This is what we are getting with a 4K camera (Hanwha PNV-9080R) during the day and at night. We are wondering if there is something we are missing about camera settings for night, or if this is really the crappy night time image we are stuck with. This shot is with the car at about 60' from the camera, mounted 9' high on the pole.
Jim, thanks for sharing those pictures, that helps greatly!
Things to consider:
(1) Force the camera into night mode / IR on - the added illumination should help to reduce / eliminate the noise
(2) Check the shutter speed and try to make it shorter (say 1/60s or 1/120s or 1/250s, in that range, experiment) that should reduce / eliminate the blur
Related: License Plate Capture 4K Test
Great feedback. After I posted that, I had that epiphany about the color mode. I believe in color mode the IR cut filer is on and therefore our IR painters are doing no good??? Also, color mode is much noiser at night due to the relatively low light. Maybe even causes a compression issue as that much noise makes a very "busy" scene to render?
Wondered about the shutter speed as well. If you lengthen that however, will the day picture suffer, or do those cameras have the ability to vary the shutter speed on a schedule ?
Jim,
Yes, IR illuminators are typically disabled in color mode. And color mode is generally noiser and compression artificating can increase.
Shutter speed is typically set as a max. In the day, the shutter might automatically go to 1/1000s (as an example) because it is so bright that the camera needs little light. At night, the camera 'wants' to slow the shutter so it can take in more light (e.g., Camera Slow Shutter / Ghosting Tested). By default, most cameras today have a shutter speed max slow of 1/30s - That is fine if you have slow moving objects (like a person casually walking) but if a car is driving by, you want to set the max 'faster' to 1/60s or 1/120s, etc.
So it looks like our night plate capture problem, is likely only solved by using an actual purpose built ALPR camera. The current camera manufacturer (not sure if I should say who in this forum?) sent an engineer on-site to do night time testing (I thought that was pretty good for them to do actually) and their conclusion is that a true ALPR camera is required to reliably capture plates at night. That being said, I was wondering 2 things.
1. Has IPVM done any ALPR camera shoot-outs?
2. Does anyone have a recommendation for an ALPR camera that they had good results with?
Jim,
We have tested multiple solutions including:
I am sure you will get some end user and integrator recommendations as well.
Jim, what did the engineer on-site do? What configuration changes did he try? I am curious because your application does not seem too hard (and we've tested many 'regular' and specialized license plate cameras).
I'm curious - and I may get slapped down by those in the know.... but are there 4k cameras that claim to be 'good' in low-light scenarios?
Or, instead, are 4K cameras known to not be that great in low light scenarios?
well from I understand the higher the resolution, the worse they do at night.
We use a Uniview 2MP camera and have great success
Client camera
Uniview camera, same scene
http://en.uniview.com/Products/Cameras/Bullet/2/IPC262ER9-X10DU/#~Product specification
These are 4K cameras that do claim to be good at low light. I think I understand now that at night, more (resolution) is not necessarily better! I suppose we could try out a 2MP camera with outstanding low light performance, but I can't afford to "try" something else that may or may not work, so I think at this point I need to recommend a true ALPR camera.
I appreciate the links to ALPR camera reviews and I'll check them out.
Thanks all. Nothing like learning from failure!!
Typically a box camera is used so that you can play with kensing and zoom the camera as needed Usually it is better to zoom the cameras and have a lower resolution vs having a larger image and more pixels to zoom in on afterwards.
Ir performance is also usually better with a bullet camera that has a flat glass vs a curved dome.
In my experience, people usually use 2mp or similar cameras for LPR. There are ultra low light cameras that can then better deal with the fast shutter required.and be less noisy.
Hanwha has a variety of other models. You may be able to work with them to return this camera and sub in a different one or borrow a demo camera to test night performance on a different model.
1- John H is right, your IR cut filter is on, likely due to color mode, though not necessarily. We run in color mode with the IR cur filter off.
2- Low light abilities and IR abilities are separate issues.
3- It doesn’t seem your using an IR pass filter. Sometimes this is good, sometimes not. That depends on #4
4- Are you trying to do LPC (license plate capture), or ALPR? If ALPR ensure the software will accept a 4K image. Most are set up for processing < 2Mp. Also, from your image above it seems you have a VERY large plate box. OK I guess if you have an 8Mp sensor, but unnecessary, actually bad for ALPR. Most ALPR software wants 32-46 pixel height on the characters.
5- From you writings above it seems you want LPC. Back to John H, disable the IR cut at night and viola....
6- Make sure you aim the IR illuminator correctly!
Here's what I'd try... Increase the shutter speed to 1/500-ish, use B&W and IR illuminators at night. Tighten up the lens' angle and expect nothing but a very dark image with a glowing license plate.
If that didn't work or I wanted to do it the (more) right way... I'd keep the existing camera as a wide-angle situational awareness camera and add a new camera to do the license plate stuff. I prefer Hanwha cameras, so I'd consider the XNV-6120R.
Thanks all for the input. In the end, we have decided to keep the existing camera as the scene overview camera, and then provide a new purpose built LPR (we are doing capture, not automated recognition). With car speeds in excess of 30MPH, I don't think a standard camera will ever get reliable plate reads at night.
UPDATE
Just in case you are curious, we recommended that due to the circumstances, the owner add a dedicated true LPR camera to each pole and use the current camera as the scene overview. The LPR camera we selected is B&W. Below is a sample capture. The owner is happy with this final resolution. 2 lane road, approximately 30MPH car speed.
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