Manuel Cedillo-Hernandez

Watermarking-based image authentication with recovery capability using halftoning technique

In this paper two watermarking algorithms for image content authentication with localization and recovery capability of the tampered regions are proposed. In both algorithms, a halftone version of the original gray-scale image is used as an approximated version of the host image (image digest) which is then embedded as a watermark sequence into given transform domains of the host image. In the first algorithm, the Integer Wavelet Transform (IWT) is used for watermark embedding which is denominated WIA-IWT (Watermarking-based Image Authentication using IWT), while in the second one, the Discrete Cosine Transform (DCT) domain is used for this purpose, we call this algorithm WIA-DCT (Watermarking-based Image Authentication using DCT). In the authentication stage the tampered regions are detected using the Structural Similarity index (SSIM) criterion, which are then recovered using the extracted halftone image. In the recovery stage, a Multilayer Perceptron (MLP) neural network is used to carry out an inverse halftoning process to improve the recovered image quality. The experimental results demonstrate the robustness of both algorithms against content preserved modifications, such as JPEG compression, as well as an effective authentication and recovery capability. Also the proposed algorithms are compared with some previously proposed content authentication algorithms with recovery capability to show the better performance of the proposed algorithms.

Transcoding resilient video watermarking scheme based on spatio-temporal HVS and DCT

Video transcoding is a legitimate operation widely used to modify video format in order to access the video content in the end-users devices, which may have some limitations in the spatial and temporal resolutions, bit-rate and video coding standards. In many previous watermarking algorithms the embedded watermark is not able to survive video transcoding, because this operation is a combination of some aggressive attacks, especially when lower bit-rate coding is required in the target device. As a consequence of the transcoding operation, the embedded watermark may be lost. This paper proposes a robust video watermarking scheme against video transcoding performed on base-band domain. In order to obtain the watermark robustness against video transcoding, four criteria based on Human Visual System (HVS) are employed to embed a sufficiently robust watermark while preserving its imperceptibility. The quantization index modulation (QIM) algorithm is used to embed and detect the watermark in 2D-Discrete Cosine Transform (2D-DCT) domain. The watermark imperceptibility is evaluated by conventional peak signal to noise ratio (PSNR) and structural similarity index (SSIM), obtaining sufficiently good visual quality. Computer simulation results show the watermark robustness against video transcoding as well as common signal processing operations and intentional attacks for video sequences.

Robust hybrid color image watermarking method based on DFT domain and 2D histogram modification

In this paper, we present a robust hybrid watermarking method applied to color images for authentication, which presents robustness against several distortions. Due to the different nature of common signal processing and geometrical attacks, two different techniques for embed a same watermark are used in this method. In the first one, the luminance component (Y) information is used to embed the watermark bit sequence into the magnitude of the middle frequencies of the Discrete Fourier Transform (DFT). In the second one, a selected region of 2D histogram composed by blue-difference and red-difference (Cb–Cr) chrominance components is modified according to the watermark bit sequence. The quality of the watermarked image is measured using the following well-known indices peak signal to noise ratio (PSNR), visual information fidelity (VIF) and structural similarity index (SSIM). The difference color of the watermarked image is obtained using the normalized color difference (NCD) measure. The experimental results show that the proposed method provides robustness against several geometric distortions, signal processing operations, combined distortions and photo editing. The comparison with the previously reported methods based on different techniques is also provided.

Robust watermarking method in DFT domain for effective management of medical imaging

In general, management of medical data is achieved by several issues of medical information such as authentication, security, integrity, privacy, among others. Because medical images and their related electronic patient record (EPR) data are stored separately; the probability of corruption of this information or their detachment from the corresponding EPR data could be very high. Losing data from the corresponding medical image may lead to a wrong diagnostic. Digital watermarking has recently emerged as a suitable solution to solve some of the problems associated with the management of medical images. This paper proposes a robust watermarking method for medical images to avoid their detachment from the corresponding EPR data in which the watermark is embedded using the digital imaging and communications in medicine standard metadata together with cryptographic techniques. In order to provide a high robustness of the watermark while preserving at the same time a high quality of the watermarked images, the generated watermark is embedded into the magnitude of the middle frequencies of the discrete Fourier transform of the original medical image. During the detection process, the watermark data bits are recovered and detected using the bit correct rate criterion. Extensive experiments were carried out, and the performance of the proposed method is evaluated in terms of imperceptibility, payload, robustness and detachment detection. Quantitative evaluation of the watermarked images is performed by using three of the more common metrics: the peak signal-to-noise ratio, structural similarity index and visual information fidelity. Experimental results show the watermark robustness against several of the more aggressive geometric and signal processing distortions. The receiver operating characteristics curves also show the desirable detachment detection performance of the proposed method. A comparison with the previously reported methods with similar purposes respect to the proposed method is also provided.

