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Dear Netters:
A few days ago I posted the request below. I would like to thank
you all for such quick and informative responses---especially over
a holiday weekend, (US & Canada). I would like to particularly thank
Dr. David Dean of Case Western Reserve University for making available
a copy of his in-press lit. review on the topic.
Thanks again to all.
-Bob
And while I have your divided attention:
re: The resent Russian yenta. As I have stated before, I am all in favour
of Flame-ing GROSS offenders of nettequete (send them a copy of the World
Almanac if it makes you feel better). I also think it's great to inform the
offender's POSTMASTER (omitting the Almanac of course). But, why perpetually
re-injure the List (and eat up bandwidth) by re-including the original post
in a List's broadcast mailing. If we've subscribe, we've seen. While I would
like to send out kudos to Mitchell Gil Maltenfort for finding the current
offender's true address, I was dismayed to find two instances of the post in
the latest issue of the (biomch-L) list (not to mention the three other
versions I encountered in other Lists' members' complaints.)
Just 2 cents... I now return you to my original intent...
Original post:
{snip}
>Some time ago I recall reading an ad for a laser based measurement/modeling
>device. The device operated by placing the object to be measured on a
>platform, a laser then scanned across the surface and reflectance(?) or
>phase shift(?) was used to obtain the measurements. In this way a model of
>the object could be obtained and exported to various software packages.
{snip}
REPLYS {trimmed}~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~
David Dean Ph.D.
Lewis L. Sadler and
Louis-Philippe Amiot ....................................
Each sent a copy of David Dean's extremely useful survey. I am including
the LEAST abbridged version here for those with a slightly different need.
It is long, but I believe well worth it.
+---------------------------------------------------------------------+
| David Dean, Ph.D., Assistant Professor |
| Departments of Anatomy, Orthodontics & Biomedical Engineering |
| Bolton-Brush Growth Study Center, 3080 Bolton Dental Bldg |
| Case Western Reserve University Voice: (216) 368-1975 |
| 10900 Euclid Avenue FAX: (216) 368-3204 |
| Cleveland, OH 44106-4905 USA E-mail: dean@lucifer.cwru.edu|
|WWW: http://www.cwru.edu/CWRU/Dept/Dent/orth/ortho/dean/deanpage.html|
+---------------------------------------------------------------------+
In Press (LA Marcus, ed.): Advances in Morphometrics. NYC:Plenum
3D Data Capture and Visualization
David Dean
Departments of Anatomy, Orthodontics, and Biomedical Engineering
Case Western Reserve University
10900 Euclid Avenue
Cleveland, OH 44106-4905 U.S.A.
E-mail: dean@lucifer.cwru.edu
Data Capture Devices I: Hand digitization
Electromagnetic Devices
1.1 DigiTracker ($3395)
Visual Circuits
3309 83rd Avenue North
Brooklyn Park, MN 55443
tel (612) 560-6205
fax (612) 659-6629
As of this writing the device has not yet been released. An OEM
version of the Ascension Flock of Birds, it is reported to be a
work-alike of the Polhemus 3DRAW. Like the Flock of Birds it's
accuracy rating is a magnitude lower, 0.1" RMS. It may have
greater utility for biometric applications than an unaltered
Flock of Birds device, which Visual Circuits retails for $2575,
because of its well-designed stylus. It is supplied with a
powerful digitizing software environment, BitBlitzer. A number of
mainstream Draw, Video, and CAD software export filters are
supplied with BitBlitzer.
1.2 Flock of Birds ($2695)
Ascension Technology Corp.
P.O. Box 527
Burlington, VT 05402
tel (802) 860-6440
fax (802) 860-6439
An early split-off from the Polhemus group. The same technology
has been adapted to tracking multiple electromagnetic 6D (xyz
coordinates and normals) sensors ("a flock") within the magnetic
field emitted by a single stationary source. Popular device for
biomechanical studies of joint movement. Translational accuracy
rated to 0.1" RMS. Above price is for single sensor device.
1.3 3DRAW ($6500)
Polhemus
One Hercules Drive, P.O. Box 560
Colchester, VT 05446
tel (800) 357-4777/(802) 655-3159
fax (801) 655-1439
This fourth generation device has been used by several
investigators to study non-human primate and human crania (see
Dean, this volume; Lele and Richtsmeier, 1992; Corner and
Richtsmeier, 1992; Richtsmeier and Walker, 1993; Vannier and
Conroy, 1989). Originally developed to be mounted on a fighter
pilot helmet to track head movements (Raab et al., 1979), this
application was soon obsoleted by laser-based sighting devices.
It consists of a platform under which a fixed 3 axis magnetic
source is emitted. A specimen can be fixed to the surface of this
platform. This object is digitized with the aid of a hand-held
stylus.
The stylus is equipped with a 3 axis magnetic sensor that
allows a small computer to determine the location of the tip in 3
space, including xyz normal information. Because it assumes the
magnetic field is constant, the work area should be kept
reasonably clear of ferrous objects. None should be within a
meter of the digitizing envelope, and other large iron objects
such as steam heated radiators and filing cabinets should be 2-3
meters away. Given a changing ferrous environment, the device
should be recalibrated (it comes with calibration software)
before each digitizing session. Unless the stylus is used very
carefully, the normal information is not very important as part
of the morphometric data collected. However, the viewpoint of the
data collection interface can be tied to the stylus. This allows
easy perusal of the data from various points of view, a crucial
error-checking step whenever potentially overlapping coordinates
are collected.
Their is firmware control of the stylus data report; it can
be set in point or continuous mode on the fly. Continuous mode is
very useful for tracing edge features (see Dean, this volume).
The accuracy of this device has been tested internally by
Polhemus using widely accepted methods (Krieg et al., 1992) and
has shown accuracy of 0.01" RMS (Root-Mean-Square), or 0.254 mm.
