Learning deep physiological models of affect

Feature extraction and feature selection are crucial phases in the process of affective modeling. Both, however, incorporate substantial limitations that hinder the development of reliable and accurate models of affect. For the purpose of modeling affect manifested through physiology, this paper builds on recent advances in machine learning with deep learning (DL) approaches. The efficiency of DL algorithms that train artificial neural network models is tested and compared against standard feature extraction and selection approaches followed in the literature. Results on a game data corpus — containing players’ physiological signals (i.e. skin conductance and blood volume pulse) and subjective self-reports of affect — reveal that DL outperforms manual ad-hoc feature extraction as it yields significantly more accurate affective models. Moreover, it appears that DL meets and even outperforms affective models that are boosted by automatic feature selection, for several of the scenarios examined. As the DL method is generic and applicable to any affective modeling task, the key findings of the paper suggest that ad-hoc feature extraction and selection — to a lesser degree — could be bypassed.The authors would like to thank Tobias Mahlmann for his work on the development and administration of the cluster used to run the experiments. Special thanks for proofreading goes to Yana Knight. Thanks also go to the Theano development team, to all participants in our experiments, and to Ubisoft, NSERC and Canada Research Chairs for funding. This work is funded, in part, by the ILearnRW (project no: 318803) and the C2Learn (project no. 318480) FP7 ICT EU projects.peer-reviewe

Statistical methods for fine-grained retail product recognition

In recent years, computer vision has become a major instrument in automating retail processes with emerging smart applications such as shopper assistance, visual product search (e.g., Google Lens), no-checkout stores (e.g., Amazon Go), real-time inventory tracking, out-of-stock detection, and shelf execution. At the core of these applications lies the problem of product recognition, which poses a variety of new challenges in contrast to generic object recognition. Product recognition is a special instance of fine-grained classification. Considering the sheer diversity of packaged goods in a typical hypermarket, we are confronted with up to tens of thousands of classes, which, particularly if under the same product brand, tend to have only minute visual differences in shape, packaging texture, metric size, etc., making them very difficult to discriminate from one another. Another challenge is the limited number of available datasets, which either have only a few training examples per class that are taken under ideal studio conditions, hence requiring cross-dataset generalization, or are captured from the shelf in an actual retail environment and thus suffer from issues like blur, low resolution, occlusions, unexpected backgrounds, etc. Thus, an effective product classification system requires substantially more information in addition to the knowledge obtained from product images alone. In this thesis, we propose statistical methods for a fine-grained retail product recognition. In our first framework, we propose a novel context-aware hybrid classification system for the fine-grained retail product recognition problem. In the second framework, state-of-the-art convolutional neural networks are explored and adapted to fine-grained recognition of products. The third framework, which is the most significant contribution of this thesis, presents a new approach for fine-grained classification of retail products that learns and exploits statistical context information about likely product arrangements on shelves, incorporates visual hierarchies across brands, and returns recognition results as "confidence sets" that are guaranteed to contain the true class at a given confidence leve

A novel Approach for sEMG Gesture Recognition using Resource-constrained Hardware Platforms

Classifying human gestures using surface electromyografic sensors (sEMG) is a challenging task. Wearable sensors have proven to be extremely useful in this context, but their performance is limited by several factors (signal noise, computing resources, battery consumption, etc.). In particular, computing resources impose a limitation in many application scenarios, in which lightweight classification approaches are desirable. Recent research has shown that machine learning techniques are useful for human gesture classification once their salient features have been determined. This paper presents a novel approach for human gesture classification in which two different strategies are combined: a) a technique based on autoencoders is used to perform feature extraction; b) two alternative machine learning algorithms (namely J48 and K*) are then used for the classification stage. Empirical results are provided, showing that for limited computing power platforms our approach outperforms other alternative methodologies.Fil: Micheletto, Matías Javier. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; ArgentinaFil: Chesñevar, Carlos Iván. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias e Ingeniería de la Computación. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación. Instituto de Ciencias e Ingeniería de la Computación; ArgentinaFil: Santos, Rodrigo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias e Ingeniería de la Computación. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación. Instituto de Ciencias e Ingeniería de la Computación; Argentin

Learning to see across domains and modalities

Deep learning has recently raised hopes and expectations as a general solution for many applications (computer vision, natural language processing, speech recognition, etc.); indeed it has proven effective, but it also showed a strong dependence on large quantities of data. Generally speaking, deep learning models are especially susceptible to overfitting, due to their large number of internal parameters. Luckily, it has also been shown that, even when data is scarce, a successful model can be trained by reusing prior knowledge. Thus, developing techniques for \textit{transfer learning} (as this process is known), in its broadest definition, is a crucial element towards the deployment of effective and accurate intelligent systems into the real world. This thesis will focus on a family of transfer learning methods applied to the task of visual object recognition, specifically image classification. The visual recognition problem is central to computer vision research: many desired applications, from robotics to information retrieval, demand the ability to correctly identify categories, places, and objects. Transfer learning is a general term, and specific settings have been given specific names: when the learner has access to only unlabeled data from the target domain (where the model should perform) and labeled data from a different domain (the source), the problem is called unsupervised domain adaptation (DA). The first part of this thesis will focus on three methods for this setting. The three presented techniques for domain adaptation are fully distinct: the first one proposes the use of Domain Alignment layers to structurally align the distributions of the source and target domains in feature space. While the general idea of aligning feature distribution is not novel, we distinguish our method by being one of the very few that do so without adding losses. The second method is based on GANs: we propose a bidirectional architecture that jointly learns how to map the source images into the target visual style and vice-versa, thus alleviating the domain shift at the pixel level. The third method features an adversarial learning process that transforms both the images and the features of both domains in order to map them to a common, agnostic, space. While the first part of the thesis presented general purpose DA methods, the second part will focus on the real life issues of robotic perception, specifically RGB-D recognition. Robotic platforms are usually not limited to color perception; very often they also carry a Depth camera. Unfortunately, the depth modality is rarely used for visual recognition due to the lack of pretrained models from which to transfer and little data to train one on from scratch. We will first explore the use of synthetic data as proxy for real images by training a Convolutional Neural Network (CNN) on virtual depth maps, rendered from 3D CAD models, and then testing it on real robotic datasets. The second approach leverages the existence of RGB pretrained models, by learning how to map the depth data into the most discriminative RGB representation and then using existing models for recognition. This second technique is actually a pretty generic Transfer Learning method which can be applied to share knowledge across modalities