They require a shielded room to increase the SNR. SQUID sensors are sensitive enough to record cardiac signals at distance. The issue is SNR.
What they are saying is that they produced a low noise sensor array and managed to increase the SNR through computation. They also stated that it was an ideal environment with no other electrical/magnetic interference.
What they are saying is that they produced a low noise sensor array and managed to increase the SNR through computation. They also stated that it was an ideal environment with no other electrical/magnetic interference.