A few weeks ago we gave you a sneak peak of some of the new features in version 3.2. To celebrate the upcoming new release we’re going to go more in depth into each of those features, starting with doorway analysis.
‘Doorway analysis’ is a new video analytics algorithm to deal with tricky doorway surveillance videos. This can be when traffic passing infront of the camera causes a lot of interference with the standard video analytics algorithm.
Depending on the type of doorway video you have there are two different ways of analysing your footage, applying an algorithm when you are at the import stage or adding a filter after the video has been imported. The algorithm method is meant for videos where the doorway is the main focus of the frame and you are trying to eliminate movement that blocks at large part of the frame. The filter method is for when a doorway is in the frame and you are interested in movement that starts or ends in that area.
The first method of Doorway Analysis we’re going to look at is the Doorway Algorithm which can be applied when you’re importing your video.
When you select Doorway Algorithm from the algorithm list the doorway options will appear below.
The popout button on the left hand side allows you to pop the doorway settings into it’s own window.
The first thing you can set is the doorway area. You can switch between setting this or the exclusion area on the left hand side. If the preview image doesn’t show the doorway (maybe a car is blocking it at that moment) then you can use the ‘clock’ buttons at the top to change the displayed frame. The button on the very right hand side will reset the frame back to the first frame.
The red box represents the doorway area. Use the corners to adjust the size and location of this area. When you’ve finished adjusting the doorway area, select Exclusion on the right hand side and create an exclusion zone in the same way.
The exclusion area will detect when a large part of the area is covered by a passing object. If this area is then covered, that frame will not be processed. The idea behind this is that if a car passes in front of the doorway, covering the exclusion area, this will not be picked up and shown as an event, cutting down on the number of events you have to review in the Review tab.
By default Doorway Occlusion Detection is selected. This is used when the door takes up 30% or more of the scene and you want to detect when the door is blocked by, for example, a person.
Normal Tracking is similar to the Event Detection algorithm but is optimised for doorway analysis. This can be used with the doorway filters which we’ll get into in a bit.
The exclusion area can be turned off by unchecking Eliminate Occluded Frames.
No. Frames to Trigger allows you to set the amount of frames, that have movement in them, needed to trigger an event in the doorway area.
Max No. To Skip is the number of frames that have moment in them before skip is turned off. Since the idea behind exclusion is to block out fast movement blocking the whole screen, such as cars passing in front of the door, this number is normally set very low.
If you are in the popout window click Accept Changes, otherwise just continue on your import as normal and then review the results in the Review tab.
For videos that contain a smaller doorway, that have been imported using either the event detection algorithm or using the Normal Tracking option above, you want add a new doorway filter.
When adding a filter, like you’ve always done, you can now choose between a standard filter and a doorway filter. With a standard filter, all movement will be caught in that area. For the doorway filter, only movement that starts or stops in that area will be displayed.
Once you’ve selected Doorway, add your filters as normal and then place your filter area over the doorway. When you go to the Review tab, select the filter like you always do and view the results.
And that should do it for Doorway Analysis. Over the coming weeks we’ll be covering more exciting features like object classification, multiple simultaneous exports, the new Grid tab and, the soon to be fan favourite, undo annotations! Oh the fun we’ll have!