Class OneEuroFilter

OneEuroFilter is a low-pass filter designed to reduce jitter in noisy signals while maintaining low latency. It's particularly useful for smoothing tracking data from XR controllers, hand tracking, or other input devices where the signal contains noise but responsiveness is important.

The filter automatically adapts its smoothing strength based on the signal's velocity:

  • When the signal moves slowly, it applies strong smoothing to reduce jitter
  • When the signal moves quickly, it reduces smoothing to maintain responsiveness

Based on the research paper: 1€ Filter: A Simple Speed-based Low-pass Filter for Noisy Input

Example: Basic usage with timestamp

const filter = new OneEuroFilter(120, 1.0, 0.0);

// In your update loop:
const smoothedValue = filter.filter(noisyValue, this.context.time.time);

Example: Without timestamps (using frequency estimate)

// Assuming 60 FPS update rate
const filter = new OneEuroFilter(60, 1.0, 0.5);

// Call without timestamp - uses the frequency estimate
const smoothedValue = filter.filter(noisyValue);

Example: Smoothing 3D positions

const posFilter = new OneEuroFilterXYZ(90, 0.5, 0.0);

posFilter.filter(trackedPosition, smoothedPosition, this.context.time.time);

See

OneEuroFilterXYZ for filtering 3D vectors

Constructors

constructor

Properties

beta dCutOff dx freq lasttime minCutOff x

Methods

alpha filter reset

Constructors

constructor

  • new OneEuroFilter(
        freq: number,
        minCutOff?: number,
        beta?: number,
        dCutOff?: number,
    ): OneEuroFilter

    Create a new OneEuroFilter

    Parameters

    • freq: number

      An estimate of the frequency in Hz of the signal (> 0), if timestamps are not available.

    • minCutOff: number = 1.0

      Min cutoff frequency in Hz (> 0). Lower values allow to remove more jitter.

    • beta: number = 0.0

      Parameter to reduce latency (> 0). Higher values make the filter react faster to changes.

    • dCutOff: number = 1.0

      Used to filter the derivates. 1 Hz by default. Change this parameter if you know what you are doing.

    Returns OneEuroFilter

Properties

beta

beta: number

Parameter to reduce latency (> 0). Higher values make the filter react faster to changes.

dCutOff

dCutOff: number

Used to filter the derivates. 1 Hz by default. Change this parameter if you know what you are doing.

dx

dx: LowPassFilter

The low-pass filter for the derivates.

freq

freq: number

An estimate of the frequency in Hz of the signal (> 0), if timestamps are not available.

lasttime

lasttime: null | number

The last time the filter was called.

minCutOff

minCutOff: number

Min cutoff frequency in Hz (> 0). Lower values allow to remove more jitter.

x

x: LowPassFilter

The low-pass filter for the signal.

Methods

alpha

  • alpha(cutOff: number): number

    Parameters

    • cutOff: number

    Returns number

filter

  • filter(x: number, time?: null | number): number

    Filter your value: call with your value and the current timestamp (e.g. from this.context.time.time)

    Parameters

    • x: number
    • time: null | number = null

    Returns number

reset

  • reset(x?: number): void

    Parameters

    • Optionalx: number

    Returns void

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