Image watermarking using DCT in selected pixel regions

A watermarking method capable of imperceptible watermark addition in grayscale images is proposed in this paper. Digital images and other digital resources can be protected from unauthorized usages by watermarking mechanism. The algorithm proposed here ensures a higher visual quality after watermark addition. Blocks or pixel regions selected for watermark hiding are such regions in the image where modifications are least noticeable by human eyes. Eligible pixel blocks chosen from the image are then transformed using discrete cosine transform to employ the mid-frequency coefficients for watermark integration.