PDA

View Full Version : Re: Number of control points for DLT



Brian Davis
03-09-1998, 06:33 AM
Following on from Rich Hinrich's posting: If one uses 16 or 50 points,
presumably some are more accurately known than others. I've often
wondered whether one should (i) calculate the residuals (i.e., differences
between "known" and predicted locations of the markers on the calibration
object), (ii) exclude those marker(s) with a large residual, and (iii) recalibrate
the cameras. This procedure would entail starting off with 16 (or 50)
markers and ending up with slightly fewer (e.g., 15 or 49) points that would be
used in the final calibration process.

I suspect that this would offer the advantage that a single, incorrectly
defined, point on the calibration cube would not degrade the calibration
procedure. I also suspect that this method would yield equivalent results
when using 16 or 50 points since you would land up using only the best
subset of the "known" calibration points.

Regards, Brian Davis
Cleveland Clinic Foundation