Video temperature monitor

• US 5,225,883 A
• Filed: 06/05/1991
• Issued: 07/06/1993
• Est. Priority Date: 06/05/1991
• Status: Expired due to Term

• Current Assignee: Babcock & Wilcox Power Generation Group Incorporated (Babcock International Group PLC)
• Original Assignee: Babcock & Wilcox Company (Babcock International Group PLC)
• Inventors: Carter, Hudson R., England, Charles C., Berthold, John W.
• Primary Examiner(s): McGraw, Vincent P.
• Assistant Examiner(s): HANTIS, KAREN
• Application Number:
  US07/711,469
• Time in Patent Office: 762 Days
• Field of Search: 250/226, 356/45, 356/41, 356/73, 359/638, 374/124, 374/137
• US Class Current: 356/45
• CPC Class Codes: F23N 2229/20 Camera viewing
• CPC Class Codes: F23N 5/085 using electrical or electromechanical means
• CPC Class Codes: G01J 2001/448 Array [CCD]
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 5/0014 for sensing the radiation from gases, flames
• CPC Class Codes: G01J 5/0018 Flames, plasma or welding
• CPC Class Codes: G01J 5/602 using selective, monochromatic or bandpass filtering
• CPC Class Codes: G08B 17/125 by using a video camera to detect fire or smoke

Abstract

An apparatus and method for providing a real-time video display and a temperature map display of an object, in particular a flame, comprises a single CCD video camera and optical equipment which focuses separate light bundles onto a photosensitive surface of the camera. A separate band pass filter is used in each light bundle to filter selected different wavelengths of light. The video signal from the camera is used in a video digitizer to obtain data which can be used to calculate a temperature map based on the different wavelengths of light of the two bundles. The video signal is also used to produce a real-time video display of the object.

Claims

1. An apparatus for providing a real-time display and temperature map of an object, comprising:

a single CCD video camera having a photosensitive surface;

dividing means for dividing a bundle of light from the object into two light bundles;

filter means for only passing a different selected wavelength of light from each divided light bundle with all other wavelengths being absorbed or reflected;

optical means for focussing the two selected wavelengths of light passed from the divided light bundles onto the photosensitive surface of the single CCD video camera, the video camera producing a video signal therefrom;

pathlength compensation means in one of the divided light bundles for adjusting an optical pathlength of the one divided light bundle to be substantially equal to an optical pathlength of the other divided light bundle;

a video digitizer connected to said camera for digitizing the video signal into a digitized signal;

a first video display connected to the video digitizer for producing a real-time display of the two selected wavelengths of light passed from the divided light bundles;

processing means connected to said digitizer for processing the digitized signal to form temperature map data calculated from relative intensities of the two selected wavelengths of light passed from the divided light bundles; and

a second video display connected to said processing means for providing a temperature map display corresponding to the temperature map data.

2. An apparatus according to claim 1, wherein said filter means includes a separate bandpass filter in the path of each of said divided light bundles.

3. An apparatus according to claim 1, including a neutral density filter in the path of one of the divided light bundles having highest intensity for equalizing the intensity of both divided light bundles before they reach the video camera.

4. An apparatus according to claim 1, wherein the optical means focuses the two divided light bundles onto separate locations on the photosensitive surface.

5. A method of forming a real-time display and temperature map of an object, comprising:

splitting a light bundle from the object into two divided light bundles;

passing a different selected wavelength of light from each divided light bundle with all other wavelengths being absorbed or reflected;

focussing the two selected and different wavelengths of light passed from the divided light bundles onto a photosensitive surface of a single CCD video camera to produce a video signal;

adjusting an optical pathlength of the one divided light bundle to be substantially equal to an optical pathlength of the other divided light bundle with pathlength compensation means;

digitizing the video signal;

using the video signal to form a first video display of a real-time display of the two selected and different wavelengths of light passed from the divided light bundles;

calculating from the digitized video signal a temperature map of the object; and

displaying the temperature map on a second video display corresponding to the temperature map data.

6. A method according to claim 5, including dividing the bundle of light coming from the object using a beam splitter to form two divided light bundles and using a mirror to divert one of the divided light bundles so that it extends in a path which is substantially parallel to the path of the other divided light bundle.

7. A method according to claim 6, including focussing the parallel divided light bundles onto separate locations of the photosensitive surface.