# US 5,710,431 A · Outdoor scene simulating apparatus for testing an infrared imaging device

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- Number: US 5,710,431 A
- Document ID: US5710431A
- Status: Granted
- Kind: A
- Application number: 08/706,588
- Filed: 1996-09-05
- Granted: 1998-01-20
- Earliest claimed: 1996-09-05
- Assignees: The United States of America as represented by the Secretary of the Navy
- Inventors: Jeffrey William Spindler
- Web page: https://patentgrep.com/patent/US5710431A

## CPC

- G01J 5/53: Reference sources, e.g. standard lamps; Black bodies
- G01J 5/061: by controlling the temperature of the apparatus or parts thereof, e.g. using cooling means or thermostats
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)

## Abstract

An outdoor scene simulating apparatus for testing an infrared imaging dev comprising an infrared source, which emits infrared energy along a first optical path. Positioned downstream from the infrared source along the first optical path is a metallic substrate which has on its front surface a simulated outdoor scene. The simulated outdoor scene is formed by coating a portion of the metallic substrate with a black ink which absorbs infrared radiation. A thermal mass abuts the substrate to provide a cooling path between the thermal mass and the substrate. The thermal mass cools the metallic substrate and black ink of the simulated outdoor scene to temperatures below ambient temperature reducing infrared emissions from the metallic substrate and black ink of the simulated outdoor scene. Infrared energy reflected from the metallic substrate is directed along a second optical path to a collimator. The collimator collects the infrared radiation reflected from on metallic substrate and then redirects the infrared radiation as a collimated beam of infrared radiation along a third optical path to the lens of the infrared imager being tested.

## Claims

### Claim 1

An apparatus for testing an infrared imaging device which is sensitive to electromagnetic radiation in a three micron to twelve micron wavelength band, said apparatus comprising:
a blackbody for generating and emitting infrared energy along a first optical path, said infrared energy having a wavelength in a range of between about three microns and about twelve microns;
a metallic substrate positioned downstream from said blackbody on said first optical path, said metallic substrate having a front surface and a rear surface, the front surface of said metallic substrate having a portion thereof coated with an infrared absorbing black ink to simulate thermal emissions from an outdoor scene, the front surface of said metallic substrate reflecting a substantial portion of said infrared energy incident upon the front surface of said metallic substrate, the front surface of said metallic substrate providing a reflecting rate greater than 0.85;
a thermal mass positioned at the rear surface of said metallic substrate, said thermal mass abutting the rear surface of said metallic substrate to cool said metallic substrate; and
a collimator positioned on a second optical path downstream from said metallic substrate, said collimator collecting said infrared energy reflected from the front surface of said metallic substrate, said collimator forming a collimated beam of infrared energy from said infrared energy collected by said collimator, said collimator directing said collimated beam of infrared energy along a third optical path to said infrared imaging device being tested.

### Claim 2 (depends on 1)

The apparatus of claim 1 wherein said blackbody comprises a flat plate blackbody.

### Claim 3 (depends on 1)

The apparatus of claim 1 wherein said metallic substrate is fabricated from aluminum sheet having a thickness of approximately 0.5 millimeters.

### Claim 4 (depends on 1)

The apparatus of claim 1 wherein said thermal mass comprises an aluminum plate set to a temperature of about twenty degrees Centigrade.

### Claim 5

An apparatus for testing an infrared imaging device which is sensitive to electromagnetic radiation in a three micron to twelve micron wavelength band, said apparatus comprising:
a flat plate blackbody for generating and emitting infrared energy along a first optical path, said infrared energy having a wavelength in a range of between about three microns and about twelve microns;
said flat plate blackbody comprising a thirty centimeter flat plate blackbody;
a metallic substrate positioned downstream from said blackbody on said first optical path, said metallic substrate having a front surface and a rear surface, the front surface of said metallic substrate having a portion thereof coated with an infrared absorbing black ink to simulate thermal emissions from an outdoor scene, the front surface of said metallic substrate reflecting a substantial portion of said infrared energy incident upon the front surface of said metallic substrate, the front surface of said metallic substrate providing a reflecting rate greater than 0.85;
said infrared absorbing black ink having a density which varies across the front surface of said metallic substrate;
said metallic substrate being fabricated from aluminum sheet having a thickness of approximately 0.5 millimeters;
a thermal mass positioned at the rear surface of said metallic substrate, said thermal mass abutting the rear surface of said metallic substrate to cool said metallic substrate;
said thermal mass comprising an aluminum plate set to a temperature of approximately twenty degrees centigrade; and
a collimator positioned on a second optical path downstream from said metallic substrate, said collimator collecting said infrared energy reflected from the front surface of said metallic substrate, said collimator forming a collimated beam of infrared energy from said infrared energy collected by said collimator, said collimator directing said collimated beam of infrared energy along a third optical path to said infrared imaging device being tested.