The VAP consortium aims to demonstrate that the paradigm of "vision as process" is basic to the function of a high-level vision system. Such a hypothesis can only be demonstrated within the context of a complete integrated vision system, where the potential benefits of continuous control of perception and of associated temporal context are evident. The project's goal is to refine existing vision techniques and to integrate them into a multi-purpose vision system.
The integration of basic techniques for the construction of a continuously operating vision system capable of interpreting a dynamically changing environment has been studied. The main emphasis is on control of perception through the use of goal directed focus of attention techniques. The approach exploits spatial and temporal contexts, multiple resolutions and controlled motion of the sensor systems.
After a first integration of a skeleton vision as process (VAP) system was demonstrated the research has concentrated on improving the individual elements and techniques of the integration.
The work is increasingly related to exploitation of active vision. 5 controllable stereo camera heads with different virtues are now in operation. Camera controllers and dynamic calibration systems have been developed. Ocular motor reflexes and a control strategy for dynamic fixation and explorative capabilities are in operation.
Real time control strategies for space variant sensors has been demonstrated for tracking, time to crash computation, and motion control based on qualitative optical flow. A new scheme of Normalized differential convolution has been developed for the filtering of missing and uncertain data. Colour information is being exploited, and a framework for recognition and matching of objects represented by attributed relational graphs has been developed using efficient probabilistic relaxation.
A system control approach based on the Discrete Event Dynamic Systems (DEDS) formalism from traditional control theory is under investigation and shows promising results.
APPROACH AND METHODS
VAP (3038) led to an initial integration of basic vision techniques. This integrated system will serve as a basis and test-bed for the continued study of techniques for control of perception at all levels of a vision system.
New techniques to interpret a dynamically changing, quasi-structured environment are being developed. These exploit goal-directed focus of attention involving controlled sensor motion. Processing is directed by goals which change dynamically in reaction to the needs of the task as well as to events in the scene. The motivation of this approach is to limit the computational complexity of the perception process by limiting the size of the internal models. These models, which must be continuously updated, describe the environment in terms of a number of qualitatively different phenomena, such as image phenomena, 3-D scene geometry, and symbolic interpretations of objects and events.
The necessary techniques are being developed in the context of integrated and continuously operating vision systems, which will serve as vehicles for testing the hypotheses. The research issues which are addressed include:
- the role of contexts and goals in the control of perception
- use of multiple resolution representation of 2-D and 3-D shapes
- description at multiple levels of abstration
- the role of a controllable sensor system in controlling perception.
VAP II will contribute to closing the gap between current vision approaches and techniques versus more general and "dynamic" multi-purpose vision systems.
The potential of such continuously operating systems as well as their facilities for actively acquiring data, opens for a new and large range of opportunities for pre-competitive research and industrial applications of machine vision.
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