In order for eLPR to function properly, the license plate in the image captured by eLPR must be at least 150 pixels wide when using a 640 x 480 pixel resolution. However, some cameras may be using a different resolution, which can cause the size of the license plate to be smaller than the required 150 pixel width and significantly reduce eLPR’s accuracy.
The current resolution of the camera, as well as the size of the license plate in the image, can be checked through the camera’s administrator settings.
1. Go to the IP address or hostname for your eLPR camera, adding /admin to the end of the address. (ex. 192.168.1.105/admin) to access the camera.
2. Click the “Setup” button in the top right-hand corner of the screen to view the camera’s administrator settings. You may be prompted to enter the username and password for the camera after clicking that button.
3. Click the “Video and Audio” button in the left-hand side menu, which will automatically open the camera’s Video Stream Settings.
4. The current resolution will be listed near the top of the Video Stream Settings page. If it is not currently set to 640 x 480 pixels then click the drop down and select 640 x 480 pixels from the menu.
- Note: 640 x 480 pixels is the recommended resolution because that is the resolution eLPR uses when processing images. A different resolution can be used. However, the size of the license plate will need to be scaled as needed to ensure it is at least 150 pixels wide when the image is scaled to 640 x 480.
5. Click the “Save” button at the bottom of the screen to save the new resolution.
Once the camera’s resolution has been updated, a live feed can be viewed with an overlay that shows the actual pixel size of the license plate in the camera’s feed.
1. One the left-hand side menu, click the “Focus” option under the “Video & Audio” sub-menu.
2. Click the “Show pixel counter” check box, which will be located directly below the camera’s live feed.
3. Two text boxes for a width and height will appear. Enter 150 in the width box, and 150 in the height box, then click the “Apply” button.
- Note: You will only enter 150 for the height and width if you’re using a 640 x 480 resolution. If a different resolution is being used, the height and width will need to be scaled. For example, if you’re using a 1280 x 960 pixel resolution, you will need to scale the height and width up to 300.
4. A red rectangular box will appear in the middle of the live feed in the exact height and width specified in the previous step. Any license plate detected by eLPR will need to be as wide as the red rectangle. The box can be dragged around the feed as needed if you want compare license plates appearing on the live feed to the width of the rectangle.