Elastic Warping of Radial Features for Shape Alignment in Sketch Retrieval

Query by sketch, which allows users to issue the query intuitively and flexibly, is an easy way of retrieving objects. In this paper, we propose an elastic warping scheme of radial features for shape alignment in the spatial domain based on the dynamic time warping algorithm. This scheme can align flexibly the non-silhouette shapes consisting of point sets with adjustable constraints. Through the optimization of the algorithm, the scheme can achieve significantly better performance than direct matching of shapes, and exhibit error tolerance for translation, scaling, or rotation. It can also apply to the retrieval of real images containing natural or artificial objects. Experimental results show that the approach can retrieve the target images successfully. Furthermore, it can find totally different images with similar shapes.