While this is more than a two-fold improvement over the original
(first generation) 3SPACE device, the generation of the device
that has commonly been used with large non-human primate and
human skull material, it is still below the acceptable range for
most dental studies.
The latest version of this device, the 3DRAW, is highly
portable. The 3DRAW table, stylus, and data handling device all
together weigh less than 12 pounds. There is a padded, hard-
shell, airline check-in carrying case available.
An interface was recently released that allows the data
collected by this device to be sent to the CADKEYS generic CAD
program. This flexible PC program can be readily tailored to most
biometric applications. It is included, gratis, with the device.
Another longstanding interface for Polhemus, Metrecom, Scientific
Accessories (see the latter two below) devices is marketed by
Mira Imaging (2257 South East, Suite 1A, Salt Lake City, UT
84106, tel. 801/466-4641, fax. 801/466-4699). This interface,
HyperspaceTM, is primarily aimed at producing a surface mesh of
solid objects. The NATO morphometrics workshop attendees tested
this software and found it difficult, but not impossible, to
adapt to morphometric applications such as single point or space
curve digitization.
Laser Light Stylus-based Digitizers
1.4 Flashpoint Model 3000i ($14,900)
Pixsys, Inc.
5680-B Central Avenue
Boulder, CO 80301
tel (303) 447-0248
fax (303) 447-3905
A device like this or the much more expensive Optotrak (section
1.4) is likely to be optimal for many morphometric studies. These
devices do not have the echo or humidity artefacts of acoustic
digitizers or the artefacts due to changing magnetic fields
common with electromagnetic digitizers. These devices are,
technologically, the newest, thus their high cost.
Both devices consist of one or more LEDs (Light Emitting Diodes)
or fiber optic light emitters. These light sources are detected
by an array of 3 light sensors mounted in a bracket so that they
are fixed in a non-collinear position. This fixed offset is used
to triangulate the position of the light source. The light source
can be attached to a stylus. Data can be collected in point or
continuous mode. There are device drivers for all the common CAD
programs.
The rated accuracy of the current model is 0.5 mm. Over the next
few years I expect to see rapid increases in the accuracy of this
device coinciding with price reductions. The entire device
weights 22.4 pounds and should be quite portable.
1.5 Optotrak ($57,500)
Northern Digital, Inc.
403 Albert Street
Waterloo, ON N2L 3V2, Canada
tel (800) 265-2741/(519) 884-5142
fax (519) 884-5142
This device has basically similar components and works in the
same fashion as the Pixsys. Its accuracy is rated at 0.1 mm in
the x-y plane, 0.15 mm in z, when the stylus is within 2.25m of
the sensors. Weighing approximately 90 pounds, not including a
computer to record and visualize data, it is not easily
transported.
Acoustic Stylus-based Digitizer
1.6 GP-12 ES ($3200)
Science Accessories Corporation
2 Research Drive, P.O. Box 825
Shelton, CT 06484
tel (203) 925-1661
fax (203) 929-9636
The stylus in this device produces a clicking sound. This sound
is differentially detected by three wall-mounted acoustic
sensors. With the three separate readings of the click, the
location of the source can be triangulated. The stylus should be
at least as flexible as that of the 3DRAW or DigiTracker (I have
not tried to use it), making complex concavities more reachable
by this probe than, for example, those used in fixed-base, servo-
mechanism digitizing arms (see next section). However this
maneuverability is not without problems. Convexities may,
however, prevent sound from reaching the acoustic sensors without
distortion. High humidity is also known to effect the quality of
the data. The manufacturer's customer's claim an accuracy of
0.01", 0.254 mm., in a cubic meter digitizing envelope. There is
a real-time driver that works with a large number of CAD programs
including: AutoCAD, Cadkey, Mastercam. Scientific Accessories is
also willing to develop a customized interface.
Rigid and Servo-mechanism Arms
1.7 Cyclone ($52,000)
Renishaw, Inc.
623 Cooper Court
Schaumburg, IL 60173
tel (708) 843-3666
fax (708) 843-1744
This device comes right out of the rapid prototyping industry. It
includes a computer terminal and digitizing base. This unjointed
arm digitizer sits in place, retreating in the Z direction as
protrusions on the object are passed under its probe on a
linearly moving platform. Successive cross sections are collected
in this manner to build up an isosurface of the object. It moves
slowly and gently enough during its slow traverse that there
should be little chance for damage of specimens (stiff casts
would be at less risk than friable originals). However, complex
convexities are ignored. A similar device, the Retroscan
($20,000) uses a drill bit to mill a model of a digitized object
from solid plastic blocks.
1.8 Diagraph 202 ($1472)
Seritex Inc.
450 Barell Avenue
Carlstadt, NJ 07072
tel (201) 939-4606
fax (201) 939-3468
The Diagraph, designed by Swiss manufacturer GPM, is used to
directly digitize objects (e.g., a bone) held rigidly in place.
One end of its rigid arm points at surface features while the
opposite end of the arm puts a pen on paper. The paper sits on a
horizontal plane of tracing (or graph) paper set at a particular
z-height. The Diagraph is useful for the collection of serial
sections for 3D reconstruction.
1.9 Faro Arm ($14,400)
Faro
125 Technology Park
Lake Mary, FL 32746
tel (800) 736-6063/(407) 333-9911
fax (407) 333-4181
Morphometricians have attempted to use digitizing arms for at
least the past 30 years. It has not been a successful in most
craniofacial applications because the objects of study have been
too topologically complex. Both of these devices have four
joints, giving them a great deal of flexibility. Even so it might
be difficult capturing some points in the orbits, temporal fossa,
posterior choanae, the palette and parts of the basicranium.
Tracing lines on bony tori or elsewhere on the skull is likely to
range between difficult and impossible. The accuracy of the
Bronze Series 6 is 0.012 inches, 0.3 mm, within a 6 foot
spherical diameter.
