Image counter-forensics based on feature injection

Starting from the concept that many image forensic tools are based on the detection of some features revealing a particular aspect of the history of an image, in this work we model the counter-forensic attack as the injection of a specific fake feature pointing to the same history of an authentic reference image. We propose a general attack strategy that does not rely on a specific detector structure. Given a source image x and a target image y, the adversary processes x in the pixel domain producing an attacked image (x) over tilde, perceptually similar to x, whose feature f((x) over tilde) is as close as possible to f (y) computed on y. Our proposed counter-forensic attack consists in the constrained minimization of the feature distance Phi(z) = vertical bar f (z) f (y) vertical bar through iterative methods based on gradient descent. To solve the intrinsic limit due to the numerical estimation of the gradient on large images, we propose the application of a feature decomposition process, that allows the problem to be reduced into many subproblems on the blocks the image is partitioned into. The proposed strategy has been tested by attacking three different features and its performance has been compared to state-of-the-art counter-forensic methods

Objective Evaluation of the Perceptual Quality of 3D Watermarking

In this paper an objective metric to measure the perceptual quality of watermarked 3D meshes is presented. The metric, which is based on a black-box approach, relies on the measurement of the roughness of 3D meshes before and after the insertion of the watermark. To calibrate the metric and to validate it, a set of psychovisual experiments has been carried out. Due to the lack of prior work in this field, a new methodology for the subjective evaluation of the quality of watermarked 3D objects is introduced. The validity of the proposed metric has been tested against a number of different 3D watermarking algorithms, showing an excellent match with the subjective evaluation of the quality stemming from the pshycovisual experiments

Watermarked 3D Mesh Quality Assessment

This paper addresses the problem of assessing distortions produced by watermarking 3D meshes. In particular, a new methodology for subjective evaluation of the quality of 3D objects is proposed and implemented. Two objective metrics derived from measures of surface roughness are then proposed and their efficiency to predict perceptual impact of 3D watermarking are assessed. Results obtained show good correlations between the proposed objective metrics and subjective assessments by human observers

Exact Histogram Specification Optimized for Structural Similarity

An exact histogram specification (EHS) method modifies its input image to have a specified histogram. Applications of EHS include image (contrast) enhancement (e.g., by histogram equalization) and histogram watermarking. Performing EHS on an image, however, reduces its visual quality. Starting from the output of a generic EHS method, we maximize the structural similarity index (SSIM) between the original image (before EHS) and the result of EHS iteratively. Essential in this process is the computationally simple and accurate formula we derive for SSIM gradient. As it is based on gradient ascent, the proposed EHS always converges. Experimental results confirm that while obtaining the histogram exactly as specified, the proposed method invariably outperforms the existing methods in terms of visual quality of the result. The computational complexity of the proposed method is shown to be of the same order as that of the existing methods. Index terms: histogram modification, histogram equalization, optimization for perceptual visual quality, structural similarity gradient ascent, histogram watermarking, contrast enhancement

An analysis of the social and economic costs of breast cancer in Italy

Breast cancer is the most prevalent cancer affecting women and it represents an important economic burden. The aim of this study was to estimate the socio-economic burden of breast cancer (BC) in Italy both from the National Health Service (NHS) and the government perspectives (costs borne by the social security system)

Technological development of hydroalcoholic extractive solutions from Calendula officinalis L. flowers by using factorial design

L., pelo processo de maceração (MAC) e de turbo-extração (TURB), empregando planejamento fatorial 32 (dois fatores e três níveis), para avaliar a influência do tempo de extração (MAC = 5, 10 e 15 dias; TURB = 5, 15 e 25 min) e da relação planta:solvente (2,5, 7,5 e 12,5%, m/V) sobre o teor de flavonóides totais e resíduo seco nas soluções extrativas. Para o processo de maceração, a relação planta: solvente de 12,5% e o tempo de 15 dias resultaram nas melhores condições para alcançar um maior teor de flavonóides totais, em relação à turbo-extração que obteve o mesmo desempenho em 5 min. Para ambos os processos, o resíduo seco foi proporcional à relação planta:solvente.The work aimed at the development of extractive solutions from the flowers of Calendula officinalis, through maceration (MAC) and turbo-extraction (TURB) processes, employing the 32 (two factors and three levels) factorial design, in order to evaluate the influence of the time (MAC = 5, 10 and 15 days; TURB = 5, 15 and 25 min) and of the plant: solvent ratio (2.5, 7.5 and 12.5%, w/v) on the flavonoid content and the dry residue yields in the extractive solutions. For the maceration process, the 12.5% (w/v) plant: solvent ratio over 15 days were the best conditions to achieve the highest flavonoid content, in the turbo-extraction process the same performance was achieved in 5 min. For both processes the dry residue was proportional to the plant: solvent ratio.Colegio de Farmacéuticos de la Provincia de Buenos Aire