The characteristics of pulsed,diode lasers and linear CCD array optical detectors are explored in the context of high ,speed ,precision dimension ,and ,location measurements ,by optical ,diffraction and interference. It is suggested that...
moreThe characteristics of pulsed,diode lasers and linear CCD array optical detectors are explored in the context of high ,speed ,precision dimension ,and ,location measurements ,by optical ,diffraction and interference. It is suggested that pixel based metrology may, with appropriate signal extraction and processing methods, be made more accurate by making edges less well defined: if the mechanism of definition loss is well understood, e.g., diffraction, the intensity distribution over many pixels can be matched to a template to within a small fraction of a pixel, obviating the need to make sub-pixel interpolations based on local intensities. The specific example,of making remote flash measurements ofthe diameter and location of an opaque cylindrical object, e.g., a fast-moving textile strand, is examined. A model is developed for calculating the diffraction pattern given the target and instrument parameters. The results are examined,and compared,with experimental data. Algorithms for ...