Xun Jin

A Secure Image Watermarking Using Visual Cryptography

In this paper we proposed a secure image watermarking algorithm for digital image using the visual cryptography. The proposed algorithm operates in discrete cosine transform (DCT) and discrete fractional random transform (DFRNT) domain which is characterized by fractional order α and random seed β. In the watermark embedding process of the proposed algorithm some blocks of a cover object is selected randomly, and they are transformed to DFRNT domain. The watermark is generated by the visual cryptography and embedded into the DCT coefficient of the DFRNTed block. The watermark extraction process is the reverse process of embedding process. The proposed watermarking algorithm has high security by the visual cryptography and the randomness of discrete fractional random transform. The experimental results show that the proposed watermarking algorithm is imperceptible and moreover is robust against JPEG compression, common image processing distortions.

Video fragment format classification using optimized discriminative subspace clustering

All video streams consist of highly compressed coded data. A video stream must be decoded to identify a video. It is impossible to decode and identify a video fragment without knowing the correct video format. Therefore, the first issue that must be addressed is classification of video formats. Although several methods exist for classifying file formats, a technology that specifically classifies the formats of video fragments has not been developed. In this paper, we present a novel approach to classify the formats of small fragments of video streams. Our classification procedure involves construction of high-dimensional feature vectors by combining synchronization patterns extracted from training fragments. The feature vectors are classified using optimized discriminative subspace clustering (ODiSC). The experimental results show a minimum classification error rate of 4.2%, and the precision of identification of the formats was greater than 91% for the four video formats whose fragment size was 256KB. Design of a novel video fragment format classification technique.Construction of high-dimensional feature vectors by combining synchronization patterns from video fragments.Design of an improved adaptive ODiSC algorithm for video format classification further optimized using a PbEA.

Imperceptibility Improvement of Image Watermarking Using Variance Selection

In this paper, we propose a method of complex region selection for digital images using variance selection. In order to improve the imperceptibility of the watermarked image, our method selects blocks based on their variance. The watermark embedding process operates in the discrete fractional random transform and discrete cosine transform domains. The watermark is embedded into the selected blocks, which are transformed into the frequency domain. For security, visual cryptography is used to encode the watermark. The watermark extraction process is the reverse of the embedding process. The experimental results show that the proposed block selection method significantly improves imperceptibility over a randomly chosen block, and that the watermarking algorithm is robust against common attacks.