Mohamed Lamine Mekhalfi

Land-Use Classification With Compressive Sensing Multifeature Fusion

In this letter, we formulate a land-use (LU) classification problem within a compressive sensing (CS) fusion framework. CS aims at providing a compact representation form after a given query image has been processed with an opportune feature extraction type. In particular, residuals are generated from the image reconstruction with dictionaries associated with the available set of possible LUs and gathered to form a single-feature image pattern. The patterns obtained from different types of features are then fused to provide the final LU estimate. Two simple fusion strategies are adopted for such purpose. As demonstrated by experiments ran on the basis of a public benchmark database, the proposed method can achieve substantial classification accuracy gains over reference methods.

A Compressive Sensing Approach to Describe Indoor Scenes for Blind People

This paper introduces a new portable camera-based method for helping blind people to recognize indoor objects. Unlike state-of-the-art techniques, which typically perform the recognition task by limiting it to a single predefined class of objects, we propose here a completely different alternative scheme, defined as coarse description. It aims at expanding the recognition task to multiple objects and, at the same time, keeping the processing time under control by sacrificing some information details. The benefit is to increment the awareness and the perception of a blind person to his direct contextual environment. The coarse description issue is addressed via two image multilabeling strategies which differ in the way image similarity is computed. The first one makes use of the Euclidean distance measure, while the second one relies on a semantic similarity measure modeled by means of Gaussian process estimation. To achieve fast computation capability, both strategies rely on a compact image representation based on compressive sensing. The proposed methodology was assessed on two indoor datasets representing different indoor environments. Encouraging results were achieved in terms of both accuracy and processing time.

Multiclass Coarse Analysis for UAV Imagery

This paper presents a novel method to “coarsely” describe extremely high-resolution (EHR) images acquired by means of unmanned aerial vehicles (UAVs) over urban areas. Standard image analysis approaches cannot be directly exploited for the automatic description of UAV images due to their EHR. For this reason, we propose an alternative approach that consists first in the subdivision of the original UAV image in a grid of tiles. Then, each tile is compared with a library of training tiles to inherit the binary multilabel vector of the most similar training tile. This vector conveys a list of classes likely present in the considered tile. Our multiclass tile-based approach needs the definition of two main ingredients: 1) a suitable tile-representation strategy; and 2) a tile-to-tile matching operation. Various tile-representation and matching strategies are investigated. In particular, we present three global representation strategies, which process each tile as a whole and two point-based strategies that exploit points of interest within the considered tile. Regarding the matching strategies, two simple measures of distance, namely, the Euclidean and the chi-squared histogram distances, are explored. Interesting experimental results conducted on a rich set of real UAV images acquired over an urban area are reported and discussed.

LBP-based multiclass classification method for UAV imagery

In order to describe images acquired with unmanned aerial vehicles (UAV), we introduce in this paper a multilabeling classification method. It starts by subdividing the original UAV image into a grid of tiles which are then analyzed separately. From each tile, a signature which encodes texture information is extracted and compared with the signatures of the tiles belonging to a pre-built training dictionary in order to acquire the binary multilabel vector of the most similar tile. In order to represent and match the tiles, we exploit a well-known texture operator and a common distance measure, respectively. Promising experimental results, in particular for some classes of objects, are obtained on real UAV images acquired over urban areas.

Real-Time Indoor Scene Description for the Visually Impaired Using Autoencoder Fusion Strategies with Visible Cameras

This paper describes three coarse image description strategies, which are meant to promote a rough perception of surrounding objects for visually impaired individuals, with application to indoor spaces. The described algorithms operate on images (grabbed by the user, by means of a chest-mounted camera), and provide in output a list of objects that likely exist in his context across the indoor scene. In this regard, first, different colour, texture, and shape-based feature extractors are generated, followed by a feature learning step by means of AutoEncoder (AE) models. Second, the produced features are fused and fed into a multilabel classifier in order to list the potential objects. The conducted experiments point out that fusing a set of AE-learned features scores higher classification rates with respect to using the features individually. Furthermore, with respect to reference works, our method: (i) yields higher classification accuracies, and (ii) runs (at least four times) faster, which enables a potential full real-time application.

