| 摘要 |
A preprocessing section binarizes input image data and calculates a total black pixel ratio. A feature extracting section detects connected components contained in the binarized image data and detects circumscribing bounding boxes that circumscribe these connected components, respectively. Based on sizes of the circumscribing bounding boxes detected and numbers of black pixels contained therein, predetermined connected components are removed. A determining section generates an edge map by using the residual connected components, and performs two-dimensional fast Fourier transform thereon to generate spectral data. The determining section performs two-dimensional fast Fourier transform on template images to generate spectral data. The determining section determines, based on these pieces of spectral data, whether or not a circular shape is contained in the input image data.
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