Fast 3D shape measurement based on color structure light projection

摘要

The recent needs of visualization of variable in time 3D objects require development of new approach towards rapid 3D shape measurements. One of them applies colour structure light projection which utilizes combined multicolour phase-shifted and colour Gray codes. The usage of colour multiplexing enables to reduce the number of images required for shape measurement to one (slow gradients of shape) or three (high gradients) images and provides quasi real-time analysis. However the usage of projection and detection of colour patterns may produce significant errors due to noncorrect analysis and interpretation of images. These phenomena are shown at exemplary results of analyzing of real colour coded fringe patterns projected onto monocolour 3D objects. The main sources of errors connected with the use of a digital colour light projector and colour CCD camera (with single and 3 CCD matrixes) are discussed. The analysis of RGB and HSI color models are shown in reference to the system calibration procedure. Additionally the basic concept of system calibration and modification of images processing for the case of color 3D object analysis is put.forward.