布林通道，收缩到极致就是低吸区，开口即是买入点
{布林收缩低吸}N:=20;BOLL:MA(CLOSE,N),NODRAW;UB:BOLL+2*STD(CLOSE,N),NODRAW;LB:BOLL-2*STD(CLOSE,N),NODRAW;差值:UB-LB;低吸区:IF(差值<0.20,差值*2,0);
DRAWBAND(低吸区,RGB(255,0,0),0,RGB(255,125,0));