Optimum Deployment of Vision Based Security Devices

John Keogh | April 16, 2013

Several of our software products, which run on iPhones, iPods, and iPads, use simple computer vision based algorithms to help to alert the user of potential security issues at their home or office. The proper deployment of these systems involves simultaneously solving several problems:

  • Placing the device where it will capture images of intruders as they enter a secured area
  • Securing the device from intruders, weather, and unintentional damage
  • Powering and configuring the system
  • Minimizing visual noise

Algorithm for capturing unauthorized entry

When you start to analyze where to deploy security devices, start the analysis outside the area to be secured. If you are securing your home, begin your analysis by examining the exterior. Are there areas that are hidden from the street or where entry would be very difficult due to thorn bushes or external barriers? Are there ways to get to a second floor entry or into the basement, including through utility or ventilation ductwork? Are there exterior areas you want to monitor regularly like the front door to see who is knocking or the back yard to watch children while they are playing?

Once you have done your external examination, walk through the inside and see what the choke points are. Typically, these are stairs or corridors that lead from one level or area of your house to another. Then, look for the paths from all of the access points to the choke points.

When you have done both the external and internal examinations, determine where the objects of value are. If you are guarding a residence, this will generally be where you sleep and where valuables are stored during the day while you are away.

Finally, determine you placement. You will want to have sufficient devices to view the areas that you want to monitor, like the front door, and those that you need to monitor, such as any internal choke points that lead to where you sleep and keep valuables. Consider whether you can put monitors back to back in such a way that they will tend to guard each other from intruders (for example, if you can see the front door from your bedroom window and a stair from a bedroom door, place one device with its back to the door and one looking out the window, in order to approach either device from behind, an intruder would need to pass through the other devices field of view).

Finally, to avoid unintentional damage and to make it more difficult for intruders to defeat a system, determine if you can place the device out of easy reach. This can be as simple as building a small shelf high up on the wall. If you do this, you may need to find an electrical contractor to place a plug where the shelf will be, so that the device has power and the device can't be pulled off the shelf by its power cord. It is best to test out the system in the proposed placement prior to having a shelf built and power supply added, to make sure that the system works well in that placement.

Power and configuration

Once you have determined the placement, you will need to power and configure the device. For EyesBot running on an iPod or iPhone, you will need to plug in the device, since the internal battery will only provide a few hours of service. An iPad would likely provide a nights worth of security, but it is best to plug these systems in as well, or you will have a depleted battery in the morning. For configuration, you will need to adjust the sensitivity so that is is appropriate for the "visual noise" meaning the reflected lights coming through windows and the like which will trip the alarms if the system sensitivity is too high. Additionally, you should attempt to minimize visual noise.

Minimizing visual noise

A visual system like EyesBot or EyesBot Watcher uses visual cues to detect motion. These visual clues are triggered by intruders, but also by anything that changes the appearance of an area, such as headlights from a car moving across a wall or even changing light levels. Additionally, the scene must have sufficient light for the device to be able to detect motion. The solution is generally to place the device pointed away from windows, or lower the sensitivity and allow for a certain number of false positives if it is placed where it will be exposed to visual noise. The least visually noisy environment will be when the device's camera is pointed at an interior wall, with the curtains drawn, and an artificial source of light illuminating the area.

Final thoughts

As processing power and software becomes more powerful, devices will be able to determine family member or worker identity and alarm if anyone who isn't supposed to be present is present. For the time being, placement, configuration, and minimizing visual noise for security devices will, along with proper physical barriers and preparation, help to secure your family or business.

Eyesbot Company

Computer vision

Artificial intelligence

Effecting the physical world