How to choose and install license plate recognition (LPR) system? The overall performance is determined by many factors such as mounting angle, distance and shutter speed setting, which are critical for deploying an LPR camera. In the past years, license plate recognition application has becoming popular in video surveillance field such as traffic monitoring, packing lot access, law enforcement, automatic toll payment, etc.
To get a high confidence level of plate recognition, a lot of factors such as camera selection, suitable lens selection, artificial lighting and installation position shall be studied before placing a purchasing security cameras. Otherwise, a good result is unexpected. In this article, we will focus on the rules how to determine the installation position of camera and how to select suitable illuminator to obtain a clear image for license plate recognition, with NST-IPA6092-NPSD as an example. Also some key parameters setting of cameras for getting a clear image for LPR are recommended in the final section.
Taking NST-IPA6092-NPSD as an example, the camera’s built-in 6~22mm lens can capture a width of field about 13~16 ft(5~8Meter).
To ensure an optimal license plate image, please adjust the lens under the conditions we suggest. (NOTE: The license plate image shall be 18% width of the screen for good license plate recognition.)
The recommended capture distance is 49-100 ft. (15-30m) for a reflective plate and 33-82 ft. (10-25m) for a non-reflective plate.
LPR CAMERA INSTALLATION
1. The camera height should be higher than 11.5 ft. (3.5 m)
2. The width of the license plate should occupy approximately 17~20% of the width of the screen.
3. Vertical angle should be NO less than 40 degrees