Entry level cost to the technology, for many, will naturally be the principle consideration and there are some good, easily affordable camera models available to give you a feel for what thermal imaging can do.  Nevertheless, you should buy the best your budget allows and pay particular attention to detector resolution.

Size matters

The higher the resolution, the greater the camera’s ability to measure smaller targets from farther away and to create sharper thermal images. This is crucial to taking precise and reliable thermal measurements. Also make sure the detector has the power to meet the specification of the display resolution.  

An LCD resolution of 640 x 480 pixels, capable of displaying 307,200 pixels of image content may sound attractive but the quality is of little value if the in-built IR detector only has a resolution of 160 x 120. It’s like watching a standard-definition transmission on an ultra HD television. Always remember the quality of the thermal image and its measurement data are determined by detector resolution.

Higher resolution thermal imaging not only provides more accurate quantitative results, it can also be very helpful in showing findings, in finer detail, to others. This can help to speed the decision-making process to ensure improvements and repairs are carried out as quickly as possible.

Consistent measurement accuracy has a significant bearing on the value of your purchase.  Ideally look for a camera that meets or exceeds ±2% accuracy and don’t forget to ask your supplier how the manufacturer assures this quality.  

Another important thing to check is that your camera has in-built tools for entering values for emissivity – the measure of efficiency in which a surface emits thermal energy – and also reflected temperature. Both have the ability to seriously skew results if the camera does not have an easy way to input and compensate for both these parameters.  

Other helpful features 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 Word-based reports.

Standard issue

Ask your supplier how thermal images are stored. For example, are they in a proprietary format that can only be read and analysed by specialised software?  You will also find models with optional JPEG storage but without all-important radiometric information. Clearly the most useful format is one that offers standard JPEG storage with full temperature analysis embedded and there are there several models that have this functionality.

Radiometric JPEGs can also be imported from wi-fi compatible cameras to 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.

Free software is supplied with most cameras enabling you to perform basic image analysis and create simple reports but look beyond that at what additional software may be available. These are no longer expensive products, yet they have the potential to add considerable value to your investment.  Also think seriously about training – a thorough understanding of the science behind infrared is vital.

Flir has put together ’12 things to consider before buying an infrared camera’, which can be downloaded from: http://www.flir.co.uk/instruments/display/?id=18092