A three-dimensional camera calibration technique is developed by combining two, 2-D camera calibrations for an orthogonal stereo viewing geometry. The left camera view (YZ view) and the right camera view (XZ view) are calibrated separately and then combined to produce an XYZ (3-D) calibration routine, Our technique employs three parallel calibration planes. One is placed along the main diagonal of the cubic experimental chamber, and the other two planes are placed known distances in front of it and behind it within the chamber. Both cameras view the calibration points on the planes simultaneously. Given the coordinates of a number of points, we use a physical model to determine the exact pixel locations of the calibration points. After inverting the model equations, we input the absolute coordinates and measured pixel locations into a least-squares fitting algorithm to obtain the experimental camera parameters for each camera individually, We then combine the two camera views via a ray-tracing method. We calibrated 3-in.(3) (7.62-mm(3)), 4-in.(3) (10.16-mm(3)), 5-in.(3) (12.70-mm(3)), and 6-in.(3) (15.24-mm(3)) chambers with accuracies between 1.66 and 2.01 pixels (0.60 and 0.77% of full field), 1.26 and 1.86 pixels (0.43 and 0.63% of full field), 1.16 and 1.34 pixels (0.33 and 0.39% of full field), and 1.91 and 2.49 pixels (0.59 and 0.77% of full field), respectively, using our 3-D camera calibration routine. (C) 1997 Society of Photo-Optical Instrumentation Engineers
