As close as possible, so that the camera can see the scanned surface and not much more. For hand-held laser scanning, the camera must also see the two calibration panels in the left and right side of the camera image.
The intersection angle (angle between camera view direction and laser light plane / projector direction) should be between 15° and 45°.
A rough estimation is: Half as much as the distance between camera and object.
Generally darker is better. Direct sunlight is too bright. But some environment light is OK, you don't need pitch black. It is most important that the environment light is CONSTANT during scanning, and the laser (or projector) must be clearly brighter in the camera image than everything else.
SL scanning is always without calibration panels. Those panels are only required for calibration of the scanner. So you would set up the scanner for the desired scan size, fix all screws, then calibrate it.
Then the scanner (on its tripod) can be placed in front of an object and scan surfaces or patches of the size for which it was calibrated (up to 600 mm with the included calibration panels, but more is possible). Larger surfaces should be scanned in small pieces, with overlapping areas, then aligned in the software.
As long as the camera and projector are not moved with respect to each other, and as long as their focus is not changed, the scanner does not need to be re-calibrated.
The laser line must be visible in the camera image on the object and on the left and right calibration panel at the same time. Thus the laser line must be rather horizontal.
Both is possible. After scanning from above, you can often reach some more surface regions from below.
The distance between laser and camera should not be too small (around half as much as the distance between camera and object). The intersection angle (angle between camera view direction and laser light plane) should be between 15° and 45°.
In general, as you like. Practically you should hold your hand at one position and rotate the laser, like this animation shows.
Also please move the laser SLOWLY, not quickly up and down.
In the camera image, the laser line should reach from the left to the right image border, and DAVID must see the laser line on the object in the middle, and on the left and right panels at the same time. The User Manual will help you, e.g. here.
The calibration patterns are included as PDF or CDR in the software (download or USB). They can be found in the subfolder “printout”. Also you can find them in your Windows Start menu under Programs → DAVID-Laserscanner3 → Printout.
You can print them in any size, so that it fits to the object you want to scan. Please see the user manual for more information.
We do not offer fully-automated 360° scanners, but our DAVID software supports self-made solutions. It can send and receive messages over a (virtual) COM port. However you will have to build the mechanics and microcontroller yourself.
Several people on our forum have built individual solutions, e.g. with turntables. They either remote-control DAVID (send commands like Start, Stop, Save from the microcontroller to DAVID), or they let DAVID control the mechanics (send messages from DAVID to the microcontroller, e.g. use the Stop message to trigger a turntable motion).
For more information, please see our page about COM Port and our Forum.
Please note that the Alignment and Fusion of several scans into one 360° result can only be fully automated in DAVID 2.x; please see here.
We are currently working on a Software Development Kit (SDK). Coming soon.
We do not offer motorized laser hardware, but you can build it yourself. You will find several solutions from our forum community.
You will need a microcontroller like the Arduino to commicate with DAVID and drive a stepper motor. One solution is "Katie" by WalterMo and Sven.
Both is possible. In general, a rotation is easier and better.
Basically it has the same advantages as Structured Light scanning:
If your solution is able to repeat exactly the same motion (same start position, same motion speed), you can scan without background. The procedure is to perform one scan of the calibration corner (“Record new motion”) during which the DAVID software learns the laser motion. From then on, repeat the exact same motion during each scan, and you can scan without background (also called “planeless scanning”).
A motor can perform an ideal motion without trembling. This usually leads to better scans.
Depends on the resolution and framerate of the camera, and also of the scan quality (resolution) you require.
If you scan too fast, you will get gaps which will be interpolated. In some applications this may be acceptable or even desired.
Ideally the laser should not move faster than one pixel per camera frame, e.g. 15 FPS, 768 pixel rows –> scan should take at least 768/15 = 51 seconds. Usual rotation speeds are between 30 and 180 degree/min.
Not yet, we are working on it.
No. Probably in a future version.
Yes! Since version 3.7, both 32 and 64 bit executables are included.
No. Sorry we have no plans for that at the moment. However some people have managed to use DAVID within a virtual machine. Also it seems to be possible to install Windows on a Mac computer using “Bootcamp”. Please understand that we cannot offer support for these systems.
At this time the software offers English, French, German, Italian, Russian, Spanish. We are working with our distributors to offer more languages. If you would like to help, please contact us.
Our paper from 2006, Low-Cost Laser Range Scanner and Fast Surface Registration Approach explains the background.
The origin (0,0,0) lies at the center of the calibration pattern, in the corner.
The X axis lies horizontally inside the right calibration panel.
The Y axis points upward.
The Z axis lies horizontally inside the left calibration panel.
If you have a mobile scanner (e.g. SLS-1) and move it after calibration, the origin and axes will move with the scanner, i.e. stay at the same position relative to the scanner.
We offer a Free Edition which can be used by anyone as long as they want. It may be sufficient for many private users. Also please use this version if you'd like to test the compatibility to your hardware (mainly camera). These are the limitations:
Also there is a comparison chart here.
The software is identical.
The USB version is shipped on a USB key. It does not require any installation, simply plug it into any Windows computer and start DAVID directly from the USB drive. Or, faster, install and run DAVID on your hard disk, but make sure the licensed USB key is plugged in.
The Single PC license can be purchased online. You send us your computer's Registration ID and we create a license file that will work only on that computer. If you need to change your PC one day, we will of course migrate the license for free.
Our licenses have no time limitation.
Each license is valid for one major release version (e.g. Version 3) and can be used with all its minor version updates (e.g. 3.1, 3.2, 3.3, 3.4, 3.5, …).
So all minor updates are free.
You can see how DAVID is evolving in our Changelog.