Copyright protection for digital image in wireless sensor network

In wireless sensor network (WSN), digital image data are transported in uncontrolled and possibly hostile environment. Thus, copyright protection has drawn much attention in behalf of the originators of the sensing data in wireless transmission. Traditional security schemes are computationally expensive, because they introduce overhead which shortens the life of the image sensors. In comparison with traditional security techniques, watermark schemes are usually light weight and do not require extensive computing and power resources. Thus they can be attractive options for wireless sensor applications. According to the feature of DCT coefficients, this paper proposes a real-time robust watermark algorithm whose coefficients are obtained through experiments. To make the watermark more robust, we embed the watermark into the low-frequency coefficients of DCT. Experimental results show that this algorithm is real-time, imperceptible and robust, thereby it can satisfy with the wireless network transmission requirements.