrometer measurements, e.g. using ambient temperature sensing or sensing of temperature within housing
• CPC Class Codes: G01J 5/80 Calibration using comparison with reference sources G01J5/52
• CPC Class Codes: H04N 25/67 applied to fixed-pattern noise, e.g. non-uniformity of response
• 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 infrared camera capable of automatically executing offset compensation so that fixed pattern noise is removed without the need of an operator comprises an offset compensation signal generation circuit and a shutter. The shutter is closed based on an offset compensation execution signal for carrying out offset compensation, the signal being automatically and periodically generated by the offset compensation signal generation circuit after execution of the first offset compensation.

Claims

1. An infrared camera comprising:

an infrared optical system;

an image pickup element;

element temperature stabilizing means thermally connected to the image pickup element;

a shutter positioned covering a viewing field of the image pickup element;

a bias power source connected to said image pickup element;

a driver circuit connected to said image pickup element;

a pre-positioned amplifying circuit connected to said image pickup element;

a display processing circuit connected to said pre-positioned amplifying circuit;

a timing generation circuit connected to said shutter, said driver circuit, and said display processing circuit;

manual offset compensation switch connected to said timing generation circuit; and

an automatic offset compensation execution signal generation circuit connected to said timing generation circuit.

2. An infrared camera according to claim 1, wherein said automatic offset compensation execution signal generation circuit outputs an offset compensation execution signal at predetermined intervals.

3. An infrared camera according to claim 1, wherein said automatic offset compensation execution signal generation circuit outputs an offset compensation execution signal and wherein the interval at which said offset compensation execution signal output is shorter during a predetermined time period after power is turned on than during a period after the predetermined time period.

4. An infrared camera according to claim 1, wherein said automatic offset compensation execution signal generation circuit includes a temperature sensor for measuring the temperature around structural elements of said infrared camera, and a temperature changing amount judging circuit connected to said temperature sensor.

5. An infrared camera, comprising:

an infrared optical system;

de-focusing means associated with said infrared optical system;

an image pickup element;

element temperature stabilizing means thermally connected to said image pickup element;

a bias power source connected to said image pickup element;

a driver circuit connected to said image pickup element;

a pre-positioned amplifying circuit connected to said image pickup element;

a display processing circuit connected to said pre-positioned amplifying circuit;

a timing generation circuit connected to said de-focusing means, said driver circuit, and said display processing circuit;

manual offset compensation switch connected to said timing generation circuit; and

an automatic offset compensation execution signal generation circuit connected to said timing generation circuit.

6. An infrared camera according to claim 5, wherein said automatic offset compensation execution signal generation circuit outputs an offset compensation execution signal at predetermined intervals.

7. An infrared camera according to claim 5, wherein said automatic offset compensation execution signal generation circuit outputs an offset compensation execution signal and wherein the interval at which said offset compensation execution signal output is shorter during a predetermined time period after power is turned on than during a period after the predetermined time period.

8. An infrared camera according to claim 5, wherein said automatic offset compensation execution signal generation circuit includes a temperature sensor for measuring the temperature around structural elements of said infrared camera, and a temperature changing amount judging circuit connected to said temperature sensor.

9. An infrared camera comprising:

an infrared optical system;

an image pickup element;

element temperature stabilizing means thermally connected to the image pickup element;

a shutter positioned covering a viewing field of the image pickup element;

a bias power source connected to said image pickup element;

a driver circuit connected to said image pickup element;

a pre-positioned amplifying circuit connected to said image pickup element;

a display processing circuit connected to said pre-positioned amplifying circuit;

a timing generation circuit connected to said shutter, said driver circuit, and said display processing circuit; and

an offset compensation execution signal generation circuit connected to said timing generation circuit;

wherein said offset compensation execution signal generation circuit outputs an offset compensation execution signal and wherein the interval at which said offset compensation execution signal output is shorter during a predetermined time period after power is turned on than during a period after the predetermined time period.

10. An infrared camera, comprising:

an infrared optical system;

de-focusing means associated with said infrared optical system;

an image pickup element;

element temperature stabilizing means thermally connected to said image pickup element;

a bias power source connected to said image pickup element;

a driver circuit connected to said image pickup element;

a pre-positioned amplifying circuit connected to said image pickup element;

a display processing circuit connected to said pre-positioned amplifing circuit;

a timing generation circuit connected to said de-focusing means, said driver circuit, and said display processing circuit; and

an offset compensation execution signal generation circuit connected to said timing generation circuit;

wherein said offset compensation execution signal generation circuit outputs an offset compensation execution signal and wherein the interval at which said offset compensation execution signal output is shorter during a predetermined time period after power is turned on than during a period after the predetermined time period.

11. An infrared camera comprising:

an infrared optical system;

an image pickup element;

element temperature stabilizing means thermally connected to the image pickup element;

a shutter positioned covering a viewing field of the image pickup element;

a bias power source connected to said image pickup element;

a driver circuit connected to said image pickup element;

a pre-positioned amplifying circuit connected to said image pickup element;

a display processing circuit connected to said pre-positioned amplifying circuit;

a timing generation circuit connected to said shutter, said driver circuit, and said display processing circuit; and

an offset compensation execution signal generation circuit connected to said timing generation circuit wherein said offset compensation execution signal generation circuit includes

a temperature sensor for measuring the temperature around structural elements of said infrared camera, and

a temperature changing amount judging circuit connected to said temperature sensor, and

said temperature changing amount judging circuit has a memory for storing a temperature at execution of offset compensation and updates content of the memory every execution of offset compensation.

12. An infrared camera, comprising:

an infrared optical system;

de-focusing means associated with said infrared optical system;

an image pickup element;

element temperature stabilizing means thermally connected to said image pickup element;

a bias power source connected to said image pickup element;

a driver circuit connected to said image pickup element;

a pre-positioned amplifying circuit connected to said image pickup element;

a display processing circuit connected to said pre-positioned amplifying circuit;

a timing generation circuit connected to said shutter, said driver circuit, and said display processing circuit; and

an offset compensation execution signal generation circuit connected to said timing generation circuit wherein said offset compensation execution signal generation circuit includes

a temperature sensor for measuring the temperature around structural elements of said infrared camera, and

a temperature changing amount judging circuit connected to said temperature sensor, and

said temperature changing amount judging circuit has a memory for storing a temperature at execution of offset compensation and updates content of the memory every execution of offset compensation.