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.