Reza Agustina

Bio: Reza Agustina is an academic researcher. The author has contributed to research in topics: Harmonic wavelet transform & Second-generation wavelet transform. The author has an hindex of 1, co-authored 1 publications receiving 6 citations.

Comparison of Discrete Cosine Transforms (DCT), Discrete Fourier Transforms (DFT), and Discrete Wavelet Transforms (DWT) in Digital Image Watermarking

Abstract: Digital Image Watermarking is used recently to secure the image by embedding another digital image. It is typically used to identify ownership of the copyright of the signal. Frequency domain transformation methods used widely in Digital Image Compression and Digital Image Watermarking. They reduce the weakness of classics digital image watermarking such as Least Significant Bit (LSB) methods which is more noise-tolerant. Popular transformation method used are Two Dimensional Discrete Cosine Transform (2D DCT), Two Dimensional Discrete Fourier Transforms (2D DFT), and Two Dimensional Discrete Wavelet Transform (2D DWT). This paper will show the comparison result of those three transformation method. The experiments are comparison analysis of image watermark quality using Peak Signal to Noise Ratio (PSNR), color converting, image resizing, image optical scanning and the noise-tolerant of the image watermarked by giving Gaussian noise.

Sonic Watermarking Method for Ensuring the Integrity of Audio Recordings

Abstract: Methods for inspecting the integrity of audio recordings become a necessity. The evolution of technology allowed the manufacturing of small, performant, recording devices and significantly decreased the difficulty of audio editing. Any person that participates in a conversation can secretly record it, obtaining their own version of the audio captured using their personal device. The recordings can be easily edited afterwards to change the meaning of the message. The challenge is to prove if recordings were tampered with or not. A reliable solution for this was the highly acclaimed Electrical Network Frequency (ENF) criterion. Newer recording devices are built to avoid picking up the electrical network signal because, from the audio content point of view, it represents noise. Thus, the classic ENF criterion becomes less effective for recordings made with newer devices. The paper describes a novel sonic watermarking (i.e., the watermark is acoustically summed with the dialogue) solution, based on an ambient sound that can be easily controlled and is not suspicious to listeners: the ticking of a clock. This signal is used as a masker for frequency-swept (chirp) signals that are used to encode the ENF and embed it into all the recordings made in a room. The ENF embedded using the proposed watermark solution can be extracted and checked at any later moment to determine if a recording has been tampered with, thus allowing the use of the ENF criterion principles in checking the recordings made with newer devices. The experiments highlight that the method offers very good results in ordinary real-world conditions.

Recent Trend of Transform Domain Image Steganography Technique for Secret Sharing

Abstract: The security of information is one of the most important attributes to be available when the secret information passes between two parties. Many techniques like watermarking, cryptography and steganography used for this purpose. Cryptography changes the position of original information or scramble the original information, but it reveals the existence of secret information. The hiding the data behind any other object is steganography characteristic. Information hiding characteristic make the steganography more popular as compare to cryptography process. In this paper transform domain-based steganography process are discussed. The main focus in transform domain steganography is the wavelet family; paper includes detail information about different wavelet used in steganography process. The procedure is investigated and contended in the provisions of its payload limit i.e., the capacity to conceal data, how much data can be covered up, and its robustness.

Resilience of selected digital watermarking algorithms to transformation, distortion and compression

Abstract: The work concerns a comparative analysis of well-known and widely used signing digital images using digital watermarks. It consists of three parts: the introduction to the subject matter, description of algorithms, and the research part. In the research part: tools, tests and results of digital watermarks resistance on the transformation, distortion and compression are presented. In conclusion, the findings are discussed and directions for further research identified.

Development of DWT–SVD based Digital Image Watermarking for Multi-level Decomposition

Abstract: In the age of digital data, the safety of digital content has gradually become paramount important. The demand for digital data in various forms such as text, images, video and audio has increased manifold. There are lots of vulnerabilities concerning digital data. It can easily be attacked, forged and manipulated to produce illegal copies. In the watermarking process, information, i.e., watermark image is inserted into a host data and extracted later in case of Copyright violation; owner of the content can demonstrate his ownership by regaining the embedded watermark. A watermark must be capable of being recovered even if a piece of content is modified or changed by several attacks. This paper uses frequency-domain technique, and the multi-level decomposition of the host image is done by using the combination of two-dimensional DWT (2D DWT) and SVD techniques. Here, the host/cover image is decomposed at six different levels separately, and the watermark image is inserted in the region of lowest frequency. After inserting a watermark, the host/cover image is reconstructed using an inverse DWT technique. By exposing the watermarked image to different image processing attacks such as pepper and salt, speckle and rotation, the robustness of various levels has been analyzed. The embedded watermark is extracted afterward and matched with the original one based on PSNR and MSE. The comparative experimental results show that the decomposition of the host image at the third level is found to be more suitable for watermarking among all other levels.