Faro manufactures a more expensive line of digitizing arms, the
Surgicom series. These are used in human surgical planning,
execution, and follow-up. A complete neurosurgical package,
including visualization software, has recently been approved for
use by the FDA is marketed by ISG Technologies (6509 Airport
Road, Mississauga, ON L4V 1S7, Canada, tel. 905/672-2100, fax.
905/672-2307). The digitizing arm is primarily used as a virtual-
reality tool in designing a surgical plan, digitizing landmarks
to set up a reference frame on the patient that matches that in
the surgical plan, and as a position tracker for surgical
instruments. Advances in the use of this and other technologies
for frameless stereotactic surgery (Zinreich et al., 1993;
Sandeman et al., 1992) will likely be furthered by the
incorporation of newer morphometric techniques.
1.10 Romer Model 2000 ($105,000)
Romer Supratech, Inc.
5145 Avenida Encinas
Carlsbad, CA 92008
tel (619) 438-7802
fax (619) 431-7940
This model is the smallest of a line of 4 arms with digitizing
envelopes of between 6.5' and 9.8' in diameter. These arms have
rotary joints making them more maneuverable than the Faro arm.
These devices are also designed to be portable. The Model 2000
weighs 17 pounds. The small base includes a table clamp and an
i/o processing unit with a serial port. It can thus be easily
adapted to use with a portable computer. The accuracy rating is
0.00125" RMS or 0.032 mm as tested by the NIST (National
Institute of Standards and Technology).
Data Capture Devices II: Remote Digitization
In this section we will not discuss multisurface, slice-based
approaches such as CT or MR-scanning. The two types of digitizers
discussed here, laser light and optical, are primarily used to
digitize one surface, the external surface. Optical systems
calibrate the X and Y values from the power of magnifcation and
the Z can be determined by the focus level.
Laser light digitization has a reasonable possibility of
providing data that can be used to construct highly accurate
surface representations of the original object, i.e., an
isosurface. Point resolution is a function of the width of the
light source beam. Scan accuracy is determined not only by beam
width, but also camera sensitivity, surface shininess, and the
system's ability to screen out artefactual reflections. In most
cases users will benefit from importing the data into a
visualization package and digitizing the required 3D landmarks
and/or lines there.
Multiple Point Source Laser Light Scanning
2.1 Digibot II ($49,000)
Digibotics
2800 Longhorn Boulevard, Suite 102
Austin, TX 78758
tel (512) 832-6544
fax (512) 832-1163
The Digibot II uses a four-axis laser light scanner which checks
sequential points on the surface. This allows some correction for
artifacts. The four axis array also obviates focusing problems
that other systems may have.
2.2 Hirez Model 3030 ($46,400)
Cyberware Laboratory, Inc.
2110 Del Monte Avenue
Monteray, CA 93940
tel (408) 675-1440
fax (408) 675-1494
This device consists of a moving source of laser light that is
detected by a video camera at a known angle of offset. Like all
of this first group of laser light digitizers, the Cyberware
scanners use multiple laser light sources. This allows the device
to cover more surface area in less time. An entire human face can
be scanned in less than 10 seconds. This is regularly done for a
number of different morphometric applications (Cutting et al.,
1988; Wohlers, 1992). However, because of the diffuse light
source artifacts, especially of complex surfaces, tend to corrupt
the data. The recommendation of scanning a surface from different
orientations and co-registering the scans can lead to compounded
artifacts. Assuming no artifacts, landmark accuracy is
approximately 0.02 inches, 0.5 mm.
One version of this device also captures color information from
the surface which can be used to render a more realistic
isosurface. One version of this device weighs less than 50
pounds.
2.3 Hyscan ($n.a.)
Hymarc Ltd. (Ottawa, Canada)
G.A. Davis Associates, Inc.
P.O. Box 36240
19959 Vernier Avenue, Suite 2B
Harper Woods, MI 48225
tel (313) 886-4101
fax (313) 886-1107
A multiple point laser device with very high accuracy, +/-
0.001", and relatively slow data acquisition on large objects.
The Hyscan accumulates data at the rate of 10,000 points per
second.
2.4 Optica ($50,000)
3D Technology, Inc.
12 Cambridge Drive
Trumbull, CT 06611-4764
tel (203) 371-8500
fax (203) 371-6300
Using a technology developed in England, but reminiscent of the
Cyberware scanner, this vendor claims 0.0008", 0.02mm accuracy
(Vinarub and Kapoor, 1992).
2.5 Rapid Profile Sensor ($40,000)
Laser Design, Inc.
9401 James Avenue South, Suite 162
Minneapolis, MN 55431
tel (612) 884-9648
fax (612) 884-9653
This device is scheduled to be available shortly. The developers
of this device claim digitizing speeds comparable with the
Cyberware scanner with greatly improved accuracy. A whole body
version of this scanner is scheduled to ship at $145,000.
Single Point Source Laser Light Scanning
2.6 CyberScan ($30,000)
CyberOptics Corp.
2505 Kennedy Street NE
Minneapolis, MN 55413
tel (612) 331-5702
fax (612) 331-3826
Sharnoa Corp.
45901 5 Mile Road
Plymouth, MI 48170
tel (313) 925-1661
fax (313) 454-7198
This single source laser sits at a pre-set "stand-off" distance
from the surface to be digitized. It has a high accuracy, 0.001"
(0.0254 mm.), but can fail on surfaces with convexities that
block the path of the scan head. These devices would take several
hours to scan an entire human face. Sharnoa uses the same scan
head and provides integration with CNC machine milling tools for
rapid prototyping.
2.7 Laser Triangulation Probe LTP 60 ($28,700 scan head, $200,000 complete
device)
Carl Zeiss, Inc.
One Zeiss Drive
Thomwood, NY 10594
tel (914) 747-1800/681-7849
fax (914) 681-7454
Perhaps the most accurate digitizing head on the market, the
accuracy of this device is rated at 2.0 microns, 0.0008". The
probe collects 100 coordinates per second when positioned 115 mm
away from the object of interest. An observation beam tracks the
surface to maintain this standoff distance. The device is
supplied with a visualization environment, Holos-UX, which allows
the user to define and locate coordinates of landmarks and
surface patches on the digitized object.
