I don't know the precise answer, but from the article the sensor sets the coldest point in its graph range to 0 and calculates everything else from that. Given

I don't know the precise answer, but from the article the sensor sets the coldest point in its graph range to 0 and calculates everything else from that. Given that the sensor is probably the most expensive part of this system, I bet that the FPGA or CPU that's running it is struggling to keep up with scanning 10,000 points 7 times a second to find the reference low to calculate everything else from.