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Monica Piñol, Angel Sappa, Angeles Lopez, & Ricardo Toledo. (2012). Feature Selection Based on Reinforcement Learning for Object Recognition. In Adaptive Learning Agents Workshop (pp. 33–39).
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German Ros, Angel Sappa, Daniel Ponsa, & Antonio Lopez. (2012). Visual SLAM for Driverless Cars: A Brief Survey. In IEEE Workshop on Navigation, Perception, Accurate Positioning and Mapping for Intelligent Vehicles.
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Naveen Onkarappa, & Angel Sappa. (2012). An Empirical Study on Optical Flow Accuracy Depending on Vehicle Speed. In IEEE Intelligent Vehicles Symposium (pp. 1138–1143). IEEE Xplore.
Abstract: Driver assistance and safety systems are getting attention nowadays towards automatic navigation and safety. Optical flow as a motion estimation technique has got major roll in making these systems a reality. Towards this, in the current paper, the suitability of polar representation for optical flow estimation in such systems is demonstrated. Furthermore, the influence of individual regularization terms on the accuracy of optical flow on image sequences of different speeds is empirically evaluated. Also a new synthetic dataset of image sequences with different speeds is generated along with the ground-truth optical flow.
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Miguel Oliveira, Angel Sappa, & V. Santos. (2012). Color Correction for Onboard Multi-camera Systems using 3D Gaussian Mixture Models. In IEEE Intelligent Vehicles Symposium (pp. 299–303). IEEE Xplore.
Abstract: The current paper proposes a novel color correction approach for onboard multi-camera systems. It works by segmenting the given images into several regions. A probabilistic segmentation framework, using 3D Gaussian Mixture Models, is proposed. Regions are used to compute local color correction functions, which are then combined to obtain the final corrected image. An image data set of road scenarios is used to establish a performance comparison of the proposed method with other seven well known color correction algorithms. Results show that the proposed approach is the highest scoring color correction method. Also, the proposed single step 3D color space probabilistic segmentation reduces processing time over similar approaches.
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Naila Murray, Luca Marchesotti, & Florent Perronnin. (2012). AVA: A Large-Scale Database for Aesthetic Visual Analysis. In 25th IEEE Conference on Computer Vision and Pattern Recognition (pp. 2408–2415). IEEE Xplore.
Abstract: With the ever-expanding volume of visual content available, the ability to organize and navigate such content by aesthetic preference is becoming increasingly important. While still in its nascent stage, research into computational models of aesthetic preference already shows great potential. However, to advance research, realistic, diverse and challenging databases are needed. To this end, we introduce a new large-scale database for conducting Aesthetic Visual Analysis: AVA. It contains over 250,000 images along with a rich variety of meta-data including a large number of aesthetic scores for each image, semantic labels for over 60 categories as well as labels related to photographic style. We show the advantages of AVA with respect to existing databases in terms of scale, diversity, and heterogeneity of annotations. We then describe several key insights into aesthetic preference afforded by AVA. Finally, we demonstrate, through three applications, how the large scale of AVA can be leveraged to improve performance on existing preference tasks
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Marc Serra, Olivier Penacchio, Robert Benavente, & Maria Vanrell. (2012). Names and Shades of Color for Intrinsic Image Estimation. In 25th IEEE Conference on Computer Vision and Pattern Recognition (pp. 278–285). IEEE Xplore.
Abstract: In the last years, intrinsic image decomposition has gained attention. Most of the state-of-the-art methods are based on the assumption that reflectance changes come along with strong image edges. Recently, user intervention in the recovery problem has proved to be a remarkable source of improvement. In this paper, we propose a novel approach that aims to overcome the shortcomings of pure edge-based methods by introducing strong surface descriptors, such as the color-name descriptor which introduces high-level considerations resembling top-down intervention. We also use a second surface descriptor, termed color-shade, which allows us to include physical considerations derived from the image formation model capturing gradual color surface variations. Both color cues are combined by means of a Markov Random Field. The method is quantitatively tested on the MIT ground truth dataset using different error metrics, achieving state-of-the-art performance.
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Naila Murray, Luca Marchesotti, & Florent Perronnin. (2012). Learning to Rank Images using Semantic and Aesthetic Labels. In 23rd British Machine Vision Conference (110.pp. 1–110.10).
Abstract: Most works on image retrieval from text queries have addressed the problem of retrieving semantically relevant images. However, the ability to assess the aesthetic quality of an image is an increasingly important differentiating factor for search engines. In this work, given a semantic query, we are interested in retrieving images which are semantically relevant and score highly in terms of aesthetics/visual quality. We use large-margin classifiers and rankers to learn statistical models capable of ordering images based on the aesthetic and semantic information. In particular, we compare two families of approaches: while the first one attempts to learn a single ranker which takes into account both semantic and aesthetic information, the second one learns separate semantic and aesthetic models. We carry out a quantitative and qualitative evaluation on a recently-published large-scale dataset and we show that the second family of techniques significantly outperforms the first one.
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Murad Al Haj, Jordi Gonzalez, & Larry S. Davis. (2012). On Partial Least Squares in Head Pose Estimation: How to simultaneously deal with misalignment. In 25th IEEE Conference on Computer Vision and Pattern Recognition (pp. 2602–2609). IEEE Xplore.
