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So, it’s critical that any electrical fault is spotted in its infancy before it has the potential to compromise service.
A popular method for detecting these faults is thermal imaging. It’s a technology that has become mainstream in the last decade whose cost has fallen substantially thanks to its scope of application across many industry sectors. It is also the subject of continuous development, presenting prospective purchasers with significant choice.
The range now extends from pocket-sized models and infrared-enabled smart phones to low cost point-and-shoot troubleshooting cameras and high end models with every function necessary for the professional thermographer. So how do you assess the best model for your needs?
Buy the best your budget allows
Most thermal imaging cameras have fewer pixels than visible light cameras, so pay close attention to detection resolution. Higher resolution infrared cameras can measure smaller targets from farther away and create sharper thermal images, both of which add up to more precise and reliable measurements.
Also, be aware of the difference between detector and display resolution. Some manufacturers will boast about a high-resolution LCD to mask their low-resolution detector when it’s the detector resolution that matters most.
For instance, LCD resolution may spec at 640 x 480, capable of displaying 307,200 pixels of image content. But if the IR detector pixel resolution is only 160 x 120, giving 19,200 measurement points, the greater display resolution accomplishes nothing as the quality of the thermal image and its measurement data are always determined by detector resolution.
Higher resolution thermal imaging not only provides more accurate quantitative results, it can also be very effective in showing findings in finer details to others. This can help speed the decision-making process for improvements and repairs.
As well as clarity of image for effective problem diagnosis, resolution is very important from a safety perspective too. For electrical inspection, there is no point in buying a low-priced, low-resolution troubleshooting camera that can only give you a clear image when it’s six inches away from the target!
Accurate and repeatable results
Consistency of measurement accuracy is a very important factor when determining the value of a camera. For best results, look for a model that meets or exceeds ±2% accuracy and ask your supplier for details of how they assure the manufacturing quality of the detector to guarantee this. That isn’t the only criteria, however.
In order to produce correct and repeatable results, your camera should include in-built tools for entering both values for emissivity – the measure of efficiency in which a surface emits thermal energy – and also reflected temperature. A cabinet may be hot in the thermal image but its shiny surface could just be reflecting the heat from overhead lighting or indeed the body heat generated by the camera operator.
A model that gives you an easy way to input and adjust these parameters will produce the accurate temperature measurements you need in the field. Other helpful diagnostics to consider are multiple moveable spots and area boxes for isolating and annotating temperature measurements that can be saved as radiometric data and incorporated into reports.
Standard file formats
Many thermal imaging cameras store images in a proprietary format that can only be read and analysed by specialised software. Others have an optional JPEG storage capability that lacks temperature information. Clearly, the most useful is a format that offers standard JPEG with full temperature analysis embedded. This allows you to email IR images without losing vital information.
Radiometric JPEGs can also be imported from Wi-Fi compatible cameras to select mobile devices using apps that allow further image editing, analysis and sharing. Also look out for models that allow you to stream MPEG 4 video via USB to computers and monitors. This is especially useful for capturing dynamic thermal activity where heating and cooling occurs rapidly and for recording motorised equipment or processes in motion.
Some cameras feature composite video output for cabling to digital recorders while others include HDMI outputs. And new mobile applications have also been developed that allow streaming video over Wi-Fi. All these capabilities help you share findings more effectively and enhance your infrared inspections and reports.
Software, study the options
Today most thermal imaging cameras come with free software so you can perform basic image analysis and create simple reports. Advanced software for more in-depth and customisable reports is also available, allowing you to take full advantage of your camera’s capability and features. Investigate these tailored software programmes thoroughly to see which makes the most sense for your needs.
And finally, don’t underestimate the importance of training. The best thermal imaging camera in the world is only valuable in the hands of a skilled operator.
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