As an effective technique of copyright protection

digital watermarking techniques have become a new focus of interest in recent years.A useful watermark scheme should be visually imperceptible and must be robust to various attacks.In this paper

a feature-based algorithm is proposed

which embedded a binary image as watermark in DCT domain by taking into account the feature of gradient and intensity of each block.Especially we embed marker bits to locate the original block of cropped image.The proposed technique could actually survive several kinds of image processing such as image cropping

shifting

blurring

noise

sharpening and JPEG lossy compression etc.The algorithm doesn't need the original image for watermark extraction and the simulation results prove its effectiveness.