*ObjectR Basic – Object Size

Technical Article | TA-20201002-TP-10

VDG Sense | Video Content Analyses | ObjectR Basic

Note: ObjectR Basic is not available in VDG Sense 2.5 or higher!

There are a several important guidelines to follow when setting up object size filters, use these to ensure they work correctly.
Important guidelines:

Take into account object size variations for objects that need to trigger a rule, for instance small or large vehicles. Adjust the the ’Far’ and ’Near’ boxes accordingly.
Take into account object size variations caused by movement and direction of the object.
Take into account the basic shape of the object. If for instance an object does have the correct height to trigger a rule but is smaller than the minimum width, it will not trigger the rule/event.
Place the ’Far’ and ’Near’ boxes in perspective as shown in the image.
Make sure the ’Far’ box is smaller than the ’Near’ box.
Make sure the bottom line of the ’Far’ box is placed higher then the bottom line of the ’Near’ box.

The last three guidelines are very important for the filter to work properly. They are used to place the visible objects in a three dimensional space so object variations between the ’Near’ and ’Far’ boxes can be calculated. As can be seen in the picture the vertical position of the car determines the actual size of the filter.

The actual filter varies between the ’Near’ and ’Far’ box depending on the vertical location of the object in the camera’s field of view.

The representative objects you use while setting up object filters will depend on the kinds of objects that will be involved in the events you plan to create (or have created). The list below provides recommendations to help you decide which types of objects you should use while setting up object filters.

People only
minimum – Set the boxes to a size slightly shorter and narrower than an average-size person. If you want to detect events involving children, use a child instead of an adult as the representative object.

maximum – Set the boxes to a size slightly larger and wider than an average-size person. If you want to detect events involving children, use a child instead of an adult as the representative object.
Vehicles only
minimum – Set the boxes to a size smaller than a compact car. If even smaller vehicles like motorcycles are a concern, make the box slightly smaller than a motorcycle.

maximum – If larger vehicles like box trucks and 18-wheelers are a concern, set the boxes to a size that is slightly larger than the largest vehicle that might be involved in an event. Otherwise, set the boxes to a size that is slightly larger than a large vehicle like a pick-up truck or a van.
Small objects only
minimum – Set the boxes to a size slightly smaller than a small object of the type you want ObjectR to recognize (e.g., a duffel bag for left item events).

maximum – Set the boxes to a size slightly larger than the small object you want ObjectR to recognize (e.g., a duffel bag for left item events).
People and vehicles
minimum – Do not use a vehicle to set the minimum size. Instead, set the boxes to a size slightly shorter and narrower than an average-size person.

maximum – Do not use a person to set the maximum size. Instead, set the boxes to the size of a larger vehicle. If larger vehicles like box trucks or 18-wheelers are a concern, set the boxes to a size slightly larger than the largest vehicle that might be involved in an event. Otherwise, set the boxes to a size that is slightly larger than a large vehicle like a pick-up truck or a van.
People and small objects
minimum – Do not use a person to set the minimum size. Instead, set the boxes to a size slightly smaller than the small object you want ObjectR to recognize (e.g., a duffel bag for left item events).

maximum – Do not use a small object to set the maximum size. Instead, set the boxes to a size slightly larger and wider than an average-size person.
Vehicles and small objects
minimum – Do not use a vehicle to set the minimum size. Instead, set the boxes to a size smaller than a small object you want ObjectR to recognize (e.g., a duffel bag for left item events).

maximum – Do not use a small object to set the maximum size. Instead, set the boxes to the maximum vehicle size. If larger vehicles like box trucks or 18-wheelers are a concern, set the boxes to a size that is slightly larger than the largest vehicle that might be involved in an event. Otherwise, set the boxes to a size that is slightly larger than a large vehicle like a pick-up truck or a van.
All object types
minimum – Set the boxes to a size smaller than a small object you want ObjectR to recognize (e.g., a duffel bag for left item events).

maximum – Set the boxes to the size recommended as a maximum vehicle size. If larger vehicles like box trucks or 18-wheelers are a concern, set the boxes to a size that is slightly larger than the largest vehicle that might be involved in an event. Otherwise, set the boxes to a size that is slightly larger than a large vehicle like a pick-up truck or a van.