| OCR Text |
Show reflected light, and electromagnetic interference is filtered in software. Software is used to calibrate the system. By requiring each light source sensing assembly to measure the positions of at least seven light sources placed at known locations, transformation matricies expressing the position and orientation of each light source sensing assembly are determined. These transformation matricies map three-dimensional space into the one-dimensional spaces of the light source sensing assemblies. The transformation is reversed to express equations of planes in terms of linear combinations of the tangens of angles between slits and midpoints of usable focal planes, implied by the output of the scanner boxes, and the elements of the transformation matricies. A three-dimensional position is established by a least mean squares approximation to the determined scanning planes. There are sources of optical, mechanical, electrical, environmental, and calibration errors. Unremovabl distortion in the objective lenses is the largest source error. Point spread and limited depth of field additional optical errors. Mechanical errors have removed to the extent that they may be distinguished unremovable electrical and optical errors. In particulart time jitter on pulses from the scanner boxes overshadows mechanical errors. Certain phenomena such as noise from the photomultiplier tubes and the associated electronics, |
