Efficient and Lossless Hiding of Electronic Patient Records in Medical Images

Abstract

Reversible data hiding (RDH) schemes proved to be a key solution to the effective management and security protection of intensely growing medical images and their associated electronic patient records (EPRs). This paper investigates the potential of a new reversible data hiding (RDH) scheme with pixel-to-block (PTB) mapping to address those challenges. Existing PTB-based schemes are inefficient due to the sub-optimal changes in the repeated pixels, direct and unconditional embedding into their least significant bits or requirement of additional knowledge of look-up table or location map. We used a PTB mapping that creates a block of size $2\times 2$ with repetition of an original pixel. These blocks are adjusted with the value of 4-bit data keeping the first (i.e. original) pixel of the block intact and modifying the others with minimum possible changes. Thereby a better embedding rate-distortion performance is obtained and the overflow and underflow problem is effectively tackled without requiring any location map or lookup table. Embedding EPR data into a large set medical images demonstrated that the proposed scheme would offer significantly better embedded image quality with high embedding capacity compared to the prominent PTB-based RDH schemes.