ASPRS 2012 Annual Conference Sacramento, California ♦ March 19-23, 2012 CROWD VOLUME ESTIMATION USING PHOTOGRAMMETRIC TECHNIQUES H. Attya, A. Habib, I. Detchev, A. Rawabdeh Geomatics Engineering Department, University of Calgary, 2500 University Dr. NW, T2N 1N4 htattya, ahabib, i.detchev, amalrawa@ucalgary.ca ABSTRACT Incidents caused by human crowds could occur in various venues and under different circumstances, the most common being sport events, festivals, and religious events. Starting as early as the nineteenth century, research efforts have been geared towards crowd behaviour monitoring strategies especially in the fields of emergency and safety management. Attempts have been made also as recent as the mid and late nineties of the last century to use computer graphics in crowd modeling and simulation. Although crowd simulation is widely applied in several fields, research related to the derivation of quantitative crowd information is quite limited and is mainly focused on crowd volume using image processing and computer vision techniques. There were some attempts in the last two decades of the twentieth century to employ real time close-range photogrammetry in pedestrian detection and counting. However, these methods are hardly being used in high-density crowd monitoring because of the extreme difficulty in individual detection and tracking under these conditions. This paper provides a conceptual framework for the utilization of close-range photogrammetry to estimate crowd volume using a low-cost digital camera. The framework starts by developing a three dimensional model of the site in question prior to its observation in the presence of a crowd. This model will be used later to geo-reference the collected images from a dynamic camera system. The 3D model together with the geo-referencing parameters of the collected imagery will be finally used to derive crowd volume parameters. Preliminary results of the developed system will be illustrated together with the plans for the implementation of the proposed framework. KEYWORDS: Crowd volume, close-range photogrammetry, low-cost camera, geo-referencing, 3D models INTRODUCTION Human crowd could be defined as the assembly of many people in a common place and sharing the same attention and goals, and interacting with each other in different ways (Macionis, 2005). Starting as early as the nineteenth century, human crowd studies caught the attention of researchers not only in the fields of emergency and safety but also in psychology and sociology. This interest is mainly geared toward understanding the behavior of the crowd in order to ensure safety and avoid tragedies, which could happen during the assembly of thousands of people in one place. Religious venues, sports events, and festivals are sometimes ideal places for tripping tragedies. Tragic examples happened in several places in the world such as in Iraq where more than 1000 people were killed and other 2000 were injured in tripping during a religious event in Baghdad in 2005. In November 2010, in Cambodia, more than 300 people were killed and hundreds were injured in a stampede during a water festival. Recently, the interest in the crowd studies extends to include wider spectrum of disciplines such as urban planning, environmental engineering, and public health. However, the goal is unified toward providing – as best as possible – comfortable conditions for the people involved in the crowd in terms of place, transportation, and public health. Image processing and computer vision techniques are widely applied in the fields of crowd simulation and volume estimation. There were some attempts also to apply real time close-range photogrammetry for pedestrian body detection and counting in non-crowded venues. The situation will be different in crowded scenes because of the difficulties in individual detection and tracking. A conceptual framework is proposed in this paper to apply close–range photogrammetry in the estimation of the crowd parameters using a low-cost digital camera.