3D scanning tutorial

What you need for real-time structured-light scanning

• One camera — any camera can be used for capturing. There is no need to worry about its frame rate.
• One projector — any projector can be used for projecting the fringe patterns. The camera and projector are perfectly synchronised in software, so the speed of either device does not affect scanning.
• Dark background — results are better with a dark background. Place a dark/black surface behind the object.

System setup

• To configure the pattern-projection window, set up multiple displays in Desktop → Screen Resolution properties, then move the patterns window onto the projector display.
• If you are using a Logitech camera you may see overly bright fringe images. Adjust the contrast and brightness in the Logitech Webcam Controller: uncheck RightLight and open Advanced Settings.
• Set exposure, gain, brightness, contrast, and colour intensity to the minimum that still produces clean sinusoidal fringes — neither too bright nor too dim.

Scanning workflow

1. Generate sinusoidal patterns first. Go to Menu → 3D Scanning → Sinusoidal Fringe Pattern Generation.
   • Select the phase-shifting method — 3-step, 4-step, or 5-step.
   • Pattern width and height should be large enough to cover the object dimensions.
   • Enter the pitch value and press Apply. To preview the pattern press Display Pattern; otherwise press Save Patterns and choose a destination. Pattern filenames must be in incremental order, for example 0.jpg, 1.jpg, 2.jpg…
2. Open the 3D Scanning module.
   • Press Enable RTS (Real-time Scanning).
   • Select the Without Ref method — no reference plane is required.
   • Press Open Camera to open the Camera module.
   • Select the CAM Argument number — important when more than one camera is attached. Try 0, then 1, then 2, etc.
   • Set the ROI (region of interest) width and height — this becomes the scanning resolution. On a slower computer, choose smaller dimensions, e.g. 400×400.
   • ROI-X and ROI-Y define the starting pixel of the new resolution; use them to crop out any part of the screen you do not want to capture.
   • Both resolutions can be tested by switching between Gray and Color mode. Images and videos can also be saved.
   • Press Initialize Camera. A grey window appears at the selected resolution.
   • Back in the 3D Scanning module, press Open Patterns.
   • Press Run Patterns and select the generated fringe patterns; the phase-shifted patterns then play through the projector.
   • A small delay value increases scanning speed; the camera must be fast enough to keep up.
   • From the left section of the 3D Scanning module press Start Point Cloud Rendering.
   • If vertical fringe patterns are used press Yes; otherwise press No.
   • The scanned point cloud then appears in the display window.
   • Adjust the Skew and Scale factors until the model resembles the original object.
   • If the point cloud is too dense, adjust the Render setting.
   • If parts are missing from the scan, check the unwrapped phase map and adjust the Range parameter — increasing it ignores more background, and vice versa.
   • Patterns, camera, and rendering can be stopped and restarted at any time.
   • When you are done, export the scanned point cloud or triangular model to disk.
3. Post-processing
   • Close everything, then import the scanned model via File → Import → Triangular Mesh → Open.
   • Apply smoothing filters, subdivision, and texturing as needed.
   • Iterate on the mesh-smoothing algorithms to finalise the scanned 3D model.

Video walk-throughs

If you prefer a visual walk-through, the following clips cover the same workflow end-to-end. The full collection lives on the Scanner V2 page.

Last updated: November 2012.