ATAPY ANPR Technology Powers a Mobile Traffic Control Solution in Sweden

ATAPY ANPR SDK Adaptation Project for Swedish Mobile Solutions Provider

	‘I started with getting the ATAPY ANPR SDK project running. I really like the simplicity of the [Application Program] Interface!’
	Zoltan Hübsch, GoldPen Computing AB

GoldPen Computing AB, a Mobile information solutions provider from Sweden, was addressed by one of their clients, Gothenburg Municipality, with a request for аn Automatic car Number Plate Recognition (ANPR) solution. The Municipality required a system which, among other features, would allow parking attendants to monitor cars parked in the city by capturing and automatically recognizing the images of car number plates with the help of smartphones. Previously, attendants had been manually entering car numbers using the device keyboard.

With this challenge, the solutions provider turned to ABBYY Europe, the Western European office of ABBYY, a leading provider of document recognition and data capture technologies . After reviewing GoldPen’s set of requirements, ABBYY brought in a partner ATAPY Software. By the time the project started, ATAPY had already developed its own ANPR Software Development Kit – the ATAPY ANPR SDK product. The product was a development library designed for building applications that could read car license plates from still images and video streams. ATAPY ANPR SDK is based on ATAPY’s image analysis experience and is powered by the ABBYY OCR SDK ABBYY FineReader Engine.

The license plate recognition process leveraged in ATAPY ANPR SDK includes a set of sophisticated imaging algorithms, including the well-known ones and ATAPY’s own findings, all tied together in an effective process specially optimized to address the specifics of car license plate images. Specialized algorithms are used to provide smart image preprocessing and binarization, detect the license plate rectangle on the image (with the help of Sobel edge detection algorithm), and segment the rectangle into individual symbols, which are then passed to ABBYY FineReader Engine for recognition.

At the time the project started, ATAPY ANPR SDK supported German, Dutch and Russian car number plates and featured recognition quality of ~90% for these license plate types (on the image corpus received from the clients).

To address the end customer’s needs in this project, the ATAPY ANPR SDK had to be:

• Enhanced to support Swedish car number plates
• Ported to mobile platform
• To implement support of Swedish license plates, ATAPY engineers analyzed several hundred images of Swedish car number plates and trained the ANPR engine accordingly.

ATAPY engineers developed a specialized Mobile Version of ATAPY ANPR SDK. To implement this version, it was necessary to port the SDK from .NET Framework 3.5 to .NET Compact Framework 3.5, and to reprogram it for working with ABBYY Mobile OCR Engine. Some methods and algorithms of .NET Framework 3.5 were missing in .NET Compact Framework; and the functionality of ABBYY FineReader Engine differs from functionality provided with ABBYY Mobile toolkit; ATAPY engineers also worked on optimization of all algorithms and routines to ensure small application footprint.

Another challenge was the skew of license plate images. Unlike capture by static cameras, capture by mobile device results in images being taken from a variety of angles. ATAPY engineers enhanced the Mobile Version of ATAPY ANPR SDK with an automatic skew/tilt correction feature enabling to correct angles of up to 25˚-30˚.

Currently, the pilot version of the mobile ANPR solution is being deployed by the Solution provider on the end customer site.

The mobile ANPR solution delivered by ATAPY Software allowed GoldPen:

• To fulfill a unique customer demand. Software products featuring mobile ANPR functionality are quite rare on the European market
• To deliver excellent customer service by offering a powerful and universal solution: the one based on one of the industry’s leading mobile OCR toolkit, providing high recognition quality and featuring skew/tilt correction
• To enjoy considerable project cost savings as a result of cooperation with ABBYY Europe and ATAPY Software as its outsourcing partner

The mobile ANPR solution by ATAPY Software is expected to bring the following benefits to the end customer:

• Considerable time and cost savings as a result of automating the car number input process
• Higher accuracy of input data: OCR instead of manual entry + a skew/tilt correction feature to minimize the possibility of recognition mistakes
• The advantage of 100% mobility: parking attendants are able to work offline, using the mobile device as an all-in-one workstation providing image capture, recognition, and a number of other important functions (defined by the final end-user application)