SEEING THROUGH FOG

A VIEWING SYSTEM HAS BEEN DEVELOPED THAT ALLOWS AN OBSERVER TO SEE THROUGH FOG, SNOW, RAIN, STORMS, FOLIAGE, FORESTS, AND SCREEN MESH. USING A GALLIUM-ARSENIDE LASER, LASER DIODE LABORATORIES HAVE DEVELOPED A GATED INFRARED ILLUMINATOR DEVICE THAT IS PORTABLE AND LOW-COST. THE DEVICE HAS A RANGE FROM 5 TO 100 METERS, DEPENDING ON CONDITIONS. ABOUT 20 WATTS OF INPUT POWER ARE REQUIRED BY THE SYSTEM. THE LASERS ARE PULSED AND A SHORT BURST OF LIGHT TRAVELS OUT AND RETURNS TO THE TRANSCEIVER. AN IMAGE INTENSIFIER TUBE IN THE DEVICE IS MAINTAINED IN THE OFF POSITION, PREVENTING THE LIGHT FROM STRIKING THE PHOTOCATHODE AND ENTERING THE TUBE. HOWEVER, WHEN THE LEADING EDGE OF THE REFLECTED LASER LIGHT FROM THE OBJECT STRIKES THE PHOTOCATHODE, THE TUBE IS SWITCHED ON. THE RESULT IS THAT THE EYE OF THE OBSERVER RECEIVES ONLY THE LIGHT REFLECTED FROM THE OBJECT. THE BACKSCATTERED LIGHT IS NOT OF HIGH ENOUGH INTENSITY TO TURN ON THE IMAGE INTENSIFIER. THE VERY RAPID GATING OF THE TUBE- 10-NSEC PULSING-IS THE KEY TO THE DEVICE.

• Supplemental Notes:
  • Vol 11, No 1, PP 17-19
• Publication Date: 1969-1

Media Info

• Serial:
  • Industrial Research
  • Publisher: Dun Donnelley Publishing Corporation

Subject/Index Terms

• TRT Terms: Backscattering; Fog; Infrared radiation; Lasers; Reflection; Visibility
• Subject Areas: Highways; Safety and Human Factors;

Filing Info

• Accession Number: 00220443
• Record Type: Publication
• Files: TRIS
• Created Date: Jan 23 1970 12:00AM