• http://home.earthlink.net/~scan3d
• vivd3d http://www.minolta3d.com/
• http://www.optimet.com/technology.htm - a novel rangefinder that uses conoscopic holography.
• http://www.diffracto.com - They sold off their line of triangulation units to Perceptron and now have joined forces with Selcom, a manufacturer of lateral effect photodiodes which can be used for rapid and accurate point acquisition.
• Papers on the Pohelmus scanner are available at: http://www.aranz.com
• FastScan Pricing is here

[10.1.3] Rangefinding devices

Principles There are four basic techniques for distance measurement using electro magnetic radiation. These are:

• Pulse Timing
• Phase Comparison
• Doppler Methods
• Interferometry

All are used in practice for distance measurement depending on the particular application.

Pulse timing, as the name suggests, involves measuring the round time for a signal to be transmitted to a reflective surface and return.

This is the principle used in Radar, DME for aircraft, LORAN, Satellite Altimetry, Airborne RADAR Altimetry, Lunar Laser Ranging etc. Some of the newer EDM instruments used by surveyor are also using pulse timing and accuracies of +/- 5mm are possible. Most of the military range finders also use pulse timing. The GPS system uses pulse timing for coarse distance measurement. Very Long Base Interferometry (VLBI) is also a pulse timing technique where signals >from pulsars are timed from two or more radio telescopes and the difference in times of arrival are converted to intercontinental distances with a precision of a few centimetres.

Phase difference involves the use of a carrier wave which may be modulated at different wavelengths. By measuring the difference in phase between the transmitted signal and the received signal after it has been reflected from the other end of the target, the distance can be determined as an integer number (unknown) of wavelengths plus a fraction of a wavelength which is known from the phase comparison. By using a range of modulation frequencies the ambiguity can be resolved. There are many applications of this technique. A wide range of carrier frequencies are used ranging from visible through infra red to microwave and right down to VLF. Typical instruments used by surveyors have accuracies of +/-(1to2 mm +1to3 parts per million) and use infra red as the carrier. Precise positioning using GPS can be achieved by phase comparison of the carrier wave signals of the various satellites. Accuracies in position of better than 1 part per million can be achieved.

Doppler techniques were used in the earlier satellite positioning systems. The received frequency of a low orbit satellite is compared with the actual transmitted signal as a function of time. The rate of change of frequency gives the slant range between the satellite and the observer while the instant when the two freqencies are the same gives the point of closest approach. By knowing the orbital parameters of the satellite which are transmitted, the observers position can be determined.

Interferometric methods are the same as those used in the original Michelson Interferometer. It is used for metrology, high precision distance measurement over short distances (up to 60 metres) and in the definition of the metre.

There are a variety of laser rangefinding devices that have been built and used over the past decade for robotics use. The 3D devices are still large, power hungry and heavy but give very nice images suitable for fast map building and navigation work. Expect to pay over $50K for these time-of-flight devices. Most AM Lidars measure phase shift between outgoing and reflected beams. A mirror system rasters the beam forming a video-camera-like image. Some devices supply the reflectance image as well as range which is nice for corresponding the two. Comprehensive references include:

· Electronic Distance Measurement by JM Rueger, Springer-Verlag

· P. Besl, ``Active, Optical Range Imaging Sensors'', Machine Vision and Applications, v. 1, p. 127-152, 1988.

A longer version of Besl's paper appears in ``Advances in Machine Vision: Architectures and Applications'', J. Sanz (ed.), Springer-Verlag, 1988.

· Other good surveys are Ray Jarvis' article in IEEE TPAMI v5n2 and Nitzan's article in IEEE PAMI v10n2.

A good report on the characterization of a particular scanner is:

· Experimental Characterization of the Perceptron Laser Rangefinder, In So Kweon, Regis Hoffman, and Eric Krotkov. Carnegie Mellon University Technical Report, CMU-RI-TR-91-1. 1991.

· M. Hebert and E. Krotkov. 3-D Measurements from Imaging Laser Radars: How Good Are They? Int. Journal of Image and Vision Computing, 10(3):170-178, April 1992

· International Journal of Robotics Research, Vol. 13, No. 4, Aug. 1994, pp 305-314. {get title}

A number of laboratory works have also demonstrated FM or chirp systems which can be highly accurate (e.g. high resolution elevation maps of coins) but these are very specialized and I don`t know of commercial devices currently.

