pwstegman / bci.js Goto Github PK

Welch's method for power spectral density estimation.

Implemented and set for release in v1.8. Need to add unit tests.

I am loading an edf using:
bci.loadEDF
In return I am getting an object that contains a channel property. Each channel contains samples, I am passing each of these samples to bci.averageBandPowers but getting this error:
TypeError: Cannot read property 'length' of undefined
at signalBandPower (C:\Users\HP\Desktop\projects\driverDrowsiness\node_modules\bcijs\lib\math\signalBandPower.js:49:41)
at Object.averageBandPowers (C:\Users\HP\Desktop\projects\driverDrowsiness\node_modules\bcijs\lib\math\averageBandPowers.js:25:29)
at getData (C:\Users\HP\Desktop\projects\driverDrowsiness\index.js:11:37)
at process._tickCallback (internal/process/next_tick.js:68:7)
at Function.Module.runMain (internal/modules/cjs/loader.js:834:11)
at startup (internal/bootstrap/node.js:283:19)
at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)

P.S In channels.sample I am getting a 1d array rather than the 2d one in bci.loadedf
This is my edf file

Multitaper method for power spectral density estimation.

Implemented in v1.8. Need to add unit tests.

Edit: Moved to v1.9

For computation of discrete prolate spheroidal (Slepian) sequences, a length up to 128 is calculated. Lengths past 128 are linearly interpolated up.

For tapers with near-unity eigenvalues for common time half bandwidths (2.5, 4, etc.) the curves are smooth enough that linear interpolation works well. A more efficient eigenvector method will help remove the need to interpolate.

When using a small FFT size, the PSD returns NaN.

Steps to reproduce.

bci.signalBandPower([1, 2, 3, 4, 5, 6, 7], 8, 256, 'alpha')
=> NaN
bci.signalBandPower([1, 2, 3, 4, 5, 6, 7], 16, 256, 'alpha')
=> NaN
bci.signalBandPower([1, 2, 3, 4, 5, 6, 7], 32, 256, 'alpha')
=> 26.416893639442556

When attempting to pack this code for use on a browser-only solution, webbci's dependence on node-osc causes webpack to error due to node-only dependencies.

ERROR in ./node_modules/node-osc/lib/safeDgram.js
Module not found: Error: Can't resolve 'dgram' in './node_modules/node-osc/lib'
 @ ./node_modules/node-osc/lib/safeDgram.js 3:12-28
 @ ./node_modules/node-osc/lib/Server.js
 @ ./node_modules/node-osc/lib/index.js
 @ ./node_modules/webbci/lib/network.js
 @ ./node_modules/webbci/index.js

If you don't expect for this code to run on the browser side only, then this is probably expected behavior.

This computes average power across channels as expected:

let power = bci.bandpower(samples, samplerate, ['alpha'], {average: true});

But this does not average across channels ({average: true} is ignored)

let power = bci.bandpower(samples, samplerate, 'alpha', {average: true});

Hello Pierce!
My name is Anton and I’m using your js package called BCI.js but I can’t understand one thing and I believe you can help me :)
I have an array of signals from EEG session which lasted for 30 seconds and I want to get average alpha band power for every second.
I divide my signals by 30 and on each subarray I’m using signalBandPower method. Is this correct or I’m doing something wrong?

Thank you in advance!