Denis Ouellet

Bio: Denis Ouellet is an academic researcher from Laval University. The author has contributed to research in topics: Geometric modeling & Camera resectioning. The author has an hindex of 4, co-authored 7 publications receiving 76 citations.

Towards computer-vision software tools to increase production and accessibility of video description for people with vision loss

Abstract: This paper presents the status of a R&D project targeting the development of computer-vision tools to assist humans in generating and rendering video description for people with vision loss. Three principal issues are discussed: (1) production practices, (2) needs of people with vision loss, and (3) current system design, core technologies and implementation. The paper provides the main conclusions of consultations with producers of video description regarding their practices and with end-users regarding their needs, as well as an analysis of described productions that lead to propose a video description typology. The current status of a prototype software is also presented (audio-vision manager) that uses many computer-vision technologies (shot transition detection, key-frame identification, key-face recognition, key-text spotting, visual motion, gait/gesture characterization, key-place identification, key-object spotting and image categorization) to automatically extract visual content, associate textual descriptions and add them to the audio track with a synthetic voice. A proof of concept is also briefly described for a first adaptive video description player which allows end users to select various levels of video description.

Cable Tension Control and Analysis of Reel Transparency for 6-DOF Haptic Foot Platform on a Cable-Driven Locomotion Interface

Abstract: A Cable-Driven Locomotion Interface provides a low inertia haptic interface and is used as a way of enabling the user to walk and interact with virtual surfaces. These surfaces generate Cartesian wrenches which must be optimized for each motorized reel in order to reproduce a haptic ensation in both feet. However, the use of wrench control requires a measure of the cable tensions applied to the moving platform. The latter measure may be inaccurate if it is based on sensors located near the reel. Moreover, friction hysteresis from the reel moving parts needs to be compensated for with an evaluation of low angular velocity of the motor shaft. Also, the pose of the platform is not known precisely due to cable sagging and mechanical deformation. This paper presents a non-ideal motorized reel design with its corresponding control strategy that aims at overcoming the aforementioned issues. A transfert function of the reel based on frequency responses in function of cable tension and cable length is presented with an optimal adaptative PIDF controller. Dynamic and static reel transparencies are evaluated experimentally with a cost function to optimize and with an analysis of friction respectively. Finally, a hybrid position/tension control is discussed with an analysis of the stability for achieving a complete functionality of the haptic platform.

MONNET: Monitoring Pedestrians with a Network of Loosely-Coupled Cameras

Abstract: MONNET is a visual surveillance system for tracking pedestrians over extended premises. The MONNET system is composed of intelligent nodes, which exchange information on the individually tracked pedestrians in an asynchronous manner. Each node in MONNET builds an appearance model for every observed pedestrian and compares it with models received from other nodes. The compact appearance models based on colour cues and face biometrics are stored locally on each node. The system is dynamically reconfigurable since its design allows for adding/removing nodes in a simple manner, comparable to the ‘plug and play’ technology. MONNET also contains an optional ‘observer’ node for interactive data visualization. This node displays a user interface which allows a human operator to observe and to interact in real-time with the distributed tracking process. MONNET was extensively tested with and without user input, and it is able to function correctly in both modes.

IMAGE — Complex situation understanding: An immersive concept development

Abstract: This paper presents an immersive Human-centric/built virtual work cell for analyzing complex situations dynamically. This environment is supported by a custom open architecture, is composed of objects of complementary nature reflecting the level of Human understanding. Furthermore, it is controlled by an intuitive 3D bimanual gestural interface using data gloves.

Virtual Environment and Sensori-Motor Activities: Visualization

Abstract: The levels of immersion and presence felt by users in a Virtual Environment (VE) are very important factors that dictate the quality of the Virtual Reality (VR) experience. Sensori-motor systems, both hardware and software, are the components of a VR system that contribute to generate the VEs and to create the feeling of being there. This paper reviews the different visualization hardware/software components that are at the heart of a VR system and provides means for assessing their performance in the context of various applications. Because of its historical and functional importance in the field of VR, visualization hardware is reviewed first (HMDs, VRDs, stereo glasses, CRT, LCD monitors and Plasma displays...). Then, a list of the most important insights, which should be addressed when designing and assembling a VR system, are discussed. Finally, visualization software is covered in the context of the available hardware components.