============== Begin part 2 ==========================
2.8 Lasar and TriCam ($50,000 and $11,000, respectively)
Perceptron, Inc.
23855 Research Drive
Farmington Hills, MI 48335
tel (810) 478-7710
fax (810) 478-7059
Single laser point devices that use radar focusing. The
digitizing envelope of the Lasar is commonly a cube of 2-3 meters
with an accuracy of 0.1 mm. The TriCam is more accurate in its
smaller digitizing envelope. The TriCam weighs a portable 20
pounds.
2.9 MessTechnik OMS 400/250 ($40,000 scan head, $193,000 complete device)
Wegu Inc.
Building II
Orchard Ridge Corporate Park
Fields Lane
Brewster, NY 10509
tel (914) 277-5753
fax (914) 277-5830
A close second to the Zeiss device, the accuracy of this device
is rated to 2.2 microns, 0.000098". The rate of data capture is
5000 points per second. The full device uses a video source and
tactile probe to insure it is following the surface carefully.
The standoff distance from the object is a function of lens
magnification, from 15 to 75 mm.
2.10 OP5 ($30,000)
Renishaw, Inc.
623 Cooper Court
Schaumburg, IL 60173
tel (708) 843-3666
fax (708) 843-1744
This laser scanning probe has a rated accuracy of 0.0001". The
probe rotates about a single axis up to 120 degrees, but must be
within 14mm of the scanned surface. It collects 200 points per
second.
2.11 Surveyor ($70,000)
Laser Design, Inc.
9401 James Avenue South, Suite 162
Minneapolis, MN 55431
tel (612) 884-9648
fax (612) 884-9653
The developers of this device claim digitizing speeds comparable
with the Cyberware scanner and accuracy improvements of at least
a magnitude, i.e., 0.05 mm. This device would be optimal for
studies requiring "dental" precision levels and rapid data
acquistion.
Moire
2.12 CadEyes ($80,000)
Medar Company
38700 Grand River
Farmington Hills, MI 48335
tel (810) 477-3900
fax (810) 477-8897
As with all moire photography, light is passed through a screen
grating. The resulting topographic pattern can be used for 3D
digitization. Medar claims 0.0001", 0.00254 mm, accuracy in the Z
dimension with this device.
2.13 Mini-Moire ($39,000)
Electro-Optical Information Systems
528 Euclid Street
Santa Monica, CA 90402
tel (310) 451-8566
fax (310) 393-2453
Electro-Optical Information Systems device works on the same
principle as the CadEyes scanner. It claims about the same
accuracy level, however it is much more portable.
Convergent Photogrammetry
2.14 Photomodeler ($895)
(Windows)
Eos Systems, Inc.
2040 West 12th Avenue
Vancouver, BC V6J 2G2 CANADA
tel (604) 732-6658
fax (604) 732-4716
This software uses standard photographs or 35mm slides to produce
a precise 3D model (AutoCAD 3D *.DXF file) of any object. The
documentation shows you how to calibrate your camera's focal
length, image aspect ratio, image position, and lens distortion
for this application. There are a few more planning few steps to
take so that all views will be complementary.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
From: j-patton@nwu.edu (Jim Patton)
Try BROWN & SHARPE in Providence, RI. They make laser scan devices.
JIM PATTON, Northwestern U. (j-patton@nwu.edu)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
Sender: grerfx00@ccmail.ca.boeing.com
I think what you're looking for is a company called
Cyberware. Here is their address:
2110 Del Monte Avenue
Monterey, CA 93949-3797
phone: 408-657-1450
fax: 408-657-1494
Good luck.
Rush Green
grerfx00@ccmail.iasl.ca.boeing.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
Sender: d.vashishth@qmw.ac.uk
Try contacting Zygo Corporation, Laurel Brook road, Middlefield, Conn. USA.
They make laser telemeter system which measures dimensions of object and is
based on the phase-shift principle.
Deepak Vashishth
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
Sender: rkippenc@vax7.curtin.edu.au
Curtin University of Technology have access to a 3-D scanner. It is Sunday,
so I do not have access to any other information but will furnish you with
more details if you think it is what you are after. Jill Smith is the
computer artist and Phil Dench the software engineer. The system was used
on Jarassic Park, although Phil is/has developed software
(Cysurf-Cyberware)). The scanner can laser scan a bust in 15 seconds and
the image immediately appears on the screen, consisting of 250,000
geometrical points. The image can be rotated, have the colour stripped out
or have portions selected for cutting pasting into other programs. Jill
uses it for milling heads and other objects.
Cameron Kippen
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
Sender: dwyer@conn.me.queensu.ca
A company you might want to call would be Hymarc in Ottawa, Ontario. We
recently had them scan a series of total knee femoral components and we
have had fantastic results with this data. They are a relatively new
company that has made major advances in this area. Their system seems to
be able to scan almost any shape from the joystick of a fighter jet to
the panels of cars. We imported our data and were able to create 3D
solid models. Good luck!
Kimberly A. Dwyer, M.S.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~
Sender: ukorde01@ype.gmpt.gmeds.com
Such a device is marketed by a firm called
LASER DESIGN Inc. from Minneapolis, Minnesota.
I know of it being used for reverse engineering
products and also for measurement/inpsection
applications.
-Uday
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
Sender: cgdanias.pg@swansea.ac.uk
The following company in the U.K. have laser insturments which
measure distances. I am using one of their lasers to measure
small displacements on teeth and I reckon that they probably have
insturments which will do what you require.
The company is,
GRAHAM & WHITE INSTURMENTS LTD.
