Crowd control: securing outdoor events
On December 31, 2014, a terrible tragedy occurred in Shanghai, where around 300,000 people had gathered for the new-year celebrations on the Bund, a water front promenade which is part of Shanghai’s historic downtown. Overcrowding on a staircase leading to an observation platform left thirty-six people dead and forty nine more injured.
This is only one sad example of the deadly force stored in crowded events. Human stampedes occur almost annually in music festivals, sports events religious festivals and night clubs. Famous examples are the July 2010, Love Parade music festival in Duisburg, Germany, where 21 people died from suffocation and at least 510 more were injured. In January 2006, over three hundred pilgrims died in Saudi Arabia as the result of overcrowding at the Jamarat Bridge, a pedestrian bridge that is part of the path believers walk through while performing the ritual Hajj pilgrimage to Mecca.
But what exactly is crowd control?
We need to differentiate between crowd control that is done with access control tools, for example controlling a large number of spectators in a closed football stadium, and crowd control in an uncontrolled open environment like a street. The first one is achieved with conventional tools like security check points, turnstiles, gates and CCTV with video analytics based counters. The second one is usually closer to ‘safe city’ projects and is more challenging and complicated since it is difficult to cover a wide area filled with people, be it for counting purposes or behavior analysis.
Accurate estimation of the number of attendees is indeed crucial for successful crowd control. Underestimating the number of people attending the Shanghai New Year’s Eve was one of the factors leading to the tragic consequences. The police underestimated the number of attendees and assigned only about 700 officers (compared to 6000 officers in previous years) to handle a crowd that turned out to be 300,000 people.
In Germany, about 1 million revelers attended the Love parade venue that could only hold 250,000.
Role of video surveillance
In general, video surveillance cameras are still the main sensor for real-time crowd control and monitoring; HD and IP network cameras have become the trend. 4K surveillance cameras have started to enter the market, but it is unlikely they will disrupt the surveillance segment. The cost of video transmission, storage, and processing (video analytics) would be prohibitive for 4K camera. Reliability would also be an issue.
For effective crowd control and monitoring, high-resolution video is critical to achieve situational awareness, as well as the ability to see greater detail within certain areas of interest. Today that means megapixel 180-degree cameras. Scallop Imaging’s cameras simultaneously combine output from multiple image sensors creating a continuous panoramic image that can cover a large outdoor scene. We’ve seen a trend moving away from pan-tilt-zoom (PTZ) cameras because inevitably, when an incident occurs, it’s likely that the PTZ camera is positioned somewhere else, and not able to see the action. Another reason for this trend is that the motor inside PTZ cameras tends to wear out over time.
Portable solutions for Temporary Events
Unlike fixed venues, short term events like music festivals, sports competitions or city marathons pose a unique challenge for outdoor crowd control. The needed infrastructure is not always readily deployed and end-users face a dilemma of whether to make a big investment in infrastructure that will be used only for a few days.
A recent trending solution for such a scenario is the deployment of a temporary surveillance system using a wireless mesh network, which is easy to establish and then take down during an incident or public event. Because it doesn’t require a fixed infrastructure, a mesh network is commonly deployed by public safety departments, municipalities and police forces. The network is usually made up of mesh network software, digital cameras, workstations, a server and mesh nodes (hardware) that share information with one another wirelessly. Radios, smart devices or mobile devices of some kind often provide communication pathways between operators. Video analytics and other technologies can then be deployed in these temporary systems.
San-Diego based MicroPower Technologies offers a solar powered wireless system that allows deployment on a per-need basis.
Flexibility is key. Utilizing an integrated solar/wireless surveillance system as an extension of the broader surveillance system allows users to deploy and redeploy the cameras as their needs evolve. We’re seeing growing interest in technology that can be quickly and easily installed directly at the points where it is needed most. Rather than, for example, installing fixed cameras on a building and then attempting to gain usable footage of a crowded event several blocks away, customers want to be able to place cameras closer to the hot spots of risk. This is particularly true for night activity, when placing cameras closer to the action helps take advantage of available light. The result is clearer, more usable video evidence.
