HDR image watermarking based on bracketing decomposition

The present paper proposes a novel watermarking scheme specifically designed for high dynamic range (HDR) images. The employed embedding strategy is based on a decomposition of the original HDR representation into multiple low dynamic range (LDR) images by means of a bracketing process. After having inserted the selected watermark into each LDR component, the final output is generated by combining the available contributions into a single HDR object. By exploiting some of the well studied properties of digital watermarking for standard LDR images, our approach is able to generate a watermarked HDR image visually equivalent to the original one, while allowing to detect the embedded information in both the marked HDR image and in its LDR counterpart, obtained through tone-mapping operators or by extracting a specific luminance range of interest from it. Several results obtained from an extensive set of experimental tests are reported to testify the effectiveness of the proposed scheme.