Laser Ranging

TCSPC modules with sequencing or imaging capability can be used to read out the data without stopping the measurement, or to acquire the complete image at a fast scanning rate. 

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The helium—ca dmium laser, which has emission at 0.442 and 0.325 p.m, is a somewhat different type of ionized gas laser (28). It operates using the ionized states of cadmium, produced by heating ca dmium in a furnace. The output of continuous, commercially available helium—ca dmium lasers ranges up to 150 mW. 

Researchers also have been investigating microlasers. These lasers range from 1 to 5 microns in diameter and are carved from a multilayered... 

Fig. 11. An array of microscopic lasers sculpted from a multi-layered semiconductor substrate. The lasers range from 1 to 5 microns in diameter, and a million of them occupy a square centimeter cm a chip. (AT T Bell Laboratories)...

Two groups within NASA, one at Goddard Space Flight Center, under the direction of Bill Heaps, and the other at the Jet Propulsion Lab under Laudenslager and McDermid, have respectively developed balloon-borne LIDAR methods for OH and developed eximer laser systems for extending the LIDAR method to lower detection thresholds. This research has important implications for both stratospheric and tropospheric research. Such laser ranging techniques also have important implications for intercomparison studies, particularly with mm-wave and far infrared emission ex periments. 

AN/GVS-5 Laser Range Finder Handheld, Looks like a binocular... 

AN/VVG-1 Laser Range Finder Mounted on M551 Sheridan... 

AVENGER Laser Range Finder HMMWV mounted... 

MMS Laser Range Finder MMS, Mast Mounted Sight on OH-58D... 

In a typical ZoloBOSS installation, a control rack located in or near the plant control room contains multiple laser sources and detectors, diode laser drivers, and a system computer. The light from the individual lasers, ranging in nominal wavelengths between 0.67 and 1.7 pm and tuned to CO, CO2, O2, and H2O absorption features are multiplexed into one single-mode fiber using Zolo s Zmux multiplexer/demultiplexer device. 

Before a test is started, the coordinates of the flare and the radiometers (see Chapter 6) used to measure radiation are determined by utilizing a laser range finder to measure distances to three fixed objects with known coordinates and a technique called "triangulation." Multiple radiometers are used to measure various radiant fluxes simultaneously. A photo of the radiation measurement system is shown in Figure 28.12. The measured radiant fluxes, through sophisticated mathematical analysis, are used to determine the coordinates of the effective "epicenter(s)" of the flame, and the radiant fraction, which is defined as the fraction of heat release from combustion that is emitted as thermal radiation [43]. Solar radiation is subtracted from the radiation measurements as appropriate. 

The first application for Nd-doped YAG lasers was in laser range finding. Nonmilitary applications include cutting, welding, and drilling of metals for the automobile industry and in medical and dental procedures. 

It is possible to produce a precise ephemeris for local use by tracking the satellites from a number of so-called fiducial stations, whose positions are known very precisely, at the same time as the measurements are taken at the new stations (Ashkenazi and Ffoulkes-Jones, 1990). These fiducial stations may be Very Long Baseline Interferometry (VLBI) or Satellite Laser Ranging (SLR) sites, which are usually at considerable distances apart (typically 1000 km), or GPS stations especially established for this purpose (eg EUREF, the European Reference Network) (EUREF, 1989). Using these fiducial stations in a... 

Using these relations it is mandatory that, B,a,A refer to an identical (conventional) earth fixed reference frame, eg to the CIO/BIH geocentric tripod. Both astronomical and GPS measurements must therefore be reduced to this frame. For this purpose the GPS measurement has to be linked to at least one fiducial point of the CIGNET (= Cooperative International GPS Network) which has a well known SLR (= Satellite Laser Ranging) derived absolute position. 

Q for cutting lasers range between excellent (0.75) and less than average (0.3). 

Measured values of a in several types of (GaAl)As lasers range from 2.2 to 6.2.2 2 number of methods have been employed in the determination of... 

Computer-assisted cardiac surgery. Lancet 353 379-380 Cash DM, Sinha TK, Chapman WC et al (2003) Incorporation of a laser range scanner into image-guided liver surgery surface acquisition, registration, and tracking. Med Phys 30 1671-1682... 

Ding, S. et al. "Estimation of intra-operative brain shift using a tracked laser range scanner." 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2007 (EMBS 2007). IEEE, 2007. 

Most machine vision systems rely on data captured by hardware with fixed characteristics. These systems include passive sensing systems—such as video cameras—and active sensing systems—such as laser range finders. In an active vision system, the parameters and characteristics of data capture are dynamically controlled by the scene interpretation system. Active vision systems may employ either active or passive sensors. In an active vision system, however, the state parameters of the sensors, such as focus, aperature, vergence, and dlumination, are controlled to acquire data that will faciKtate scene interpretation. 

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