Shape feature is a very important feature used to depict image

it is difficult to describe shape. This paper proposes "distance distribution histogram"

a region-based shape feature which uses the dimensional distribution information of pixels in binary image to describe the image shape. The basic idea is to get shape feature by calculating the distribution of pixels in different distance regions. In the method

the selection of datum mark and the partition of distance region are two important parts to assure that the feature can have good invariant performance under some rigid transformation. After the distance distribution histograms have been calculated for different images

Quadratic-form distance is then used to compare the similarity of the images. The experiments have been done in a database consisting of 3000 binary trademark images

the results show that this shape feature can depict the image well

and it has very excellent invariant performance under translation

scale and rotation. When the feature is used for binary trademark image retrieval

it is obvious that the retrieval results fit with human's visual perception well. From the experiments

it can be concluded that the distance distribution histogram feature is really an effective shape feature for binary trademark image retrieval.