Three-dimensional model acquisition using rotational stereo and image focus analysis

Abstract

We present a digital vision system for acquiring the complete 3D model of an object from multiple views. The system uses image focus analysis to obtain a rough 3D shape of each view of an object and also the corresponding focused image or texture map. The rough 3D shape is used in a rotational stereo algorithm to obtain a more accurate measurement of 3D shape. The rotational stereo involves rotating the object by a small angle to obtain stereo images. It offers some important advantages compared to conventional stereo. A single camera is used instead of two, the stereo matching is easier as the field of view remains the same for the camera (but the object is rotated), and camera calibration is easier since a single stationary camera is used. The 3D shape and the corresponding texture map are measured for 4 views of the object at 90 degree angular intervals. These partial shapes and texture maps are integrated to obtain a complete 360 degree model of the object. The theory and algorithms underlying rotational- stereo and integration of partial 3D models are presented. The system can acquire the 3D model (which includes the 3D shape and the corresponding image texture) of a simple object within a 300mm x 300mm x 300mm volume placed about 600 mm from the camera. The complete model is displayed using a 3D graphics rendering software (Apple’s QuickDraw 3D Viewer). Both computational algorithms and experimental results on several objects are presented.