Specifications of the vehicle license plate recognition system

Maximum acceptable traffic speed for successful recognition

Up to 255 km/hr for simultaneous processing of 4 traffic lanes (surveillance zones) by one computer (25 fps per channel) Up to 10 km/hr for simultaneous processing of 16 traffic lanes (surveillance zones) by one computer (in switching mode)

Probability of license plate recognition under real traffic conditions
For detection of sought vehicles with a maximum error probability of 4%	At least 92% during daylight hours At least 92% during hours of darkness
For automated violation detection with a maximum error probability of 0.5% (for automated traffic ticket generation under real traffic conditions and using images imported from other systems)	At least 75%
For license plates visually recognizable at a distance of 40 m (clean license plates compliant with the requirements of the Vienna Convention on Road Traffic, November 8, 1968)	At least 99% during daylight hours At least 99% during hours of darkness

Capability to recognize dirty license plates
For evenly distributed soiling	Lowest acceptable license plate image contrast – 10% (contrast visibility of characters against the background: 25 units of 256 unit scale)
For irregular, spotty soiling	Maximum acceptable soiling - 12% (ratio of soiled area to total plate number area)
Number of different types of recognizable license plates	More than 300, including: all types of license plates of CIS countries and the Baltic states 20 European countries 5 Latin American countries and the United States
The main types of single-line and double-line license plates of many countries of Europe, Asia, North and South America (regular civil as well as specialty plates, including diplomatic, commercial, military, police, etc.) using roman or cyrillic characters, as well as specialized characters of foreign national alphabets, are supported. The specific set of recognizable license plate characters can be customized individually.
Supported image input methods for recognition purposes	Standard analog CCTV cameras Digital megapixel high-resolution cameras Digital still images Digital video files
Certified method for calculating vehicle speed	Certified radiolocation speed measurement instrument (radar) Certified optical method using video images

Specifications of standard video sensors
Width of surveillance scene for one CCTV camera	3 m for a frontally positioned video camera 3.2-3.7 m for a video camera with up to 10-20є lateral divergence from the direction of traffic
Width of surveillance scene for one 1-megapixel video camera	6.5 m for a frontally positioned video camera
Width of surveillance scene for one 3-megapixel video camera	11 m for a frontally positioned video camera
Camera angle range for stable recognition	Vertical ± 30º Horizontal ±20º
Maximum acceptable skew of a license plate	10º in any direction
An extended range for license plate skew can be set for any fixed angle up to 180º.
Illumination in the surveillance scene	≥50 lux for CCD cameras with low light sensitivity of 0.05 lux ≥20 lux for CCD video cameras with low light sensitivity of 0.0002 lux 0 lux for video cameras with infrared illumination
During hours of darkness, 50 lux is guaranteed by road lighting standards and regulations.
Maximum electronic shutter speed of video cameras	1/250 s — for vehicle speeds ≤10 km/hr 1/500 s — for vehicle speeds ≤ 40 km/hr 1/1000 s — for vehicle speeds ≤ 150 km/hr
It is recommended to reduce electronic shutter speed for video cameras having a vertical angle exceeding 15є or a horizontal angle exceeding 10є, as well as for vehicle cameras