Data Hiding in Perceptually Masked OpenEXR Image

High dynamic range (HDR) imaging is able to capture and display significantly more colors when compared to the legacy imaging technology. Recently, HDR environment is gaining popularity and becoming common in our daily life, which resulted in the growing number of HDR images. In this work, a technique is put forward to first perceptually mask a HDR image, and then hide data into the masked HDR image. Specifically, pixels in the OpenEXR file, which are stored in half floating point precision format, are manipulated. First, a predictor is utilized to predict pixel values, where well predicted pixel locations are flagged and utilized as the venues to hide data. On the other hand, the ill predicted pixel locations are flagged as unusable. Next, each pixel is divided into segments of 5 bits, and the segments are XOR-ed and permuted to mask the perceptual semantic of the HDR image. Data hiding then takes place at locations flagged as usable, which further distorts the quality of the image. The proposed method is both reversible and separable. The basic performance of the proposed joint technique is evaluated by using 6 HDR images. In the best case scenario, 91% of pixels in the image can be utilized for data hiding purpose while the perceptual semantic of the original image is completely masked.