Lidar with streak-tube imaging, including hazard detection in marine applications; related optics
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H04N-007/18
G01P-003/36
출원번호
UP-0023042
(2004-12-27)
등록번호
US-7683928
(2010-04-21)
발명자
/ 주소
Lubard, Stephen C.
McLean, John W.
Sitter, Jr., David N.
Bowker, J. Kent
Gleckler, Anthony D.
출원인 / 주소
Arete' Associates
대리인 / 주소
Lippman, Peter I.
인용정보
피인용 횟수 :
1인용 특허 :
15
초록▼
The system and method relate to detection of objects that are submerged, or partially submerged (e.g. floating), relative to a water surface. One aspect of the invention emits LIDAR fan-beam pulses and analyzes return-pulse portions to determine water-surface orientations and derive submerged-object
The system and method relate to detection of objects that are submerged, or partially submerged (e.g. floating), relative to a water surface. One aspect of the invention emits LIDAR fan-beam pulses and analyzes return-pulse portions to determine water-surface orientations and derive submerged-object images corrected for refractive distortion. Another defines simulated images of submerged objects as seen through waves in a water surface, prepares an algorithm for applying a three-dimensional image of the water surface in refractive correction of LIDAR imaging through waves—and also models application of the algorithm to the images, and finally specifies the LIDAR-system optics. Yet another emits nearly horizontal pulses to illuminate small exposed objects at tens of kilometers, detects reflected portions and images successive such portions with a streak-tube subsystem. Still others make special provisions for airborne objects.
대표청구항▼
What is claimed is: 1. A system for detecting objects submerged, or partially submerged, relative to a water surface; said detecting system comprising: a LIDAR subsystem emitting thin fan-beam light pulses from above such water surface toward such objects and detecting reflected portions of the fan
What is claimed is: 1. A system for detecting objects submerged, or partially submerged, relative to a water surface; said detecting system comprising: a LIDAR subsystem emitting thin fan-beam light pulses from above such water surface toward such objects and detecting reflected portions of the fan-beam pulses; and means for analyzing the reflected pulse portions to determine water-surface orientations and therefrom derive submerged-object images corrected for refractive distortion. 2. The system of claim 1, particularly for use in detecting solid objects, including objects that are floating partially submerged, wherein: the LIDAR subsystem emits said pulses at an angle that is within an angular range from one to fifteen degrees off the horizontal; and the analyzing means comprise: means for using precise range resolution of the reflected pulse portions to determine quantitatively each of multiple said water-surface orientations; and means for applying Snell's Law in conjunction with said multiple quantitatively determined water-surface orientations, to develop corrections for refraction at such water surface. 3. The system of claim 1, particularly for use in detecting solid objects, including objects that are floating partially submerged, wherein: the LIDAR subsystem comprises a deflection device sweeping a succession of the thin fan-beam light pulses across such objects and such water surface rapidly enough to substantially capture all said determined water-surface orientations in a consistent common configuration. 4. The system of claim 3, particularly for detecting such objects near a water craft; and wherein: the LIDAR subsystem is mounted to such craft; and the deflection device operates cyclically. 5. The system of claim 1, wherein: the LIDAR subsystem is carried along over the water surface in a generally progressive motion defining a succession of adjacent or overlapping measurement swaths; and the fan-beam pulses are repeated rapidly enough to capture said determined water-surface orientations in a nearly consistent common configuration in adjacent or overlapping swaths. 6. The system of claim 2, wherein: said angle is also within an angular range from two to ten degrees off the horizontal. 7. The system of claim 2, wherein: said angle of emission is on the order of five degrees, or less, from horizontal. 8. The system of claim 2, particularly for use in detecting and imaging solid objects that are mines, or other manufactured mechanical articles, or other hazards to navigation such as flotsam and jetsam; and wherein: said angle of emission is on the order of five degrees, or less, from horizontal. 9. A method of implementing a LIDAR system that corrects for refraction in LIDAR imaging through waves in a water surface; said method comprising the steps of: defining simulated images of submerged objects as seen through waves in a water surface with a LIDAR system; preparing an algorithm for applying a three-dimensional image of the water surface in refractive correction of LIDAR imaging through waves; modeling application of the algorithm to the simulated images with an assumed or actual three-dimensional image of the water surface to determine requirements of range and pixel resolution for successful operation of the LIDAR system; and based upon the determined range and pixel resolution requirements, specifying optics for the LIDAR system. 10. The method of claim 9, further comprising the steps of: preparing a second algorithm for capturing a three-dimensional image of the water surface based on ranging data obtained with a LIDAR system over a generally horizontal grid of positions; and modeling application of the second algorithm to actual ranging data obtained with a LIDAR system to verify adequate performance of the second algorithm as to resolution in the ranging direction and in horizontal grid directions. 11. A system for detecting exposed solid objects, at ranges on the order of tens of kilometers or less; said system comprising: a LIDAR subsystem for emitting nearly horizontal, thin fan-beam light pulses to illuminate such exposed solid objects at ranges on the order of tens of kilometers or less, and for detecting nearly horizontal reflected portions of the fan-beam pulses returned from such exposed objects; and a streak-tube subsystem for imaging successive reflected fan-beam pulse portions. 12. The system of claim 11, wherein: the light pulses are eye-safe. 13. An integrated system for detecting solid objects submerged, or partially submerged, relative to a water surface near a water craft and also for detecting airborne objects; said system comprising: a LIDAR subsystem, mounted to such water craft: emitting thin fan-beam light pulses from above such water surface, at an angle on the order of five degrees, or less, off horizontal, toward such submerged, or partially submerged, solid objects; and emitting additional thin fan-beam light pulses exclusively toward such airborne objects; and detecting reflected portions of the fan-beam pulses; first means for analyzing the reflected and detected portions of pulses emitted toward such submerged, or partially submerged, solid objects to: determine multiple water-surface orientations quantitatively, and from the multiple quantitatively determined water-surface orientations, derive submerged-object images corrected for refractive distortion; and second means for separately analyzing the reflected and detected portions of said additional pulses emitted toward such airborne objects exclusively, to therefrom derive airborne-object images. 14. The integrated system of claim 13, wherein: the first analyzing means also recognize and image airborne objects that reflect portions of pulses emitted toward such submerged, or partially submerged, solid objects. 15. The integrated system of claim 13, wherein: the LIDAR subsystem comprises means for sweeping a sequence of the light pulses across such submerged, or partially submerged, solid objects and such airborne objects in a substantially continuous succession. 16. The integrated system of claim 13, wherein: the LIDAR subsystem comprises means for sweeping a sequence of the light pulses across such submerged, or partially submerged, solid objects and such airborne objects in a succession that is interrupted to skip past objects in a narrow range of elevations at and just below the horizon.
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이 특허에 인용된 특허 (15)
Gerdt David W. (Charlottesville VA) Gilligan Lawrence H. (Charlottesville VA), Atmospheric obscurant penetrating target observation system with range gating.
Kent Bowker ; Stephen C. Lubard, Displaced-beam confocal-reflection streak lindae apparatus with strip-shaped photocathode, for imaging very small volumes and objects therein.
Jain Atul (1545 E. Mendocino Dr. Altadena CA 91001), System for relative motion detection between wave transmitter-receiver and irregular reflecting surface.
Bowker Kent (Essex MA) Lubard Stephen C. (Woodland Hills CA), Underwater imaging in real time, using substantially direct depth-to-display-height lidar streak mapping.
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