Texture classification of proteins using support vector machines and bio-inspired metaheuristics

6th International Joint Conference, BIOSTEC 2013, Barcelona, Spain, February 11-14, 2013[Abstract] In this paper, a novel classification method of two-dimensional polyacrylamide gel electrophoresis images is presented. Such a method uses textural features obtained by means of a feature selection process for whose implementation we compare Genetic Algorithms and Particle Swarm Optimization. Then, the selected features, among which the most decisive and representative ones appear to be those related to the second order co-occurrence matrix, are used as inputs for a Support Vector Machine. The accuracy of the proposed method is around 94 %, a statistically better performance than the classification based on the entire feature set. This classification step can be very useful for discarding over-segmented areas after a protein segmentation or identification process

Recognition of facial expressions in presence of partial occlusion

Nowadays, both computer vision researchers and psychology experts show an increased interest for human facial expression analysis. Despite the huge amount of research that has been dedicated to this area, almost all of them concern data recorded in controlled laboratory conditions, which does not always reflect the real world environment in which the human face is partially occluded. Six basic facial expressions are investigated in that case, i.e.when the eyes and eyebrows or the mouth regions are left out. We are interested in finding which part of the face comprised sufficient information with respect to the entire face, in order to correctly classify these six expressions. Each image from the two databases used is convolved with a set of Gabor filters having various orientations and frequencies. The new feature vectors are classified using a maximum correlation classifier and the cosine similarity measure approaches. Overall, the method provides robustness against partial occlusion

Facial expression analysis under partial occlusion

Six basic facial expressions are investigated when the human face is partially occluded, i.e. when the eyes and eyebrows or the mouth regions are occluded. Such occlusions occur when a person wears glasses (e.g. in VR application) or a mouth mask (e.g. in medical application). More specifically, we are interested in finding the part of the face that contains sufficient information in order to correctly classify these six expressions. Two facial image databases are employed in our experiments. Each image from the database is convolved with a set of Gabor filters having various orientations and frequencies. The new feature vectors are classified by using a maximum correlation classifier and the cosine similarity measure approaches. We find that, overall, the facial expression recognition method provides robustness against partial occlusion, the classification accuracy only decreasing from 89.7% (no occlusion) to 84% (eyes region occlusion) and 83.5% (mouth region occlusion) for the first database and from 94.5% (no occlusion) to 91.5% (eyes region occlusion) and 87.2% (mouth region occlusion) for the second database, respectively

An analysis of facial expression recognition under partial facial image occlusion

In this paper, an analysis of the effect of partial occlusion on facial expression recognition is investigated. The classification from partially occluded images in one of the six basic facial expressions is performed using a method based on Gabor wavelets texture information extraction, a supervised image decomposition method based on Discriminant Non-negative Matrix Factorization and a shape-based method that exploits the geometrical displacement of certain facial features. We demonstrate how partial occlusion affects the above mentioned methods in the classification of the six basic facial expressions, and indicate the way partial occlusion affects human observers when recognizing facial expressions. An attempt to specify which part of the face (left, right, lower or upper region) contains more discriminant information for each facial expression, is also made and conclusions regarding the pairs of facial expressions misclassifications that each type of occlusion introduces, are drawn

Non-negative Dimensionality Reduction for Mammogram Classification

Directly classifying high dimensional datamay exhibit the ``curse of dimensionality'' issue thatwould negatively influence the classificationperformance with an increase in the computationalload, depending also on the classifier structure. Whenworking with classifiers not affected by this issue (suchas Support Vector Machines, for instance), thecomputational load still exists due to the required timein computing the kernel matrix. Moreover, theperformance is affected when a few samples per classis available for the training procedure. One commonsolution is to carry out a feature extraction step forreducing the data dimension prior to classification.The paper describes the application of NonnegativeMatrix Factorization (NMF) for extracting featuresfrom mammogram medical images with differentresolution, further used for recognizing breast tumors.For comparison, Principal Component Analysis (PCA)and Independent Component Analysis (ICA) wereexplored. Experiments show that NMF methodoutperforms PCA and ICA, leading to higherclassification accuracy