The benefit of this solution is the ability to deploy cameras according to immediate needs, e.g. at a parking lot during a major event, and then re-deploy them to other hot spots in the next big event without running costly and time consuming cables.
However, an important factor that needs to be taken into account is the limited transmission range that wireless cameras have and the image quality which is not Megapixel. This type of portable solution is suitable for securing a defined ‘hotspot’ but might not be as relevant when securing the long route of a marathon.
Portable solutions are not just for video surveillance. temporary fences and even vehicle barriers are available. “Parking for temporary events like football games, political meetings, freshman matriculation day and open houses requires only a temporary solution. Our solution is in the form of portable, towable barriers. These barriers can be deployed quickly and effectively, even in places where it’s impossible to excavate for a permanent foundation.These mobile crash barriers can be towed into position by a medium-sized pick-up truck or equivalent. They deploy in 15 minutes and can be operated locally or remotely for guard protection. Deployment, retrieval and operation are all hydraulic. The barriers stop and disable a 15,000-pound vehicle (6803 kg) moving at 30 mph (48 kph). Once positioned, the mobile barricade is separated from its transporter and lowered into position by means of a battery-operated hydraulic power system, which is then used to raise or lower the barrier for normal or emergency tasks.
Information transmission
Another challenge outdoor events pose is how to transmit high quality video streams from the cameras to a remote security center reliably and in a cost efficient way for processing, storage and viewing
There are several option including transmitting the information over cable, over a dedicated wireless networks, or using 3G/LTE networks. In the latter configuration, cameras will compete in bandwidth with civilian cell phones that use the same network. The solution is to reduce the requirement to transmit video all the time. This can be done with an edge computing device that runs video analytics. The device stores video locally and will only stream back video when a video analytics alarm is triggered.
GV-Edge Recording Manager is a tool designed for recording management of remote GV-IP Cameras and GV-Target Cameras. It is an integrated interface from which you can assess live view, assign recording to NAS servers, enable recording, play back videos and view storage space without visiting each host´s Web interface. Any connection with hosts can be disabled without affecting or stopping the hosts´ normal functioning.
GV-Edge Recording Manager also supports live view display and video playback of hosts connected to GV-Video Server, and GV-Recording Server.
Through GV-Edge Recording Manager, you can have GV-IP Cameras or GV-Target Cameras record to NAS servers and also view the storage information such as the occupied space and remaining space. GV-NAS Systems are also available at your choice.
Wireless networking for surveillance solves the need for cables, which might not always be optional or easy to install (either due to specific area considerations or due to cost if it is a temporary event). However, this type of networking is more difficult than wired networking: having to overcome difficulties such as, limited range, obstructions (houses, trees etc.) and complicated configurations when many cameras are involved. NVT’s IP transmission product technology allows for the deployment and PoE powering of cameras, event monitors and other IP sensor devices deployed at great distances using very cost effective coax cable.GV-POEX0100 is a single-port, 10/100 PoE extender that can extend the distance between a PoE switch and a GV-IP Camera by 100 m (328.08 ft) for every extender installed. They can be serially connected, with no additional power supply, to transmit power and data to a GV-IP Camera as far as up to 600 meters (1968.5 ft) away from a PoE switch.
The maximum distance allowed between a PoE switch and a GV-IP Camera depends on the PoE switch type, PoE power output of the connected device (PD) and the type of power supply.
“In the case of the recent NY City Marathon, NVT supplied coax connected transmission devices that needed to be fully operational at distances of up to 3,000ft in order to provide effective situational awareness for the securing of this large event.
Physicists are trying to understand the dynamics of crowds. Their analysis of video footage from events like the Saudi Arabian pilgrims stampede and the German Love Parade helped identify the phenomenon termed “crowd turbulence” – as the scene becomes more and more crowded, more and more people push forward trying to move. The overall pressure of the masses moves through the crowd causing people to fall and eventually to be crushed to death. Hopefully, advances in video surveillance and video analytics will give better ways to count people and identify the ‘tipping-point’ beyond which a crowded event has the potential to become deadly.
Role of Video Analytics
The ‘classical’ video analytics like detecting loitering and unattended baggage are not a good fit for a crowded scene. Masses of people standing and moving at one point near a race track and large numbers of bags in the scene will create too many alarms to make this solution practical.
