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By James Piper
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Increasing numbers of front-line maintenance and engineering technicians use thermal-imaging technology to detect problems before they result in equipment breakdowns, system outages or expensive repairs. But while the benefits of imaging technology are well documented, the process of selecting a suitable system is not.
Selecting the proper system entails identifying the ways technicians will use the technology, then selecting a system that most closely matches the organization’s needs.
No matter the system selected, managers need to keep in mind that the technology in use today is far superior to early-generation systems. Besides being bulky and difficult to use, older systems used liquid nitrogen to cool imaging components. The cameras produced low-quality, low-resolution images that were difficult to interpret or to use in quantifying temperature variations, and two people using the same camera often produced widely different results.
Today’s thermal imaging cameras weigh less than 5 pounds, have no special cooling needs and allow users to transfer high-resolution color images to computers and other hardware. Most importantly, the images captured by a camera, which can detect temperature differences as small as 0.05 Celsius, can be duplicated by other users.
The systems also are more portable than those of yesteryear, although variability still exists. If technicians will use the system in relatively confined spaces — such as manholes, steam line tunnels, or electrical vaults — small, lightweight cameras become much more appealing options.
The temperature range of the objects to be scanned also affects the purchasing decision. High-temperature applications, such as boilers and steam lines, have different imaging requirements than roofs and electrical equipment. Not all cameras perform equally well over different temperature ranges.
The size of the objects being examined as well as their distance from the camera will determine the type of lens that should be used. Some systems come with only a wide-angle lens, while others come with a 50 mm medium lens. Still others have 100 mm telephoto lenses. Several systems offer interchangeable lenses.
Another essential factor is the camera’s image-storage capacity. In some applications, users might need to take and store large number of images before transferring the images to a computer. In other applications, only a few images at a time need to be stored. Managers need to make certain the camera has enough storage capacity for the application requirements.
Finally, managers should consider who will use the system. Some systems are extremely simple to use while others are complex. A general rule is that more complicated systems offer more features, which in turn requires more training. If many technicians will use the system, training can become a significant expense.
Many of today’s infrared imaging systems offer a common set of features, but managers also can select from additional features to more closely match the needs of their applications. Among the features to consider:
Resolution. Resolution helps determine image quality. Most systems offer resolutions of between 120 pixels square and 320 pixels square. The higher the resolution, the more detailed the image.
Lenses. The size of the objects being scanned and their distance from the imaging system determine the type of lens required. For example, producing thermal images of motor bearings or electrical contacts requires a standard lens, but imaging overhead power-line equipment from the ground requires a telephoto lens. Systems might come with one fixed lens or with multiple, interchangeable lenses.
Locator. For some applications — particularly those where the target is small or far from the camera — it is important to aim the camera directly at a specific location. Similarly, if the scanner detects a hot spot, it can be difficult to identify that specific location on the object. To assist users, some manufacturers include a laser in the camera that projects a small dot onto the target, making it easier to locate hot spots.
Software. Perhaps the biggest differentiator among imaging systems is the accompanying software. Low-end systems include software that allows users to produce an image and export it to a computer. At the other extreme, high-end systems offer software that allows the user to add text and voice comments and link them to individual images, as well as to edit images and combine several images into a composite image.
Display size. As with video cameras, most thermal imaging systems come with a viewfinder and an LCD display that typically measures 3 inches by 5 inches. This dual display allows technicians to use the system in a range of ambient-lighting conditions.
Thermal imaging has seen many advances in recent years, and the industry is not standing still. Manufacturers of thermal imaging systems are offering advances that will further enhance system capabilities.
One important advance involves the adoption of standards. The thermal imaging industry is maturing, and as a result, standards are emerging that will address issues ranging from image quality to imaging procedures and user training.
As more users invest in thermal imaging, the range of applications for thermal imaging also will expand. Today, the technology is widely used to inspect electrical equipment, mechanical equipment, piping systems, roofs and building thermal systems. Potential new uses include corrosion detection, environmental monitoring and control applications, and detecting the location of termites and other infestations in buildings.
As the applications expand, so will system capabilities. Managers should watch for higher-resolution systems, starting with those offering 640- by -480 pixel detectors. At least one thermal imaging camera on the market offers a resolution of 1,280 pixels by 960 pixels. Higher-resolution detectors will result in higher-quality, more detailed images.
Resolution is important, but so are the quality and accuracy of the resulting color image. Most cameras now produce 16-bit thermal images. New generation systems will offer 32-bit images as the standard.
Also, just as the quality of detectors in digital cameras has improved so will the quality of the thermal-imaging detectors. Future detectors will offer even higher levels of sensitivity, while reducing the level of noise produced.
While today’s systems are small compared to those of a few years ago, future systems will be smaller and lighter still. Advances in system design and manufacturing methods will reduce their size, weight, and cost. Some manufactures already have introduced cameras that weigh as little as 1 pound while offering the same features more commonly found in heavier cameras.
Future systems also will offer even more software capabilities. In part, this improvement comes from the maturation of the industry. Once manufacturers mastered the basics, they looked for ways to enhance performance. One of the most common enhancements has been improved software capabilities and performance. And as users have better understood its benefits of infrared diagnostic technology, they have pushed manufacturers to include even more enhancements.
James Piper is a national facilities consultant based in Bowie, Md., with more than 25 years’ experience in facilities management.
The capabilities of today’s infrared imaging systems vary widely. In general, more capabilities and features cost more, but some features are common to most systems now on the market. They include:
— James Piper