Filtering of over- and under-estimated heights using interferometry

I am using SNAP for interferometric estimation of heights. The estimation is well performed but for some pixels, the height is over- and under-estimated. My objective is to find a way is SNAP to filter or mask those pixels.
Thanks for who can suggest me a solution…

you can use the valid-pixel expression in the band properties to exclude pixels with low coherence. Have a look here: Subsidence map in 3d view