Visual hull
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Visual hull is a geometric entity created by shape-from-silhouette 3D reconstruction technique. This technique assumes the foreground object in an image can be separated from the background. Under this assumption, the original image can be thresholded into a foreground/background binary image, which we call a silhouette image. The foreground mask, known as a silhouette, is the 2D projection of the corresponding 3D foreground object. Along with the camera viewing parameters, the silhouette defines a back-projected generalized cone that contains the actual object. This cone is called a silhouette cone. The upper right thumbnail shows two such cones produced from two silhouette images taken from different viewpoints. The intersection of the two cones is called a visual hull[1], which is a bounding geometry of the actual 3D object (see the bottom right thumbnail).
[edit] References
- ^ A. Laurentini (February 1994). The visual hull concept for silhouette-based image understanding. IEEE Trans. Pattern Analysis and Machine Intelligence. 150-162.