Fast indoor scene description for blind people with multiresolution random projections

A multiresolution random projection for image representation is presented.An indoor scene description for visually impaired people is proposed.Experiments are conducted on four different indoor datasets.Results qualify the framework for a near-real time blind assistance technology. Object recognition forms a substantial need for blind and visually impaired individuals. This paper proposes a new multiobject recognition framework. It consists of coarsely checking the presence of multiple objects in a portable camera-grabbed image at a considered indoor site. The outcome is a list of objects that likely appear in the indoor scene. Such description is meant to uplift the conscience of the blind person in order to better sense his/her surroundings. The method consists of a library containing (i) a bunch of images represented by means of the Random Projections (RP) technique and (ii) their respective list of objects, both prepared offline. Thus, given an online shot image, its RP representation is generated and matched to the RP patterns of library images. It thus inherits the objects of the closest image from the library. Extensive experiments returned promising recognition accuracies and a processing lapse of real-time standard.

Sparse coding joint decision rule for ear print recognition

Abstract. Human ear recognition has been promoted as a profitable biometric over the past few years. With respect to other modalities, such as the face and iris, that have undergone a significant investigation in the literature, ear pattern is relatively still uncommon. We put forth a sparse coding-induced decision-making for ear recognition. It jointly involves the reconstruction residuals and the respective reconstruction coefficients pertaining to the input features (co-occurrence of adjacent local binary patterns) for a further fusion. We particularly show that combining both components (i.e., the residuals as well as the coefficients) yields better outcomes than the case when either of them is deemed singly. The proposed method has been evaluated on two benchmark datasets, namely IITD1 (125 subject) and IITD2 (221 subjects). The recognition rates of the suggested scheme amount for 99.5% and 98.95% for both datasets, respectively, which suggest that our method decently stands out against reference state-of-the-art methodologies. Furthermore, experiments conclude that the presented scheme manifests a promising robustness under large-scale occlusion scenarios.

Ear recognition via sparse coding of local features

Abstract. An efficient scheme for human ear recognition is presented. This scheme comprises three main phases. First, the ear image is decomposed into a pyramid of progressively downgraded images, which allows the local patterns of the ear to be captured. Second, histograms of local features are extracted from each image in the pyramid and then concatenated to shape one single descriptor of the image. Third, the procedure is finalized by using decision making based on sparse coding. Experiments conducted on two datasets, composed of 125 and 221 subjects, respectively, have demonstrated the efficiency of the proposed strategy as compared to various existing methods. For instance, scores of 96.27% and 96.93% have been obtained for the datasets, respectively.

Decomposing global solar radiation into its diffuse and direct normal radiation

ABSTRACT This work presents a model based on Radial Basis Function (RBF) to estimate the diffused solar radiation (DSR) and direct normal radiation (DNR) fractions of solar radiation from global solar radiation in a semiarid area in Algeria based on a database measured between 2013 and 2015. The data has been collected at Applied Research Unit for Renewable Energies, (URAER) at Ghardaia city situated in the south of Algeria. The experimental results show that RBF model estimates DNR and DSR with high performance. The difference between the measured and the predicted values show a normalised Root Mean Square Error (nRMSE) of 0.033 and 0.065 for DNR and DSR, respectively. The obtained values of Determination Coefficient (R²) and Correlation Coefficient (R) are: 97.3%, 98.60%, respectively for DNR and 88.89%, 91.12% For DSR. However, the obtained results are very plausible and showed that RBF model estimates the DSR and DNR with good accuracy.

Ensemble of Deep Models for Event Recognition

In this article, we address the problem of recognizing an event from a single related picture. Given the large number of event classes and the limited information contained in a single shot, the problem is known to be particularly hard. To achieve a reliable detection, we propose a combination of multiple classifiers, and we compare three alternative strategies to fuse the results of each classifier, namely: (i) induced order weighted averaging operators, (ii) genetic algorithms, and (iii) particle swarm optimization. Each method is aimed at determining the optimal weights to be assigned to the decision scores yielded by different deep models, according to the relevant optimization strategy. Experimental tests have been performed on three event recognition datasets, evaluating the performance of various deep models, both alone and selectively combined. Experimental results demonstrate that the proposed approach outperforms traditional multiple classifier solutions based on uniform weighting, and outperforms recent state-of-the-art approaches.