![[Theory of Operation]](images/theory.gif) |
| Theory of Operation |
![[Laser Tube]](images/laserTube.gif)
![[Camera & CCD]](images/cameraCCD.gif)
The Cyberware 3D Scanners are designed to scan a wide variety of objects
in many configurations. The following sections describe how the scanners work
and how they are controlled.
Theory of Operation
The scanner operates on the principle that light in a straight line, reflected off an object, can be viewed at a different angle to reveal a profile of the surface. The greater the angle between the light source and the viewing point, the more pronounced the description of the shape; however, the risk of a given surface being in shadow also increases. The scanner uses a plane of laser light which can be distinguished from most ambient light, and has two viewing points positioned at equal angles on both sides of the light source. A beam splitter (one-way mirror) is used to overlay the two images, so that if one side is shadowed, the other will normally contain the data. A system of mirrors inside the scanner enables the optics to be contained in a smaller space than would otherwise be necessary.
| |||
| Blue Line | Incoming Laser Line | ||
| Red Line | Outgoing Laser Line | ||
| Laser Tube | ||
| Camera Lens and CCD | ||
At each point in the course of a scan, a series of data samples (typically 512) are taken vertically along the reflection of the line, and stored as the "range" of that point from the plane of reference. As the object moves past the scanner, repeated sets of these data samples (normally between 200 and 1000) are made and sent to the host computer to be stored as a grid of range values. If, at a given point, the scanner receives no reflection (or too weak to detect) or the surface is out of the allowable range, the system stores a special range value called a void. Void values can be handled in various ways in the software.
Because of the nature of determining the range in this way, the scanner
cannot detect surfaces farther away than the plane of reference. For this
reason, placement of the object is very important. Also, the scanner only
looks straight horizontally in a direction normal to the plane of reference,
so any surfaces that are obscured at that angle of view will not be scanned.
If you keep this in mind, you should be able to inspect an object and predict
how well it will be represented.
Data
The SCSI Interface is responsible for instructing the scanner and the motor,
as well as receiving the raw data. The SCSI Interface then passes the data
to the host computer via SCSI protocol. The host computer may be running
software for display and manipulation of the data, or for transfer to a
milling machine. Conversion routines translate the data into a variety of
formats.
Speed
Most systems operate at 60 Hz, and the scanner contains a crystal set for
recording 30 frames per second. If your order specified a 50 Hz system, the
crystal was changed to 25 frames per second. The crystal is not
user-serviceable; notify the factory if a change is required.
Motion Platform
The motion platform should provide a stable base for the object and the
scanner. Place it on a solid floor so that no other motion jars the platform.
It should be large enough to accommodate the objects and the scanner, and it
should be at a comfortable height for the operator. The scanner platform
should be adjustable to accommodate different heights. If scanning a live
subject, the platform should be comfortable and easily accessible so that
the subject can remain perfectly still while being scanned. Please reference
the Site Preparation section of this User
Guide for more information.
Motor
The motor should move the scanner or object at a constant speed, making a
servo motor the most likely choice for motion control. Make adjustments in
resolution by changing the speed and length of scan, as described in the
section Custom Motion.
Controls
Brightness (3030 ONLY)
You can adjust the scanner to compensate for your object's Surface Brightness by directly changing the range camera F-stop inside the scanner head. Open the panel on the side of the scanner head by removing the 8 hex head screws (2.5 mm). Move the F-stop dial on the right-most camera (behind the controller boards). Most objects will use the standard setting of 4.
If you have an RGB or HRC option with your scanner, you can also adjust the Color Brightness by directly adjusting the color camera F-stop. Open the panel on the side of the scanner head and move the F-stop dial for the left-most camera. Most environments will use the standard setting of 4.
When you set up a color scanner, adjust the F-stop until you are satisfied
with the image colors. You may set the F-stop between indents if necessary.
Once you have the F-stop appropriately adjusted for the room, it should not
need to be adjusted again unless the room lighting changes.
Sensitivity
With certain objects or room conditions, you may wish to make a
sensitivity adjustment. This changes the
threshold of light strength that the scanner will recognize. If you are
getting excessive spikes in your images or surfaces are not being seen (voids),
adjusting the sensitivity may help.
Power
The Power Supply provides power for the motion platform, as well as the
scanner head. It contains the main power switch, located on the front. To
verify power throughout the system, power lights are located on the Power
Supply and on the side of the scanner case.
Software
Scanning is controlled by the Echo software running on the host computer. Depending on the type of motor, you may need to initially name a motion source file which describes the motion and type of scan. The laser turns on automatically when the image command is given, and turns off when the scanning is complete. If there is a motion platform, the image command also calls motion commands which are appropriate for the type of motor.
For safety, the laser always turns off after 30 seconds, even if the motion
stops and or if the system is still in the process of scanning an image.
Motion Platforms
For specific information about controls on Cyberware motion platforms, refer to the Scanning Notes for that platform.
There is an extensive alignment procedure that is done at the factory so that
all the optics interact correctly. Normally no subsequent alignment is needed
unless the system has undergone a great deal of shock. If the scanner has
been damaged and realignment is necessary, the scanner head must be
returned to the factory. Please contact
Cyberware Support for further information.
Cleaning
All Cyberware scanners have been designed to run trouble-free with a minimum of regular maintenance.
There is no routine cleaning required for any parts of the scanner or platform. However, situations may arise that would require cleaning of the optics (mirrors and/or lenses). Note that the mirrors are front surface type and are very easily scratched. They should be cleaned only if absolutely necessary. Need for cleaning will be minimized by placing the dust cover on the scanner after each use.
The performance is not affected by even considerable quantities of dust on the optics, but if used in locations with a high dust content, users may want to use a soft optical brush or optical cleaning compressed gas to remove dry dust. This should be done before using tissues and optical cleaner, as loose dust will scratch the mirrors when they are rubbed with a tissue.
Fingerprints should be cleaned from mirrors or lenses as soon as they are noticed. Fingerprints and other substances may be cleaned with a lens tissue dampened with a lens cleaner. Wash your hands well before attempting to clean the optics, because any skin oil will penetrate the tissue and streak the optics. Bunch a clean tissue into a puff shape, apply a drop of cleaner, and gently wipe the surface. Use the tissue for only a few wipes, throw it away, and then use another clean tissue.