Automatic Number Plate Recognition (ANPR) made simple by Ushio Epitex LED technology
30 Sep 2020
As a longstanding manufacturer of LEDs, Ushio Epitex is positioned as a leading producer of optical components for Automatic Number Plate Recognition (ANPR) systems. The unification of a camera, near-infrared (NIR) LEDs, and a carefully curated database has brought previously untold benefits, with ANPR technology assisting electronic toll collection (ETC), car park management, and law enforcement.
Why is ANPR better for your business?
- Database cross referencing – A well-publicised benefit of ANPR is the ability to cross reference number plates with vehicles of interest in a database. Traffic management and law enforcement use ANPR in many countries to check vehicles against metrics such as car tax, insurance validation, stolen vehicles, as well as detecting, deterring, and disrupting organised crime.
- Time efficiency – A vehicle can be identified in a matter of microseconds. A positive result will mean the vehicle can be admitted to the next stage of the process, such as the opening of a gate or barrier to allow them to pass through. This is of particular importance in time sensitive industries, such as logistics and haulage.
- Cost efficiency – In most cases, the presence of a human for the verification of each vehicle is no longer required. While you would have an initial outlay to set up your system, employee costs will be saved in the long run.
- Fewer erroneous results – As humans, we all make mistakes, but ANPR systems are widely recognised for having a rate of success above 99%. Human error contributes to slower processing time and can also increase costs.
- Tighter security – Automatic surveillance of vehicular activity can track movements and also contribute evidence in the case of an accident or theft. ANPR also contributes to peace of mind in these situations as people are inclined to feel safer about leaving their vehicle unattended in a place they know utilises such technologies.
- Accurate resource management – Much like a ‘clock-in, clock-out’ system in the workplace, punctuality of human resources and shipments can be monitored to ensure that a business is running to its full potential. Further analysis can lead to the ‘ironing out’ of kinks in the supply chain.
Where do Ushio’s Epitex NIR LEDs fit into the ANPR system?
The NIR LED portion of the electromagnetic spectrum includes wavelengths of 700-1,000 nanometres (nm). This is the closest region of infrared radiation to visible light and begins just beyond the limit of detection by the human eye. Ushio’s NIR LEDs are used to briefly illuminate the subject for a high-definition infrared camera, much in the same way the ‘flash’ works in a conventional camera.
Which Ushio LEDs are used in ANPR applications?
The top four Epitex LED types that Ushio recommends as the crucial NIR component come from the Moulded, EDC, EDCF, and SMBB (standard, D, and DS) families. The most requested NIR wavelength for ANPR applications is 850 nm, although 940 nm is also very popular. The SMBB-DS series boasts the most powerful IR LEDs currently on the market. Ushio is happy to work with clients to find out which LED would suit your device. With such a wide range of options, it is also possible for us to put together a design specifically for you:
More is better: High-power LEDs give you quality and quantity
- Brighter – it goes without saying, the more power fed into the light, the brighter the resulting image will be. This avoids under-exposure, which would threaten to make an image unreadable.
- Clearer – even machines can struggle to make out fine details if the image is lacking true clarity. The increased brightness is fine, but to gain the crispest clarity at a greater distance, the higher the power, the better the end result.
- Wider – It is not only linear distance that improves alongside output power; this concept also applies laterally too. The amount of viable information in a captured image is directly reliant on the width of illumination, as well as the depth.
- Faster – when attempting to capture a fast moving object, speed is everything. While the camera needs an accurate and very fast shutter speed, the corresponding ‘flash’ from the LED but also be accurate to the microsecond (μs). The pulse duration required by most ANPR/ETC systems falls between 1 and 10 μs.
Ushio Epitex SMBB-850 series: 3 variants, 4 lenses,
and up to 3,700 mW of pulsed optical output power
Having established the preferred NIR wavelength for ANPR/ETC applications, the next step is to choose the ideal power and spectral width. The required specification can vary significantly based on a number of factors including the intended environment, distance from the target, the desired lateral width, and how detailed the final image needs to be. All LED package types come with a variety of different options, perhaps too many to list in one article, so we will concentrate on our ANPR clients’ favourite LED series.
The SMBB850DS series has a total pulsed output power of 3,700 mW, while the intensity of the emitted radiation remains dependant on the chosen lens. The flat and 05 lens types allow the radiation output to be emitted from the SMBB package at a broader angle, thereby achieving a less-focused, lower radiant intensity. In the case of the SMBB850DS-1100, the flat and 05 lens types provide 1,200 mW/sr (milli-Watts per steradian) and 5,300 mW/sr, respectively. For applications requiring a highly-focused, high-intensity output, the 02 and 03 lens types tighten the radiant beam and focus the output power at a narrower, intensified angle. The 02 lens type, in particular, provides a very high intensity as the light is crammed into an angle of ±10° to intensify the radiance up to 16,000 mW/sr.
EDC: the perfect solution when you are short on space
While the SMBB family remains ever popular, sometimes Ushio’s clients are looking for a single-chip package with a smaller footprint. Of course, Ushio would not want to compromise the high-power offerings from the SMBB class, so the EDC family was developed. Offering the same wavelength range as the SMBB packages, EDC LEDs bring the true benefits of miniaturisation by taking up a space of just 3.5 mm x 3.5 mm.
The tip of the solid state iceberg
Ushio’s all-encompassing expertise in the field brings various opportunities to customise chip and packaging technologies such as the chip design, epitaxial growth, device process, optical design, thermal management, and electrical & mechanical design. Beyond solid state lighting, Ushio has over half a century of experience in the manufacture and customisation of device and optical technologies. With this unrivalled knowledge and the willingness to sit down with customers to find the most suitable, bespoke solution to their needs, Ushio has been established as the trusted partner of companies and clients across the globe.
Contact Ushio for help with all LED and laser diode applications
To begin your EMEA sales enquiries regarding Epitex ANPR LEDs, Ushio Europe’s SSL Sales Director, Ardan Fuessmann, can be reached via our contact page. If you would like to be well-informed on our LED collection before approaching Ushio directly, you can access the datasheets for all Ushio Epitex LEDs by visiting ushio.eu/product-category/products/led. When you are ready, Mr. Fuessmann will be readily available to discuss all of your solid state lighting needs and is more than happy to guide you through our entire LED and laser diode portfolio.
If you are based outside of the EMEA region, you can still place orders with Ushio's other regional solid state lighting departments:
Asia: https://www.ushio.co.jp/en/led/epitex/
Americas: https://www.ushio.com/technology/led/
Further reading regarding Ushio's recent SSL achievements
Spectro broadband LED series is the most powerful ever (June 2019)
SMBB LED family expanded to 1100 nm and 1150 nm by Ushio (June 2019)
Ushio unveils 660 nm single-mode high-power red laser diode (January 2020)
Ushio’s Epitex D-Series SWIR LEDs now up to four times more powerful (July 2020)
Epitex SMBB & EDC: Versatile, high-power LEDs (September 2020)
