Pei-Ju Chiang’s research while affiliated with National Cheng Kung University and other places

Structured light systems often suffer interference of the fringes by blooming when scanning metal objects. Unfortunately, this problem cannot be reliably solved using conventional methods such as the high dynamic range (HDR) method or adaptive projection technique. Therefore, this study proposes a method to adaptively suppress the oversaturated areas that cause blooming as the exposure time increases and then fuse the multi-exposure time decoding results using a decoding inheritance method. The experimental results demonstrate that the proposed method provides a more effective suppression of blooming interference than existing methods.

Three-dimensional (3D) scanning systems are widely used nowadays for multiple applications. If the object is too large, it is a challenge to provide the detailed characteristics of the scanned object. Improving the spatial resolution of the scanning process is essential in improving the quality of the reconstruction results. Accordingly, this study has proposed an active stereo vision system for improving the spatial resolution. It is well known that the reconstruction quality of stereo vision systems is severely impaired for objects with limited features on their surfaces, thereby, in the present study, an active stereo vision system is proposed in which stripe patterns are projected onto the object surface with various rotation angles in order to facilitate a more accurate and complete detection of the matching points. Notably, the point clouds obtained by the projected patterns at each rotation angle are formed within the same world coordinate system. As a result, the final reconstructed 3D object can be obtained by merging sets of point clouds directly without the need for a prior registration process. In practice, the quality of the reconstruction results obtained by stereo vision systems is commonly degraded by the effects of noise. Therefore, this study also proposes a two-step (multi-decoding pattern and Epipolar line) method for removing the incorrect matching points and improving the reconstruction results accordingly. The performance of the proposed reconstruction system is evaluated experimentally and compared with that of a general active stereo vision system. The experimental results show that the active stereo vision system presented in the present study provides a low-cost, convenient and effective approach for performing the reconstruction of 3D objects with high spatial resolution.