DCT-domain watermarking techniques for still images: detector performance analysis and a new structure

Abstract

In this paper, a spread-spectrum-like discrete cosine transform (DCT) domain watermarking technique for copyright protection of still digital images is analyzed. The DCT is applied in blocks of 8x8 pixels, as in the JPEG algorithm. The watermark can encode information to track illegal misuses. For flexibility purposes, the original image is not necessary during the ownership verification process, so it must be modeled by noise. Two tests are involved in the ownership verification stage: watermark decoding, in which the message carried by the watermark is extracted, and watermark detection, which decides whether a given image contains a watermark generated with a certain key. We apply generalized Gaussian distributions to statistically model the DCT coefficients of the original image and show how the resulting detector structures lead to considerable improvements in performance with respect to the correlation receiver, which has been widely considered in the literature and makes use of the Gaussian noise assumption. As a result of our work, analytical expressions for performance measures, such as the probability of errors in watermark decoding and the probabilities of false alarms and of detection in watermark detection, are derived and contrasted with experimental results.

Image Compression Using Discrete Cosine Transform (DCT) & Discrete Wavelet Transform (DWT) Techniques

“…In DCT, the whole image is divided into n*n blocks. Then DCT is applied to these blocks [5]. The changes across the width and height of the blocks are expressed as high order terms and the average value in a block is expressed as low order terms.The DCT transforms the image into pixels.…”

A Novel DWT-SVD Canny-Based Watermarking Using a Modified Torus Technique

“…Ganic and Eskicioglu [6]'s method is based on DWT-SVD, but the data is embedded on different frequencies. Hernandez et al [7] measured the performance for the DCT domain-based watermarking technique. DWT is widely used in watermark embedding due to its various advantages over other transforms [8][9][10].…”

Hop Horse-Image Authentication Scheme

“…The watermarking techniques applied in spatial and frequency domains are reviewed in [8], [9] and [10]. The methods proposed in [9] and [10] concentrated on the frequency and wavelet based techniques, evaluating the surveyed techniques through comparison and performance analyses.…”

“…The methods proposed in [9] and [10] concentrated on the frequency and wavelet based techniques, evaluating the surveyed techniques through comparison and performance analyses. Several watermarking techniques applied in spatial domain store the watermarking information into the LSBs [11] - [16].…”