用形状轮廓上点的坐标位置相对于形状重心位置的分布关系描述形状，提出一种极坐标下形状轮廓点分布直方图描述符(contour points distribution histogram)，该描述符不仅符合人眼的视觉直观感受、计算简单，而且其本质上具有缩放和平移不变性。用动态规划算法(dynamic programming algorithm)来度量轮廓点分布直方图之间的距离，部分解决了轮廓点分布直方图对于旋转不变性的要求。在多个形状图像数据库中的实验结果表明，该方法在单目标封闭轮廓的形状图像检索中取得了良好效果。

Using the distribution relations between the coordinates of the points on shape contour and the centroid of the shape to describe a shape, a novel shape descriptor CPDH (contour points distribution histogram) is proposed under polar coordinate. This descriptor not only satisfies the human’s visual perception and easy to be calculated, but also it essentially has the properties of invariant to scaling and translation. We also suggest using the Dynamic Programming Algorithm to measure the distance between CPDHs, and that the DP algorithm can partly solve the need of the CPDH’s invariant to rotation. With a great deal of experiments in several shape databases, it is shown that this algorithm, used in image retrieval of shape with a single closed contour, can get favorable results.