Your best chance of catching a Tennessee plate will be early in the evening, while there is still some ambient light but your camera is in B/W mode. Search for B* as a wildcard.
@EMPIRETECANDY, this is one time I wish I had been wrong. So there is no hope of using the 5231 camera with a 740nm infrared source.
Yes, same on 5241 too. That may need a special project to do this change, not sure if need any hardware change. I will make some checking.
That is certainly wonky behavior, in B/W mode the camera is concluding the box and cab are the same shade of color. From the B/W shot you'd think this truck was all white when it very clearly is not. This definitely offers some insight into whats happening with the TN plates, the camera thinks the whole plate is white in B/W mode. I'm curious if theres anything in software that can fix this or if its a hardware problem.
It's very much a hardware problem, but it can only be solved if you illuminate the truck at a different infrared frequency than 850nm, and if your camera is sensitive to that new IR frequency. If two colors reflect equally well at 850nm wavelength IR light, then they will appear to be the same shade of gray (or white) to the camera sensor.
This right here.
That is not true. There is no 'color determination' by the camera. The cam does not sit there and look at the scene and determine that two colors are the same and then displays it in black and white as the same shade of grey. The sensor is picking up reflected IR light and is sensitive to the wavelength around the 850nm band. Every optic system, whether it be biologic or electronic, perceives an image in specific electromagnetic bands. Your eyes can't see cellphone signals, but they are there. Just like your eyes can't see IR at 850nm.
Good points and yes I agree, I live in TN, I still have one of the old style plates but I'd love to get an illuminator at 750nm to test the theory out. Anyone know where you can buy an IR illuminator with 750nm LEDs?
Read the rest of this thread. I've already gone down this path. You can buy 730nm or 740nm illuminators, but the Dahua camera models that most of us use for LPR are insensitive to those IR wavelengths, as confirmed by @EMPIRETECANDY. They are optimized for 850nm IR, and are essentially "blind" below 800 nm.
Fair enough, I've read the State's response and unsurprisingly they refuse to admit there's an issue and are not going to spend any more money on redesign, even though they also admit they did zero LPR testing. Outside of heavy pressure from law enforcement, I think waiting for a newer camera is the only option at this point, sucks.
Unfortunately, this entire mess was a combination of bad decisions and bad politics. The Dept. of Revenue screwed up because it never occurred to them to test the plates. Once the nighttime visibility issue was revealed, Flock Safety screwed up by claiming they could fix the problem in software, because they have thousands of their cameras deployed in TN and they didn't want their customers to lose faith in the product.
he's working it from the inside. Product must continue to move, and influencing the LPR tech, helps his cause.
I have not. I've spoken to a police officer, and according to him the situation is only getting worse as more of the new plates are issued. Both Rekor and Flock Safety have been tweaking their LPR software to improve IR readability, but there's only so much that can be done when the contrast between the letters and background is so poor.
