Study On 3D Measurement Using Shape From Silhouette

The 3D reconstruction technology of object model has been widely used all over the world, thereby better accuracy and higher calculating speed have been demanded. Shape from Silhouette is a passive vision method, which can fastly measure 3D object with simple apparatus and algorithm. The handle and occlusion of the object can be reconstructed and the result will not be affected by surface material of the object. In this paper, we reconstructed the 3D model of object using Shape from Silhouette and combined the result with the one of laser scanning method, which will make the data complete and perfect.In this paper, a stationary CCD camera has been placed to face to a turnable stage. The silhouette of object on the turnable stage has been observed from multiple views through rotating. A bright background has been used to improve the contrast of images. An acquiring and processing system has been built. The 3D reconstruction algorithm has been studied based on Shape from Silhouette, and a 3D octree volume element structure model has been achieved through refining. The data will be used in 3D model repairing of laser scanning method. The main research work in this paper is as follows:1. According to the specialties of all kinds of 3D measure method, the Shape from Silhouette has been chosen to reconstruct the 3D model of object. The mathematics model of Shape from Silhouette measure was founded.2. A measurement system for Shape from Silhouette was built to acquire the multiple view images. The rotating measure of real objects has been carried out with fixed angle interval.3. The clear contour of input images can be extracted using developed image processing algorithm. The object has been represented as octree volume element structure. The node cube was projected on all views images and intersected. The"space carving"has been achieved. The model has been refined in level-by-level manner.4. The real object has been measured using this system and the complete 3D model has been obtained. The measurement accuracy was evaluated based on a normal sphere. The measurement accuracy is better than 0.5mm.5. The data of Shape from Silhouette has been combined with the one of laser...