A guide to investing in high-speed cameras for crash testing

by Alan Neal, Photo-Sonics International Ltd.

It is hard to foresee a time when safety will stop being a key issue for the automotive industry. Vehicle manufacturers continue to invest heavily in the development of improved safety features to attract customers, while the need to comply with government regulations gives ongoing impetus to progress in this area.

Nor is there likely to be any reduction in the key role played by crash testing in the development of safer vehicles. Greater reliance on computer modelling within the industry has not eliminated the need to carry out real crash tests as part of the automotive R&D process. As a result, demand for increasingly effective high-speed cameras capable of recording crash test impacts will continue unabated in the years ahead.

Traditionally, film-based 16mm cameras have been the industry standard. Recent years have seen the development of an alternative in the shape of digital imaging equipment. Inevitably, some parts of the automotive industry have been slower to embrace high-speed digital cameras than others. One reason is lack of familiarity with the technology. Another is the natural desire to await developments in what is a fast-moving field - and to be sure that the technology has evolved to an acceptable stage of maturity before committing investment.

The truth of the matter is very simple. The latest generation of digital high-speed cameras offers high-quality performance and a range of valuable benefits for organisations engaged in crash testing. Now is the time to give serious consideration to investing in a digital imaging system.

Weighing Costs and Benefits

Going digital can be a big step. Replacing traditional high-speed cameras with state of the art digital equivalents will involve a significant investment. It is vital, then, to be certain that you are making the right decision. This means understanding - and quantifying - the benefits that would result from the upgrade to digital imaging. It also means developing a clear appreciation of how much can be achieved within your existing budgetary constraints.

Along with ease of operation, the main advantage of digital imaging technology is improved efficiency. Digital cameras generate data that can be downloaded straightaway, enabling image sequences to be viewed and analysed immediately after recording. Compare this to traditional film-based cameras, where film needs to be developed - a stage that can take several days if no on-site processing facility is available. Digital imaging, then, can shorten the time from crash to quantitative and qualitative analysis from days to minutes, with all the associated benefits. It also removes film processing costs altogether.

Moreover, these benefits can be achieved without any detriment to image quality. High-speed digital imaging technology has taken important strides since it made its first appearance several years ago. In particular, manufacturers have focused their attention on overcoming the inevitable technical limitations of the first generation of equipment. As a result, the latest generation of high-speed digital cameras are a factor superior to their predecessors in the vital areas of both resolution and sensitivity.

The level of performance that can be achieved by a digital camera is largely a function of the sensor it incorporates. Important technical advances have been made in this respect, such as the development of CMOS sensors, which are incorporated in PhotoSonics Airborne digital cameras. The sensor has been designed exclusively for high-speed use, and to provide the right combination of sensitivity, high resolution and speed, without blooming. This means that the camera can offer resolutions of 512 x 512 pixels up to 1280 x 1024 pixels at frame rates of 50 to 200,000 pictures per second.

Assessing Your Needs

Once you have established that digital imaging could provide you with cost-effective benefits, you will need to consider precisely what equipment to invest in. The first step is to identify cameras suited to the various crash test scenarios that you are likely to encounter. Different digital cameras are designed with different applications in mind, and so have different specifications and characteristics. Our view at Photo-Sonics is that there is no such thing as a universal camera. For example, a camera designed to record crash test events in the confined spaces of a footwell or a car door will need to be significantly more compact than a camera specified for off board use. The key is to ensure that the equipment you invest in is fit for the intended purpose.

Although digital cameras can be operated on a stand-alone basis, one of the great advantages of going digital is the ability to control multi-camera systems from a single workstation. This means you will need to make sure that your network, if you have one, is compatible with your choice of digital imaging equipment. It also means that your network will have to deal effectively with the huge amount of data that the new high-resolution digital cameras generate if it is to deliver the download times usually demanded. Existing Ethernet networks cannot cope with these higher data rates, so we have incorporated Gigabit Ethernet technology into the design. To achieve maximum flexibility of operation, it is also important to ensure that your digital camera network uses standard protocols.

Lighting is another key issue that is often overlooked. Even more so than with film-based photographic systems, digital cameras cannot deliver optimum performance if they are expected to operate in an environment with obsolete or inappropriate lighting. Investing in a lighting system can be a major commitment in its own right - in some instances costing as much as the digital equipment itself. As a rule of thumb, though, the more sensitive the digital camera, the more likely it is to be able to work with existing lighting systems.

The lighting issue is a useful reminder that going digital is not just a question of high technology. Although a significant leap forward in technical terms, digital imaging is, in the final analysis, a form of photography and the laws of physics still apply. Consequently, photographic skills and expertise, e.g., an appreciation of issues such as aperture, light and focus, are still required. The temptation to fall prey to an "anyone can do it" mentality needs to be avoided.

Choosing a Supplier

Currently, the market for digital imaging equipment suitable for automotive crash test applications is occupied by a number of specialist manufacturers. When deciding which of these to buy equipment from, here are four issues to bear in mind:

1) Backwards Compatibility. As noted earlier, digital imaging is a very fast-moving field, with technical advances constantly giving rise to the development of new, improved models. Sometimes this can act as a disincentive to deciding to go digital, because of the fear that equipment invested in today will be obsolete tomorrow. The key, then, is to ensure that the supplier you choose offers backwards compatibility, which will enable you to continue using existing equipment in tandem with any advanced models or components that may become available and that you may decide to buy.

2) After-sales Support. Clearly, there are significant advantages if your supplier can offer you ready access to direct support and servicing, avoiding the unacceptable delays that can result from sending equipment a long way away.

3) Understanding. Always look for a supplier that can show a genuine, hands-on grasp of all the technical and operational issues related to the use of digital imaging equipment. In essence, this means demonstrating substantial engineering expertise and applications knowledge.

4) Track Record. In digital imaging, as in so many fields, there is no substitute for a proven pedigree. Ensure that your supplier has an impressive track record and can demonstrate wide and long specialist experience of the industry.

At Photo-Sonics, we build our offering around these principles - and I'm sure our competitors would make similar claims. The aim must always be to ensure that organisations make the right decision about going digital, and then to help those that do to reap the valuable rewards that can result. In this way, companies like Photo-Sonics can contribute to the rapid take-up of digital imaging technology that is widely predicted for the years ahead.

Copyright © 2007 Photo-Sonics International Ltd. This article may not be copied, reproduced or displayed on any other website - in whole or in part - without the express WRITTEN consent of Photo-Sonics International Ltd.

 

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