A robust digital image watermarking scheme based on bat algorithm optimization and SURF detector in SWT domain Ali Pourhadi 1 & Homayoun Mahdavi-Nasab 1,2 Received: 15 July 2019 /Revised: 4 April 2020 /Accepted: 22 April 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract This paper presents an optimized robust digital image watermarking scheme based on Stationary Wavelet Transform (SWT) using Bat optimization Algorithm (BA) and Speed- Up Robust Feature (SURF). The proposed scheme applies high-frequency coefficients of the SWT of the host image in the BA framework to optimize watermark strength factors in the embedding process, considering relevant attacks. On the final step of this process, the SURF detector is employed on the watermarked image for getting point features used for geometric distortion correction. For watermark extracting, the primary step is to correct probable geometrical distortions, utilizing the SURF rotation and scaling invariance property, and the procedure goes on by executing the reverse of embedding phase steps. For evaluating the capabilities of the proposed algorithm, different types of image processing operations such as Gaussian filtering, scaling, rotation and salt and pepper, Poison, speckle, and Gaussian noise, have been used as attacks. According to the experimental results, the proposed combination of techniques exhibits an overall superior performance in both imperceptibility and robust- ness metrics in various situations compared to state-of-the-art and relevant methods. Keywords Image watermarking . Stationary wavelet transform . Speed-up robust feature . Bat algorithm . Arnold transform 1 Introduction In recent years, the immense growth of information technologies and ease of accessibility to digital information has led to the investigation of new types of efficient techniques of safe data- Multimedia Tools and Applications https://doi.org/10.1007/s11042-020-08960-0 * Homayoun Mahdavi-Nasab mahdavinasab62@gmail.com 1 Department of Electrical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran 2 Digital Processing and Machine Vision Research Center, Najafabad Branch, Islamic Azad University, Najafabad, Iran