Re: [Algorithms] Low pass filter on quaternions

[Jon W. <jw...@gm...>]

The problem is that Quaternions are not quite linear enough. Running a naive
filter on the axis component when the rotation is close to identity (and the
axis component is small) may cause excessive jitter.

The motion capture tools people have had this problem for a long time. I
believe they convert to Euler, and run low-pass filtering there (possibly
higher than just first order), and then convert back, because Euler is less
sensitive around any particular spot.

I'd also be interested in hearing from anyone who has done this in anger!

Sincerely,

jw


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On Sun, Mar 28, 2010 at 10:22 AM, Juan Linietsky <re...@gm...> wrote:

> I don't have any code handy, but since for a lowpass filter you need the
> "difference",  I guess you can obtain that with the inverse or something
> similar.. Also keep in mind it may be easier to just lowpass a 3x3 matrix
> since you want to rule out high freq noise
> ------Original Message------
> From: John McCutchan
> To: Game Development Algorithms
> ReplyTo: Game Development Algorithms
> Subject: [Algorithms] Low pass filter on quaternions
> Sent: Mar 27, 2010 23:14
>
> Hi,
>
> I have a sequence of quaternions and want to filter out any high
> frequency changes. I'm wondering if anyone has a paper or some code
> for performing a low pass filter on quaternions?
>
> Thanks,
> --
> John McCutchan <jo...@jo...>
>
>
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