Reversible data hiding with automatic contrast enhancement for
Reversible data hiding with automatic contrast enhancement for medical images Authors: Guangyong Gao, Shikun Tong, Zhihua Xia, Bin Wu , Liya Xu , Zhiqiang Zhao Source:Signal Processing,178 (2021) 107817 Reporter: Sisheng Chen Date: 2020. 12 1
Outline • Introduction • Proposed scheme • Experimental results • Conclusions 2
Introduction(1/2)--- RDH with contrast enhancement (RDHCE) Improvement of visual quality of the marked image Relative contrast error (RCE): Relative mean brightness error (RMBE): Mean opinion score (MOS) 3
Introduction(2/2)--- RDH with contrast enhancement (RDHCE ) l The regions of interest (ROI) l contrast stretching algorithm 4
Proposed scheme (1/4) — main idea(1/2) 5
Proposed scheme (2/4) —Regions of interest and NROI segmentation c 2 c 1 Location map : LM 1 1 1 1 ATD: 1 1 0 1 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 6
Proposed scheme (3/4) —Automatic histogram stretching(1/2) l histogram shifting [1, 10] [0, 255], 5 127, 6 128 r=0. 7 PCR[0, 5]=78/82=0. 9512
Proposed scheme (3/4) —Automatic histogram stretching(2/2) l Histogram stretching Lmin =1 Lmax =6+4 -1
Proposed scheme (4/4) —Embedding data into ROI(1/2) 1 th iteration 16 16 Secret data 1 1 0 1 0 9
Proposed scheme (4/4) —Embedding data into ROI(2/2) 2 th iteration 16 16 10 10 Secret data 2 10
Proposed scheme (5/6) —Embedding data into NROI(1/2) • Preprocessing • Data embedding Replacing at most three least significant bits (LSBs) of the pixels in NROI with secret data. 11
Proposed scheme (5/6) —Embedding data into NROI(2/2) • Side information: LM, PSROI, PSNROI , Dshift, klast, ROI’max , ROI’min , Lmax and Lmin The length of side information: L Side information L: 18 pixels N is embedded in the first two pixels’ LSBs … … … 12
Proposed scheme (6/6) —Extraction of secret data and recovery(1/3) • Extract data from the NROI L: 18 pixels N is embedded in the first two pixels’ LSBs … … … LM, PSROI, PSNROI , Dshift, klast, ROI’max , ROI’min , Lmax and Lmin Secret data 13
Proposed scheme (6/6) —Extraction of secret data and recovery(2/3) 14
Proposed scheme (6/6) —Extraction of secret data and recovery(3/3) 15
Experimental results (1/4) 16
Experimental results (2/4) 17
Experimental results (3/4) 18
Experimental results (4/4) Relative contrast error (RCE): Relative mean brightness error(RMBE): Mean opinion score (MOS) 19
Conclusions pthis paper, proposed a new algorithm based on RDH with contrast enhancement for medical images ØAutomatically stretch the histogram of the ROI to achieve larger embedding capacity and better visual perception. 20
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