A robust reconstruction of sparse biomagnetic sources

Inequality constraints are introduced to a normalized minimum-L ₁-norm estimator, which gives a sparse solution of the biomagnetic inverse problem. The constraints have a numeric tolerance to take into account the measurement ambiguity caused by noise. Computer simulation and phantom-data analysis show how the solution is improved by the constraints with a moderate tolerance; the improvement is examined in noisy conditions such that signal-to-noise ratios (SNR´s) are lower than 10 dB.