1 May 2001 Shape measurement by digital speckle temporal sequence correlation with digital light projector
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Optical Engineering, 40(5), (2001). doi:10.1117/1.1360708
A new method of three-dimensional shape measurement, called digital speckle temporal sequence correlation, is presented. Random digital speckle is projected on the reference plane, which is moved N times in equal depthwise steps. At each step, speckle image is captured by a CCD camera and saved in a computer as the reference-plane set R(t ). Replacing the reference plane with the object, the modulated speckle image O was also captured. The cross correlation between any subimage O(x ,y) in O and the serial subimages R(x ,y ;t ) located at the same position in R(t ) is approximately quadratic. The position of the main peak of the correlation curve is the height of the object point. In order to measure speckle-sets complicated objects, two new methods, called multiple reference-speckle-sets and multiple correlation-peak optimization, are also presented. Experiment proves them very effective. Our method surpasses the limitations of the horizontal correlation in previous methods and is a true temporal sequence correlation method. It is simple in principle and offers higher measurement precision without complicated phase-unwrapping and calibration processes, and can be used to measure discontinuous and spatially isolated shapes.
Hongjun Dai, Xianyu Su, "Shape measurement by digital speckle temporal sequence correlation with digital light projector," Optical Engineering 40(5), (1 May 2001). https://doi.org/10.1117/1.1360708


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