As technology evolves and improvements are made, we always want the latest releases and thermography is no exception to this. We ask for more resolution, a higher sensitivity, and more versatility. The question is, do we really need all this?
In 2003, the mid-level thermal imagers had a resolution of 160 x 120, today we’re looking at imagers with resolutions of 320 x 240 or even 640 x 480. Does your application require that high of a resolution? Or is 160 x 120 enough for you to see what you need to see?
When considering resolution, we focus on superior image quality and superior hot spot detection capacity of smaller targets at greater distances. For this discussion, I will focus on imagers with resolutions of 160 x 120 comparably to 320 x 240.
Taking two imagers with the same lens type (view angle), an imager with 320x240 could see an object half the size of a 160 x 120 imager or it could see the same sized object at twice the distance. That being said, at 40’ with a 25° lens a 160x120 imager would have a field of view of approximately 17’ x 13’ with an IFOV of 1.34". Whereas an imager with 320 x 240 would have the same field of view with an IFOV of 0.67".
The difference in imager resolution has a cost. It’s approximately double. If budget limitations are not an issue, the higher resolution is an obvious choice. However, for those where budget limitations don't allow you to double your costs, is there another option?
Yes. Use a zoom lens with a 160 x 120 resolution imager.
If I use the same imager with a 15° lens my field of view at 40’ will be approximately 10’ x 7’ and an IFOV of 0.79". You lose a little field of view, however if your target measures 10’ x 7’ or less, you’ve saved anywhere from $3000 to $4000.
Something to think about.