LPR Through Glass
- Thread starter popz3210
- Start date
sebastiantombs
Known around here
Off hand, unless you can mount the camera directly to the glass or completely block any light from getting to the glass from the inside, it won't work.
I have six cams behind glass. None of them doing LPR duty. Three of them are in upstairs windows with black cloth behind them, between the cam and the blinds and curtains. They do well with very little to no reflections on the glass. These are used for wide angle overviews and stay in color 24/7. Depending on the time of year and time of day, there can be some sun glare for 20-30 minutes when the sun is directly on the window.
The other three are cams at my front door behind the glass side windows. They work well in daylight but do have some issues with reflected glare at night due to the light-colored shear curtains hung behind them. These also stay in color 24/7.
Here is an example of one of the three upstairs window cams. It is mounted on a board in the window behind the blinds. Normally the curtains are pulled across the blinds but I have pulled them back for reference.
Here is an example of one of the three front door cams. Note the shear curtains which do not give adequate blocking of light from inside.
Hope this helps.
The other three are cams at my front door behind the glass side windows. They work well in daylight but do have some issues with reflected glare at night due to the light-colored shear curtains hung behind them. These also stay in color 24/7.
Here is an example of one of the three upstairs window cams. It is mounted on a board in the window behind the blinds. Normally the curtains are pulled across the blinds but I have pulled them back for reference.
Here is an example of one of the three front door cams. Note the shear curtains which do not give adequate blocking of light from inside.
Hope this helps.
richardgohth
Getting the hang of it
yes in a vehicle.
so long as the reflection off the glass into the camera is managed, its no issue.
If the illuminator is NIR then test first that the glass has not IR filter ( usually for heat )
The issue is typically IR reflections when shooting through glass, if you turn that off it should be fine, I am considering the same since I didn't get enough zoom out of my turret to catch plates but I do not want a big ass bullet on the front of my house
saltwater
Getting comfortable
Yes, I have two cameras behind glass in a letterbox, solely for LPR. Daytime capture is a breeze. The cameras are up as close as possible to the glass, with one side nearly touching the glass and the other side off at an angle. IR reflection, from the camera is a problem. To alleviate the problem, I placed a black coloured carboard cover along the side of the camera to the glass. My next problem is that the IR from the camera does not illuminate fully my target distance between 20 - 30 metres, in this regard I'm not sure if that is because of the IR passing through the glass at an angle. I'm now researching off-camera IR illuminators. The below images do not show my hack-job of a lens hood to the glass.
