Six ways to deal with camera backlight installation

Determine the backlight type first

• Continuous strong backlight: Such as glass curtain wall lobby and west-facing floor-to-ceiling windows.
• Periodic backlighting: Such as entrances and exits exposed to direct sunlight in the morning and evening.
• Instant bright light: Such as the car lights at the entrance and exit of the garage.

Six processing methods

1. Adjust the installation position (preferred): Move the camera to the same side as the light, or raise the angle to allow the strong light source to come out of the picture. This is the cheapest and most effective method and should be given priority.
2. Enable wide dynamic range (WDR): Select a true wide dynamic range (≥120dB) model and redefine the metering area. Place the focal target at the metering center.
3. Add fill light: Add soft fill light to the foreground side to reduce the light ratio. Pay attention to the fill light intensity being sufficient but not causing new overexposure. It is recommended to use LED fill light with adjustable brightness.
4. Block or weaken the light source: Apply insulation film to windows and install awnings/louvers to reduce background brightness from the source.
5. Switch to special equipment: Use a special license plate camera (with strong light suppression) for the entrance and exit license plate scene. Much better than universal models.
6. Adjust the installation angle and focal length: Appropriately shorten the focal length and reduce the proportion of strong light sources in the picture, which can significantly improve the overall metering.

Parameter coordination

• After turning on wide dynamic range, do not set the lower limit of the shutter too high, otherwise the dark parts will not be brightened.
• Do not enable wide dynamic range and backlight compensation (BLC) at the same time, as the two algorithm goals conflict.
• In car light scenes at night, you can set the upper limit of the shutter speed (such as 1/2000s) to suppress halo, and use fill light to ensure the license plate is readable.

Acceptance method

Don't debug only on cloudy days or at night. Live images and video screenshots should be viewed during the period when backlighting is strongest (such as the afternoon on a sunny day). Make sure the face/license plate can be recognized before accepting.