{
  "id": 12925,
  "title": "Choice of bandpass filter",
  "url": "/competitions/inria-bci-challenge/discussion/12925",
  "author_name": "",
  "post_date": "2015-03-19T19:46:29.107Z",
  "votes": 1,
  "comment_count": 2,
  "views": 1453,
  "content": "<p>Hi guys, here I have another question for the choice of bandpass filter.</p>\n<p>I realize filters can be categorized into two types:</p>\n<p>-&nbsp;Infinite impulse response (IIR)<br>- Finite impulse response (FIR)</p>\n<p>Literature suggests Butterworth filter, which is a common IIR filter. May I know why this is the prime choice in our BCI project here? Is it because of the tradition? Or is it because this is the result of trial and error as compared with other kind of filters?</p>\n<p>Your reply will be deeply appreciated. Thank you so much!</p>",
  "messages": [
    {
      "id": "67279",
      "postDate": "03/19/2015 19:46:29",
      "content": "<p>Hi guys, here I have another question for the choice of bandpass filter.</p>\n<p>I realize filters can be categorized into two types:</p>\n<p>-&nbsp;Infinite impulse response (IIR)<br>- Finite impulse response (FIR)</p>\n<p>Literature suggests Butterworth filter, which is a common IIR filter. May I know why this is the prime choice in our BCI project here? Is it because of the tradition? Or is it because this is the result of trial and error as compared with other kind of filters?</p>\n<p>Your reply will be deeply appreciated. Thank you so much!</p>",
      "rawMarkdown": "",
      "votes": null
    },
    {
      "id": "67286",
      "postDate": "03/19/2015 19:59:30",
      "content": "<p>Hi,</p>\n<p>For ERP classification, the type and the band of the bandpass filter is not a critical parameters.</p>\n<p>An ERP as a typical frequency content that rarely exceed 10 Hz, so the important thing is to cut off the DC value, and remove HF noise. I usually choose to filter between 1 and 20Hz.</p>\n<p>As for the type of filter, i suppose IIR are preferred because for an equal order, they are more selective than an equivalent FIR. This could be important for online application (lower order =&gt; less lag)</p>\n<p>I recommend this paper : <em>&quot;Interactions Between Pre-Processing and Classification&nbsp;Methods for Event-Related-Potential Classification&quot;</em>,&nbsp;J. Farquhar &#183; N. J. Hill</p>\n<p>The authors studied a lot of different preprocessing methods (including HP cutoff frequency) and their influence on performances.</p>\n<p>Alex</p>",
      "rawMarkdown": "",
      "votes": null
    },
    {
      "id": "67729",
      "postDate": "03/23/2015 17:17:21",
      "content": "<p>Hi Alexandre, thank you for recommending your paper to me. This is very helpful in my learning of this expert subject!</p>",
      "rawMarkdown": "",
      "votes": null
    }
  ],
  "comments": [
    {
      "id": 67286,
      "author_name": "alexandrebarachant",
      "author_url": "",
      "post_date": "03/19/2015 19:59:30",
      "content": "<p>Hi,</p>\n<p>For ERP classification, the type and the band of the bandpass filter is not a critical parameters.</p>\n<p>An ERP as a typical frequency content that rarely exceed 10 Hz, so the important thing is to cut off the DC value, and remove HF noise. I usually choose to filter between 1 and 20Hz.</p>\n<p>As for the type of filter, i suppose IIR are preferred because for an equal order, they are more selective than an equivalent FIR. This could be important for online application (lower order =&gt; less lag)</p>\n<p>I recommend this paper : <em>&quot;Interactions Between Pre-Processing and Classification&nbsp;Methods for Event-Related-Potential Classification&quot;</em>,&nbsp;J. Farquhar &#183; N. J. Hill</p>\n<p>The authors studied a lot of different preprocessing methods (including HP cutoff frequency) and their influence on performances.</p>\n<p>Alex</p>",
      "votes": null,
      "replies": []
    },
    {
      "id": 67729,
      "author_name": "pukkinming",
      "author_url": "",
      "post_date": "03/23/2015 17:17:21",
      "content": "<p>Hi Alexandre, thank you for recommending your paper to me. This is very helpful in my learning of this expert subject!</p>",
      "votes": null,
      "replies": []
    }
  ],
  "raw_markdown_by_id": {
    "67279": "",
    "67286": "",
    "67729": ""
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  "source": "meta"
}