# Robust Image Embedded Watermarking Using DCT and Listless SPIHT
## 1 Introduction  
With the rapid growth in technology, the internet has become the most popular channel for every user to download digital multimedia data like images and videos. Since the environment of internet is open, this data can easily be tampered with or manipulated, for which data integrity must be ensured. Digital watermarking is a common technique that used to verify this integrity. The watermarking technique consists of three parts, namely: (i) the watermark; (ii) the embedding stage, and; (iii) the verification stage. In the embedding stage the algorithm incorporates the watermark into the host image. However, the algorithm extracts and authenticates the watermark in the verification stage. The goal of image authentication is to verify the originality of the host image by detecting malicious manipulations. There are two essential requirements for image watermarking. One is invisibility, i.e., the visual quality of the watermarked images should not be destroyed by embedding the watermark. The other is robustness, i.e., the watermark should be able to resist attacks, even if the attacks are deliberately made [1]. Digital watermarking techniques are performed in the spatial domain [2] and in the transformed domain [3; 4; 5; 6; 7]. The transformed domain is more robust and operates more imperceptibility than the spatial domain [8; 9]. In the transform domain DCT make use of energy distribution properties and human visual system scheme for embedding the watermark [10]. Blind watermarking schemes with interesting results havebeen proposed in [11; 12]. Some of the other transformed-domain watermarking schemes have been proposed in [13; 14; 15; 16; 17]. SVD (singular value decomposition) is alsoused in watermarking where the properties of U coefficients (after SVD decomposition) modification cause less degradation of image quality [17; 18; 19; 20; 21; 22]. Some of the watermarking techniques using the Ridgelet transform are also proposed [23; 24]. The CRT-based scheme, which provides robustness against some common image processing manipulations, is proposed in [25; 26]. Digital watermarking is also performed using segmentation of DCT blocks [27]. Each DC coefficient is extracted and stored in a matrix before processing, making it expensive in terms of memory requirement [28]. [PERSON] and [PERSON] [6] used middle DCT coefficients for embedding watermark. The algorithm is not very robust against JPEG compression. Watermarking schemes can be implemented in VLSI (very large scale integration) chips. Hardware implementation in consumer electronic devices such as digital camera, PDAs, and mobile devices requires low power, high reliability, real-time performance and easy integration. For example, viability of integration of watermarking chips in any digital camera or JPEG codec. Several issues related to hardware implementation of several watermarking algorithms for images and videos have been reported by [PERSON] et al. [29]. DCT domain watermarking is popular for hardware implementation because there are a number of fast algorithms exists [30; 31; 32; 33; 34]: \(8\times 8\) DCT is mostly used for hardware implementation; \(4\times 4\) DCT provides less computation at a cost of less energy compaction. SPIHT [35] is a benchmark algorithm for the compression of still images and videos in an embedded fashion. It has precise rate control, i.e., the user can set any target bit rate (compression ratio) to reconstruct the compressed images. However, SPIHT uses an auxiliary list, which causes a lot of memory management problem for hardware realization. To overcome this listless SPIHT has been proposed which does not make use of auxiliary lists [36]. The state information that keeps track of set partitions is held in a state marker table in the memory. This algorithm takes less memory and is easy to implement in hardware compared to a conventional JPEG. Recently, CRT-based watermarking with some results has been reported in [25; 26].