Semnan University International Journal of Nonlinear Analysis and Applications 2008-6822 12 Special Issue 2021 12 01 A new image watermarking algorithm by using contourlet transform accompanied by PSO algorithm 563 570 5356 10.22075/ijnaa.2021.5356 EN Khosro Jalali Department of Electrical Engineering, Nour Branch, Islamic Azad University, Nour, Iran Javad Vahidi Department of Mathematics, Iran University of Science and Technology, Tehran 1684613114, Iran Department of Mathematical Sciences, University of South Africa, UNISA0003, South Africa Seyed Saleh Mohseni Department of Electrical Engineering, Nour Branch, Islamic Azad University, Nour, Iran Hadi Dehbovid Department of Electrical Engineering, Nour Branch, Islamic Azad University, Nour, Iran Journal Article 2021 01 12 One of the ways to enhance the security and concealment of data used today is image watermarking. In image watermarking operation, we try to hide image inside another image without letting others know about the hidden image. In this paper, Contourlet Transform and SVD Transform are used to embedded watermark in the host image. The PSO Optimization Algorithm is also used in the watermark extraction step to find the best scale factor. The results of the proposed algorithm in this article show an improvement over the comparative methods. https://ijnaa.semnan.ac.ir/article_5356_b751163cff963b81ab649f136a2193f9.pdf