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Pure position permutation image encryption algorithms,commonly used as image encryption investigated in this work are unfortunately frail under known-text attack.In view of the weakness of pure position permutation algorithm,we put forward an effective decryption algorithm for all pure-position permutation algorithms.First,a summary of the pure position permutation image encryption algorithms is given by introducing the concept of ergodic matrices.Then,by using probability theory and algebraic principles,the decryption probability of pure-position permutation algorithms is verified theoretically; and then,by defining the operation system of fuzzy ergodic matrices,we improve a specific decryption algorithm.Finally,some simulation results are shown. 相似文献
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INTRODUCTION Due to the development of communicationtechnology, information security becomes an increasingly important problem. The wide use omultimedia technology and the improvement innetwork transmission gradually enable direct acquisition of information clearly through imagesHence, data security has become a critically important issue. Many encryption algorithms havebeen proposed to protect valuable data from unauthorized parties. The basic methods can be classified into th… 相似文献
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Flower image retrieval is a very important step for computer-aided plant species recognition.In this paper,we propose an efficient segmentation method based on color clustering and domain knowledge to extract flower regions from flower images.For flower retrieval,we use the color histogram of a flower region to characterize the color features of flower and two shape-based features sets,Centroid-Contour Distance(CCD)and Angle Code Histogram(ACH),to characterize the shape features of a flower contour.Experimental results showed that our flower region extraction method based on color clustering and domain knowledge can produce accurate flower regions.Flower retrieval results on a database of 885 flower images collected from 14 plant species showed that our Region-of-Interest(ROD based retrieval approach using both color and shape features can perform better than a method based on the global color histogram proposed by Swain and Ballard(1991)and a method based on domain knowledge-driven segmentation and color names proposed by Das et al.(1999). 相似文献
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A flower image retrieval method based on ROI feature 总被引：1，自引：0，他引：1
INTRODUCTION There are about 250000 named species offlowering plants and many plant species that havenot been classified and named. Plant classificationand identification is a very old field. So far, thistime-consuming process has mainly been carriedout by taxonomists and/or botanists. A significantimprovement can be expected if the plant identifi-cation can be carried out by a computer automati-cally or semi-automatically with the aid of imageprocessing and computer vision techniqu… 相似文献
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