Three-Dimensional Shape Measurement Based On Color-Coded

The world we observe is three dimensional (3-D) ,whereas the camera captures two dimensional images with depth information missed. To review the objective world correctly and completely, 3-D measurement techniques draw a lot attention. With the rapid development of computers, 3-D measurement techniques are widely used recently. The coded structure light method is becoming popular because of its advantages which are high precision, rapid and easy to implement.A color-coded method is proposed in this thesis. By employing this method, the color-coded stripe patterns created by software are projected to an object by a digital projector. The images of the object are captured by a CCD camera positioning with an angle to the projector. The 3-D information can be obtained after decoding and processing of the images which are transferred to the computer. In this thesis, the technique for 3-D measurement based on color-coded method is studied both theoretically and experimentally.Firstly, kinds of structure light methods are studied and color fringe projection is focused on. Based on the analysis and comparison of coding methods, a color-coded method is proposed. Color patterns cover more information compared with black-and-white fringe projection. However, it also has a higher demand of the anti-disturbance of the system as well as the feasibility of the decoding arithmetic. The method proposed reduces the difficulty of decoding process. Besides, it conquers the defect that color coding is more sensitive to noise.Secondly, based on the function in optical triangulation, the mathematical model of the 3-D measurement system is presented. Then, an effective self-checking decoding method is proposed and the process of the capture images such as filtering is introduced followed by the map texture technique we use to make the object surface more vivid. After establishment of the system, the calibration methods are studied.Finally, the 3-D measurement experiments are designed based on the theoretical analysis. The results of two objects are presented, which proves the availability of the method proposed in this thesis.