135 Hatfield Road
St.Albans
Hertfordshire
AL1 4LZ
ENGLAND
Tel. (code to UK) 01727 59373
Fax. (code to UK) 01727 44272
Christo
END REPLYS~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
============== End part 2 ============================
A few days ago I posted the request below. I would like to thank
you all for such quick and informative responses---especially over
a holiday weekend, (US & Canada). I would like to particularly thank
Dr. David Dean of Case Western Reserve University for making available
a copy of his in-press lit. review on the topic.
Thanks again to all.
-Bob
And while I have your divided attention:
re: The resent Russian yenta. As I have stated before, I am all in favour
of Flame-ing GROSS offenders of nettequete (send them a copy of the World
Almanac if it makes you feel better). I also think it's great to inform the
offender's POSTMASTER (omitting the Almanac of course). But, why perpetually
re-injure the List (and eat up bandwidth) by re-including the original post
in a List's broadcast mailing. If we've subscribe, we've seen. While I would
like to send out kudos to Mitchell Gil Maltenfort for finding the current
offender's true address, I was dismayed to find two instances of the post in
the latest issue of the (biomch-L) list (not to mention the three other
versions I encountered in other Lists' members' complaints.)
Just 2 cents... I now return you to my original intent...
Original post:
{snip}
>Some time ago I recall reading an ad for a laser based measurement/modeling
>device. The device operated by placing the object to be measured on a
>platform, a laser then scanned across the surface and reflectance(?) or
>phase shift(?) was used to obtain the measurements. In this way a model of
>the object could be obtained and exported to various software packages.
{snip}
REPLYS {trimmed}~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~
David Dean Ph.D.
Lewis L. Sadler and
Louis-Philippe Amiot ....................................
Each sent a copy of David Dean's extremely useful survey. I am including
the LEAST abbridged version here for those with a slightly different need.
It is long, but I believe well worth it.
+---------------------------------------------------------------------+
| David Dean, Ph.D., Assistant Professor |
| Departments of Anatomy, Orthodontics & Biomedical Engineering |
| Bolton-Brush Growth Study Center, 3080 Bolton Dental Bldg |
| Case Western Reserve University Voice: (216) 368-1975 |
| 10900 Euclid Avenue FAX: (216) 368-3204 |
| Cleveland, OH 44106-4905 USA E-mail: dean@lucifer.cwru.edu|
|WWW: http://www.cwru.edu/CWRU/Dept/Dent/orth/ortho/dean/deanpage.html|
+---------------------------------------------------------------------+
In Press (LA Marcus, ed.): Advances in Morphometrics. NYC:Plenum
3D Data Capture and Visualization
David Dean
Departments of Anatomy, Orthodontics, and Biomedical Engineering
Case Western Reserve University
10900 Euclid Avenue
Cleveland, OH 44106-4905 U.S.A.
E-mail: dean@lucifer.cwru.edu
Data Capture Devices I: Hand digitization
Electromagnetic Devices
1.1 DigiTracker ($3395)
Visual Circuits
3309 83rd Avenue North
Brooklyn Park, MN 55443
tel (612) 560-6205
fax (612) 659-6629
As of this writing the device has not yet been released. An OEM
version of the Ascension Flock of Birds, it is reported to be a
work-alike of the Polhemus 3DRAW. Like the Flock of Birds it's
accuracy rating is a magnitude lower, 0.1" RMS. It may have
greater utility for biometric applications than an unaltered
Flock of Birds device, which Visual Circuits retails for $2575,
because of its well-designed stylus. It is supplied with a
powerful digitizing software environment, BitBlitzer. A number of
mainstream Draw, Video, and CAD software export filters are
supplied with BitBlitzer.
1.2 Flock of Birds ($2695)
Ascension Technology Corp.
P.O. Box 527
Burlington, VT 05402
tel (802) 860-6440
fax (802) 860-6439
An early split-off from the Polhemus group. The same technology
has been adapted to tracking multiple electromagnetic 6D (xyz
coordinates and normals) sensors ("a flock") within the magnetic
field emitted by a single stationary source. Popular device for
biomechanical studies of joint movement. Translational accuracy
rated to 0.1" RMS. Above price is for single sensor device.
1.3 3DRAW ($6500)
Polhemus
One Hercules Drive, P.O. Box 560
Colchester, VT 05446
tel (800) 357-4777/(802) 655-3159
fax (801) 655-1439
This fourth generation device has been used by several
investigators to study non-human primate and human crania (see
Dean, this volume; Lele and Richtsmeier, 1992; Corner and
Richtsmeier, 1992; Richtsmeier and Walker, 1993; Vannier and
Conroy, 1989). Originally developed to be mounted on a fighter
pilot helmet to track head movements (Raab et al., 1979), this
application was soon obsoleted by laser-based sighting devices.
It consists of a platform under which a fixed 3 axis magnetic
source is emitted. A specimen can be fixed to the surface of this
platform. This object is digitized with the aid of a hand-held
stylus.
The stylus is equipped with a 3 axis magnetic sensor that
allows a small computer to determine the location of the tip in 3
space, including xyz normal information. Because it assumes the
magnetic field is constant, the work area should be kept
reasonably clear of ferrous objects. None should be within a
meter of the digitizing envelope, and other large iron objects
such as steam heated radiators and filing cabinets should be 2-3
meters away. Given a changing ferrous environment, the device
should be recalibrated (it comes with calibration software)
before each digitizing session. Unless the stylus is used very
carefully, the normal information is not very important as part
of the morphometric data collected. However, the viewpoint of the
data collection interface can be tied to the stylus. This allows
easy perusal of the data from various points of view, a crucial
error-checking step whenever potentially overlapping coordinates
are collected.
Their is firmware control of the stylus data report; it can
be set in point or continuous mode on the fly. Continuous mode is
very useful for tracing edge features (see Dean, this volume).
The accuracy of this device has been tested internally by
Polhemus using widely accepted methods (Krieg et al., 1992) and
has shown accuracy of 0.01" RMS (Root-Mean-Square), or 0.254 mm.
