Combining the active digitizing technique with the passive stereo vision, a novel method is proposed to acquire the 3D data from two 2D images. Based on the principle of stereo vision, and assisting the active dense structure light projecting, the system overcomes the problem of data points matching between two stereo images, which is the most important difficulty occurring in stereo vision. An algorithm based on wavelet transform is proposed here to auto-get the threshold for image segment and extract the grid points. The system described here is mainly applied to digitize the 3D objects in time. Comparing with the general digitizers, it performs the translation from 2D images to 3D data completely, and gets over some shortcomings, such as slow image acquiring and data processing speed, depending on mechanical moving, painting on the object before digitizing, and so on. The system is the same with the non-contact and fast measurement and modeling for the 3D object with freedom surface, and can be employed widely in the fields of Reverse Engineering and CAD/CAM. Experiment proves the efficiency of the new use of shape from stereo vision (SFSV) in engineering.