Robustness and imperceptibility are two conflicting requirements which should be considered while designing a new image watermarking scheme. To balance these two requirements, the watermark should be embedded in the most perceptually significant components of an image based on human visual properties, instead of random selections of the embedding regions. In fact, human visual system is studied deeply in the past two decades . Therefore, it is widely accepted and recommended that for providing the highest possible level of robust and imperceptible image watermarking techniques, the characteristics of human visual system (HVS) should be exploited. Some of these important characteristics are listed as following:
- Human eyes are less sentient of noise in textured area then smooth area.
- Human eyes are less sentient of noise in high-resolution bands then low-resolution bands.
- Human eyes are less sentient of noise in the area of image where background brightness is low or high.
HVS can be used to improve the imperceptibility during the embedding process; thus, in this article, we have taken advantage of visual entropy and edge entropy to select watermarking embedding region. The visual entropy is used to quantify the texture content of an image; in other words, it is a well-known measure describing of an image’s texture.