Illumination and imaging devices and methods

• US 7,579,592 B2
• Filed: 02/23/2001
• Issued: 08/25/2009
• Est. Priority Date: 02/25/2000
• Status: Active Grant

• Current Assignee: Teledyne FLIR LLC (Teledyne Technologies Incorporated)
• Original Assignee: Qinetiq Limited (QinetiQ Group PLC)
• Inventors: Kaushal, Tej
• Primary Examiner(s): Porta; David P
• Assistant Examiner(s): LEE, SHUN K
• Application Number:
  US10/204,856
• Publication Number:
  US 20030047683A1
• Time in Patent Office: 3,105 Days
• Field of Search: 250/330, 359/291
• US Class Current: 250/330
• CPC Class Codes: A61B 2090/366 using projection of images directly onto the body
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/489 Blood vessels
• CPC Class Codes: F21W 2131/406 for theatres, stages or film studios
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 5/0022 for sensing the radiation of moving bodies
• CPC Class Codes: G02B 23/12 with means for image conversion or intensification
• CPC Class Codes: H04N 9/3161 using laser light sources using laser beams scanning the display screen H04N9/3129

Abstract

A thermal torch (12) comprises an infrared camera (22) and a visible light emitter (28, 26) arranged so as to illuminate hot objects with visible light. This projection of visible light onto the scene, rather than observing it at infrared wavelengths converted to visible light by a display screen, makes viewing the scene more natural. Applications include medical imaging equipment, night driving systems, stage lights, and security lights. The profile of the beam of visible light can be modulated with a beam profiler (26) which may be a LCD. The infrared camera (22) and visible projector (28,26) may be bore-sighted to facilitate overlying of the visible projected image onto the scene.

Claims

1. A projector device comprising:

a passive thermal infrared detector for detecting an intensity pattern of thermal infrared radiation emitted by objects in an observed scene and incident upon the device from a direction;

an emitter adapted to emit a beam of radiation of visible light; and

emitted beam control means for modulating the intensity of the emitted visible light beam to at least two intensity levels, said intensity levels based on the intensity pattern of said detected thermal infrared radiation, and for controlling the direction of said emitted visible light beam to selectively illuminate said objects of different temperature in the observed scene.

2. A device according to claim 1 in which the emitter has an emitted beam patterner, and in which the detector is adapted to detect the cross-sectional profile, or pattern, of said objects passively detected in an observed scene in infrared, and in which the emitter is adapted to emit an emitted beam with a variable cross-sectional profile which is modulated by the beam patterner to match the profile or pattern in infrared, and to superpose an equivalent visible light pattern over the infrared pattern in the observed scene.

3. A device according to claim 2 in which the beam patterner comprises a spatial light modulator (SLM) adapted to control an image emitted by the emitter.

4. A device according to claim 3 in which the spatial light modulator is provided at or between an alignment element adapted to align an emitted visible light image with a detected thermal infrared image and a source of visible light.

5. A device according to claim 1 in which an optical alignment element is provided to register the emitted beam with said objects, the alignment element being at least partially reflective to radiation of one of the thermal infrared and visible light, and at least partially transmissive to radiation of the other of the thermal infrared and visible light.

6. A device according to claim 5 in which the alignment element comprises a beam splitter.

7. A device according to claim 1 comprising a hand-held torch.

8. A device according to claim 1 in which signals produced by the detector are passed substantially unprocessed to the emitter.

9. A device according to claim 1 which has a sensor sensitive to visible light, and a directional or image projector as the emitter, and deselection control means being adapted to identify areas of the scene being observed by said sensor that are the source of a significant amount of radiation of visible light to the device, and being adapted to deselect those regions for illumination by the visible light emitter.

10. A device according to claim 1 which has said passive thermal infrared detector with a plurality of pixels and said emitter adapted to project an image with substantially the same number of pixels.

11. A method of visibly representing a thermal mapping of an observed scene comprising the steps of:

receiving thermal infrared radiation of a first wavelength from said observed scene; and

using the received infrared radiation to control the projection of visible light of at least two different intensities onto the observed scene, said intensity of light representing the intensity of said received thermal infrared radiation, the visible light being projected in a visible light pattern onto the observed scene that mirrors and overlays the thermal infrared map of the observed scene.

12. A method according to claim 11 comprising providing a user with a hand-held torch to project the visible light pattern onto the observed scene.

13. A method of improving the safely of driving in the dark comprising mounting on a vehicle a visible light projector which operates in accordance with claim 11 and illuminating thermal objects in an observed scene with visible light.