A New Approach to 3D Modeling Using Structured Light Pattern

Abstract

As the need for using and developing three dimensional (3D) surface modeling grows increasingly due to its wide range of applications, new techniques are developed and optimized to fulfill the requirements. The two main image ranging techniques refer to the active and passive approaches. In the active projector ranging technique, a single camera and a pattern projector with high focusing performance are used to obtain reliable measurement on the images taken. The passive projector ranging technique is based on finding correspondence between stereo images taken from the same object surface. Both techniques use a light projector which projects a structured light pattern. One of the advantages of using structured light is adding some extra features to the object which can include inherently featureless objects to be reconstructed in this way. In this study, the significant advantages of the two techniques are combined to implement a practical 3D modeling technique. First, a color slit pattern has been designed to uniquely labeling and precisely extracting the image points along slits edges. The label of any image points is assigned according to hue value of next and previous slits where the sequence of colors has maximum hue value differences on adjacent slits. Then, edge points of slits are extracted along the epipolar lines of stereo images and labeled simultaneously.Applying two strategies together, we've enhanced the unique and precise occurrences of the slits. The first strategy was background elimination which reduced the effects of surface color as a result. The second strategy was a color ordering for light slits which simplified matching of a correct point among corresponding epipolar points. Finally, the designed slit pattern has been applied using a flat wall, an industrial part and a human face. The color point clouds of the three different surfaces have been calculated and the calculated points on the flat wall have represented an acceptable accuracy of the designed pattern. The stability of the point extraction and labeling algorithm has been tested for an industrial part and the point cloud of the human face shows the capability of the proposed algorithm to get and assign the true color of the scene to the point cloud. Therefore, the proposed slit pattern has reduced the effects of imaging and point extraction noises.