Acuity Research

20863 Stevens Creek Blvd. #200

Cupertino, Ca. 95014

tel: 408-252-9639

fax: 408-725-1580

net: contact@acuity.com or Bob Clark, rrc@acuity.com

The AccuRange 400 is an optical distance measurement sensor with a range of 0 to 16m for most diffuse reflective surfaces. It operates by emitting a collimated laser beam that is reflected from the target surface and collected by the sensor. 0.5mm short-term repeatability, RS-232 output and optional 4-20mA current loop. Also PW and analog indication of range available. Visible or IR output available. (670nm and 780nm respectively) Around $2500. 5VDC@300mA. 50KHz sampling rate.

Atomic Energy of Canada Ltd. (AECL)

contact: Narinder Bains (nbains@bart.candu.aecl.ca)

net: 905.823.9040 x6120

Laser Eye ranging system. It consists of a robotic head with a combined vision / range sensor. The sensor provides colour images and distance to an object in the centre of the camera field of view. There is of course software to process images from the camera and detect a target, to control the head, communication, nice GUIs, etc. Is being used for vehicle navigation.

From the head position you get the bearing to the target and the rangefinder provides you with the distance. Angular resolution is better than 0.05 degree, the distance can be measured up to 100m with accuracy of ~5 cm. Note that the range measurement is 1D along the camera axis.

The cost of the vision system and complexity of the software depends on your specific application: how difficult is it to detect and track your vehicle, how fast is it moving, is it possible to use special markers, is illumination constant, etc.

ERIM (Environmental Research Institute of Michigan)

ERIM has built a number of custom AM laser rangefinders including those used in the ALV (Autonomous Land Vehicle) program. CMU and Martin Marietta have both used this systems in extensive work. Basic system was a 128x64 2fps 20m (ambiguity interval) system.

Erwin Sick GmbH.

PLS-100: This device measures distance by TOF from 4 cm up to 80 m, guaranteed range of 4 m (at a black lether target), is eye-safe (IEC Class 1), takes a 180 degree scan in 20 ms, total 25 scans a second, angle resolution 0.5 degree (361 scan points in a scan). This device is build in a industrial IP65 case. And it is rather cheap (6.900,- DM + VAT, in Germany).

$15K LED based IR ranging system. 15cm diameter rotating scanning device with collimated LED light beam that uses phase differences to calculate distance. Range 0.6 to 6m. 2.5cm resolution, 15cm accuracy. 1Khz update rate

Hammamatsu Corp.

New Jersey

tel: 908.231.0960

fax: 908.231.1539

Hamamatsu S4282 Light Modulation Photo IC The size of a normal transistor (approx 1/4" square). It has 4 leads, Vcc, Gnd, Vout, LED. All you do is attach an IR LED to the LED lead to give you an instant IR proximity detector (the photo diode detector is built into the part). Two can be aimed at each other and they won't interfere since they'll be out of phase. They have another model with a lens over the photo diode that is claimed could be used up to 30 feet! Hammamatsu also sells a number of photo sensors like color sensors, position sensitive detectors, pyroelectric sensors.

· S4282-11 short range $7.75 single unit

· S4282-72 long range $19.00 single unit

net: info@hymarc.com

Hyscan laser digitizing systems. High speed 3D surface mapping. Hyscan probe retrofits to any CMM, CNC, or any other translation device. 10,000 points/sec.

Model 25 Model 50

Accuracy +/-0.025mm +/-0.050mm

Resolution (Z) 0.003mm 0.003mm

Depth of field 40mm 80mm

Scan width 70mm 80mm

Stand-off 100mm 100mm

Size 260x110x65mm

Weight 2.2kg

IBEO Lasertechnik

Ingenieurburo fur

Elektronik + Optik

Fahrenkron 125

D 2000 Hamburg 71

tel: 040 645 87 - 01

fax: 040 645 87 - 101

2D and 3D laser scanners. 8frame/sec, 220 degree view, 4600 points/sec. Accuracy +/- 20mm (1 sigma) from 0.5 - 500? 24W power. System specs can be configured for variety of applications

Manufactures semiconductor laser diode packages and cylindrical lenses. Packages and small and rugged.

Odetics has made a number of smaller laser scanners. That is, smaller than their larger ERIM and Perceptron brethren. I have not heard any independent reviews of the product however.

