Pedestrian Protection Systems: Issues, Survey, and Challenges <s> VI. CONCLUDING REMARKS <s> In this paper a statistical model of pedestrian behavior is proposed. This model is intended to be an important part of a study on the feasibility of car-to-pedestrian accident prediction. The proposed approach is phenomenological as it is based on a four discrete states Markov chain. These four states: "standing still", "walking", "jogging", and "running" are related to the pedestrian pace. First, given the former pedestrian state the current one is calculated. Then, the pedestrian speed vector is split up into the norm and the angle. Information on the statistical distribution of these quantities is available. Their values follow from the present pedestrian discrete state. The proposed model has been compared with related work. It has been used to generate statistically significant pedestrian trajectories and to predict car-to-pedestrian impacts. Simulation results are given based on an evaluation database of car and pedestrian accidents. <s> BIB001 </s> Pedestrian Protection Systems: Issues, Survey, and Challenges <s> VI. CONCLUDING REMARKS <s> This paper presents investigations into the role of computer-vision technology in developing safer automobiles. We consider vision systems, which cannot only look out of the vehicle to detect and track roads and avoid hitting obstacles or pedestrians but simultaneously look inside the vehicle to monitor the attentiveness of the driver and even predict her intentions. In this paper, a systems-oriented framework for developing computer-vision technology for safer automobiles is presented. We will consider three main components of the system: environment, vehicle, and driver. We will discuss various issues and ideas for developing models for these main components as well as activities associated with the complex task of safe driving. This paper includes a discussion of novel sensory systems and algorithms for capturing not only the dynamic surround information of the vehicle but also the state, intent, and activity patterns of drivers. <s> BIB002
Pedestrians are the most vulnerable road users, and therefore, they require maximum protection on the road. The large number of fatalities and injuries show the importance of developing pedestrian protection systems. This paper discussed the global nature of the pedestrian safety problem and the initiatives taken by research groups to address it. It provided a comprehensive understanding of various issues, approaches, and challenges in improving pedestrian safety, including a comparative discussion of different approaches that have been developed recently. Pedestrian protection systems offer many important research problems to work on, such as development of different types of sensors, processing of sensor information to extract relevant features, analysis and classification of these features to detect and track pedestrians, behavior and intent analysis of drivers and pedestrians, as well as human factors and interfaces. In the last five years, we have seen a considerable research activity throughout the world, particularly in Europe and Japan. This is a very positive development. Such research has already produced a lot of important results and also produced a clearer and better understanding of the remaining challenges to work on. Much of the current research on pedestrian protection systems is toward improving and characterizing their performance. In order to ensure robust and reliable performance in all kinds of environmental conditions, it is necessary to carry out systematic experimental validation. In comparing the performance of different systems, it is also important to test the systems using standardized data sets and performance metrics. Availability of large standardized data sets capturing pedestrians in various environmental conditions is therefore important to accelerate the development of reliable pedestrian protection systems. New types of nonvisible light sensors such as thermal IR and LASER scanners show promise of improving the detection in situations where visible light sensors would be less effective. Although these sensors are expensive at present, mass production is likely to reduce the costs of these devices. Research on sensor fusion and registration would also be very important to ensure performance enhancement using the combination of sensors. Infrastructure-mounted sensors are also likely to complement vehicle-mounted sensors in generating a complete picture of surroundings by filling blind spots of vehicles. Furthermore, detection from infrastructure-based sensors is less complex due to the static background. Research on detecting pedestrians and vehicles for surveillance as well as traffic analysis would therefore be very valuable in the development of infrastructurebased collision avoidance systems. For a complete system, effective communication between infrastructure and vehicles would be essential. An effective pedestrian protection system needs to not only detect pedestrians but also predict the possibility of collision, which is based on modeling of pedestrian behaviors. Behavior modeling and prediction is an active area of research. In particular, Monte Carlo method in particle filtering framework is a promising approach for integrating pedestrian detection with collision prediction. One of the challenges in behavior modeling, specifically for collision predictions, is the scarcity of real-world data, since accidents are rare events, and performing the experiments to collect data would involve human subjects in potentially dangerous situations. Hence, a large number of experiments using trajectory simulation in addition to the available real-world accident data would be the only acceptable method in developing and characterizing such systems BIB001 . Finally, in addition to the extraction of information about surrounding objects, it is also important to ascertain the driver's state in order to generate appropriate warnings or actions so that the system would help the driver rather than cause distraction. For example, if a driver has already seen a pedestrian and is taking appropriate action, one may not want to alarm the driver unnecessarily. For this purpose, it is important to not only look outside the vehicle to detect dangerous situations but also look inside the vehicle in order to assess the state and intent of the driver BIB002 . It is seen that the research on pedestrian protection systems is in the process of reaching maturity. The success of this research should eventually find systems in future automobiles and help in saving lives and reducing injuries to pedestrians on the road. 