Calibration and merging of IR scans Refraction task

Task

Markers are placed on plane. Two scans captured - with glass (markers P) and without glass (markers P'). Markers are detected on both scans and their positions in 3d space are obtained.

The task is to find relation between sets of markers (rotation, offset) that minimizes distance between P and P'. Known data are only glass surface (point and normal) and set of refracted points (scan with glass).

Input:

• Color and IR imagers wavelength - 400-865
• Laser Wavelength = 850 nm +- 10 nm, 20°C
  • It is assumed that light rays travel only in one direction - from object through glass to detector, because scan can be captured without IR emitter.

1. Glass is triplex 8 mm (4+4 mm)

Assumptions

1. Near IR light

1. Stereopair
   1. Point cloud generated from depth map is only considered. Camera generates depth frame from two depth sensors - they are parallel and have short baseline.

Camera placement

Plane with markers placed at 50 cm from camera. Glass placed between camera and plane with markers (near plane) with some rotation angle.

Marker

Marker captured with glass (P) and without glass (P'):

1. L - scan point of origin
2. P - marker detected with glass
3. P' - marker detected without glass
4. O - point of intersection of LP' with glass plane
5. O' - point of intersection of LP with glass plane
6. ON, O'N' - normal to glass plane