Origin Instruments

854 Greenview Drive

Grand Praire, TX 750750-2438

tel: 214.606.8740

fax: 214.606.8741

The Dynasight sensor is a 3-D optical radar that provides real-time 3-D measurements of passive targets with sub-millimeter resolution. Automatic search and track is provided, eye-safe operation and no adjustments or alignment required. Original application was head tracking of computer users but end- effector tracking is also viable. Operatin range depends on target size 0.1-1.5m for 7mm target, 0.3-4m for 25mm target and 1 to 6m for 75mm targets. RS-232 interface. Accuracies 1mm cross range and 4mm down range, resolutions 0.1mm cross range and 0.4mm down range.

A number of labs have built light stripe devices using projected light LCD shutters and laser line projectors determine distance through geometry (as opposed to directly measuring distance through time-of-flight means) One common need is that of generating the laser line.

http://www.3ddigitalcorp.com/?48,32

Below is information on papers authored or co-authored by CamSys associates and published by various journals and conferences.

PapersComments

D. J. Lewison and D. Lee, "Determination of Forming Limits by Digital Image Processing Methods", Proceedings of International Body Engineering Conference and Exposition, Paper 01-3168, September 28-30, 1999, Detroit, Michigan, to be published in 1999.Different methods are proposed to determine the point of incipient necking under sheet forming conditions.

D. J. Lewison and D. Lee, "An Evaluation of Different Experimental Methods to Determine Forming Limits", Proceedings of the Fourth International Conference and Workshop on Numerical Simulation of 3D Sheet Forming Processes, September 13-17, 1999 at Besancon, France, to be published, 1999.A video camera is used to record the entire process of neck initiation and fracture under sheet forming conditions.

Tata, M. M., Oh, J. S., and Lee, D., "The Nature of Localized Deformation in 6111-T6 Aluminum Alloy and Polycarbonate", Integral Fastening Program Report Number IFP-97-08, Rensselaer Polytechnic Institute, Troy, NY; Journal of Materials Science, Vol. 33, pp. 2781-2794, 1998.The extent of localized deformation in deforming aluminum and polycarbonate samples is determined using CamSys software.

P. E. Smith and D. Lee, "Determination of Forming Limits for Aluminum Alloys", Proceedings of International Body Engineering Conference & Exposition (IBECā98), September 29-October 1, 1998, Detroit, MI, Society of Automotive Engineers (SAE), Automotive Body Materials, SAE Publication-331, Vol. 2, pp. 121-128, 1998.Two improved methods of determining the incipient necking point are described.

Sawyer, W. G., Blanchet, T., Knapp. K. N. II, and Lee, D., "Friction Modeling and Experimentation for Injection Molded Parts", Journal of Injection Molding Technology, December, 1997, Vol. 1, No. 4, pp. 224-228, 1997.Friction is always present in mechanical components and metal forming. One method to determine the friction coefficient under a sliding condition is described.

Manthey, D.W., E.M. Hitchcock, D.A. Prinn, and D. Lee, "Innovations in Video Acquisition and Processing Methods for Visual Databases", Proceedings of the 19th Annual Interservice/Industry Training Systems and Education Conference, December 1997, pp. 543-553.An article discussing a more efficient way to create models of real objects for use in simulators.

Sankaran, V., Lee, D., Hitchcock, E. M., Kadikis, A., and Park, B. J., "Automated Fiber Identification and Analysis System", Proceedings of the 78th World Conference of the Textile Institute, May, 1997, The Textile Institute, Manchester, England, Vol. II, pp. 325-345.This paper explains how a computer-aided method can be used to determine cashmere from wool fibers.

Prinn, D., Manthey, D. W., Hitchcock, E. M., and Lee, D., "Improved Methods to Reproduce 3-D Surfaces of Objects", Proceedings of the International BodyEngineering Conference (IBEC): Body Assembly and Manufacturing, September 30-October 2, 1997, Vol. 30, pp. 73-80.An article discussing a way to measure auto body panels using unstructured light.

Prinn, Douglas A., David W. Manthey, Edward M. Hitchcock, and Daeyong Lee, "SurfaceGen: A PC-Based 3-D Surface Reconstruction System," Proceedings Numérisation 3D - Human Modeling Conference, May 28-29, 1997.A technique for measuring surfaces using a patented target process and unstructured light.

