A statistical reduced-reference method for color image quality assessment

Although color is a fundamental feature of human visual perception, it has been largely unexplored in the reduced-reference (RR) image quality assessment (IQA) schemes. In this paper, we propose a natural scene statistic (NSS) method, which efficiently uses this information. It is based on the statistical deviation between the steerable pyramid coefficients of the reference color image and the degraded one. We propose and analyze the multivariate generalized Gaussian distribution (MGGD) to model the underlying statistics. In order to quantify the degradation, we develop and evaluate two measures based respectively on the Geodesic distance between two MGGDs and on the closed-form of the Kullback Leibler divergence. We performed an extensive evaluation of both metrics in various color spaces (RGB, HSV, CIELAB and YCrCb) using the TID 2008 benchmark and the FRTV Phase I validation process. Experimental results demonstrate the effectiveness of the proposed framework to achieve a good consistency with human visual perception. Furthermore, the best configuration is obtained with CIELAB color space associated to KLD deviation measure

On color image quality assessment using natural image statistics

Color distortion can introduce a significant damage in visual quality perception, however, most of existing reduced-reference quality measures are designed for grayscale images. In this paper, we consider a basic extension of well-known image-statistics based quality assessment measures to color images. In order to evaluate the impact of color information on the measures efficiency, two color spaces are investigated: RGB and CIELAB. Results of an extensive evaluation using TID 2013 benchmark demonstrates that significant improvement can be achieved for a great number of distortion type when the CIELAB color representation is used

Flexible Smart Textile Coated by PVDF/Graphene Oxide With Excellent Energy Harvesting Toward a Novel Class of Self-Powered Sensors: Fabrication, Characterization and Measurements

Because of some of their diverse benefits, intelligent textiles have attracted a great deal of interest among specialists over the past decade. This paper describes a novel approach to the manufacture of intelligent piezoelectric polymer-based textiles with enhanced piezoelectric responses for applications that extract biomechanical energy. Here we report a highly scalable and ultrafast production of smart textile piezoelectric containing graphene oxide nanosheets (GONS) dispersed in polyvinylidene fluoride (PVDF). In this work, Cotton textiles (CT) were functionalized and by graphene oxide (GO), using PVDF as a binder to obtain a CT-PVDF-GO material. Tetraethyl orthosilicate (TEOS) was further grafted as a coating layer to improve the surface compatibility, resulting in the CT-PVDF-GO-TEOS composite. The research results show that the addition of GONS significantly improves PVDF's overall crystallization rate on CT. More specifically, the piezoelectric β-phase content (100 % higher F[β]) and crystallinity degree on the piezoelectric properties of composite cotton fiber has been improved effectively. Consequently, this fabricated piezo-smart textile has a glorious piezoelectricity even with comparatively low coating content of PVDF-GONS-TEOS. Based on it, the as-fabricated piezoelectric textile device has resulted in the output voltage of up to 13 mV for a given frequency (fm = 8 Hz) at fixed strain amplitude value (0.5 %). It is believed that this research may further reveal the field of energy harvesting for possible applications in the future.. In addition, the set of experimental results that illustrate the smart textile was carried out and discussed, and how it can be used as a wearable device source for this smart textile. Finally, the approach described in this study can also be used to construct other desirable designs, for a wearable low-consumption sensor, etc

Reduced reference 3D mesh quality assessment based on statistical models

International audienceDuring their geometry processing and transmission 3D meshes are subject to various visual processing operations like compression, watermarking, remeshing, noise addition and so forth. In this context it is indispensable to evaluate the quality of the distorted mesh, we talk here about the mesh visual quality (MVQ) assessment. Several works have tried to evaluate the MVQ using simple geometric measures, However this metrics do not correlate well with the subjective score since they fail to reflect the perceived quality. In this paper we propose a new objective metric to evaluate the visual quality between a mesh with a perfect quality called reference mesh and its distorted version. The proposed metric uses a chosen statistical distribution to extract parameters of two random variable sets, the first set is the dihedral angles related to the reference mesh, while the second set is the dihedral angles related to the distorted mesh. The perceptual distance between two meshes is computed as the Kullback-Leibler divergence between the two sets of variables. Experimental results from two subjective databases (LIRIS masking database and LIRIS/EPFL general purpose database) and comparisons with seven objective metrics cited in the state-of-the-art demonstrate the efficacy of the proposed metric in terms of the correlation to the mean opinion scores across these databases

Interpretable Aide Diagnosis System for Melanoma Recognition

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Experimental study on a scaled test model of soil reinforced by stone columns

International audienceThis paper presents results of experimental tests on soil specimens reinforced by stone columns. The experimental investigations have been conducted by the setup of a laboratory scale model. Main objective is to evaluate the effects of various reinforcing materials and stone columns configurations on the axial deformation during a vertical loading test of cylindrical samples of unreinforced and reinforced soil. The findings have been compared to existing experimental results proposed in the literature. The specimens of soil have consisted of an analogic material of glass beads poly-dispersed grain size smaller than 50 μm. Two reinforcing materials have been considered as ballasts: crushed sand and coarser granularity glass beads (0.7 – 1.0 mm). The results show that the material type and spacing between columns in a triangular or square configuration can greatly affect the reinforcement efficiency

Improving dielectric properties of composites thin films with polylactic acid and PZT microparticles induced by interfacial polarization

Although polylactic acid (PLA) is widely identified as a biodegradable polymer, its use is limited due to the inherently poor mechanical properties. Therefore, the strengthening of PLA with microscale particles like lead zirconate titanate (PZT) is a promising field of research that has only just begun to be explored. Piezoelectric polymer-PZT films are encouraging materials for modern technological applications in energy harvesting. The PLA/PZT composites were developed using the solvent casting technique. The mechanical characteristics and dielectric properties of the considered films were investigated. X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Spectroscopy and Scanning Electron Microscopy (SEM) were used, respectively, to examine the influence of these fillers at the molecular level, crystal structure change and micro charges dispersion inside the polymer matrix. Thermogravimetric Analysis (TGA) was used to examine the stability and thermal degradation of the films. The effect of the content (0.1–1 wt.%) of PZT on these properties has also been studied. The results indicate that the addition of PZT content induces considerable improvement in the β-phase and dielectric constant of microcomposites films compared to that of pure PLA