Practical 3-D measurement using Optimal Intensity-Modulated Projection and Intensity-Phase Analysis

In Three-dimensional (3-D) image measurement field, pattern projection measurement methods based on the image intensity analysis are expected, because those can detect more numbers of stripes order by single projection. However, in the case when the intensity difference between stripes is narrow, the detecting of stripes order becomes difficult.In order to improve the detection accuracy of stripe order, and shorten the measurement time, we use the Optimal Intensity-Modulation Projection (OIMP) technology, and to improve depth range measurement accuracy, we propose an Intensity-Phase Analysis (IPA) technique for observation pattern image. In IPA technique, to start with, the observation pattern is segmented by stripes intensity, and then in every segment, 3-D information of all pixels of the stripe are calculated by phase analysis. By using a combination of OIMP and IPA, a high-speed (single projection and double image captures) and high-accuracy 3-D image measurement can be realized, and the problems of phase unwrapping can also be solved.