Robust multi-bit watermarking for HDR images in the Radon-DCT domain

High Dynamic Range (HDR) imaging is rapidly emerging as an innovative approach for digitally representing and reproducing real scenes with a wide range of intensity levels, which can be hardly managed by current standard methods for image capture and display. In order to protect the intellectual property of HDR images, a novel blind multi-bit watermarking method exploiting both their peculiar characteristics and the properties of the Radon-Discrete Cosine Transform (RDCT) for the embedding process, is here proposed. The performed experimental tests demonstrate the possibility of marking HDR images without significantly altering their perceptual characteristics, while guaranteeing the recovery of the embedded information even from Low Dynamic Range (LDR) images obtained through the application of different tone-mapping operators (TMOs).