6 months ago · 6 min read
Automatic Passenger Counting in Trains with Security Cameras
Trains, subways and trams are key to improve traffic within cities and between cities. While urbanization lets cities and traffic grow at a rapid pace, it is key that public transportation can scale accordingly as well.
Demand and usage behavior can change because of various reasons. While new city districts, infrastructure projects, new firms and employers have a long term effect, rush hour, events, demonstrations and festivals create short-time peaks. Shifting customer preferences and alternative offers create another influence on the demand of public transport vehicles.
It is the challenge of public-transport providers to measure and forecast these various long-term and short-term factors and adjust the services accordingly. To get the necessary information and data, providers must perform passenger counting. While there are multiple strategies to passenger counting (which are covered in depth here), this article focuses specifically on how security cameras inside trains can be leveraged.
Security cameras are often already installed inside trains, subways or trams to increase passenger safety and prevent vandalism. Using these existing cameras instead of dedicated sensors for passenger counting can cut the cost of passenger counting by up to 80%.
The image below shows two typical floor layouts of public transport vehicles including the location of cameras. As one can see multiple cameras are installed per wagon to capture the entire area.
Depending on the location and mounting of the cameras the perspective of the camera and the obtained counting results vary:
- 1If the cameras only capture the inside of the train the total number of passenger, as well as the absolute difference between stations can be obtained. This application therefore gives an estimate on the occupancy of the train.
- 2If additionally the entrances of the vehicle are clearly visible, the exact in- and outflows can be measured at every station. This scenario makes use of a so called crossline application.
Train Layout 1 in the image corresponds to number one in the list. Whereas Train Layout 2 due to the additional entry facing cameras 5, 6 and 7 can also capture the exact passenger in and outflow.
Using Cameras for Passenger Counting
The colored overlays in the image below illustrate counting zones. As one can see cameras one to four create four counting zones (yellow, red, green, blue) in which passengers are counted. Adding the numbers from each zone one obtains the total vehicle occupancy.
In the second layout one has six additional counting lines illustrated as blue horizontal lines which measure the in and outflow with camera 5, 6 and 7.
Following this example of one wagon, passenger counting can be performed for an entire vehicle. By aggregating the data even further it is possible to even capture an entire public transportation network which is described here.
Retrieving the Results from the Vehicles
Most already installed cameras are not smart enough to perform passenger counting as accurate as required by public transport providers. Therefore an additional device which performs the computation is usually needed. This can be the onboard computer of the vehicle, a server located in the data center of the public transport provider or a server located inside the cloud.
In any case there needs to be a data connection from the train to the provider. The bandwidth requirement is lowest for on-board computing. When performing the image processing outside of the train, bandwidth can be saved by only evaluating the compressed, low resolution images from the cameras every X seconds.
Setting up Video Analytics
Setting up Isarsoft video analytics solutions is a matter of a few mouse clicks. Thanks to the interactive drag and drop interface anyone can setup the counting objectives.
For the occupancy application one adjusts counting areas in form of rectangles for every camera. These correspond to the counting zones mentioned before.
For the counting line application a line must be adjusted to the middle of the doors such that people are counted when entering or leaving the vehicle.
Analyzing the Data
The Isarsoft Dashboard provides all necessary statistics. For the purpose of simplicity it has predefined time ranges such as:
- last hour
- last 24 hours
- last 30 days
to display either microscopic or macroscopic trends. For a more detailed analysis one can also select a custom time range or export the data to Excel format. In any case, data from multiple cameras can be aggregated to understand the bigger picture.
Reference Project: Subway of Munich, Germany
Isarsoft solutions are used by transport companies with the highest demands on accuracy, performance and service quality.
Patrick Chuh, project manager and responsible for the planning of the video technology at the Münchner Verkehrsgesellschaft (MVG) says about Isarsoft: "The solutions of lsarsoft GmbH help us as MVG to observe the utilization of our infrastructure, to determine the number of passengers and ultimately to increase customer-satisfaction.
In demanding application scenarios such as the Oktoberfest, Isarsoft solutions have proven to be very helpful in daily operations. Particularly noteworthy are the high counting accuracy and the quick setup of our existing camera systems."
MVG is a public transport company and the operating company for subway, tram and bus services in Munich. As the parent company of MVG, Stadtwerke München (SWM) is responsible for the safe transport of around 600 million passengers a year. For this purpose, the entire network with a total route length of over 100 kilometers as well as the vehicle fleet with 300 buses, over 100 trams and almost 600 subway wagons must be managed and appropriately serviced. MVG's services are integrated into the Munich Transport and Tariff Association (MVV), of which the City of Munich is a stakeholder.
The Oktoberfest, also known as Wiesn, is the world's largest folk festival. Over a period of two weeks, several million visitors from all over the world come to Munich to enjoy Bavarian beer and the unique atmosphere and culture at the Theresienwiese. The MVG transports a large proportion of visitors to and from the festival grounds. The Theresienwiese underground station (U4 / U5) is particularly crowded in the evenings on Friday and Saturday evenings. The frequency is three minutes at peak times.