Pengamanan Hak Cipta Citra Digital dengan Teknik Watermarking Menggunakan Metode Hybrid SVD dengan DWT

Era zaman digital saat ini, internet telah menjadi sebuah kebutuhan sehari-hari, yang memberikan kemudahan terhadap pengguna untuk melakukan aktivitas transmisi file, namun demikian data tersebut membutuhkan proteksi dari tangan yang tidak bertanggung jawab. Dalam penelitian ini di ajukan sebuah metode digital watermarking dalam melakukan perlindungan terhadap motif batik. Adapun algoritma yang diterapkan yaitu Hybrid Singular Value Decomposition dengan Discrete Wavelete Transform, setelah dilakukan experimen penerapan Hybrid Image Watermarking DWT dengan SVD nilai alpha dapat mempengaruhi tingkat imperceptibility terhadap citra watermarked, karena nilai alpha menunjukkan tingkat ketampakan (visible) watermark pada cover image. Semakin rendah nilai alpha maka tingkat ketampakan watermark semakin berkurang dan tingkat imperceptibility semakin tinggi. Dari pengujian yang dilakukan dengan object motif batik ditemukan nilai alpha terbaik yaitu nilai alpha 0.01, karena mendapatkan nilai PSNR tertinggi dari yang lainnya, sedangkan Berdasarkan pengujian tingkat robustness metode Hybrid Image Watermarking DWT-SVD pada subband LL memiliki tingkat ketahanan yang cukup tinggi terhadap upaya menghilangkan watermark yang menjadi identitas kepemilikan sah terhadap suatu citra digital selama citra watermarked tidak direkayasa dengan serangan noise.

An Adaptive Visible Watermark Embedding Method based on Region Selection

Aiming at the problem that the robustness, visibility, and transparency of the existing visible watermarking technologies are difficult to achieve a balance, this paper proposes an adaptive embedding method for visible watermarking. Firstly, the salient region of the host image is detected based on superpixel detection. Secondly, the flat region with relatively low complexity is selected as the embedding region in the nonsalient region of the host image. Then, the watermarking strength is adaptively calculated by considering the gray distribution and image texture complexity of the embedding region. Finally, the visible watermark image is adaptively embedded into the host image with slight adjustment by just noticeable difference (JND) coefficient. The experimental results show that our proposed method improves the robustness of visible watermarking technology and greatly reduces the risk of malicious removal of visible watermark image. Meanwhile, a good balance between the visibility and transparency of the visible watermark image is achieved, which has the advantages of high security and ideal visual effect.

Multipurpose Watermarking Algorithm for Medical Images

Considering the existing medical image watermarking algorithms, a single function often has limitations, and a multipurpose watermarking algorithm for medical images is proposed. First, medical images are divided into regions of interest (ROIs) and regions of noninterest (RONIs). Then, the authentication watermark produced for each subblock of the ROI is embedded into the corresponding mapping subblock. The visible watermark is embedded into the RONI, and, finally, the watermark information and constructed authentication information in each subblock of the ROI are embedded into the corresponding RONI subblock. Simulation results show that the embedded visible watermark can protect and facilitate medical image management. In addition, the proposed algorithm has strong robustness and very good visual quality. It can simultaneously realize copyright protection and content authentication and also has high tamper localization capability.

FCM-Based Approach for Locating Visible Video Watermarks

The increased usage demand for digital multimedia has induced significant challenges regarding copyright protection, which is the copy control and proof of ownership. Digital watermarking serves as a solution to these kinds of problems. Among different types of digital watermarking, visible watermarking protects the copyrights effectively, since the approach not only prevents pirates but also visually proves the copyright of the broadcasted video. A visible watermark could be in any location on the frame (corner, center, diagonal, etc.). In addition, it could either completely or partially disappear for some frames. The same video also might have multiple watermarks. In order to strengthen the techniques of adding visible watermarks, there is a need to discover the weakness of the used watermarks. Since the major step of attacking a visible watermark is to locate it accurately, in this paper, a Fuzzy C-Means (FCM)-based approach is proposed to locate visible watermarks in video. Broadcasting channels are used to utilize video logos, which can be considered as a form of visible watermark that represents a trademark or symbol to declare the intellectual property ownership. In general, a high-standard video watermark has such properties as a clear background with distinctive shape without additional texture obscuring the watermark area. In addition, the probability of the logo appearing in the four corners of the video frames is higher than in the center. Based on these common properties of the video watermark, the proposed scheme locates the visible watermark using the Fuzzy C-Means technique without any prior information. The proposed technique has two stages: the first stage is positioning, and the second is masking (extracting the watermark mask). Due to real-world limitations such as noise, shadowing, and variations in cameras, the positioning stage is developed by employing gradient and Fuzzy C-Means classifier techniques. By using the dilation and erosion operators, the masking stage is developed to extract the watermark mask. Using a set of trademark videos, the proposed algorithm is tested and evaluated. A comparative study shows that the proposed FCM-based technique is able to achieve higher accuracy at a reasonable computational cost in comparison to the most related and recent published work. The proposed technique could locate different watermarks with high symmetry in their pattern, even if they appeared mutually in the same location. Still, it will be a challenge if the symmetry is low between used watermarks in the same location.