Taken from the book Bollinger on Bollinger Bands.
In a conversation in one of the forums, I discovered that the best way to describe this indicator is not to name it normalized, perhaps the best term is “Related to Volatility”.
The SMI is normalized according to its standard deviation around a mean calculated with an exponential moving average of 24 periods by default.
//**********************************************************************************
//*
//* Se normaliza el SMI dado un numero: Por defecto es igual que el RSI
//* Autor: Rafa Barreto
//*
//**********************************************************************************
ValorEMA=24
MiSMI = SMI[10,3,5](Close)
Bollinger2UpSMI = ExponentialAverage[ValorEMA](MiSMI) + (2 * STD[ValorEMA](MiSMI))
Bollinger2DnSMI = ExponentialAverage[ValorEMA](MiSMI) - (2 * STD[ValorEMA](MiSMI))
SMINormalizado = (MiSMI - Bollinger2DnSMI) / (Bollinger2UpSMI - Bollinger2DnSMI)
Return SMINormalizado