Abstract: Head pose estimation is a critical problem in many computer vision applications. These include human computer interaction, video surveillance, face and expression recognition. In most prior work on heads pose estimation, the positions of the faces on which the pose is to be estimated are specified manually. Therefore, the results are reported without studying the effect of misalignment. We propose a method based on partial least squares (PLS) regression to estimate pose and solve the alignment problem simultaneously. The contributions of this paper are two-fold: 1) we show that the kernel version of PLS (kPLS) achieves better than state-of-the-art results on the estimation problem and 2) we develop a technique to reduce misalignment based on the learned PLS factors.
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German Ros, Jesus Martinez del Rincon, & Gines Garcia-Mateos. (2012). Articulated Particle Filter for Hand Tracking. In 21st International Conference on Pattern Recognition (pp. 3581–3585).
Abstract: This paper proposes a new version of Particle Filter, called Articulated Particle Filter – ArPF -, which has been specifically designed for an efficient sampling of hierarchical spaces, generated by articulated objects. Our approach decomposes the articulated motion into layers for efficiency purposes, making use of a careful modeling of the diffusion noise along with its propagation through the articulations. This produces an increase of accuracy and prevent for divergences. The algorithm is tested on hand tracking due to its complex hierarchical articulated nature. With this purpose, a new dataset generation tool for quantitative evaluation is also presented in this paper.
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Jose Carlos Rubio, Joan Serrat, & Antonio Lopez. (2012). Unsupervised co-segmentation through region matching. In 25th IEEE Conference on Computer Vision and Pattern Recognition (pp. 749–756). IEEE Xplore.
Abstract: Co-segmentation is defined as jointly partitioning multiple images depicting the same or similar object, into foreground and background. Our method consists of a multiple-scale multiple-image generative model, which jointly estimates the foreground and background appearance distributions from several images, in a non-supervised manner. In contrast to other co-segmentation methods, our approach does not require the images to have similar foregrounds and different backgrounds to function properly. Region matching is applied to exploit inter-image information by establishing correspondences between the common objects that appear in the scene. Moreover, computing many-to-many associations of regions allow further applications, like recognition of object parts across images. We report results on iCoseg, a challenging dataset that presents extreme variability in camera viewpoint, illumination and object deformations and poses. We also show that our method is robust against large intra-class variability in the MSRC database.
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Jose Carlos Rubio, Joan Serrat, & Antonio Lopez. (2012). Multiple target tracking and identity linking under split, merge and occlusion of targets and observations. In 1st International Conference on Pattern Recognition Applications and Methods.
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Cesar Isaza, Joaquin Salas, & Bogdan Raducanu. (2012). Synthetic ground truth dataset to detect shadow cast by static objects in outdoor. In 1st International Workshop on Visual Interfaces for Ground Truth Collection in Computer Vision Applications (art. 11). ACM.
Abstract: In this paper, we propose a precise synthetic ground truth dataset to study the problem of detection of the shadows cast by static objects in outdoor environments during extended periods of time (days). For our dataset, we have created a virtual scenario using a rendering software. To increase the realism of the simulated environment, we have defined the scenario in a precise geographical location. In our dataset the sun is by far the main illumination source. The sun position during the simulation time takes into consideration factors related to the geographical location, such as the latitude, longitude, elevation above sea level, and precise image capturing day and time. In our simulation the camera remains fixed. The dataset consists of seven days of simulation, from 10:00am to 5:00pm. Images are captured every 10 seconds. The shadows' ground truth is automatically computed by the rendering software.
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Laura Igual, Joan Carles Soliva, Antonio Hernandez, Sergio Escalera, Oscar Vilarroya, & Petia Radeva. (2012). Supervised Brain Segmentation and Classification in Diagnostic of Attention-Deficit/Hyperactivity Disorder. In High Performance Computing and Simulation, International Conference on (pp. 182–187). IEEE Xplore.
Abstract: This paper presents an automatic method for external and internal segmentation of the caudate nucleus in Magnetic Resonance Images (MRI) based on statistical and structural machine learning approaches. This method is applied in Attention-Deficit/Hyperactivity Disorder (ADHD) diagnosis. The external segmentation method adapts the Graph Cut energy-minimization model to make it suitable for segmenting small, low-contrast structures, such as the caudate nucleus. In particular, new energy function data and boundary potentials are defined and a supervised energy term based on contextual brain structures is added. Furthermore, the internal segmentation method learns a classifier based on shape features of the Region of Interest (ROI) in MRI slices. The results show accurate external and internal caudate segmentation in a real data set and similar performance of ADHD diagnostic test to manual annotation.
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Mohammad Ali Bagheri, Qigang Gao, & Sergio Escalera. (2012). Three-Dimensional Design of Error Correcting Output Codes. In 8th International Conference on Machine Learning and Data Mining (pp. 29–).
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Mohammad Ali Bagheri, Qigang Gao, & Sergio Escalera. (2012). Error Correcting Output Codes for multiclass classification: Application to two image vision problems. In 16th symposium on Artificial Intelligence & Signal Processing (pp. 508–513). IEEE Xplore.
Abstract: Error-correcting output codes (ECOC) represents a powerful framework to deal with multiclass classification problems based on combining binary classifiers. The key factor affecting the performance of ECOC methods is the independence of binary classifiers, without which the ECOC method would be ineffective. In spite of its ability on classification of problems with relatively large number of classes, it has been applied in few real world problems. In this paper, we investigate the behavior of the ECOC approach on two image vision problems: logo recognition and shape classification using Decision Tree and AdaBoost as the base learners. The results show that the ECOC method can be used to improve the classification performance in comparison with the classical multiclass approaches.
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