虚拟结构光编码算法将三维(3D)数据编码成二维(2D)彩色条纹图像的相位信息,以实现数据压缩存储。在将2D彩色条纹图像解码成3D数据时,需要计算条纹相位并进行相位展开,最后映射为3D数据。2D图像的压缩存储会使相位级次索引图出现边缘量化错误,导致3D数据z方向信息解码错误。针对这一问题,改进了虚拟结构光3D数据解码过程,提出了一种有效的局部相位误差修正算法,以提高3D数据的解码精度。数据解码过程中,建立算法,得到绝对相位展开与相对相位展开的准确差值,利用两者差值固定的特点,对其突变区域建立相位补偿机制,抑制相位级次索引图边缘量化误差而引起的3D数据解码错误。实验验证了所提算法的有效性,对编码得到的2D图像压缩存储后,改进的数据解码方法可有效提高虚拟结构光3D数据编码算法的稳健性,与中值滤波算法相比,所提方法可将数据解码方均根误差平均降低9.7%。

Based on a virtual structured-light data coding algorithm, three-dimensional (3D) data can be encoded into the phase of a two-dimensional (2D) color fringe image to complete the data compression. In the process of decoding a 2D color fringe image to 3D data, phase calculation and phase unwrapping are required. Due to the compression and storage of the 2D image, a quantization error exists at the edge of the phase index map, which will cause a local error in the unwrapping phase and will result in a 3D data decoding error in the z direction. To overcome this limitation, the decoding process of virtual structured-light 3D data is improved. The proposed algorithm can revise the local phase error and enhance the 3D data decoding accuracy efficiently. In the proposed algorithm, deviation between absolute phase unwrapping and relative phase unwrapping is calculated. Since the deviation is fixed, phase compensation is performed when the local deviation is changed sharply, and the local error of the decoded 3D data caused by the edge quantization error of the phase index map is suppressed. Experiments are conducted to verify the effectiveness of the proposed algorithm, which makes the virtual structured-light 3D data encoding algorithm more robust after compressing and storing the encoded 2D images. In comparison with the median filtering algorithm, the proposed algorithm can reduce the root-mean-square error of data decoding by an average of 9.7%.