Methods (450, 750) are disclosed for embedding a watermark into an image (400, 700). The watermark comprises at least one basis pattern. A real part of the basis pattern(s) (410, 710) is added to the image (400, 700) to form a watermarked image (420, 730). The basis pattern(s) has scale and rotation invariant properties. The pattern(s) is preferably added to the image at a low intensity to make the pattern(s) invisible or imperceptible to the human visual system under normal viewing conditions. Methods (800, 900) are also disclosed for detecting a watermark from a watermarked image (810, 910). The watermark image (810, 910) is correlated with the basis pattern to provide a result image (830, 950). Peaks in the result image (830, 950) correspond with positions where the basis pattern was detected in the watermarked image (830, 950)