Pixels per foot
By Martha Entwistle
Updated Thu December 6, 2007
I had a chance to attend an IQinVision event on Tuesday (hence the no blogging) that was organized to push the concept of using pixels per square foot to spec video surveillance needs. There were about 12 people there, all integrators and consultants, and it was a good chance to talk shop. IQinVision VP and co-founder Paul Bodell (not pictured) delivered a concise presentation that seemed to make a lot of sense.
The crux? If you want forensic quality video, you should spec the surveillance system so that you've got at least 40 pixels per foot of area being watched. So, if you've got a one megapixel camera, with field of view 1280 pixels wide by 1024 pixes high, you can cover about 32 feet wide by about 25 feet high/deep (if I'm doing my math right and understanding the concept correctly, which I think I am). If you try to cover more area, you'll be setting your customer up for some blurry pictures of bad guys. The good news (for IQinVision and their resellers, anyway) is that you can use the same calculations for all cameras and show that fewer megapixel cameras cover more space than the equivalent analog cameras (which use TV lines instead of pixels) and thus justify their cost.
But don't trust me, IQ will do the calculating for you here (well, it will pick the camera and lens you need for the space you're looking at).
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