LIDAR system

• US 7,701,558 B2
• Filed: 09/21/2007
• Issued: 04/20/2010
• Est. Priority Date: 09/22/2006
• Status: Active Grant

• Current Assignee: GeoEye Analytics, Inc. (Geoeye Incorporated)
• Original Assignee: Leica Geosystems AG (Hexagon AB)
• Inventors: Aindow, Alan, Walsh, Gregory C.
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Ratcliffe; Luke D
• Application Number:
  US11/903,302
• Publication Number:
  US 20080074640A1
• Time in Patent Office: 942 Days
• Field of Search: 356 301- 285
• US Class Current: 356/5.01
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4818 using optical fibres
• CPC Class Codes: G01S 7/483 Details of pulse systems
• CPC Class Codes: G01S 7/4865 Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak peak detection in noise, signal conditioning G01S7/487
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating

Abstract

Methods for using spectrally separated light pulses to collect more LIDAR information are presented. In one embodiment, a monochromatic pulse is transmitted to collect range information and a white pulse is transmitted a short time afterwards to collect spectral responsivity information or color of the target. In another embodiment, the white light pulse is used to collect both range and spectral responsivity information of the target. In another embodiment, the spectral separated laser is spatially spread in order to collect range information over more than one point at a time.

Claims

1. A method of obtaining both location information and spectral information regarding an object, the method comprising:

generating a laser pulse;

dividing the laser pulse into a monochromatic laser pulse and a wave-length broadened white laser pulse;

delaying the wave-length broadened white laser pulse with respect to the monochromatic laser pulse;

combining the monochromatic laser pulse and the delayed wave-length broadened white laser pulse to provide a combined laser pulse signal;

directing the combined laser pulse signal to a point on the object and receiving a corresponding return light signal that includes a laser pulse portion and a broadband portion;

providing the laser pulse portion of the return light signal to optical detector and timing electronics to generate object location information;

dividing the broadband portion of the return light signal into a number of spectral components;

providing each of the spectral components to an associated intensity-related measuring/detection circuit triggered by timing signals received from the optical detector and timing electronics to generate corresponding object spectral information such that the object location information and object spectral information regarding the point on the object are extracted simultaneously from the same laser pulse.

2. A method as in claim 1, and further comprising:

repeating the steps of claim 1 for a plurality of sequentially scanned laser pulses to obtain object location information and object spectral information regarding a plurality of points on the object to create a point cloud database relating to the object.

3. A method as in claim 1, and further comprising:

coupling a separate secondary illumination light source to the monochromatic laser pulse.

4. A method as in claim 3, and wherein the secondary illumination light source comprises a secondary laser.

5. A method as in claim 3, and wherein the secondary illumination light source comprises a super bright white LED.

6. A method as in claim 3, and further comprising:

synchronizing sampling of return light from the secondary illumination light source with the generated laser pulse.

7. A system for generating both location information and spectral information for a plurality of points on an object, the system comprising:

a pulsed laser that generates a sequence of laser pulses;

a beam splitter that splits each laser pulse into a direct monochromatic laser pulse and a wave-length broadened white laser pulse, the wave-length broadened white laser pulse being time delayed with respect to the direct monochromatic laser pulse;

a beam combiner that combines the direct monochromatic laser pulse and the time delayed wave-length broadened white laser pulse to provide a combined laser pulse;

macro-optics that transmits the combined laser pulse to a point on the object and receives a corresponding return signal from the point on the object, the return signal including a received laser pulse signal and a received broadband signal;

a filter that separates the received laser pulse signal and the received broadband signal;

an optical detector connected to the filter to detect the received laser pulse signal and that generates object location-related information and timing signals relating to the received laser pulse signal;

a wavelength separator connected to the filter to divide the received broadband signal into a plurality of spectral components;

for each spectral component, an associated intensity-related detector that is triggered by the timing signals generated by the optical detector to generate object spectral information; and

whereby object location-related information and object spectral information are simultaneously generated for each of a plurality of points on the object.