This is the Gaussian Filter, as described by John F. Ehlers in his publication “Gaussian and other Low Lag Filters”.
Indicator Description
Using the Gaussian Filter indicator, you may choose a pole filter number between 1 and 4. A 1 pole filter (yellow) will have a better approximation to price, whereas the 4 pole filter (blue) has superior smoothing.
Other Library indicators
Other than the Gaussian Filter, this category includes the Adaptive Laguerre Filter, the Butterworth Filter, the Laguerre Filter, the Coral Filter, the Distant Coefficient Filter and the MAAF. You may also review our indicators from the moving averages or the trend analysis categories, such as the Directional Movement Index, Zerolag TEMA, Zerolag HATEMA, Triple Weighted Moving Average, Sine WMA, Range Weighted Moving Average or the Efficiency Ratio. The Indicator Spotlight newsletter furthermore discussed the Efficiency Ratio here. Finally, you may want to review our Indicator Spotlight on the Fibonacci Retracement Levels (with video).
The Gaussian Filter is available for NinjaTrader 8.