How to set up cameras for LPR in indoor parking lots

Description

• License plate recognition (LPR) requires special camera settings that are different from normal monitoring.
• The proper settings according to the monitoring environment can help you get clear license plate images and improve LPR performance.
• This article will show you how to set up cameras for LPR, specifically in indoor parking lots.

※ Note

Once the setup for LRP is complete, the video becomes very dark 
and may not be suitable for monitoring objects other than license plates.

1. Select Image preset mode

Figure 1. Image preset mode setup

• For ease of use, there are different image presets for different purposes, so it's important to choose the one that best suits the situation in the camera.
• In the camera menu, go to [Video & Audio] -> [Camera setup]
• In this case, select [Number plates] as the Image preset mode
• [Number plates] mode is used to improve the ability to identify the license plate of a car in daytime and at night. However, for specialized environments like indoor parking lots, this is not enough.
• It is set to a faster shutter speed to recognize license plates of fast-moving vehicles.

2. Additional settings for Gain and Iris

• Typically, indoor parking lots have low light levels, so the car automatically turns on its headlights. The camera also increases the gain to almost maximum to increase the brightness of the footage.
• When a vehicle is detected, the license plate is over-saturated by the sudden brightening of the environment by the headlights.
• To avoid this, it's recommended to adjust the camera's gain and Iris values for LPR so that the image brightness doesn't change too much when the amount of ambient light changes.
• 

• Figure 2. Example of an oversaturated license plate situation

•  
• For the P AI camera, select P-Iris to [Manual] to fix it and optimize the values while looking at the license plate. AGC should be set to [Low] to minimize the change.

Figure 3. P-Series AI camera setting

• For the X AI camera, select Iris to [Manual] to fix it and optimize the [Iris F-No] values while looking at the license plate. And AGC should be set to [Low] to minimize the change.
• And AGC decreases the Level(Max Gain) by no more than 30 dB to prevent saturation.

Figure 4. X-Series AI camera setting