Forgive my ignorance, but if this system would require liquid nitrogen cooling to detect heat from a human, how do commercial (now almost cheap) thermal cameras work? Are they not sensing IR? The can certainly distinguish the different temperatures of different people, without needing to be cooled themselves.<p>How is this system better than a commercial IR camera -- besides the very obvious and valid reason that this is DIY, and started long before those were cheap?<p>&gt; <i>&quot;The most amazing part is not that it glows, but that it glows brightly enough to illuminate the stand. It’s not just the “temperature mapped to an image” of a regular heat vision camera, we see the actual long-wave light being emitted and reflected – a soldering iron turned into a lightbulb!&quot;</i><p>How is that different from this image, which shows a duck&#x27;s IR being reflected by water, made by a cheap-o &quot;regular heat vision camera&quot;? <a href="http:&#x2F;&#x2F;thermal-imaging-blog.com&#x2F;wp-content&#x2F;uploads&#x2F;2012&#x2F;05&#x2F;ducks-22.jpg" rel="nofollow">http:&#x2F;&#x2F;thermal-imaging-blog.com&#x2F;wp-content&#x2F;uploads&#x2F;2012&#x2F;05&#x2F;d...</a>