| dc.description.abstract | From the earliest pinhole camera to the Monocular camera, humans want to record the objects and events.However, the camera can only record two-dimensional (2D) images, and can never record the three-dimensional(3D) information in the real world. So we need instruments to build 3D models to preliminary 3D information in the real world.
3D models have been widely used in various fields. Self-driving and Robotic vacuum cleaner measure distance and obstacles in front. The dynamic capture of the human face during film shooting, recording the actor′s face changes to facilitate the post processing. Modeling of the teeth and various organs in medical treatment can be used to observe the health of the patient or to establish an accurate model. How to record real items more accurately becomes another topic.
Nowadays, among many different technologies from 3D modeling, the 3D modeling based on structured light usually faces the problems of lacking depth of field and image distortion caused by angle of view. This study is also based on structured light and hoped these two problems can be improved. In addition, the measurement is performed without a reference plane and the system′s mobility is improved. This study combines a micro-projector with a mobile phone to provide structured light with a micro-projector, and then capture a structured-light image with a mobile phone. In the past, the most commonly algorithm used in structured light systems was three step phase shifting. It reconstructs the image after obtaining the phase difference, but this method is easy to cause deformation in the position of a large angle of view. So this study combine binary coding and phase shifting method. Binary coding located the fringes on the sample accurately, find out the position corresponding to the reference plane, and then clearly know the angle of view of the sample corresponding to the camera, and use triangulation to correct the aberrations at this angle of view. Because the relative angle of view between the camera and the sample can be calculated using the previously recorded binary coded fringes, three-dimensional information can be reconstructed without the need for information on the reference plane. Finally, the combination of the phase shifting method is to further obtain more detailed phase information after obtaining the position of the fringe to obtain more complete three-dimensional information.
In this study, tablets, balls and face masks are used as samples after the system architecture is completed. The plate is used as a sample to test the accuracy of the absolute height of the reconstruction. Placing the plate within 20 cm to 40 cm from the reference plane, the reconstruction error is within 0.5 cm. Using table tennis and contact balls as known samples, test the accuracy of reconstructing simple geometric surfaces. Find the radius with circular fitting and spherical fitting, and also place the table tennis and contact ball within 20 cm to 40 cm from the reference plane. The errors of table tennis and contact ball fits within 0.12 cm and 0.1 cm. Eventually, the face mask proves that it can reconstruct three-dimensional information of more complex structures.
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