jeffpack1957 0 Posted December 7, 2007 In discussions with ExtremeCCTV, I've learned their LPR camera's are highly dependant on the reflectivity of license plates. Plastic covers over license plates defeats any LPR at nightime. Even dirty or older plates fail. Has anyone else experienced these sorts of problems, and what have you done to eliminate them? I guess I could illuminate the view area to help more at nightime? Any other thoughts? Share this post Link to post Share on other sites
Scruit 0 Posted December 7, 2007 In discussions with ExtremeCCTV, I've learned their LPR camera's are highly dependant on the reflectivity of license plates. Plastic covers over license plates defeats any LPR at nightime. Even dirty or older plates fail. Has anyone else experienced these sorts of problems, and what have you done to eliminate them? I guess I could illuminate the view area to help more at nightime? Any other thoughts? I have a home-built LPR setup using a BW camera, 55mm lens with 850nm filter and a seperate 850nm IR emitter. My car has smoked license plate covers, and the camera finds it very difficult to read my plate. My wife's plates are not covered, and they are easy to read. I've also noticed that today's covering of snow really makes the camera struggle becuase it has a manual iris lens. I have an auto-iris lens that should be arriving today so we'll see if that helps. Reflectivity is a big issue at night for me - a light coat of dirt can reduce the reflected light enough so the plate disappears compared to the bright taillights or headlights. Reading plates forma car facing towards me with hi-breams on was a struggle in and of itself and I coudl only solve it using the reflectivity of the plate so but reducing the reflectivity with any kind of covering kills my LP camera. Share this post Link to post Share on other sites
rory 0 Posted December 7, 2007 Didnt notice a huge issue when working on this one, but im sure if they are too dirty then you wont get the plate .. if its too dirty to see it with your own eyes then the camera wont see it either. Share this post Link to post Share on other sites
jeffpack1957 0 Posted December 8, 2007 They really arent that dirty, and are easily visible in the same camera during the day. But a clean plate, shows up well. Or a newer one. Share this post Link to post Share on other sites
rory 0 Posted December 8, 2007 The ones in the images above, all from a REG camera, the SD Plates are rentals and are White Plates, and typically not that clean. The others are Blue plates with Yellow Text. Share this post Link to post Share on other sites
jeffpack1957 0 Posted December 8, 2007 as my nightime pics, arent near to yours. All I'd see is the tailights and license. It appears from the reflection on the bumper, there is some illumination of the area. I'm still thinking about illuminating the area some, just to see how or if it helps. The current area has no illumination at all. Share this post Link to post Share on other sites
rory 0 Posted December 8, 2007 No, its pitch dark, there was a car behind that one. The REG cameras are specifically for pitch dark situations and have built in IR. As you can see, they also work during the day. They are basically plug and play cameras. Share this post Link to post Share on other sites
jeffpack1957 0 Posted December 19, 2007 I boosted the IR up to max and I'm back to 90%+ recognition. I'm still awiating a response from ExtremeCCTV as to whether I've a camera problem, or what. They tell the IR is good for 5 years, and I think I'm just past 1 year. They told me long ago, that this time of year (NW) plates get abit of road dirt and cuts down the reflectivity of the plate. Yea, I'll buy that. So my question to extreme is what do other folks do this time of year, the same thing I did, and then turn it back down come spring? No answer yet. Share this post Link to post Share on other sites
dtonsberg 0 Posted December 20, 2007 ALPR is an exact science and some company's have alot invested in R&D. FYI PIPS was just purchased for over $90M by Federal Signal. These higher end products to take factors like, snow, rain, headlights, plate light, tail lights, speed, etc...into account. While you may experience partial success with a novice built system, most systems are tuned to take into account either the broad base of plates (like Extreme CCTV, now Bosch). If you want performance you will go to a company like PIPS, Zamir or INEX to get a system that works all of the time, not half or less of the time which is my experience in general with ALPR systems like Extremes. Share this post Link to post Share on other sites