Calibration

Projector Setup

Start DAVID by running “Start_DAVID3_x64” from the USB flash drive. If you wish to update your software to the latest version, go to www.david-3d.com to download the most updated version. If you use 32-bit system (not recommended), run “Start_DAVID3”. 

The DAVID-LASERSCANNER interface window will be opened up. On the left hand side:

1. Select "DAVID SLS-2" as your setup type.
2. Set up the Screen ID so that the stripe pattern is shown on your projector. (usually 2)
3. Choose the camera you are using for the 3D Scan.

Scan Object Setup

• Working Distance 
  Place the scan object in front of the projector. Adjust the working distance to make sure the screen projected from the projector covers the entire object, not less, not much more either.  (insert an image of a scan object with illuminated stripes on the body) Working Distance is the distance between the object to be scanned and the projector. 

• Projector focus
  Dial “focal ring” located on top of the projector to focus the projected stripped image on the scan object. Depending on your projector model, if the projector is perfectly focused, the fine lines between the projector's pixels may cause a fine noise in the scan. If that happens, we recommend to set the projection slightly out of

• Position of the camera
  To adjust the location and angle of the camera, loose the thumbscrew on the bottom of the camera to slide it. Make sure the screws are tightened up once the location is adjusted. If necessary, adjust the working distance again to fit the object on to the projected screen.

• Exposure time
  The Exposure should be set to the same value as the frame rate of the projector (usually 1/60s), otherwise the camera image will flicker/pulsate when looking at the projection.

• Camera focus
  Adjust the aperture of the camera so that you will get a rather bright picture. Look at the camera image and watch the sharpness of the object and the sharpness of the projected black and white stripes. Dial the camera focus to get a sharp image
  

• Camera brightness/ aperture:
  The “Projector Brightness” slider in the software should be set to the maximum. It should only be reduced had a clean modulation is not possible in the following. Adjust the mechanical aperture. Consider only those areas in the camera image which show the regular waves. The displayed intensity curves (red) must be sinusoidal and may neither be undersaturated nor oversaturated. i.e. the red sine curve should be cropped at the blue lines. Note: if the curves are strongly flattened in the dark area without being close to the lower blue lines, the ambient light may be too strong. In this case darken the room. The Aperture dial on the camera has a scale f-stop from 16 to 1.4). Even for very bright condition (small objects), please avoid setting f-stop higher than 16. Otherwise the sharpness could be lost. If necessary, better reduce the value “Projector Brightness” in the software.

•  Fasten
  Lock down the camera and project’s position by fastening all screws including projector, camera and camera slide. The camera lens dials can be fixed with their locking screws.focus. This will not reduce the scan quality.  (insert an image of the camera dial lock)