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SL Scanning with Pre-Recorded Images

Usually you should work with a live camera which DAVID supports. Especially for beginners, it is much easier to find the right setup (positions, image brightness…) with a live camera.

However sometimes it may be necessary to use pre-recorded images, e.g. when the camera not supported directly.

The following applies to DAVID 3.7 and newer:

HOWTO: Pre-Record Images

Make your settings in DAVID,then right-click on the projected pattern (usually on Screen 2), select “Save Pattern Sequence”. These are the images you should project into your scene (on the calibration panel or on the scanned object). Use any image viewer (full screen on projector) to project those images. You can also use DAVID to project patterns one by one: Use the “Show first pattern” / “Show next pattern” options in that pop-up menu.

HOWTO: Use the Pre-Recorded Images

You can use the ImageGrabber to calibrate and/or scan with pre-recorded images. The ImageGrabber plus a set of images replace a live camera. However DAVID will still project the pattern sequence on a projector or screen - ignore that.

The images files should be named like this:

  • Camera Calibration image: filename should contain “cam_calib”
  • SL pattern images: filenames should contain “image” and be sorted alphabetically
  • Texture or White Balance image: filename should contain “texture”[/list]

HOWTO: Create Pre-Recorded Images from a live scan in DAVID

You can also do it the other way round: Use a live camera, and let DAVID store the images so you can see what the images look like and what names they have:

  1. Create a subfolder “SL-TestSequence” inside your DAVID application folder
  2. Use a live camera and calibrate or scan
  3. Look at the images inside the SL-TestSequence folder


  1. When you select different SL parameters (e.g. “Quality”, “Default”, “Speed”), the number of patterns changes –> your pre-recorded images won't work any more.
  2. About the order of pattern images: During live scanning, the order is different (less ordered, more “scrambled”) than the order which “Save Pattern Sequence” gives you. Don't worry about it: The order of “Save Pattern Sequence” is the same as the ImageGrabber expects, and the same as exported in the “SL-TestSequence” folder.
david3_user_manual/image_grabber.txt · Last modified: 2014/06/06 18:38 (external edit)