Sharma - School of Electrical & Electronics Communication Engineering, Galgotias University, Greater Noida, India.
Chauhan - School of Electrical & Electronics Communication Engineering, Galgotias University, Greater Noida, India.
Khanam - Department of CSE, Sharda University, Greater Noida, India.
Singh - Department of ECE, KIET Group of Institutions, Delhi-NCR, Ghaziabad, India.

In this paper a novel digital watermarking algorithm is proposed. The proposed method comprises of a watermarking embedding and extraction algorithm using bio inspired optimization technique. Dragonfly algorithm (DA) is based on the static and dynamic swarming behaviors of dragonflies in nature. The dragonfly algorithm is used to optimize the scaling factor of the watermarking so that an optimal watermark is embedded. Watermarking algorithms take as input a cover image and the message. The cover image in the proposed method is decomposed into sub bands using discrete wavelet transform (DWT). Thereafter, it is converted to discrete cosine blocks (DCT). An optimal scaling factor is required for performing the watermarking. In this paper, DA is used for computing the scaling factor. The DA generated scaling factor is optimal and improves the performance of the watermarking. The inverse DWT and DCT are computed to extract the watermarked image from the cover image. The proposed method is applied on different images to evaluate the performance. The results obtained are compared with other state of the art methods.

Image watermarking, Dragonfly optimization, Discrete Wavelet Transform, Copyright protection