Anyone who is interested in modern thermal imaging cameras will encounter concepts such as “image-combining”, “image fusion” or “MSX® technology”.

Many wonder what this means and what the difference is. Even more important is to know whether these features are relevant in practice and it is worthwhile to pay a premium for them.

In the following, we explain exactly the individual terms and explain the subtle differences and meanings. In the end we give our conclusion whether the whole thing is really worthwhile in everyday life.

What is “Image-Combining / -Fusion / MSX®”?

  • On this website the term “Image-Combining” appears frequently. This is an umbrella term for a digital image processing technique where several images are combined into one. How this is done, however, it does not express yet. It can stand for, for example, “picture-in-picture” or “image fusion”.
  • Image-Fusion


    Image fusion is the combination of several images into one comprehensive image. In the case of thermal imaging cameras, an image of a digital camera in the visible spectrum is usually computed with the infrared image. The result is a higher contrast depth.

  • MSX® is a technology patented by FLIR and counts as an image fusion. The manufacturer promotes a clear improvement in the recognizability of details in thermal images.

How does image-combining work?

  • Bild-in-Bild


    In the picture-in-picture view, the image from the visual spectrum is placed over the infrared image or vice versa. Sometimes, a percental attenuation of the opacity of one of the images is possible. However, the color transitions which falsify the thermal information encoded in colors are problematic.


  • More complex image processing algorithms are used, for example, in MSX®. The visual spectrum provides valuable information about the edges of objects for the resulting image. The thermal image alone often looks “out of focus” because optical information, which indicates the spatial limitations of objects, is missing. To put it simply, the resulting image thus consists of an image of the visual spectrum with edge recognition and the actual thermal image. The colors of the digital camera were only used for edge recognition and do not play a role anymore, since they would falsify the result.

Is this feature worthwhile?

Image Combining




Image fusion is particularly valuable in infrared cameras with low resolution of the infrared sensor. A relatively cheap digital camera is then integrated into the device and can contribute to get more meaningful thermal images.

One thing to keep in mind, however, is the fact that (even though many manufacturers my say otherwise) that the thermal information can not be enhanced “magically” with this feature.

High-resolution thermal imaging cameras provide already very nuanced images and have features like Image-Fusion on board anyway.