Hybrid SURE threshold. Xxxxxx and Xxxxxxxxx (Xxxxxx and Xxxxxxxxx, 1995) brought to evidence that the SURE threshold tends to be too low when the noise level is very high. To mitigate this inconvenience, they proposed the hybrid SURE threshold TSURE hybrid, which replaces the SURE threshold by the universal threshold when the noise level is high: , − ≤ ,⎨TSURE , X 2 Nσ2 ϵN TSURE hybrid =
