A contrast-sensitive reversible visible image watermarking technique

A reversible (also called lossless, distortion-free, or invertible) visible watermarking scheme is proposed to satisfy the applications, in which the visible watermark is expected to combat copyright piracy but can be removed to losslessly recover the original image. We transparently reveal the watermark image by overlapping it on a user-specified region of the host image through adaptively adjusting the pixel values beneath the watermark, depending on the human visual system-based scaling factors. In order to achieve reversibility, a reconstruction/ recovery packet, which is utilized to restore the watermarked area, is reversibly inserted into non-visibly-watermarked region. The packet is established according to the difference image between the original image and its approximate version instead of its visibly watermarked version so as to alleviate its overhead. For the generation of the approximation, we develop a simple prediction technique that makes use of the unaltered neighboring pixels as auxiliary information. The recovery packet is uniquely encoded before hiding so that the original watermark pattern can be reconstructed based on the encoded packet. In this way, the image recovery process is carried out without needing the availability of the watermark. In addition, our method adopts data compression for further reduction in the recovery packet size and improvement in embedding capacity. The experimental results demonstrate the superiority of the proposed scheme compared to the existing methods

New Cloud-Based Service for Broadcasting and Identification for Solving Data Traffic Re-Using for Mobile Communications

In recent decades, the majority of mobile communications data traffic has relied on RF technology. Even if optimization efficiency for use or reuse is implemented, there are limits to the growing traffic demand for RF communications. Visible light communications (VLC) is a new technology that can work with RF to overcome these limitations. The standard for VLC was published in 2011 as IEEE 802.15.7, which specifies specifications for the MAC layer and PHY layer. This standard is one of the first for this technology. The light emission decoding operation at the receiver in IEEE 802.15.7 is mainly based on photo detectors. However, with the development of image sensors (photodiode arrays) in smart devices, changes to the IEEE 802.15.7 specification are being considered. This expansion will primarily focus on communications with image sensors, called optical camera communications (OCC). In this paper, we analyze the performance of camera communication systems based on different types of image sensor architectures. We then propose OCC-ID, a novel streaming service application that uses camera communication and a cloud model. The proposed architecture is a general implementation scenario for camera communications. Optical camera communication has great potential in future wireless communications due to the advantages of VLC and business trends. A revision of the IEEE 802.17.5 standard is currently under study. However, OCC's issues regarding timing, data rate, and interference still need to be resolved. Synchronization is an important issue because the signal received from the camera is a discrete image from the transmitter without any feedback information and because camera communication applications are based on a transmission topology. Roller blinds have more advantages in terms of timing than overall blinds. In this study, we present and evaluate the performance of two image detection techniques, namely rolling shutter and global shutter. The performance of the two image sensors and their considerations will play an important role in the standard's contribution. Finally, we propose a new service application for OCC based on cloud architecture, called OCC-ID. Invisible identification can be accomplished using visible light communications, camera communications, and cloud computing technology. The ID is integrated into the optical channel using OOK or OOK frequency shift modulation. The receiver uses the camera to decode the information embedded in the LED and then transmits it to the cloud server transmission link based on the detected ID. The OCC-ID system shows the advantages of dynamic content management compared to traditional identification systems

Bits from Photons: Oversampled Image Acquisition Using Binary Poisson Statistics

We study a new image sensor that is reminiscent of traditional photographic film. Each pixel in the sensor has a binary response, giving only a one-bit quantized measurement of the local light intensity. To analyze its performance, we formulate the oversampled binary sensing scheme as a parameter estimation problem based on quantized Poisson statistics. We show that, with a single-photon quantization threshold and large oversampling factors, the Cram\'er-Rao lower bound (CRLB) of the estimation variance approaches that of an ideal unquantized sensor, that is, as if there were no quantization in the sensor measurements. Furthermore, the CRLB is shown to be asymptotically achievable by the maximum likelihood estimator (MLE). By showing that the log-likelihood function of our problem is concave, we guarantee the global optimality of iterative algorithms in finding the MLE. Numerical results on both synthetic data and images taken by a prototype sensor verify our theoretical analysis and demonstrate the effectiveness of our image reconstruction algorithm. They also suggest the potential application of the oversampled binary sensing scheme in high dynamic range photography

A Study of Image Fingerprinting by Using Visual Cryptography

As digital media has made our life more colourful because of its advantages like easier to access, copy and distribute. But as what we have seen, series of malice activities like copyright infringement, counterfeiting, piracy and information distortion make damages to both the producers and the users of digital products. So we really need some technology to protect the copyright, authenticity, integrity of the digital products and the intellectual property of the users. There are many techniques such as Digital watermarking and Visual Cryptography both have been widely used for protection of data either in text, video, sound or digital images form in modern network time. Digital watermarking is an evolving field that requires continuous effort to find for the best possible method in protecting multimedia content. But Visual Cryptography is a special encryption technique to hide information in images in such a way that it can be decrypted by the human vision if the correct key image is used. Both techniques addresses the growing concerns of theft and tampering of digital media through the use of advanced signal processing strategies to embed copyright and authentication information within media content in their respective manner. In this paper we have discussed image fingerprinting with the help of visual cryptography technique. Keywords: Authentication, Digital Media, Digital Watermarking, Fingerprinting, Image, Piracy, Visual Cryptograph