Watermarking of Raw Digital Images in Camera Firmware

In this article we investigate 'real-time' watermarking of single-sensor digital camera images (often called 'raw' images) and blind watermark detection in demosaicked images. We describe the software-only implementation of simple additive spread-spectrum embedding in the firmware of a digital camera. For blind watermark detection, we develop a scheme which adaptively combines the polyphase components of the demosaicked image, taking advantage of the interpolated image structure. Experimental results show the benefits of the novel detection approach for several demosaicking techniques.