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