//@version=2
// Logic:
// determine ratio of current volume to current price range.
// If ratio greater 150% of the average ratio of the past 100 bars then assume wash trade and replace suspicious volume with
// an hypothetical volume equivalent to 75% of the 100 bar average (75% because the average might also be distorted by past wash trades;
// if anyone knows how to replace this with a median value let me know), normalized by current range.
study("Wash Volume Remover [Dia]")
lb=input(100, title = "Lookback Period")
th=input(3.0, minval=1.0, title = "Threshold")
range=high-low
ratio=volume/range
newvol=ratio<th*sma(ratio,lb)?volume:max(0.75*(sma(volume,lb)+sma(ratio,lb)*(range-sma(range,lb))),0)
plot(newvol,color=open<close?green:red,style=columns)