TL;DR: For optimal LPR camera performance, mount it 8-10 feet high, face it directly at vehicles, ensure good lighting, and avoid obstructions. Keep it 10-30 feet from plates, adjust focus, and protect from weather.
If you have an Automatic License Plate Recognition camera it’s important to make sure it’s positioned correctly to make sure you can capture license plates accurately. Setting things up the right way from the start saves you from the hassle of endless adjustments and potentially missing out on vital information.
Whether you’re setting up a surveillance system for security, traffic monitoring, or parking management, understanding the best LPR camera placement can make a significant difference. Here are eight vital considerations and best practices to keep in mind when positioning a camera for LPR.
1. Camera Angle and Height
Even though it may be obvious, the angle and height the camera is positioned in plays an important role in capturing clear images of license plates. Ideally, the camera should be placed at a height of 3 to 10 feet from the floor, and an angle of no more than 45 degrees from the vehicle’s license plate. This minimizes distortion and ensures that the license plate is within the camera’s field of view for a longer duration, allowing for better image capture and recognition.
Takeaway: Place your camera at a height between 3 and 10 feet from the ground, and at an angle no more than 45 degrees from the license plate.
Ideal height and angle for an LPR camera
2. Distance from Target Vehicle
The distance between the camera and the vehicles you want to capture is another important thing to consider, after all, a camera acts like an eye, the further away something is, the harder it is to see clearly. For the best results, the camera should be positioned at a range of 10 to 100 feet away from the vehicle (depending on your camera’s resolution), and should not exceed 113 feet.
Positioning the camera so the license plate faces straight on, rather than at an angle, will increase the accuracy of the plate reads. But it’s worth noting that if you’re wanting to detect the make, model and color of the vehicle, then a slightly side-on angle can actually help, so it becomes a bit of a trade-off. It’s worth thinking about what matters the most to you, and the results you want to capture when setting this up.
It’s essential to consider the speed of the vehicles as well, as faster-moving vehicles may require the camera to be positioned closer to ensure accurate capture. The general rule of thumb is, if you can’t see and read the license plate clearly when you pause the video, then the LPR software won’t be able to either.
Takeaway: Position your camera at a range of 10 to 100 feet away from the vehicle (depending on your camera resolution).
3. Field of view
The type of lens on the cameras you use can also affect how well they capture license plates. We recommend using a narrower field of view camera, rather than a wide angle. This helps keep the area of detection narrow and makes sure the license plate is in focus, improving your results overall.
Takeaway: Use a narrower field of view camera rather than a wide angle.
External illumination for LPR cameras at night
4. Lighting Conditions
Lighting conditions can significantly impact the performance of an LPR camera, especially depending on the quality of camera you have available, and if you want to capture plates at night. Ensure the camera is positioned to avoid direct sunlight or glare from headlights, which can obscure license plates.
Consider using cameras with infrared capabilities to improve performance in low-light conditions or during nighttime, although it is even better to use external illumination for the scene where possible because the visibility will be better than using the camera’s inbuilt infrared.
Takeaway: Position your camera to avoid direct sunlight, and glare from headlights.
5. Environmental Factors
Weather and environmental conditions can affect the performance of an LPR camera. Make sure that the camera is weatherproof and can withstand exposure to elements such as rain, snow, and dust. Additionally, consider the presence of trees, poles, or other potential obstructions that could interfere with the camera’s line of sight. It’s worth viewing the camera live feed to spot any objects or obstacles that might be blocking the view.
Takeaway: Make sure your camera is robust enough to withstand adverse weather conditions.
6. Regulatory Compliance
Installing a camera for LPR can be a great way to boost your security, but it shouldn’t come with a side of legal headaches!
Before you set it up, take a moment to check any regulatory requirements or privacy concerns related to surveillance in your area. Ensure that the camera placement complies with local laws and regulations regarding surveillance and data collection. Following this best practice can save you a lot of hassle down the road, keeping your focus on security—not paperwork.
7. Optional additional controls
Depending on your camera, you may also have some more specific settings control such as:
Shutter speed
We recommend using the highest possible shutter, ideally around 1/1500, to minimize blur from vehicle movement and to maximize your results.
Focus
If your camera has focus capabilities, ensure you’re setting it so to the license plate at the point where the vehicle is largest in the frame, this is when the LPR software will capture the image to read the plate. If it’s out of focus, you might lose readability.
Resolution
Use the highest possible resolution on your system. While it isn’t absolutely necessary to have the highest-definition camera on the planet, it’s a given that the higher the resolution, the clearer the plate read.
Bit rate
If your camera field of view is narrow and focused on the plate detection area, then camera bitrate is less important. But if your camera has a wide field of view and there is lots of background activity around the plate detection area, then a higher bitrate will improve the plate detection in the foreground.
Key takeaways for LPR camera placement
To wrap up, how well license plate recognition works really comes down to where you place your cameras and how you set them up. The more control you have over these details, the better your results will be.
By following all of these best practices, you’re less likely to have to make changes to your set up, so you can sit back, relax and let the LPR software do its job.
Here’s a quick summary of what we’ve covered:
- Place your camera at a height between 3 and 10 feet from the ground, and at an angle no more than 45 degrees from the license plate.
- Position your camera at a range of 10 to 100 feet away from the vehicle (depending on your camera resolution).
- Use a narrower field of view camera rather than a wide angle.
- Position your camera to avoid direct sunlight, and glare from headlights.
- Make sure your camera is robust enough to withstand adverse weather conditions.
Next steps
If you’re looking at setting LPR up, but don’t want to fork out for an expensive set of specialized cameras, Videoloft LPR might be perfect for you.
Find out how Videoloft lets you turn your existing camera setup into an LPR system.
Check out our free demo, or if you’re ready to upgrade your system head here for a free trial.