People reidentification in surveillance and forensics: A survey

Abstract: The field of surveillance and forensics research is currently shifting focus and is now showing an ever increasing interest in the task of people reidentification. This is the task of assigning the same identifier to all instances of a particular individual captured in a series of images or videos, even after the occurrence of significant gaps over time or space. People reidentification can be a useful tool for people analysis in security as a data association method for long-term tracking in surveillance. However, current identification techniques being utilized present many difficulties and shortcomings. For instance, they rely solely on the exploitation of visual cues such as color, texture, and the object’s shape. Despite the many advances in this field, reidentification is still an open problem. This survey aims to tackle all the issues and challenging aspects of people reidentification while simultaneously describing the previously proposed solutions for the encountered problems. This begins with the first attempts of holistic descriptors and progresses to the more recently adopted 2D and 3D model-based approaches. The survey also includes an exhaustive treatise of all the aspects of people reidentification, including available datasets, evaluation metrics, and benchmarking.

International Trends of Pattern Recognition Research A Brief Introduction to the 18th International Conference on Pattern Recognition

Abstract: A brief of the 18th International Conference on Pattern Recognition is introduced in this pa- per,And more details about the organized workshops,tutorials,Plenary speaks and invited pa- per are presented also.

User-centric design and evaluation of a real-time battle-field visualization virtual environment

Abstract: The ever-increasing power of computers and hardware rendering systems has, to date, primarily motivated the creation of visually rich and perceptually realistic virtual environment (VE) applications. Comparatively very little effort has been expended on the user interaction components of VEs. As a result, VE user interfaces are often poorly designed and are rarely evaluated with users. Although usability engineering is a newly emerging facet of VE development, user-centered design and usability evaluation in VEs as a practice still lags far behind what is needed. This paper presents a structured, iterative approach for the user-centered design and evaluation of VE user interaction. This approach consists of the iterative use of expert heuristic evaluation, followed by formative usability evaluation, followed by summative evaluation. We describe our application of this approach to a real-world VE for battlefield visualization, describe the resulting series of design iterations, and present evidence that this approach provides a cost-effective strategy for assessing and iteratively improving user interaction design in VEs. This paper is among the first to report applying an iterative, structured, user-centered design and evaluation approach to VE user interaction design.

Distributed target tracking using self localizing smart camera networks

Abstract: This paper describes a novel decentralized target tracking scheme for distributed smart cameras. This approach is built on top of a distributed localization protocol which allows the smart camera nodes to automatically identify neighboring sensors with overlapping fields of regard and establish a communication graph which reflects how the nodes will interact to fuse measurements in the network. The new protocol distributes the detection and tracking problems evenly throughout the network accounting for sensor handoffs in a seamless manner. The approach also distributes knowledge about the state of tracked objects amongst the nodes in the network. This information can then be harvested through distributed queries which allow network participants to subscribe to different kinds of events that they may be interested in. The proposed scheme has been used to track targets in real time using a collection of custom designed smart camera nodes. Results from these experiments are presented.

Wireality: Enabling Complex Tangible Geometries in Virtual Reality with Worn Multi-String Haptics

Abstract: Today's virtual reality (VR) systems allow users to explore immersive new worlds and experiences through sight. Unfortunately, most VR systems lack haptic feedback, and even high-end consumer systems use only basic vibration motors. This clearly precludes realistic physical interactions with virtual objects. Larger obstacles, such as walls, railings, and furniture are not simulated at all. In response, we developed Wireality, a self-contained worn system that allows for individual joints on the hands to be accurately arrested in 3D space through the use of retractable wires that can be programmatically locked. This allows for convincing tangible interactions with complex geometries, such as wrapping fingers around a railing. Our approach is lightweight, low-cost, and low-power, criteria important for future, worn consumer uses. In our studies, we further show that our system is fast-acting, spatially-accurate, high-strength, comfortable, and immersive.