One nice thing about the Supreme Court is that every ruling comes with at least one (or two if the ruling is not unanimous) experts explaining the situation. And if any of the remaining Justices disagree, or feel that something was left out, of those two opinions, they can add their own.

In this case, the dissent wrote:

    Unlike an x-ray scan, or other possible "through-the-wall" techniques, the detection of infrared radiation emanating from the home did not accomplish "an unauthorized physical penetration into the premises,"

and:

    While the Court "take[s] the long view" and decides this case based largely on the potential of yet-to-be-developed technology that might allow "through-the-wall surveillance," ante, at 38-40; see ante, at 36, n. 3, this case involves nothing more than off-the-wall surveillance by law enforcement officers to gather information exposed to the general public from the outside of petitioner's home. All that the infrared camera did in this case was passively measure heat emitted.

https://supreme.justia.com/cases/federal/us/533/27/