Monday, December 15, 2008

DCRI - surveillance levels

In his work for the US Army Night Vision lab, John Johnson developed a standard which, when you look at it, seems so downright obvious it's amazing it took someone this long to come up with it, as is the case with many great but simple concepts.

John Johnson realized that this simple comment 'We want a video surveillance system so we can see what's going on' is as loaded as it gets. The problem lies in 'what you want to see' and 'what you want to take away from it'.

He broke down 'seeing' into 4 steps, abbreviated to DCRI. D for detection, C for classification, R for recognition and I for identification. Let's take a deeper look at those.

I have a nice thermal camera (yes, I saved up for it) pointing at a distant treeline. I see a glowing blob moving through the trees. After watching it for a second or two I convince myself I have DETECTED something moving. Don't know what yet.

The guards are alerted.

It moves closer and appears a little bigger. I can see it is walking upright - it is certainly taller than it is wide. I convince myself it is human. I CLASSIFY it as a human. Good or bad, man or woman, I have no clue. but a person it is.

The guards are dispatched, along with some big slobbering doggies.

As it comes closer, and I now switch from my thermal camera to something that can reveal finer detail, I realize it is not moving at a steady walking pace - instead it is making erratic moves, almost trying to avoid detection and occasionally crouching. With IR illumination, and especially if it is in the spectrum where there is no visible light whatsoever so the person does not know he is under surveillance, I catch a glimpse of the clothing. The clothes, rifle and overall demeanor are a total give away. I know it's not a good person. I RECOGNIZE it as an intruder.

The guards proceed to engage.

As I zoom in I catch the face and other tell-tale marks of who it is. I have IDENTIFIED it not only as a man, but if I can't put a name to him yet, with the printed image from my video management system, I soon will.

How does Bosch take this principle into our development of products? Unlike many active IR and thermal solutions out there that claim only distance when it comes to their night vision products, Bosch infrared imagers provide performance parameters based on the DCRI principles…so what? It means you can effectively specify cameras based on what YOU are trying to achieve. Hopefully this posting will help you think about what the system really needs to do, which should in turn drive the right selection of parts.

DCRI - equally valid during the day or night. Simple, but effective. Wish I'd thought of it.

1 comment:

Mike said...

Wonderful! A very simple concept that makes a BIG impact on performance. This is a very practical way to manage a customer's expectations prior to deploying any system. I have been surprised at how casually the marketplace tends to "throw megapixel" at difficult applications with the belief that Identification needs will be achieved by default.