Byungwoo Cho

1. Introduction Optical encryption, such as double random phase encryption (DRPE) [1,2,3,4,5,6,7,8,9,10,11,12,13], has been an important technique for protecting the private data recently. It can encrypt the primary data by using a 4f imaging system with two different random phase masks. For encryption in DRPE, the primary data are multiplied by the first random phase mask, which follows uniform distribution with range [0, 2 π ].

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3. Results The characteristics of the extracted features must be determined in vacant parking slot detection cases to understand the processing mechanism of NNs. For this reason, feature map visualization was employed, and NNs with an excellent classification performance were used to increase the reliability of the feature analysis outcome. Various ROI combinations were utilized to train and test the NNs to achieve an outstanding performance.