MaterialFlow
by Fastcom Technology S.A.

Object Airlock: The aim of this document is to describe a video-processing based system to verify the contents of an object airlock. The system verifies that only objects are present inside the airlock, and does not allow persons to access the secure zone via the airlock.

Problem Specification
The problem to be solved is preventing anybody from going through an airlock from a non-secured zone to a secured one; the said airlock being reserved for passing inert objects between the two zones.

The advantage of a video processing-based system is that it does not present any physical constraints, and thus the size of the objects, as well as the architecture of the airlock facility, need not be fixed.

Technical Proposal
When entry is requested, the Fastcom system starts to track the persons who are bringing the object into the airlock. This tracking is performed as long as someone is present inside the airlock and as long as the entry door remains open.

Once the entry door is closed, an analysis of the airlock contents is performed using sophisticated motion detection algorithms for a user-adjustable duration. If any motion is detected, the entry door will be reopened and the person(s) must leave the airlock. If no motion was detected, the second (secure) door is unlocked allowing the object to be recovered from the other side.

The analysis can be uni-directional or bi-directional, i.e. object detection can be performed only on entry (with free exit for persons and objects), or the object detection can be performed in both directions.

Note that to be detected a person must be visible, and thus the risk of person hiding behind objects depends on the size and shape of the object(s).

In addition, the system ensures that the two doors can never be opened at the same time, except for a possible maintenance mode.

This functionality can be achieved in one of two ways: the Fastcom system performs motion detection, while the door access logic is handled by a customer-supplied PLC (Programmable Logic Controller); or the Fastcom system performs the motion detection and directly controls the doors without the need of a PLC.

These two possibilities are described in the following table:

Camera Solution
Fastcom proposes two solutions for the camera placement, depending on security and cost requirements.

Proposed solution 1: Single ceiling-mounted camera
The first proposed solution uses a single camera mounted vertically on the ceiling to allow a full overview of the airlock. This solution implies lower material costs, but with a greater risk of "blind spots" in the airlock due to object shape or size.

Proposed solution 2: Multiple cameras (up to 4)
Another solution could be implemented by using several cameras per airlock. Increasing the number of cameras provides greater sensitivity of analysis and a higher degree of security.

Possible configuration: an airlock with two ceiling-mounted cameras
with an optional control camera

Additional functionality
It is possible to extend the functionality of the system.

For example, if it is known that the airlock will be used always for similarly-sized objects (e.g. suitcases), a minimum and maximum size of the objects could be set. This will allow the system to reject any other objects or people that are outside of the permitted range. In the case of laterally-mounted cameras it is also possible to impose a maximum and minimum height limit.

In addition if the form of the objects is known in advance (e.g. rectangular cases) their features could be used to identify the objects and exclude both persons and forbidden objects, gaining an additional level of security.

Technical limitations
A video-processing based system imposes certain limits. As a visual system, it requires good, stable lighting and absence of strong shadows. This implies an absence of sunlight, and transparent walls or doors must be used with caution (i.e. only if external lighting will not influence the interior of the airlock).

Additionally, a visual system must be able to see the person or objects it is analyzing. A person hiding behind (or inside) a large object will be invisible to the camera. The use of multiple cameras and restricting object size will reduce this risk.

Finally, as a motion detection system, it is necessary that the objects be inanimate. For example, the moving leaves of a potted plant would be detected as motion and rejected as a possible security hazard.

Example procedure
Normal use

1. Person badges for access to airlock;
2. Person enters airlock with object;
3. Person places object and leaves the airlock. The door closes and is locked by the system. The Fastcom system performs the motion detection;
4. After a user-defined delay if there has been no motion, the secure door is unlocked;
5. The object can be recovered from the secure side;
6. SMACS checks if the airlock is empty.

Alarm case

1. Person badges for access to airlock;
2. Person enters airlock with object;
3. Person places object and remains inside the airlock.  The door closes and is locked by the system.  The Fastcom system performs the motion detection;
4. During the user-defined delay motion is detected, the entry (non-secure) door is unlocked;
5. The person must leave the airlock via the entry door;
6. SMACS checks if the airlock is empty.