Comments on “Optimized gray-scale image watermarking using DWT-SVD and Firefly Algorithm”

This study shows that a recently proposed image watermarking scheme in the paper “Optimized gray-scale image watermarking using DWT-SVD and Firefly Algorithm” (Agarwal, Mishra, Sharma, & Bedi, 2014) has a fundamental flaw in its design. The extracted watermark is not the embedded watermark, actually it is determined by the reference watermark, which leads to false positive detection problem. Hence, it invalidates the objective of the scheme and cannot be used for the protection of rightful ownership. The weakness of the scheme designing is illustrated with an example.