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

$3

• 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. |

$3

▸ filter(value, timestamp): number

Returns the filtered value.

#### Parameters

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

$3

▸ reset(): void

Resets the internal state of the filter.

$3

▸ setBeta(beta): void

Sets the Beta parameter

#### Parameters

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

$3

▸ 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. |

$3

▸ 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. |

$3

▸ 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. |

$3

▸ 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

![DOI](https://doi.org/10.1145/2207676.2208639)

`
@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}
}
``