Input Image Guide
Detailed information about input image requirements and recommendations for optimal ANPR performance.
High-resolution images (>3MB) contain a lot of redundant data which might result in slightly slower recognition processes and will definitely increase the data bandwidth required. Therefore, resolution is optimized for a certain character size of license plate: between 16px – 80px in which the full vehicle is visible from the front results in the most accurate recognition with the fastest response time. The license plate image should be and visible.
Read brief guide for input images: here
Camera Configuration
Two of the most important factors affecting ANPR accuracy are camera placement and image selection. We highly recommend using Adaptive Recognition’s purpose-built ANPR cameras (e.g. FreewayCAM) for maximum efficiency.
To achieve the highest possible performance for your ANPR system with our cloud service, please optimize the following variables:
- Camera image settings (use faster shutter speeds to reduce blur, as the license plate must be );
- Light conditions (make sure that the license plate is not under- or overexposed);
- Angle of capture (when the camera captures the license plate from an acute angle it might seem distorted).
Recommended exposure times:
- Below 30 km/h [20 mph]: recommended exposure time is under 1⁄200 s [5000 μs]
- At or around 50 km/h [30 mph]: recommended exposure time is under 1⁄800 s [1250 μs]
- Above 100 km/h [60 mph]: recommended exposure time is 1⁄1250 s [800 μs]
When setting up your camera, try to capture the license plate at as direct an angle as possible, mounting the camera high enough and angled slightly downward so as to avoid direct headlight/taillight glare. Accuracy may degrade beyond a 40-degree horizontal or vertical angle.
Resolution: 1080p (1920×1080) or 720p (1280×720) are usually good choices.