While this is more than a two-fold improvement over the original
(first generation) 3SPACE device, the generation of the device
that has commonly been used with large non-human primate and
human skull material, it is still below the acceptable range for
most dental studies.
The latest version of this device, the 3DRAW, is highly
portable. The 3DRAW table, stylus, and data handling device all
together weigh less than 12 pounds. There is a padded, hard-
shell, airline check-in carrying case available.
An interface was recently released that allows the data
collected by this device to be sent to the CADKEYS generic CAD
program. This flexible PC program can be readily tailored to most
biometric applications. It is included, gratis, with the device.
Another longstanding interface for Polhemus, Metrecom, Scientific
Accessories (see the latter two below) devices is marketed by
Mira Imaging (2257 South East, Suite 1A, Salt Lake City, UT
84106, tel. 801/466-4641, fax. 801/466-4699). This interface,
HyperspaceTM, is primarily aimed at producing a surface mesh of
solid objects. The NATO morphometrics workshop attendees tested
this software and found it difficult, but not impossible, to
adapt to morphometric applications such as single point or space
curve digitization.
Laser Light Stylus-based Digitizers
1.4 Flashpoint Model 3000i ($14,900)
Pixsys, Inc.
5680-B Central Avenue
Boulder, CO 80301
tel (303) 447-0248
fax (303) 447-3905
A device like this or the much more expensive Optotrak (section
1.4) is likely to be optimal for many morphometric studies. These
devices do not have the echo or humidity artefacts of acoustic
digitizers or the artefacts due to changing magnetic fields
common with electromagnetic digitizers. These devices are,
technologically, the newest, thus their high cost.
Both devices consist of one or more LEDs (Light Emitting Diodes)
or fiber optic light emitters. These light sources are detected
by an array of 3 light sensors mounted in a bracket so that they
are fixed in a non-collinear position. This fixed offset is used
to triangulate the position of the light source. The light source
can be attached to a stylus. Data can be collected in point or
continuous mode. There are device drivers for all the common CAD
programs.
The rated accuracy of the current model is 0.5 mm. Over the next
few years I expect to see rapid increases in the accuracy of this
device coinciding with price reductions. The entire device
weights 22.4 pounds and should be quite portable.
1.5 Optotrak ($57,500)
Northern Digital, Inc.
403 Albert Street
Waterloo, ON N2L 3V2, Canada
tel (800) 265-2741/(519) 884-5142
fax (519) 884-5142
This device has basically similar components and works in the
same fashion as the Pixsys. Its accuracy is rated at 0.1 mm in
the x-y plane, 0.15 mm in z, when the stylus is within 2.25m of
the sensors. Weighing approximately 90 pounds, not including a
computer to record and visualize data, it is not easily
transported.
Acoustic Stylus-based Digitizer
1.6 GP-12 ES ($3200)
Science Accessories Corporation
2 Research Drive, P.O. Box 825
Shelton, CT 06484
tel (203) 925-1661
fax (203) 929-9636
The stylus in this device produces a clicking sound. This sound
is differentially detected by three wall-mounted acoustic
sensors. With the three separate readings of the click, the
location of the source can be triangulated. The stylus should be
at least as flexible as that of the 3DRAW or DigiTracker (I have
not tried to use it), making complex concavities more reachable
by this probe than, for example, those used in fixed-base, servo-
mechanism digitizing arms (see next section). However this
maneuverability is not without problems. Convexities may,
however, prevent sound from reaching the acoustic sensors without
distortion. High humidity is also known to effect the quality of
the data. The manufacturer's customer's claim an accuracy of
0.01", 0.254 mm., in a cubic meter digitizing envelope. There is
a real-time driver that works with a large number of CAD programs
including: AutoCAD, Cadkey, Mastercam. Scientific Accessories is
also willing to develop a customized interface.
Rigid and Servo-mechanism Arms
1.7 Cyclone ($52,000)
Renishaw, Inc.
623 Cooper Court
Schaumburg, IL 60173
tel (708) 843-3666
fax (708) 843-1744
This device comes right out of the rapid prototyping industry. It
includes a computer terminal and digitizing base. This unjointed
arm digitizer sits in place, retreating in the Z direction as
protrusions on the object are passed under its probe on a
linearly moving platform. Successive cross sections are collected
in this manner to build up an isosurface of the object. It moves
slowly and gently enough during its slow traverse that there
should be little chance for damage of specimens (stiff casts
would be at less risk than friable originals). However, complex
convexities are ignored. A similar device, the Retroscan
($20,000) uses a drill bit to mill a model of a digitized object
from solid plastic blocks.
1.8 Diagraph 202 ($1472)
Seritex Inc.
450 Barell Avenue
Carlstadt, NJ 07072
tel (201) 939-4606
fax (201) 939-3468
The Diagraph, designed by Swiss manufacturer GPM, is used to
directly digitize objects (e.g., a bone) held rigidly in place.
One end of its rigid arm points at surface features while the
opposite end of the arm puts a pen on paper. The paper sits on a
horizontal plane of tracing (or graph) paper set at a particular
z-height. The Diagraph is useful for the collection of serial
sections for 3D reconstruction.
1.9 Faro Arm ($14,400)
Faro
125 Technology Park
Lake Mary, FL 32746
tel (800) 736-6063/(407) 333-9911
fax (407) 333-4181
Morphometricians have attempted to use digitizing arms for at
least the past 30 years. It has not been a successful in most
craniofacial applications because the objects of study have been
too topologically complex. Both of these devices have four
joints, giving them a great deal of flexibility. Even so it might
be difficult capturing some points in the orbits, temporal fossa,
posterior choanae, the palette and parts of the basicranium.
Tracing lines on bony tori or elsewhere on the skull is likely to
range between difficult and impossible. The accuracy of the
Bronze Series 6 is 0.012 inches, 0.3 mm, within a 6 foot
spherical diameter.