Kim, H.J., and D. Lee, "Further Development of Experimental Methods to Verify Computer Simulations", Proceedings, NUMISHEET '96, Dearborn, MI, September 29 - October 3, 1996, Edited by J.K. Lee, G.L. Kinzel and R.H. Wagoner, Columbus, OH, pp. 316-323.

Manthey, David W., Rebecca M. Pearce, and Daeyong Lee, "The Need for Surface Strain Measurement," Metalforming, Vol. 30, No. 5 (May 1996), pp. 48-54.An article explaining how measuring the stretch in sheet metal helps fix forming problems.

Manthey, D. W., and D. Lee, "Recent Developments in a Vision-Based Surface Strain Measurement System," The Journal of The Minerals, Metals, & Materials Society (JOM); Vol. 47, No. 7 (July 1995), pp. 46-49.This paper is available online from JOM. It shows a truly portable system for measuring surface shape and strain.

Manthey, D. W., R. M. Pearce, and D. Lee, "Portable 3D Data Acquisition Technology for Computer Image Generation Visual Databases", Final Report for SBIR Phase I Contract No. N61339-94-C-0058, Naval Air Warfare Center Training Systems Division (NAWCTSD), Orlando, FL, February, 1995.A report on the feasibility of using video cameras, GPS (Global Positioning Satellites), and other equipment to construct flight simulator and shiphandling databases.

Manthey, David W., Keith N. Knapp II, and Daeyong Lee, "Calibration of a laser range-finding coordinate-measuring machine," Optical Engineering, Vol. 33, No. 10 (October 1994), pp. 3372-3380.A clever way to calibrate a laser-based 3D surface scanner, simplifying hardware setup.

Manthey, D. W., R. M. Bassette, and D. Lee, "Application of the Latest Technology in Surface Strain Analysis for Metal Stamping Problem Solving," Total Process Improvement: PMA Technical Symposium Proceedings 1994, Vol. 4, pp. 397-409.More on strain measurement.

Manthey, D. W., and J. P. Farhat, "Comparison Between Steel and Aluminum Strain Rate Effects," Proceedings of The PRESSTECH International Conference & Exposition, October 18-21, 1993, pp. 323-334.

-- also published as --

Manthey, David, and Joseph Farhat, "Comparing Steel and Aluminum Strain Rate Effects," The Fabricator, April, 1994, pp. 36-38.The speed at which metal is stretched affects how far it can be deformed before breaking.

Manthey, D. W., R. M. Bassette, and D. Lee, "Comparison of Different Surface Strain Measurement Techniques Used for Stamped Sheet Metal Parts," Proceedings of International Body Engineering Conference (IBEC) : Body Assembly & Manufacturing, September 21-23, 1993, pp. 106-111.Verification that computerized strain measurement is valid.

Kapij, M. I., D. W. Manthey, and D. Lee, "The Development of Knowledge Based Systems to Solve Metal Stamping Problems," Best Manufacturing Solutions: Proceedings of the PMA Technical Symposium 1993, Vol. 3, pp. 67-76.More on strain measurement.

M. I. Kapij and D. Lee, "Evaluation of Surface Strain Measurement Methods for Thermoformed Plastic and Stamped Metal Parts," Society of Plastics Engineers Annual National Technical Conference '92 Proceedings, 1992, pp. 1578-1581.

M. I. Kapij, J. Moleski, T. Ohwue, J. H. Vogel, and D. Lee, "Comparison of Different Surface Strain Measurement Methods Used for Deformed Sheet Metal Parts," Society of Automotive Engineers Automotive Stamping Applications and Analysis SP-897, 1992, pp. 73-85.

J. H. Vogel and D. Lee, "The Automated Measurement of Strains from Three-Dimensional Deformed Surfaces," Journal of Metals, Vol. 42, 1990, pp. 8-13.

J. H. Vogel and D. Lee, "An Automated Two-View Method For Determining Strain Distributions on Deformed Surfaces," Journal of Material Shaping Technology, Vol. 6, 1989.

http://www.orten.fr/

Low-cost scanners:

Price from USD 3000 and up to about USD 7000

More information about non contact theodelite style total stations

Non reflector based total stations

These total stations for surveying and other applications need no reflector and operates up to 1000m in distance with a few cm in accuracy. This accurate system can be set to scanning patterns and is motorized to scan automatically. The total station can generate wire models of terrain and add photos over the 3 D shapes. Speed is high and up to 3600 3D coordinates per hour can be calculated and measured.

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