Other analytics, such as face capturing and face recognition are also impractical in an outdoor event where there is no way to control the environment and make sure the cameras have a good view of people’s faces.
Video analytics tools are typically used for smaller crowds and are used in such instances as in prison yards, bars and other situations where there are a limited number of objects/people to be identified and analyzed. In such scenarios, the video and analytics are expecting to capture something specific – a certain face, a license plate image, a certain traffic pattern in the crowd or to see if a crowd is dispersing. Larger crowds/more objects make facial recognition ineffective because the faces are too small and/or occluded.
However, some video analytics can solve the need for detecting overcrowding and detecting aggressive behavior, like a fight that takes place in a crowded environment. Such an event might escalate and cause a stampede.
In some instances you know that there is a very high likelihood of a crowd, such as in and around a football stadium on a match day. Other times you will have unexpected crowd build up, such a protest march, or disruption at an airport terminal. It is important to be able to plan for both eventualities.Video analytics is an important part of this process in being able to detect and flag early that there is an ‘unusual’ congregation of people. Being able to display to the operator a live-feed of what is occurring and also the ability to roll-back and review what has triggered the incident is key to helping them to contain and control the situation.
Our new video analytics are now able to perform reliable detection and tracking under crowded urban environment. The system could perform real-time crowd size estimation; identify dominant patterns and statistics of the crowd, pick-up suspicious unknown and other hidden information. Apart from crowd analytics, new video analytics are now able to very reliably detect suspicious human behavior such as violence, attacks, battering, breaking and entering etc. I2R’s aggression detection system had achieved beyond 90% accuracy in live trial at Singapore safe city project” stated Leman. Despite recent advances, video analytics are still very limited in a crowd-scenario. Crowd scenes are by nature detail-rich and this affects the reliability of video-analytics. According to Leman, a detection accuracy rate of 70% or more is a realistic expectation in this context.
Alternative surveillance cameras: Drones and Cell phones
Traditional pole-mounted cameras are still the most prevalent method of surveillance. However, other platforms have potential to become relevant in coming years. Aerial surveillance using cameras on drones is gaining momentum in tandem with vast capability improvements and cost reduction of commercial drones.The challenge is in video transmission from drones to the ground. It could be costly over LTE and unreliable over WIFI. The solution is to enable edge computing on drone for video analytics. However, video analytics on video from drone is more challenging. It may require video stabilization and detection using different approaches from ground’s video analytics.
The GV-Mobile NVR System is designed for digital surveillance of transportation. It can be set up in a public transit to record images from the GV-IP cameras installed in the vehicle and connected to dual monitors with one monitor displaying live view and the other displaying alarm-triggering events. The hot-swap storage drives also provide convenient access to recordings and allow data backup in minutes.
With the GPS receiver, the GV-Mobile NVR System is able to transmit the GPS data collected from the satellite to the GV-GIS(Geographic Information System) through mobile network connection for vehicle tracking.
Another potential camera, found in almost every pocket is the cell phone camera. Mobile phones, in theory, have enough resolution to be useful in large crowd scenes. These mobile devices might play a larger role in surveillance once more cloud-based services become available and video management systems (VMS) are able to be used on mobile devices.
Theme One is Next-Generation IP Camera, which will be featuring GeoVision’s cloud-centric surveillance infrastructure, the Cloud Series. Cloud Series delivers nearly all the features a small business may need in an IP-based surveillance installation. All models in the series support local as well as cloud storage at 1080p recording to provide compelling video quality. To meet the standards and requirements of various sites, the series offers a wide range of options, including popular models such as outdoor, indoor, night vision and Wi-Fi.
The GV-NAS System is a Linux-based, network-attached storage device designed to store GV-IP Camera recordings.
The GV-NAS System features RAID to ensure data security, rendering data recovery possible. Allowing access from multiple users over multiple platforms (mobile devices and desktop), user accessibility is customizable, keeping your data accessible and secure at the same time. Management over a mass number of GV-IP Cameras is made easy with GV-Edge Recording Manager, which provides an integrated interface where you can assign recordings to the designated folder in GV-NAS Systems.
Reference: a&s Magazine
