... threshold1
The robust threshold used here is set as $0.1*(I_{98}-I_{2}) + I_{2}$ where $I_{n}$ is the $n$th percentile of the image $I$.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.