The present paper proposes a blind multi-bit watermarking method for High Dynamic Range (HDR) images. The proposed
approach is designed in order to guarantee the watermark imperceptibility both in the HDR marked image and in its Low
Dynamic Range (LDR) counterpart, being thus robust against significant non-linear distortions such as those performed
by tone-mapping operators (TMOs). In order to do so, the wavelet transform of the Just Noticeable Difference (JND)-
scaled space of the original HDR image is employed as embedding domain. Moreover, a visual mask taking into account
specific aspects of the Human Visual System (HVS) is exploited to improve the quality of the resulting watermarked image.
Specifically, bilateral filtering is used to locate information on the detail part of the HDR image, where the watermark
should be preferably embedded. A contrast sensitivity function is also employed to modulate the watermark intensity
in each wavelet decomposition subband according to its scale and orientation. An extensive set of experimental results
testifies the effectiveness of the proposed scheme in embedding multi-bit watermarks into HDR images without affecting
the visual quality of the original image, while being robust against TMOs.