# RST Resilient Watermarking Scheme Based on DWT-SVD and Scale-Invariant Feature Transform
## 1 Introduction
Two bits of a watermark are being embedded into a 32 \(\times\) 32 macro-block in the high frequency band of SVD-DCT blocks. This method does not require any additional information except a key for extraction. [PERSON] et al. [11] embedded the watermark after DCT into four quadrants/blocks performed by SVD, which DCT coefficients are mapped to, and singular values of the watermark after DCT are embedded into each quadrant. [PERSON] et al. [12] proposed a DWT and SVD based watermarking scheme, embedding the watermark information into singular values of the host image's DWT sub-bands. In [13], with the help of directive contrast operation as well as wavelet coefficients, [PERSON] and [PERSON] obtained the reference image and embedded the watermark into a reference image based on SVD and DWT. [PERSON] et al. [14] proposed an optimized image watermarking based on DWT-SVD and the Firefly algorithm. The singular value of a binary watermark is embedded into the three-level low frequency sub-band, also known as LL sub-band, by the use of optimized scaling factors. In [15], [PERSON] et al. made an analysis on DWT watermarking scheme and DWT-SVD watermarking scheme used in RGB images, concluding that the hybrid DWT-SVD based scheme has better performance than the conventional DWT based scheme. [PERSON] and [PERSON] [16] proposed a robust watermarking scheme based on DWT, SVD, and DCT with Arnold encryption, solving the false positive problem. In [17], [PERSON] et al. proposed integer wavelet transform (IWT) and SVD based watermarking, making use of these transforms properties to solve the false positive problem. To optimize the scaling factor, the artificial bee colony (ABC) algorithm is applied to improve the quality of watermarking. Although SVD is applied in the watermarking scheme because of its stability, robustness of schemes based on SVD and other transforms to geometrical attacks is not satisfying. Rotation, scaling, and translation (RST) [18] are common geometrical attacks in image processing. Because of RST attacks on the host image, the watermark cannot be detected and extracted as normal. It is urgent to research and propose the watermark method with the resistance to the RST attacks [19]. To solve this problem, the scale-invariant feature transform (SIFT) [20] is applied in image watermarking, which is a type of efficient method for interesting points detection and extraction, as well as local feature description. Due to its significant function, SIFT is widely applied in computer vision field, such as image matching and image object recognitions. There are some characters in SIFT, including invariant character to RST and robustness against affine transform. Thus, SIFT can be applied in various kindsof fields such as object recognition, image indexing, segmentation, registration, and data hiding [21]. In recent years, SIFT is applied extensively in watermarking. [PERSON] et al. [22] proposed a novel image watermarking scheme using local invariant features, as well as embedding the watermark into the patches in circle shapes generated by SIFT. To deal with the synchronization errors, [PERSON] et al. [23] proposed an adaptive watermarking scheme based on DFT and SIFT. In this method, DFT is performed on the sub-image selected from the host image for watermark embedding. In [24], [PERSON] et al. proposed image watermarking scheme based on SIFT and DWT, where they applied the DWT on the selected SIFT areas. [PERSON] and [PERSON] [25] proposed an anti-geometrical attacks watermarking scheme based on IWT and SIFT. This scheme applied SIFT on the red components of the image, extracted the feature points and performed IWT on the blue and green components to extract low-frequency coefficients for watermark embedding. [PERSON] et al. [26] proposed a robust watermarking scheme based on SIFT and DCT, embedding the watermark into the selected feature region after DCT. In [27], [PERSON] and [PERSON] proposed a watermarking algorithm based on SVD and SIFT to solve the synchronization problem.