A system for making distance measurements of remote points using a phenomenon related to the time of flight of an illuminating beam. A modulated beam of light is directed at the target area. The modulated beam has temporally varying information impressed upon it, such that the time of flight of the
A system for making distance measurements of remote points using a phenomenon related to the time of flight of an illuminating beam. A modulated beam of light is directed at the target area. The modulated beam has temporally varying information impressed upon it, such that the time of flight of the beam to the target and back can be related to the temporal signature of the received beam. An acousto-optic modulator is used to perform frequency conversion of the modulated light reflected from points in the field, before that light impinges on the pixels of a detector array. The AO modulation frequency is close to the illuminating light modulation frequency, so that the converted mixed frequency falls within the limited parallel reading rate range of the detector array, and contains the temporal signature information of the modulated light received from the target within signals of manageable frequencies.
대표청구항▼
1. A system for remote distance measurement, comprising: a light source assembly configured to transmit modulated light to a point whose distance is to be measured in the field of view of said system;a pixelated detector, adapted to receive light reflected from said point and imaged onto a pixel of
1. A system for remote distance measurement, comprising: a light source assembly configured to transmit modulated light to a point whose distance is to be measured in the field of view of said system;a pixelated detector, adapted to receive light reflected from said point and imaged onto a pixel of said detector; said received light having a temporal signature arising from the distance of said point from said system;an acousto-optic modulator, disposed relative to said pixelated detector, such that said received reflected light passes therethrough before impinging on said pixelated detector; anda control system adapted to calculate said distance of said point from the temporal signature of said received light,wherein said acousto-optic modulator is excited with a travelling modulating acoustic wave generated from a pair of acoustic waves having a difference in waveform which mix acoustically in said acousto-optic modulator, such that passage of modulated light received from said point through said acousto-optic modulator, generates a converted modulated optical wave containing said temporal signature information in a frequency range substantially less than that related to said modulation of said transmitted light. 2. A system according to claim 1, wherein said frequency range substantially less than that of said modulation of said transmitted light falls within the rate at which the pixels of said detector can be read. 3. A system according to claim 1, wherein said modulation of said transmitted light is of sufficiently high speed that said distance measurement can be performed with a predetermined accuracy. 4. A system according to claim 3 wherein said modulation speed is substantially higher than said rate at which the pixels of said detector can be read in parallel. 5. A system according to claim 1, wherein each segment of said acousto-optic modulator is configured to modulate received light containing information relating to a different point in said field of view. 6. A system according to claim 1, wherein light traversing each segment of said acousto-optic modulator impinges onto an associated pixel in said pixelated detector. 7. A system according to claim 1, further comprising a grey level detector, such that said system can combine an image of said field of view together with said distance information. 8. A system according to claim 1, wherein said transmitted light is amplitude modulated with a predetermined modulation frequency, and said temporal signature is the modulation phase delay of said received light relative to said transmitted light. 9. A system according to claim 1, wherein said transmitted light is frequency chirped, and said temporal signature is the frequency of said received light relative to said transmitted light. 10. A system according to claim 1, wherein said transmitted light has a temporal coding scheme applied to it, and said temporal signature is the temporal code of said received light relative to said transmitted light. 11. A method for remote distance measurement, comprising the steps of: transmitting modulated light to a point whose distance is to be measured;providing a pixelated detector, positioned such that light reflected from said point is imaged onto a pixel of said detector, said received light having a temporal signature by virtue of the distance of said point;providing an acousto-optic modulator disposed relative to said pixelated detector, such that said received reflected light passes therethrough before impinging on said pixelated detector;exciting said acousto-optic modulator with a travelling modulating acoustic wave generated by inputting a pair of acoustic waves having a difference in waveform which mix acoustically in said acousto-optic modulator, such that when modulated light received from said point is passed through said acousto-optic modulator, a converted modulated optical wave is generated containing said temporal signature information in a frequency range substantially less than that related to said modulation of said transmitted light; andcalculating said distance of said point from the temporal signature of said received light. 12. A method according to claim 11 wherein said pixelated detector measures the temporal signature of phase difference between light transmitted to said remote line and light received from said point with an accuracy characteristic of said modulation frequency, and at a rate characteristic of said frequency range substantially less than that related to said modulation of said transmitted light. 13. A method according to claim 11, wherein said frequency range substantially less than that related to said modulation of said transmitted light falls within the rate at which the pixels of said detector can be read. 14. A method according to claim 11, wherein said modulation of said transmitted light is of sufficiently high speed that said distance measurement can be performed with a predetermined accuracy. 15. A method according to claim 14 wherein said modulation speed is substantially higher than said rate at which the pixels of said detector can be read in parallel. 16. A method according to claim 11, wherein each segment of said acousto-optic modulator modulates received light containing information relating to a different point in said field of view. 17. A method according to claim 11, wherein light traversing each segment of said acousto-optic modulator impinges onto an associated pixel in said pixelated detector. 18. A method according to claim 11, further comprising the step of detecting the grey level at each pixel, such that said system can combine an image of said points whose distance is measured together with said distance information. 19. A method according to claim 11, wherein said transmitted light is amplitude modulated with a predetermined modulation frequency, and said temporal signature is the modulation phase delay of said received light relative to said transmitted light. 20. A method according to claim 11, wherein said transmitted light is frequency chirped, and said temporal signature is the frequency of said received light relative to said transmitted light. 21. A method according to claim 11, wherein said transmitted light has a temporal coding scheme applied to it, and said temporal signature is the temporal code of said received light relative to said transmitted light.
연구과제 타임라인
LOADING...
LOADING...
LOADING...
LOADING...
LOADING...
이 특허에 인용된 특허 (2)
Phillips Mark W. ; Suni Paul J. M. ; Thomson J. Alex L., Fiber-based ladar transceiver for range/doppler imaging with frequency comb generator.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.