We present a novel approach for place recognition and loop closure detection based on binary codes and disparity information using stereo images. Our method (ABLE-S) applies the Local Difference Binary (LDB) descriptor in a global framework to obtain a robust global image description, which is initially based on intensity and gradient pairwise comparisons. LDB has a higher descriptiveness power than other popular alternatives such as BRIEF, which only relies on intensity. In addition, we integrate disparity information into the binary descriptor (D-LDB). Disparity provides valuable information which decreases the effect of some typical problems in place recognition such as perceptual aliasing.The KITTI Odometry dataset is mainly used to test our approach due to its varied environments, challenging situations and length. Additionally, a loop closure ground-truth is introduced in this work for the KITTI Odometry benchmark with the aim of standardizing a robust evaluation methodology for comparing different previous algorithms against our method and for future benchmarking of new proposals. Attending to the presented results, our method allows a fast and more effective visual loop closure detection compared to state-of-the-art algorithms such as FAB-MAP, WI-SURF and BRIEF-Gist.
In this document, a real-time fog detection system using an on-board low cost b&w camera, for a driving application, is presented. This system is based on two clues: estimation of the visibility distance, which is calculated from the camera projection equations and the blurring due to the fog. Because of the water particles floating in the air, sky light gets diffuse and, focus on the road zone, which is one of the darkest zones on the image. The apparent effect is that some part of the sky introduces in the road. Also in foggy scenes, the border strength is reduced in the upper part of the image. These two sources of information are used to make this system more robust. The final purpose of this system is to develop an automatic vision-based diagnostic system for warning ADAS of possible wrong working conditions. Some experimental results and the conclusions about this work are presented.
This paper presents a non-intrusive approach for monitoring driver drowsiness using the fusion of several optimized indicators based on driver physical and driving performance measures, obtained from ADAS (Advanced Driver Assistant Systems) in simulated conditions. The paper is focused on real-time drowsiness detection technology rather than on long-term sleep/awake regulation prediction technology. We have developed our own vision system in order to obtain robust and optimized driver indicators able to be used in simulators and future real environments. These indicators are principally based on driver physical and driving performance skills. The fusion of several indicators, proposed in the literature, is evaluated using a neural network and a stochastic optimization method to obtain the best combination. We propose a new method for ground-truth generation based on a supervised Karolinska Sleepiness Scale (KSS). An extensive evaluation of indicators, derived from trials over a third generation simulator with several test subjects during different driving sessions, was performed. The main conclusions about the performance of single indicators and the best combinations of them are included, as well as the future works derived from this study.
Tracking non-rigid objects from video is useful in robotic systems such as HMIs or robotic manipulator arms which interact with deformable objects. This paper proposes a method for sequential model-based 3D reconstruction of deformable objects and camera localization in real time. Nonrigid SFM methods commonly process a video sequence offline in a batch way. While there are real-time methods for rigid models, reconstruction of deformable 3D shapes for real-time applications is still unsolved. Dense approaches offer promising results, but processing all frames in batch, offline. We propose a real-time non-rigid reconstruction method based on a known deformable model. Object shape and pose is tracked by realtime estimation of camera pose and deformation coefficients. An extensive evaluation of the algorithm on several data sets, and comparison with state-of-the-art techniques is performed. The tests include different outlier rates, noise levels and occlusions handling.
This paper presents a sequential non-rigid reconstruction method that recovers the 3D shape and the camera pose of a deforming object from a video sequence and a previous shape model of the object. We take PTAM (Parallel Mapping and Tracking), a state-of-the-art sequential real-time SfM (Structure-from-Motion) engine, and we upgrade it to solve non-rigid reconstruction. Our method provides a good trade-off between processing time and reconstruction error without the need for specific processing hardware, such as GPUs. We improve the original PTAM matching by using descriptor-based features, as well as smoothness priors to better constrain the 3D error. This paper works with perspective projection and deals with outliers and missing data. We evaluate the tracking algorithm performance through different tests over several datasets of non-rigid deforming objects. Our method achieves state-of-the-art accuracy and can be used as a real-time method suitable for being embedded in portable devices.
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