A Proposal of Feature Extraction Method for Press-Through-Package Designs Based on Fourier Transformation
Authors: Yuuki Hosozawa, Masaomi Kimura
Abstract: In order to prevent medical accidents which originate in using drugs, we need to properly use proper drugs. In Japan, we often use PTP (Press-Through-Package) sheets as a packaging unit of medical drug tablets. In order to prevent PTP sheets from design confusion, we need to establish the method to estimate the similarity of PTP sheets. In this paper, in order to acquire the knowledge about characteristics of PTP design, we applied Fourier transformation to PTP design. Under the assumption that marks and string letters in the design can be approximated into rectangles, we defined the (approximated) function that expresses PTP design. The function consists of a prototile, expressing a layout of rectangles, and its copies. We found Fourier transformation of the function can be expressed as the product of a contribution from the layout of the copies and a contribution from the prototile, the latter of which is found to have large value along lines perpendicular to line segments connecting centers of the rectangles at the center of the FFT image of a PTP design. Based on our discussion and the results of experiments, we obtained the knowledge that the similarity index of PTP design should consist of the similarity of prototiles in PTP sheets in low spatial frequency region and the similarity of the layout of prototile copies.
Keywords: Press through package, Package design, Fourier transformation, Medical safety
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