Of all of the questions that I address on a daily basis, the most common misunderstanding that I speak on is that of license plate detection. It seems that each day a customer will say to me “I would also like for the camera to capture license plates.” Unfortunately, this isn’t as simple as it sounds. License plate capture is quite a sophisticated application, and therefore requires a camera that is designed exclusively for that application. In order to maximize the possibility of clearly capturing plates, a license plate recognition camera (LPR) is necessary.
While it may be possible for a non-LPR camera to capture license plates, the conditions need to be just right. While perfect lighting conditions, close proximity to the camera, or a slow-moving or parked car are ingredients that may allow for success with a standard camera, it is rare that these conditions exist at the same time. LPR cameras are specifically designed to produce high-quality images of vehicle license plates regardless of speed, lighting or weather conditions, thereby allowing for accurate vehicle identification.
To put it into perspective, imagine a vehicle at night, and consider the situation that the car itself is projecting. A license plate is made of reflective metal; on either side of the plate are headlights shining and reflecting off of the plate. Regardless of the quality of the camera that you possess, this effect is simply impossible to overcome without the added technology of an LPR camera. The advanced technology of an LPR camera will filter out visible light while delivering infrared light, thereby allowing the camera to capture an image of the license plate.
In addition to plate identification, LPR software can aid business owners and their security teams by archiving the activity at their properties. With LPR cameras and software, you are able to log each vehicle that comes in or out of your facility, as well as the time of their entrance or exit. This can certainly be helpful to you as you address time disputes with employees, or even help to settle disputes regarding vehicle damage, or if a vehicle was ever present at your lot. Visit our website to see our full line of LPR cameras and software.
Filed under: Beginning CCTV, CCTV Articles, CCTV Camera, General Technology, Guides, IP Cameras, Security Camera
Being a consultant in the security camera industry, I get a phone call everyday asking, “Will this security camera be able to capture a license plate?” or, “I bought this camera the other day and it doesn’t work right – it won’t pick up license plates.” It’s important to consider that not just any security camera can do that job, but rest assured you won’t have to spend an arm and a leg on one that can. Here are a couple of pointers to keep in mind when shopping for a license plate camera.
Pick the Right Camera
What a lot of people do not recognize is that if you want to capture a license plate with a camera, you’re going to have to purchase one that is used strictly for nothing but catching license plates. Unfortunately, it’s not quite as easy as getting any camera, setting the lens so the picture is wide, and then expecting to capture great detail. The best starting point is to look at box cameras. Box cameras themselves are small, but once you put them inside an outdoor housing, they become bulky but ideal solutions. Box cameras usually allow swappable lenses, so with the correct zoom lens, the camera can easily be pointed and manually zoomed to the right location for license plate sightings. Believe it or not, the picture in the upper right hand corner was taken at 100ft away. We used an IP camera and added a 5 – 50mm lens and were able to catch this view 100 feet away (and really could have gotten it further). Although that is an impressive plate caught with an IP camera, you can get the same result with an analog camera (sometimes even better). This picture in all black and white, was taken by a License Plate Recognition Camera, and believe it or not, it’s an analog.
Pick a Good Spot for the Camera
A decision that is just as important as picking the right camera is picking a spot for the camera, or picking a spot so the camera can see the spot that is ideal for catching license plates. There are a few situations that are just absolutely ideal for catching plates, such as directly before a speed bump, in front of a stop sign, or even at the driveway where cars will be pulling in and out. You will greatly increase your chances of capturing a license plate if you pick the spot in your parking lot where the cars are forced to slow or stop.
Unless the area you are trying to capture license plates is very well lit 24/7, you will have to consider the illumination range. Illumination range is the distance the IR lights will reflect so the camera can see in the dark. If you use a box camera, you may have to use an IR illuminator (which will add IR to any camera) if your camera lacks infrared options. Be mindful that the particular license plate camera will not need to see to the end of the parking lot, just to the area where you are hoping to see the plate.
Catching license plates is something that isn’t very hard if you know what camera to buy, what lens to put on that camera, where to point the camera, and have sufficient lighting. While this may involve moving the camera around a few times to acquire an optimal position, it’s ultimately an easy and worthwhile use of time.