Why you shouldn’t use a video security camera as an ALPR camera

Many of the larger and know smaller security camera manufactures are now jumping on the ALPR bandwagon and producing so called LPR capable surveillance cameras. What does that mean, LPR capable?

Security Camera

Capable meaning, the camera is equipped with some feature to see a license plate. This could mean many things including IR lights, low light sensitive and so forth. LPR or ALPR or ANPR, which is all of the same, are very specialized cameras. While at ISC West a gentleman from Boeing approached and sales person whom was selling an ALPR solution. I happen to over hear the conversation. The scientist, I’m assuming the gentlemen from Boeing was a scientist, asked the sales person what makes the camera or ALPR so special.  The response was; well that’s not important at this time. 

So what is so special about an ALPR camera? IPVM.com published an article about License Plate Capture Shootout. In the natural selection process to determine which product to test IPVM.com only testest and write about sponsor provided equipment and then try to provide an unbiased report, they’ve selected 3 cameras. One from each of the IPVM self created categories. These categories are Super Low Light Cameras, Integrated IR Cameras, and finally the Purpose Built License Plate Cameras. Now, take into account only one camera claims to be an actual LPR camera. The other two are compromises for ALPR cameras and do not claim to be ALPR cameras but can be used as such.

In my experience, LPR cameras are typically a two-lens system. IPVM.com only tested cameras with single lens; the purpose built license plate camera also only has one lens, a monochrome or Black and White lens. The testing criteria developed by IPVM.com were based on daytime performance, nighttime performance and speed below 10mph and above 40mph. As a disclaimer, having many years of actual ALPR experience design and deploying systems, this article was very difficult to read. I felt it missed the point of LPR but then soon realized the good information it provided. 

The test does not specify the software used only cameras. Ahh, but let me tell you the cameras selected would make impressive cameras for a video surveillance deployment. Camera one which is a bullet style camera has a specification of 1080p resolution. Camera two has a resolution of 1.3 MP and camera three a resolution of 720p. Very impressive, but do you see the issue here?  It’s apparent that the cameras that are surveillance cameras (1,3) trying to be LPR camera will fail miserably at night capture. Experienced integrators that have deployed HD cameras outdoors can tell you all about it.  So it’s no surprise to see results like this:

Picture Courtesy of IPVM.com

Video cameras have one purpose and that is to function as a video camera. Going back to the Boeing Scientist ‘s question, “ What makes the ALPR camera so special”? The short answer is it reads license plates very well, because it’s sole purpose is to read license plates day or night and with a high level of accuracy. 

Picture Courtesy of IPVM.com

At ISC West 2014 I saw it with my own eyes a camera that will change all of what I just said. It will make me eat my words that a video camera cannot be a LPR camera. A company by the name of Image Sensing Systems has developed a dual purpose LPR camera. Dual purpose in that it can function as a surveillance camera and LPR camera with PTZ functionally. I’ll have more on this camera once it’s released.

Like all good things, this article must also come to an end. Thanks to the research that IPVM.com released regarding using video surveillance cameras as LPR camera. The result in my opinion is that video cameras will fail miserably as LPR cameras.  A video camera is not suited to meet the higher demands of the outdoor environment for such a precision task of scanning and identifying the digits of a license plate.  Specialized ALPR camera is made for that very reason.

In closing I leave you with this. I attended a workshop for filmmakers. Making movies is a hobby of mine. The presenter was the Director of Photography for Saturday Night Live. When I walked in to the room that was arranged as a movie set with cameras from small to impressive posed on tripods.  The presented started with this, “ I’m showing you my tools. Every camera you see here I have operated, there is no magical camera that does it all, each camera in this room has it’s purpose, and is good for that purpose only.”