Faro manufactures a more expensive line of digitizing arms, the
Surgicom series. These are used in human surgical planning,
execution, and follow-up. A complete neurosurgical package,
including visualization software, has recently been approved for
use by the FDA is marketed by ISG Technologies (6509 Airport
Road, Mississauga, ON L4V 1S7, Canada, tel. 905/672-2100, fax.
905/672-2307). The digitizing arm is primarily used as a virtual-
reality tool in designing a surgical plan, digitizing landmarks
to set up a reference frame on the patient that matches that in
the surgical plan, and as a position tracker for surgical
instruments. Advances in the use of this and other technologies
for frameless stereotactic surgery (Zinreich et al., 1993;
Sandeman et al., 1992) will likely be furthered by the
incorporation of newer morphometric techniques.
1.10 Romer Model 2000 ($105,000)
Romer Supratech, Inc.
5145 Avenida Encinas
Carlsbad, CA 92008
tel (619) 438-7802
fax (619) 431-7940
This model is the smallest of a line of 4 arms with digitizing
envelopes of between 6.5' and 9.8' in diameter. These arms have
rotary joints making them more maneuverable than the Faro arm.
These devices are also designed to be portable. The Model 2000
weighs 17 pounds. The small base includes a table clamp and an
i/o processing unit with a serial port. It can thus be easily
adapted to use with a portable computer. The accuracy rating is
0.00125" RMS or 0.032 mm as tested by the NIST (National
Institute of Standards and Technology).
Data Capture Devices II: Remote Digitization
In this section we will not discuss multisurface, slice-based
approaches such as CT or MR-scanning. The two types of digitizers
discussed here, laser light and optical, are primarily used to
digitize one surface, the external surface. Optical systems
calibrate the X and Y values from the power of magnifcation and
the Z can be determined by the focus level.
Laser light digitization has a reasonable possibility of
providing data that can be used to construct highly accurate
surface representations of the original object, i.e., an
isosurface. Point resolution is a function of the width of the
light source beam. Scan accuracy is determined not only by beam
width, but also camera sensitivity, surface shininess, and the
system's ability to screen out artefactual reflections. In most
cases users will benefit from importing the data into a
visualization package and digitizing the required 3D landmarks
and/or lines there.
Multiple Point Source Laser Light Scanning
2.1 Digibot II ($49,000)
Digibotics
2800 Longhorn Boulevard, Suite 102
Austin, TX 78758
tel (512) 832-6544
fax (512) 832-1163
The Digibot II uses a four-axis laser light scanner which checks
sequential points on the surface. This allows some correction for
artifacts. The four axis array also obviates focusing problems
that other systems may have.
2.2 Hirez Model 3030 ($46,400)
Cyberware Laboratory, Inc.
2110 Del Monte Avenue
Monteray, CA 93940
tel (408) 675-1440
fax (408) 675-1494
This device consists of a moving source of laser light that is
detected by a video camera at a known angle of offset. Like all
of this first group of laser light digitizers, the Cyberware
scanners use multiple laser light sources. This allows the device
to cover more surface area in less time. An entire human face can
be scanned in less than 10 seconds. This is regularly done for a
number of different morphometric applications (Cutting et al.,
1988; Wohlers, 1992). However, because of the diffuse light
source artifacts, especially of complex surfaces, tend to corrupt
the data. The recommendation of scanning a surface from different
orientations and co-registering the scans can lead to compounded
artifacts. Assuming no artifacts, landmark accuracy is
approximately 0.02 inches, 0.5 mm.
One version of this device also captures color information from
the surface which can be used to render a more realistic
isosurface. One version of this device weighs less than 50
pounds.
2.3 Hyscan ($n.a.)
Hymarc Ltd. (Ottawa, Canada)
G.A. Davis Associates, Inc.
P.O. Box 36240
19959 Vernier Avenue, Suite 2B
Harper Woods, MI 48225
tel (313) 886-4101
fax (313) 886-1107
A multiple point laser device with very high accuracy, +/-
0.001", and relatively slow data acquisition on large objects.
The Hyscan accumulates data at the rate of 10,000 points per
second.
2.4 Optica ($50,000)
3D Technology, Inc.
12 Cambridge Drive
Trumbull, CT 06611-4764
tel (203) 371-8500
fax (203) 371-6300
Using a technology developed in England, but reminiscent of the
Cyberware scanner, this vendor claims 0.0008", 0.02mm accuracy
(Vinarub and Kapoor, 1992).
2.5 Rapid Profile Sensor ($40,000)
Laser Design, Inc.
9401 James Avenue South, Suite 162
Minneapolis, MN 55431
tel (612) 884-9648
fax (612) 884-9653
This device is scheduled to be available shortly. The developers
of this device claim digitizing speeds comparable with the
Cyberware scanner with greatly improved accuracy. A whole body
version of this scanner is scheduled to ship at $145,000.
Single Point Source Laser Light Scanning
2.6 CyberScan ($30,000)
CyberOptics Corp.
2505 Kennedy Street NE
Minneapolis, MN 55413
tel (612) 331-5702
fax (612) 331-3826
Sharnoa Corp.
45901 5 Mile Road
Plymouth, MI 48170
tel (313) 925-1661
fax (313) 454-7198
This single source laser sits at a pre-set "stand-off" distance
from the surface to be digitized. It has a high accuracy, 0.001"
(0.0254 mm.), but can fail on surfaces with convexities that
block the path of the scan head. These devices would take several
hours to scan an entire human face. Sharnoa uses the same scan
head and provides integration with CNC machine milling tools for
rapid prototyping.
2.7 Laser Triangulation Probe LTP 60 ($28,700 scan head, $200,000 complete
device)
Carl Zeiss, Inc.
One Zeiss Drive
Thomwood, NY 10594
tel (914) 747-1800/681-7849
fax (914) 681-7454
Perhaps the most accurate digitizing head on the market, the
accuracy of this device is rated at 2.0 microns, 0.0008". The
probe collects 100 coordinates per second when positioned 115 mm
away from the object of interest. An observation beam tracks the
surface to maintain this standoff distance. The device is
supplied with a visualization environment, Holos-UX, which allows
the user to define and locate coordinates of landmarks and
surface patches on the digitized object.
