Monday, January 24, 2011

Understanding Object Counting Application

The Object Counting module of the Digital Video Recorder (DVR) can automate the task of counting objects passing by. When set and activated, the DVR can count objects such as people entering a store, automobiles along a highway, luggage on a conveyor belt, or even products on an assembly line. This is invaluable to users that need an exact number of objects that come and go.

What Can I Count?

Usually, the answer to this question is either “cars along a highway” or “people entering a store”. Note that the answers are not as simple as “cars” or “people” but rather “car along a highway” or “people entering a store”.
The fundamental idea used in object counting is that the objects being counted are passing through a boundary or zone. This zone is not necessarily a physical zone but rather a logical or virtual zone.
The phrase “passing through” is very important. It means that objects being counted must be moving. Objects that are not moving, or objects that are static, can not be counted. In addition to the condition that the objects must be moving, the objects must pass through some boundary or zone.
The zone, in the case of people, may be a door entrance, a hallway or a corridor. In the case of cars, the zone may be a junction, an arbitrary point along the highway or a gate entrance to some parking lot.
Objects may stop inside the zone for a short while. The important thing is that the object is just passing through it and is not meant to stay there for a long time. This also means that an object need not be moving all the time. The point is that the object moved in and eventually will move out of the zone.
These conditions make counting cars in a parking lot or counting people in a crowd watching a basketball game not suitable applications of this Object Counting function. But counting cars passing through a McDonald’s drive-through, or counting people entering a 7-11 store make very suitable applications.

Other Applications of Object Counting:

Other than above examples, Object Counting can be used to count the following:
1. Passenger luggage unloaded from an airplane. One suitable location for the camera is the place where the bags are put onto the luggage conveyor.
2. Products passing through an assembly line in a manufacturing plant.
3. Palettes unloaded from a truck or stacked into a warehouse.

Some more complex applications that may not be as obvious are as follows:
1. Count the number of times the same truck went in and out a facility;
2. Count the number of times a conveyor belt made complete cycles;
3. Count the number of people above 4’ tall entering a theater;
4. Count the number of big people entering a restaurant;
5. Count only trucks, not cars or bicycles.

Where Should I Place The Camera?

Choosing the location and position of cameras used for counting are usually different from the locations and positions of cameras used for surveillance and monitoring. Considering the examples given above, the primary consideration is that the camera should see the object being counted fully.