I need better side cameras - what would work?
Here is a sample video: Trash throwing black and white cop lookalike SUV? - YouTube
I have these here mainly for criminal damaging of stuff on my side and the neighbor across the street. For less than thoughtful people throwing garbage in my yard it is a civil issue. Sometimes I am bored so I may take civil actions up as a hobby.
This YouTube video is 4K or 8MP but the left and right cameras are 2MP and the middle camera is 4MP. I am considering buying a 1/1.2" sensor 8MP camera for the sides. Should I expect enough quality to read a plate? All the cameras are varifocal, the left one was zoomed in all the way. None of the cameras or fixed focus or fixed iris as well. I cannot find any cameras that use the more than awesome IMX585 but I have found some using the IMX485 so this is what I'm looking at.
Comments
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The quality of the left camera looks very good for a 2MP but this resolution probably won't be enough to read the plate (though in this case it looks like the car doesn't actually seem to have a valid plate at the front anyway!).
The right camera is also pretty good, though there is some motion blur of the moving vehicle. You can improve this by setting a minimum shutter speed in the camera's settings to try to freeze the motion better. But again, 2MP is probably not enough here for plates.
Your plan for 8MP cameras for each side is a good one if you want to be able to read plates. And make sure you get a camera with a medium-length lens (not too wide-angle), or ideally a varifocal one whose focal length can be adjusted. Separate IR lighting for night vision is probably also a good idea - the distances here mean that built-in camera IR lighting may be insufficient for good night images.
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My current exposure settings on the 2 MP cameras are:
- Anti-flicker: Outdoor
- Mode: Shutter Priority
- Shutter: 1/250
- Auto Iris: ON
- 3D NR: on with a grade of 50
I'll try 1/500 to make the cars less fuzzy. The cars travel around 50 MPH. Oddly the camera shutter setting will go up to 1/100,000.
Sadly the current Dahua 1/1.2" cameras are 2.8, 3.6 or 6mm fixed with no varifocal options. And I don't know what 6mm on a 1/1.2" sensor converts into zoom wise. There are decent 1/1.8" choices so I may pick up one of those instead, they go up to 12mm which is the limit of my current three cameras.
I also changed the Backlight compensation to HLC. WDR on the 2MP cameras seems somewhat broken but the highlight compensation should help in the night.
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Yes, it's not easy to work out exactly what kind of view you will get with a particular focal length and sensor size. Probably the best way to compare models would be to look at the "Field of View" details in the camera's datasheet instead, as this gives you a number that is directly compatible between models with different lenses and sensors.
This is the main advantage of varifocal lenses: they allow you to set the field of view to exactly what you need at install time, rather than guessing what you need at purchase time.
1/500 will certainly freeze the motion better, however this will only work during the daytime in good light. At night you'll likely need a much slower shutter speed in order to avoid excessive noise, which will inevitably cause motion blur for cars travelling at 50 mph. This could be ameliorated somewhat by installing powerful IR lighting that comes on at night.
