A new visible watermarking technique applied to CMOS image sensor

This paper presents a new visible watermarking solution for CMOS image sensor which can enhance secure features of captured images. Visible watermarks are embedded in the Bayer format image data and can be transferred by the subsequent interpolation process. A piecewise function is setup based on the gray scale resolution characteristics of human eyes. Watermark stretch factor can be adaptively chosen according to the gray value of the current pixel. The advantage of this algorithm is that the watermark has the same visibility in different image brightness region. A number of color images have been used to test the method. In order to check the robustness of watermarked images, we conducted adding noise and filtering experiments, results show that the visibility of watermark is also good after the experiments. The approach allows a digital watermark to be embedded in an image immediately upon its capture, before leaving the imaging chip.

[1]  Annajirao Garimella,et al.  VLSI implementation of online digital watermarking technique with difference encoding for 8-bit gray scale images , 2003, 16th International Conference on VLSI Design, 2003. Proceedings..

[2]  R. Lukac,et al.  Camera Image Watermark Transfer by Demosaicking , 2006, Proceedings ELMAR 2006.

[3]  Saraju P. Mohanty,et al.  VLSI implementation of invisible digital watermarking algorithms towards the development of a secure JPEG encoder , 2003, 2003 IEEE Workshop on Signal Processing Systems (IEEE Cat. No.03TH8682).

[4]  Saraju P. Mohanty,et al.  VLSI architecture and chip for combined invisible robust and fragile watermarking , 2007, IET Comput. Digit. Tech..

[5]  Saraju P. Mohanty,et al.  VLSI implementation of visible watermarking for secure digital still camera design , 2004, 17th International Conference on VLSI Design. Proceedings..

[6]  Graham A. Jullien,et al.  CMOS image sensor with watermarking capabilities , 2005, 2005 IEEE International Symposium on Circuits and Systems.

[7]  Deepa Kundur,et al.  Hardware implementation perspectives of digital video watermarking algorithms , 2003, IEEE Trans. Signal Process..

[8]  Andrew Z. Tirkel,et al.  A Unique Watermark for Every Image , 2001, IEEE Multim..

[9]  Dai Jing-min.  New technology of infrared image contrast enhancement based on human visual properties , 2008 .

[10]  Jiying Zhao,et al.  Human visual system based adaptive digital image watermarking , 2008, Signal Process..

[11]  Deepa Kundur,et al.  VLSI implementation of a real-time video watermark embedder and detector , 2003, Proceedings of the 2003 International Symposium on Circuits and Systems, 2003. ISCAS '03..