Subscriber Discussion

Abandoned Object In Crowded Scene - Who Can Provide Accurate Alarm?

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Fredrik Ahlsen
Mar 11, 2018

Almost every supplier of video analytics say they can detect "Static/Abandoned Objects" but what is your experience with detection of left objects in crowded scenes? Like detection of a bag left of the floor in a busy shopping mall or in the middle of the railway station terminal.

I have been looking at solutions from Avigilon, Agent VI and VCA Technology, but I`m also open for others.

I know that they can provide accurate alarms for left objects in a empty space, but can any provider out there give acurate alarms in a scene where hundreds, and maybe thousends of people walking by the object every hour?

I perfer to get feedback from your real life experience, please let me know if you give me feedback based on experiece or from what you have seen/read in marketing from the supplier. An estimate of false/positive alarm ratio would also be interesting.

UM
Undisclosed Manufacturer #1
Mar 11, 2018

If someone tells you they can accurately detect bag left behind with low false alarm rate in a busy scene, laugh at them and trust someone else. Bombers usually use trash cans anyway.

JH
John Honovich
Mar 11, 2018
IPVM

Fredik, good question. The key parameter I have seen used to reduce false alarms when analyzing abandoned object in crowded scenes is dwell / delay time.

For example, take a train station or an airport. If I put my bag or suitcase down, am I dropping off a bomb or just resting? That's one reason why the delay time can be set very long. Otherwise, you will be responding to nuisance alerts all day long (until you shut it off).

I have not heard anyone recently make any claims about improvements in this area. I would be curious to hear what others have seen.

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UI
Undisclosed Integrator #2
Mar 11, 2018

I’m pretty familiar with the concept and I would say the issue is more environmental and operational than technology. 

I will agree in a static environment almost any analytic manufacturer can do object left behind and object removed.

In a crowded environment the issues revolve around timing as John said and also how many objects the analytic can identify and track in a single scene.  Some are limited to less than 30 while others claim 300 or more.  How busy is the scene if the package is under a bench and hundreds are waiting to catch a train after a ball game?

Now let’s talk the hard part, operations:

Lets say someone wants to explode a device at the end of a marathon race.  There are hundreds of people milling about and various chairs, backpacks, vendor carts and temporary trash cans around.  

Your security team gets an alert that something looking like a McDonalds large bag is “left behind”.  

What do you do?  

Evacuate the area, call in a bomb squad?  Frighten the community and stop the event?  Review video to see what appears to be a 10 year old leaving it?  Maybe that’s it and you caused a huge unappreciated commotion.

Or, disregard because it appears innocent and when it goes off, share more liability than if you hadn’t been alerted?

What’s the timing?  1 minute too short?  10 minutes too long to track and too long to prevent?

Manage the expectations and operational requirements.

 

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Fredrik Ahlsen
Mar 11, 2018

Thanks to both John and Undisclosed Manufacturer #2 for your input.

I agree on the use of dwell time, but what happen when a group of people walk in front of the object that is detected as abandoned. Completely covering the object for a few seconds. I fear that this will cause the analytics to loose track of the object and start the dwell time all over again.

I also see the challanges regarding operations, but I`m asking about this functionality because a client is requesting it. So in this case is a shopping mall and if an alert go off I think they will simply send out a security guard to investigate. Making me think: the security guards might be asking for a raise pretty soon.

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UI
Undisclosed Integrator #2
Mar 11, 2018

The issue of a temporarily blocked object has been worked around.  Some analytics can manage a blocked item for more than 15 minutes in a crowd.  Again, how many objects can be placed in memory matters. 

By the time 15 minutes has expired the person could have delivered the device and detonated.

In my experience, once you explain the potential pitfalls most people asking for it stop asking.

Think through several scenarios with them, all starting with “What if”

Device dumped in trash can?  Won’t be detected.  No alarm.

Trash can moves in scene, becomes new object.  Alarm.

Shopping cart left somewhere?  Alarm.

Alarm from item.  Rush guard over and what?

Alarm from item.  Ignore it and it blows up and people die?  Then what?  Are you better or worse off?

No detector, no alarm, device detonates.  Are you better or worse off?

This is why, after spending millions on analytics the NY Transit Agency invested in posters that say “See Something, Say Something”

We won’t talk about agencies hearing something and doing nothing because it doesn’t apply here.

 

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U
Undisclosed #3
Mar 11, 2018

Fredrik,

I think this is an opportunity for you to display your expertise and earn the customers trust by explaining to them why they can't get what they want.

What they are asking for simply does not exist at this time.

It's tough to tell customers this because there are lots of unscrupulous folk who will sell your customer a half-assed solution that they will never be happy with - and will never work as the customer wants it to.

There are numerous strings here on IPVM that discuss the technical and operational weaknesses of object left behind analytics.

Manufacturer President: "Customer Is Now Very Angry"

Boston Bombings - Outrageous Manufacturer Claims

City Video Surveillance Guide

From the City Surveillance Guide:  Key Findings #9: 

Analytics: LPR/ALPR analytics are the most common types used. 'Video' analytics were uncommonly used, e.g., loitering, face recognition, object left behind, or direction of travel analytics. The key barrier to wider adoption cited was inadequate performance given the cost.

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