1€ filter typescript version

Provides a typescript implementation for the 1€ filter.

Install

npm install 1eurofilter

Minimal example

import {OneEuroFilter} from '1eurofilter'

let frequency = 120; // Hz
let mincutoff = 1.0; // Hz
let beta = 0.1;      
let dcutoff = 1.0; 

let f = new OneEuroFilter(frequency, mincutoff, beta, dcutoff);

let noisyvalue = 2.1;
let timestamp = 0.0; // in seconds

let filtered = f.filter(noisyvalue, timestamp);

Doc

constructor

• new OneEuroFilter(freq, mincutoff, beta, dcutoff)

Constructs a 1 euro filter.

Parameters

| Name | Type | Default value | Description | | :------ | :------ | :------ | :------ | | freq | number | undefined | 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). | | dcutoff | number | 1.0 | Used to filter the derivates. 1 Hz by default. Change this parameter if you know what you are doing. |

filter

▸ filter(value, timestamp): number

Returns the filtered value.

Parameters

| Name | Type | Description | | :------ | :------ | :------ | | value | number | Noisy value to filter | | timestamp | number | (optional) timestamp in seconds |

reset

▸ reset(): void

Resets the internal state of the filter.

setBeta

▸ setBeta(beta): void

Sets the Beta parameter

Parameters

| Name | Type | Description | | :------ | :------ | :------ | | beta | number | Parameter to reduce latency (> 0). |

setDerivateCutoff

▸ setDerivateCutoff(dcutoff): void

Sets the dcutoff parameter

Parameters

| Name | Type | Description | | :------ | :------ | :------ | | dcutoff | number | Used to filter the derivates. 1 Hz by default. Change this parameter if you know what you are doing. |

setFrequency

▸ setFrequency(freq): void

Sets the frequency of the signal

Parameters

| Name | Type | Description | | :------ | :------ | :------ | | freq | number | An estimate of the frequency in Hz of the signal (> 0), if timestamps are not available. |

setMinCutoff

▸ setMinCutoff(mincutoff): void

Sets the filter min cutoff frequency

Parameters

| Name | Type | Description | | :------ | :------ | :------ | | mincutoff | number | Min cutoff frequency in Hz (> 0). Lower values allow to remove more jitter. |

setParameters

▸ setParameters(freq, mincutoff, beta): void

Sets the parameters of the 1 euro filter.

Parameters

| Name | Type | Description | | :------ | :------ | :------ | | freq | number | An estimate of the frequency in Hz of the signal (> 0), if timestamps are not available. | | mincutoff | number | Min cutoff frequency in Hz (> 0). Lower values allow to remove more jitter. | | beta | number | Parameter to reduce latency (> 0). |

Related publication

@inproceedings{10.1145/2207676.2208639,
    author = {Casiez, G\'{e}ry and Roussel, Nicolas and Vogel, Daniel},
    title = {1 € Filter: A Simple Speed-Based Low-Pass Filter for Noisy Input in Interactive Systems},
    year = {2012},
    isbn = {9781450310154},
    publisher = {Association for Computing Machinery},
    address = {New York, NY, USA},
    url = {https://doi.org/10.1145/2207676.2208639},
    doi = {10.1145/2207676.2208639},
    pages = {2527–2530},
    numpages = {4},
    keywords = {noise, jitter, lag, precision, filtering, responsiveness, signal},
    location = {Austin, Texas, USA},
    series = {CHI '12}
}