Thermal Imaging Cameras: The Features That Matter Most
by Brent Lammert
Thermal imaging cameras are versatile tools, but they can be a significant investment. Understanding key features helps you define your needs and expectations so you can get the most for your money.
There are so many applications for thermal imaging that it is important to know how you will use it and why you want to add it to your toolbox. Instead of attempting to meet many needs, focus on meeting the needs of the primary users. Otherwise, choosing a thermal imaging device for general use risks ending up with one that meets no one’s needs and therefore is not used.
Thermal imaging cameras have a wide range of features. Designs can measure temperatures at specific points or present a snapshot of the heat signatures in an area. Some cameras are for measuring objects at a distance or focusing on a limited temperature range. Size, portability and even the types of files created vary by device.
Devote time to evaluating your needs and specifying the features that will best meet them. Concrete specifications and details on how the tool will be used can be used to prioritize features and narrow your purchasing options.
Some features are more important than others. The most important ones affect an image’s level of detail but also determine accuracy, reliability and precision. These six features determine the quality of the measurements taken by a thermal imaging camera.
Resolution is usually the first specification people evaluate when selecting a thermal imaging camera, and for a good reason, it determines image detail and measurement performance. Resolution is based on the number of detector elements on the focal plane and is usually expressed as pixel count or with Horizontal and Vertical resolution such as 160x120. A 160x120 camera has a detector with 160 pixels across, 120 pixels tall, and a pixel count of 19,200 pixels. Another standard resolution is 384x288 (110,592 pixels). The higher IR resolution improves the detail in the image and the ability to measure targets, even small ones, from farther away. The two images below clearly show the difference between these image resolutions.
Many thermal cameras also include a built-in visual camera. A low-resolution optical camera is helpful to add graphic detail to the thermal image with Picture in Picture or Fusion modes. Look for higher resolution cameras such as 8 MP if you plan to include high-quality visual and thermal images in your reporting. The ease of taking both the thermal and the visual pictures simultaneously will save you time in the field and in your reporting.
There are three types of focus — fixed, manual, and auto— each with a specific purpose. Fixed focus reduces cost and complexity and offers less clarity over the working distance. Fixed focus cameras can be a good choice for technicians who need quick measurements while working close to equipment or when detailed reporting is not required. On the other hand, manual focus and autofocus provide sharp images over a broader range of distances with noticeable improvements in image quality. The quality and type of lens, combined with the ability to manually or automatically adjust the focus, determine not only image clarity but also measurement precision. An out-of-focus image will blur background temperatures with the target being measured and can lead to significant error. It is an important feature that expands the versatility of the camera.
The camera’s frame rate indicates the number of images taken per second. Most products on the market offer a frame rate of 9 Hz or slower. In comparison, HIKMICRO cameras are 25 Hz or faster. Higher frame rates provide smoother video and easier viewing for the operator. This is especially important for measurements on fast-moving objects or for panning across a scene to inspect a larger area.
As with any significant equipment investment, the warranty and customer service are important. While the best warranty is the one you never have to use, a generous warranty helps safeguard your purchase. At HIKMICRO, we offer a three-year warranty on the system and 10 years on the detector.
A feature that often goes unnoticed during buying decisions is battery life. When you are in the field or at a job site, long battery life comes in handy. You don’t want your thermal imaging camera to die when there’s still work to be done. Thermal cameras offer either internal batteries or interchangeable (tool style) batteries. For internal batteries, make sure the run time will be adequate for a full day of operation. For systems with interchangeable batteries, ensure it includes at least two batteries and that the charger can recharge both.
The goal when purchasing a thermal imaging camera is to get the most desired features for your target price point. Picking the best option takes forethought and research. While features such as laser pointers and built-in lighting may be helpful, they have little impact on the image quality or the camera’s reliability. High IR resolution, decent optical resolution, multiple focus modes, high frame rates and a warranty that shows that the company backs their product are far more important.
Thermal Camera—A Combination of Intelligent Technology and Application: