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5 Rules to Design License Plate Camera Application
1. Location and Trajectory:
Please note the following diagram:

In order to obtain the most optimal image, place the camera where it can obtain a clear, straight view of the license plate. A low angle is recommended to get the clearest license plate images.

YES       YES
Low Angle
    High Angle  
2. Choose the right lens and setting
A.   Lens (Auto Iris Aspherial Lens)

An Auto Iris Lens is required for using with the OK-SEM-7540LPDN camera.
You must properly adjust the DC Level to use with Auto Iris.

Recommended Lenses (Made in Japan):

5.0mm~60.0mm Aspherical Auto Iris Vari-Focus F1.6 1/3" Lens / CS Mount

B.   Adjust DC Level for Lighting on day time or night time usage:

Day time and night time usage will require different fine-tuning for best results.
Recommend to adjust the camera base on actual time of day. You must properly adjust the DC Level when using Auto Iris lens. Otherwise, it might result in a too bright or too dark image. The License Plate Camera requires more light sources to support plate reflection at night. A light source is required to obtain the best image.
C. Focusing
After you choose the right lens, focusing is the most important thing. You need to take time to focus.
3. Adjust Shutter Speed: Video Demo Link (http://www.okinausa.com/media.html)
                       Before                                          After

Camera to object moving speed
Shutter Speed
1/250 sec.
30~60 Km/hr
(19~37 mi/hr)
50~80 Km/hr
(31~50 mi/hr)
1/500 sec.
50~80 Km/hr
(31~50 mi/hr)
80~100 Km/hr
(50~62 mi/hr)
80~100 Km/hr
(50~62 mi/hr)

Shutter speeds of 1/250 and 1/500 are the recommended settings.
Please use the chart in the installation manual when selecting shutter speed.
4. Rule of 1 / 7
In order to ensure optimal images, make sure the camera is placed so that the license plate will take up at least 1/7 total width of the viewable screen area.   
If the drive way is too wide, you must add more cameras to cover the other part.
5. High Resolution and FPS Setting for DVR
The quality of the DVR used is one of the most important factors for this application.
A high-resolution DVR capable of recording at 20 to 30 FPS per channel is the minimum requirement for recording of OK-SEM-7540LPDN images. To have optimal recorded playback performance, a 30 FPS DVR is suggested.

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