为了快速实现花瓶等具有回转体性质文物的三维数字化,提出了一种非接触式测量方法,并研制了一套文物数字化三维重建系统,克服了文物三维重建时内腔信息缺失以及纹理畸变的问题。对于内腔,通过光学镜片改变激光测距仪光束的方向,结合转台和导轨的运动来获取文物内腔的点云数据;外形点云由线激光扫描仪结合转台运动来获取;为减小文物纹理的畸变,通过相机搭配远心镜头来获取文物不同转动角度位置的纹理图像,然后把所有角度位置提取的像素依次拼接在一起,形成完整的外形纹理展开图。最后介绍了对系统测量误差进行标定与补偿的方法。实验结果表明:此系统可实现对花瓶类文物的三维数字化,重建精度在0.5 mm以内。可满足在博物馆现场对文物进行快速安全三维数字化的需求。

Herein, a new method for noncontact measurement is presented to quickly digitize vases and other objects with rotary properties. This study develops a cultural-relic digital three-dimensional (3D) reconstruction system, which overcomes the problems of missing inner cavity information and texture distortion in cultural-relic 3D reconstruction. For the inner cavity, the beam direction of the laser range finder is changed by an optical mirror. The point cloud data of the cultural-relic inner cavity is acquired by combining the movement of the turntable and the guide rail. The point cloud data of appearance is obtained by a line laser scanner combined with the turntable motion. High-resolution orthoscopic texture images of the cultural relic at different rotation angle positions are obtained using telecentric lens and a camera to reduce the distortion of the cultural-relic texture. All the extraction pixels are then stitched together to reconstruct a complete appearance texture unfolding. Finally, the method of calibration and compensation for the system measurement error is introduced. Experimental results show that the proposed method can realize the 3D digitization of vases. The overall reconstruction error of the cultural relic is less than 0.5 mm; hence, it can meet the demands of a rapid and safe 3D digitization of cultural relics in the museum site.