针对基于NURBS方法描述的自由曲线曲面模型，本文给出了一种基于控制点坐标差分数据的NURBS自由曲面的数据优化压缩复原方法。该方法以权因子为基础，利用离散余弦变换，对控制顶点坐标分量的差分值矩阵进行变换，然后进行量化压缩处理，在有效压缩数据的同时使传送的压缩数据中携带了压缩复原数据的累积误差。最后，通过对压缩复原图像与原始图像进行比较，说明了该数据优化压缩方法的有效性。

An optimized data compression method of freeformed NURBS surfaces based on the differential data of  coordinates of the control points is improved from the model of freeformed curves and surfaces described by the NURBS method. Discrete cosine transform (DCT) is applied to the differential data matrix of coordinates of the control points associated with weights and then quantization compression is carried out in the optimized data compression method. Accumulated errors of the recovered data generated from data compression are transferred together with the compressed data in addition to the high efficiency of data compression. Finally,it is proved the data compression method is effective and useful by comparing the  recovered picture with the original one in an example.