============== Begin part 2 ==========================
2.8 Lasar and TriCam ($50,000 and $11,000, respectively)
Perceptron, Inc.
23855 Research Drive
Farmington Hills, MI 48335
tel (810) 478-7710
fax (810) 478-7059
Single laser point devices that use radar focusing. The
digitizing envelope of the Lasar is commonly a cube of 2-3 meters
with an accuracy of 0.1 mm. The TriCam is more accurate in its
smaller digitizing envelope. The TriCam weighs a portable 20
pounds.
2.9 MessTechnik OMS 400/250 ($40,000 scan head, $193,000 complete device)
Wegu Inc.
Building II
Orchard Ridge Corporate Park
Fields Lane
Brewster, NY 10509
tel (914) 277-5753
fax (914) 277-5830
A close second to the Zeiss device, the accuracy of this device
is rated to 2.2 microns, 0.000098". The rate of data capture is
5000 points per second. The full device uses a video source and
tactile probe to insure it is following the surface carefully.
The standoff distance from the object is a function of lens
magnification, from 15 to 75 mm.
2.10 OP5 ($30,000)
Renishaw, Inc.
623 Cooper Court
Schaumburg, IL 60173
tel (708) 843-3666
fax (708) 843-1744
This laser scanning probe has a rated accuracy of 0.0001". The
probe rotates about a single axis up to 120 degrees, but must be
within 14mm of the scanned surface. It collects 200 points per
second.
2.11 Surveyor ($70,000)
Laser Design, Inc.
9401 James Avenue South, Suite 162
Minneapolis, MN 55431
tel (612) 884-9648
fax (612) 884-9653
The developers of this device claim digitizing speeds comparable
with the Cyberware scanner and accuracy improvements of at least
a magnitude, i.e., 0.05 mm. This device would be optimal for
studies requiring "dental" precision levels and rapid data
acquistion.
Moire
2.12 CadEyes ($80,000)
Medar Company
38700 Grand River
Farmington Hills, MI 48335
tel (810) 477-3900
fax (810) 477-8897
As with all moire photography, light is passed through a screen
grating. The resulting topographic pattern can be used for 3D
digitization. Medar claims 0.0001", 0.00254 mm, accuracy in the Z
dimension with this device.
2.13 Mini-Moire ($39,000)
Electro-Optical Information Systems
528 Euclid Street
Santa Monica, CA 90402
tel (310) 451-8566
fax (310) 393-2453
Electro-Optical Information Systems device works on the same
principle as the CadEyes scanner. It claims about the same
accuracy level, however it is much more portable.
Convergent Photogrammetry
2.14 Photomodeler ($895)
(Windows)
Eos Systems, Inc.
2040 West 12th Avenue
Vancouver, BC V6J 2G2 CANADA
tel (604) 732-6658
fax (604) 732-4716
This software uses standard photographs or 35mm slides to produce
a precise 3D model (AutoCAD 3D *.DXF file) of any object. The
documentation shows you how to calibrate your camera's focal
length, image aspect ratio, image position, and lens distortion
for this application. There are a few more planning few steps to
take so that all views will be complementary.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
From: j-patton@nwu.edu (Jim Patton)
Try BROWN & SHARPE in Providence, RI. They make laser scan devices.
JIM PATTON, Northwestern U. (j-patton@nwu.edu)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
Sender: grerfx00@ccmail.ca.boeing.com
I think what you're looking for is a company called
Cyberware. Here is their address:
2110 Del Monte Avenue
Monterey, CA 93949-3797
phone: 408-657-1450
fax: 408-657-1494
Good luck.
Rush Green
grerfx00@ccmail.iasl.ca.boeing.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
Sender: d.vashishth@qmw.ac.uk
Try contacting Zygo Corporation, Laurel Brook road, Middlefield, Conn. USA.
They make laser telemeter system which measures dimensions of object and is
based on the phase-shift principle.
Deepak Vashishth
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
Sender: rkippenc@vax7.curtin.edu.au
Curtin University of Technology have access to a 3-D scanner. It is Sunday,
so I do not have access to any other information but will furnish you with
more details if you think it is what you are after. Jill Smith is the
computer artist and Phil Dench the software engineer. The system was used
on Jarassic Park, although Phil is/has developed software
(Cysurf-Cyberware)). The scanner can laser scan a bust in 15 seconds and
the image immediately appears on the screen, consisting of 250,000
geometrical points. The image can be rotated, have the colour stripped out
or have portions selected for cutting pasting into other programs. Jill
uses it for milling heads and other objects.
Cameron Kippen
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
Sender: dwyer@conn.me.queensu.ca
A company you might want to call would be Hymarc in Ottawa, Ontario. We
recently had them scan a series of total knee femoral components and we
have had fantastic results with this data. They are a relatively new
company that has made major advances in this area. Their system seems to
be able to scan almost any shape from the joystick of a fighter jet to
the panels of cars. We imported our data and were able to create 3D
solid models. Good luck!
Kimberly A. Dwyer, M.S.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~
Sender: ukorde01@ype.gmpt.gmeds.com
Such a device is marketed by a firm called
LASER DESIGN Inc. from Minneapolis, Minnesota.
I know of it being used for reverse engineering
products and also for measurement/inpsection
applications.
-Uday
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
Sender: cgdanias.pg@swansea.ac.uk
The following company in the U.K. have laser insturments which
measure distances. I am using one of their lasers to measure
small displacements on teeth and I reckon that they probably have
insturments which will do what you require.
The company is,
GRAHAM & WHITE INSTURMENTS LTD.
135 Hatfield Road
St.Albans
Hertfordshire
AL1 4LZ
ENGLAND
Tel. (code to UK) 01727 59373
Fax. (code to UK) 01727 44272
Christo
END REPLYS~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~
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