An efficient color descriptor based on global and local color features for image retrieval

In the context of content-based image retrieval (CBIR) problem, an image is represented by feature vectors called descriptors, whose efficiency is essential to obtain a good performance in the image indexing and retrieval tasks. In this paper, we propose an algorithm to obtain an efficient color-based descriptor, which is a combination of Color Correlogram (CC) and Dominant Color (DC). The color-based descriptors, such as Histogram Intersection (HI) and DC take into account the global distribution of color in an image, while CC takes into account the local color distribution. So the combination of global and local color distribution provides a good image description. By its design, the proposed descriptor is more compact compared with the CC descriptor, which allows reducing computational complexity. Using the Average Retrieval precision (ARP) with different factors the effectiveness of the proposed descriptor is evaluated and compared with the conventional color-based descriptors, such as HI, CC and DC. The image database used in this work contains 500 images with 25 categories randomly selected from the Corel Dataset.

Robust digital image watermarking using interest points and DFT domain

In this paper we present a robust watermarking method, in which the watermark is embedded into the magnitude of the middle frequencies of the Discrete Fourier Transform (DFT). To allow the correct watermark detection, even if the image has been distorted, the Speeded Up Robust Feature (SURF) is used. During the embedding process the SURF points are estimated and stored in advance to be used during the detection process. In the detection process, the SURF points of the distorted image are estimated, which are used together with the stored ones to compute the affine-transformation parameters. Using these parameters the geometric distortion is corrected before applying the cross-correlation operation used for watermark detection. The quality of the watermarked image is measured using the Peak Signal to Noise Ratio (PSNR) and Structural Similarity Index (SSIM). Experimental results show that the proposed method provides robustness against several geometric distortion and signal processing operations.

Robust Image Watermarking Using Feature Points and Image Normalization

In this paper we present a robust image watermarking method against geometric distortions and several attacks of signal processing. Initially, the original image is normalized and the feature points are then extracted. Furthermore, the locally most stable feature points are obtained and used to generate several non-overlapped circular regions. Texture-based image block classification in Discrete Cosine Transform (DCT) domain is also used to get watermark imperceptibility. The watermark is embedded and extracted into classified regions using the DCT domain. In the detector stage, the watermark can be obtained without the original image. The experimental results show the watermark robustness against geometric distortion such as rotation, scaling and various other Affine Transformation, and common signal processing attacks, such as JPEG compression and noise contamination.

Improved unseen-visible watermarking for copyrigth protection of digital image

Nowadays consumers of worldwide can capture digital image and video scene using several multimedia devices such as smartphones, tablets and cameras. Thus, the data captured may be easily copied or transmitted without any control and as consequence the intellectual property of the owner can be infringed, causing economic or moral damages. This fact suggests the necessity to develop security tools such as watermarking, to confront problems associated with the copyright protection. In this paper we propose an improved unseen-visible watermarking algorithm for copyright protection of digital color images. Unseen-visible watermarking is a recent approach that takes advantages of the visible and invisible watermarking, such as the readability and imperceptibility respectively, preserving the robustness of both. The design of the proposed method is based on Just Noticeable Difference (JND), Total Variation-based image decomposition and an image enhancement criterion. The watermark can be readable with a naked eye through the manipulation of image enhancement of the display device. Experimental results show that the scheme is effective for digital color images, preserving a high imperceptibility and its computational complexity is low.

Image-adaptive steganalysis for LSB Matching steganography

This paper proposes an image-adaptive steganalysis algorithm for LSB-Matching steganography. In the proposed method, the content features of the input image are analyzed in order to obtain a classification composed by plain and non-plain regions. In this context, only the plain regions of the input image are considered to determine if the image contains or not hidden information. The experimental results show that the proposed steganalysis algorithm outperforms the conventional LSB-Matching steganalysis algorithms in terms of detection performance and the same time minimizes the inter-database error. The results are shown through the ROC curves that illustrate a better performance of the proposed algorithm.

Content Based Video Retrival System for Mexican Culture Heritage Based on Object Matching and Local-Global Descriptors

Multimedia data and networking technologies have had a highly growing during the last decade, with these changes users have changed from text to content based video retrieval systems due to its better performance. We propose a fast content-based video retrieval system which involves the combination of a local descriptor obtained from the speeded-up robust feature algorithm together with an effective and fast object matching operation. To save computational time, compressed video data are partially decoded in order to get discrete cosine transform coefficients of key frames, which are used to obtain sub-block coefficients and a down-sampling version of frames. The preliminary results are ranking using an efficient color descriptor based on color correlogram and dominant color descriptors. To measure the performance of the proposed technique the precision and recall metrics are used. The experimental results show the accuracy of the proposed method applied to a database of Mexican Culture Heritage videos.