LPR System Integrator Achieves Clear Long-Range License Plate Capture with 25mm Telephoto Lens
Case Study: Long-Range License Plate Recognition (LPR)
Our customer is a systems integrator specialising in traffic monitoring and smart-city solutions. Their license plate recognition (LPR) deployments require cameras that can read number plates reliably from a distance, in varied lighting, and around the clock. Plates that are blurred, distorted or too small to resolve simply cannot be processed.
The Challenge
To capture plates accurately, the LPR cameras needed to overcome several demanding conditions:
- Long working distance: plates had to be resolved clearly across multiple lanes and at highway distances.
- Varied lighting: strong daytime glare, low-light dusk and 24/7 operation including night traffic.
- Image clarity: sufficient resolution and contrast for accurate character recognition.
- Outdoor durability: reliable operation in heat, cold and harsh weather.
Their previous optics lacked the reach and sharpness needed, causing missed reads and false results.
The Solution: 5MP 25mm F1.8 Telephoto Lens
We supplied our 5MP telephoto lens with a 25mm focal length and F1.8 aperture, engineered for long-distance surveillance and LPR. Key specifications include:
| Parameter | Specification |
|---|---|
| Resolution | 5MP high definition |
| Focal Length / Aperture | 25mm / F1.8 large aperture |
| Field of View | 1/2" H:11° V:6° D:14° (narrow angle for long reach) |
| Coating | Multi-layer AR coating for high transmission and low flare |
| Operating Temperature | -40°C to +85°C |
| Waterproof Level | IP68 (rugged outdoor design) |
The narrow 14° diagonal field of view magnifies distant plates, while the F1.8 aperture and multi-layer AR coating keep images bright and contrasty with minimal glare — exactly what LPR algorithms need for accurate recognition.
Implementation
- Lens samples were tuned to the customer's 5MP sensors for optimal plate resolution.
- The compact Φ14mm barrel and M12-compatible design simplified integration into their existing camera housings.
- Field trials were run across day and night traffic to validate recognition accuracy at target distances.
Results
| Metric | Outcome |
|---|---|
| Long-range capture | Plates resolved clearly across multiple lanes and highway distances |
| Recognition accuracy | Sharper, higher-contrast images improved character recognition |
| All-weather reliability | IP68 sealing and a -40°C to +85°C range ensured stable outdoor operation |
| Integration | Compact design shortened development and deployment time |
With the new lens, the customer's LPR systems delivered dependable, high-accuracy plate recognition in real-world traffic conditions, day and night.
Conclusion
For license plate recognition, optical reach and clarity make all the difference. By combining a 25mm focal length, F1.8 aperture, 5MP resolution and multi-layer AR coating, our telephoto lens helped the integrator read plates reliably at long range in any lighting. Whether for traffic enforcement, parking systems or smart-city monitoring, the right optics turn difficult plates into clear, actionable data. Contact us to find the ideal lens for your LPR project.
