HR: 0800h
AN: G21C-1290    [Abstracts]
TI: Geodetic Laser Scanning: Refractive Optics Offer Wide Variety of Scan Patterns
AU: * Carter, W E
EM: bcarter@ce.ufl.edu
AF: University of Florida, Department of Civil and Coastal Engineering, Gainesville, FL 32611 United States
AU: Shrestha, R L
EM: rshre@ce.ufl.edu
AF: University of Florida, Department of Civil and Coastal Engineering, Gainesville, FL 32611 United States
AU: Slatton, C K
EM: cslat@ce.ufl.edu
AF: University of Florida, Department of Civil and Coastal Engineering, Gainesville, FL 32611 United States
AU: Slatton, C K
EM: cslat@ce.ufl.edu
AF: University of Florida, Department of Electrical and Computer Engineering, Gainesville, FL 32611 United States
AU: Shrestha, K Y
EM: kshres@gmail.com
AF: University of Florida, Department of Civil and Coastal Engineering, Gainesville, FL 32611 United States
AU: Cossio, T
EM: tcossio@ecel.ufl.edu
AF: University of Florida, Department of Electrical and Computer Engineering, Gainesville, FL 32611 United States
AB: Most commercial geodetic laser mapping instruments use reflective element scanners, often a single nutating or oscillating mirror, and sometimes dual axis units, to create a specific pattern of laser spots on the surface being mapped. The user may be able to set the scanning speed (scan lines per second) and field of coverage (range of scan angles), but the basic pattern of points sampled is fixed. Engineers developing scanners for a surprisingly diverse set of applications, ranging from bar code scanning, to compensating for image motion in astronomical telescopes, to scanning spectrometers, have increasingly turned to refractive scanners-most particularly to scanners that utilize "Risley prisms." Samuel Doty Risley (1845-1920), an ophthalmologist, invented an optometer that contained a pair of thin prisms that rotated in opposite directions about their optical axes to change the convergence of light rays from a single source. He used his optometer measure the visual acuity of patients eyes, as a function of distance. In this original application, both prisms were driven by a common gear assembly, which resulted in a nearly linear scan line. But if the prisms are driven independently in both direction and angular speed, a wide variety of scan patterns can be generated. The University of Florida is developing, a photon counting geodetic laser scanning instrument that will use a Risley prism scanner. The scanner, being built by Sigma Space Inc., will be capable of producing nearly linear scan lines (saw tooth pattern from moving platform), circular scans lines (helical pattern from a moving platform) and any number of rosette scan patterns that are particularly interesting for fixed ground based work. The flexibility provided by the scanner offers the possibility of using the same sensor for airborne and ground based geodetic laser scanning. Examples of the scanner patterns and the initial results from laboratory and early field tests will be presented.
DE: 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
DE: 1294 Instruments and techniques
DE: 1640 Remote sensing (1855)
DE: 1824 Geomorphology: general (1625)
DE: 1855 Remote sensing (1640)
SC: Geodesy [G]
MN: Fall Meeting 2005