Circular scanning of the image provides an efficient and simple way to achieve feature extraction of 2-D images. The obtained features are insensitive to object's position, orientation, and scale. The main shortcoming of the method is that such features do not uniquely determine the shape of an object. An overview of the method is presented. An experiment with recognition of latin capitals in two different fonts and scales is described and results are given.
Bozidar D. Vojnovic,
"Application of circular scanning of images to invariant pattern recognition," Optical Engineering 31(5), (1 May 1992). https://doi.org/10.1117/12.56160