<html><head></head><body><div class="ydpc5cc1e04yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div><div dir="ltr" data-setdir="false">> <span>The viewer indicates 60 fps, so 16 ms per frame</span></div><div dir="ltr" data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false"><span>Kalman filter to estimate tempo from successive frames?</span></div><div dir="ltr" data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false"><span></span><br></div><div><br></div><div class="ydpc5cc1e04signature"><div dir="ltr" style="font-family:Helvetica, Arial, sans-serif;font-size:16px;">Noah Vawter's electronic music instrument lab: <a href="https://youtube.com/diydsp" rel="nofollow" target="_blank">youtube.com/diydsp</a></div></div></div>
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On Sunday, March 21, 2021, 10:43:17 AM EDT, Ben Stuyts <ben@stuyts.nl> wrote:
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<div><div id="yiv5783001583"><div>Awesome, thanks for the link! I watched the two Youtube demos there, and the timing is not too bad. The viewer indicates 60 fps, so 16 ms per frame. That would also be a limiting factor of course.<div class="yiv5783001583"><br class="yiv5783001583" clear="none"></div><div class="yiv5783001583">Ben</div><div class="yiv5783001583yqt8031820908" id="yiv5783001583yqt97092"><div class="yiv5783001583"><br class="yiv5783001583" clear="none"><div><br class="yiv5783001583" clear="none"><blockquote class="yiv5783001583" type="cite"><div class="yiv5783001583">On 21 Mar 2021, at 03:39, John P Shea <<a rel="nofollow noopener noreferrer" shape="rect" class="yiv5783001583" ymailto="mailto:info@extrinia.com" target="_blank" href="mailto:info@extrinia.com">info@extrinia.com</a>> wrote:</div><br class="yiv5783001583Apple-interchange-newline" clear="none"><div class="yiv5783001583"><div class="yiv5783001583"><div class="yiv5783001583"><a rel="nofollow noopener noreferrer" shape="rect" class="yiv5783001583" target="_blank" href="https://github.com/nai-kon/PlaySK-Piano-Roll-Reader">https://github.com/nai-kon/PlaySK-Piano-Roll-Reader</a></div><br class="yiv5783001583" clear="none"></div><div class="yiv5783001583"><br class="yiv5783001583" clear="none"><div class="yiv5783001583gmail_quote"><div class="yiv5783001583gmail_attr" dir="ltr">On Sat, 20 Mar 2021 at 10:35 pm, Ben Stuyts via Synth-diy <<a rel="nofollow noopener noreferrer" shape="rect" class="yiv5783001583" ymailto="mailto:synth-diy@synth-diy.org" target="_blank" href="mailto:synth-diy@synth-diy.org">synth-diy@synth-diy.org</a>> wrote:<br class="yiv5783001583" clear="none"></div><blockquote class="yiv5783001583gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Has anybody ever tried pointing a video camera at the piano roll and do some real-time machine vision type of recognition? Would the resolution (i.e. timing) be good enough?<br class="yiv5783001583" clear="none">
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Ben<br class="yiv5783001583" clear="none">
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> On 19 Mar 2021, at 23:06, Didrik Madheden <<a rel="nofollow noopener noreferrer" shape="rect" class="yiv5783001583" ymailto="mailto:nitro2k01@gmail.com" target="_blank" href="mailto:nitro2k01@gmail.com">nitro2k01@gmail.com</a>> wrote:<br class="yiv5783001583" clear="none">
> <br class="yiv5783001583" clear="none">
> On Fri, 19 Mar 2021 at 22:29, Jean-Pierre Desrochers <<a rel="nofollow noopener noreferrer" shape="rect" class="yiv5783001583" ymailto="mailto:jpdesroc@oricom.ca" target="_blank" href="mailto:jpdesroc@oricom.ca">jpdesroc@oricom.ca</a>> wrote:<br class="yiv5783001583" clear="none">
>> An optic based reader would look about like this:<br class="yiv5783001583" clear="none">
>> [Image]<br class="yiv5783001583" clear="none">
>> <br class="yiv5783001583" clear="none">
>> Notice the big horizontal LEDs bar over the row of holes in reading..<br class="yiv5783001583" clear="none">
>> <br class="yiv5783001583" clear="none">
>> Not very nice..<br class="yiv5783001583" clear="none">
> <br class="yiv5783001583" clear="none">
> The cable management could be nicer, but I would personally not mind.<br class="yiv5783001583" clear="none">
> But I can see two problems:<br class="yiv5783001583" clear="none">
> 1) It doesn't look original.<br class="yiv5783001583" clear="none">
> 2) Even if you don't care about that, it obscures the currently played<br class="yiv5783001583" clear="none">
> line, which might be aesthetically important.<br class="yiv5783001583" clear="none">
> <br class="yiv5783001583" clear="none">
>> On the other hand a vacuum based reader would look like the original thing:<br class="yiv5783001583" clear="none">
>> [Image]<br class="yiv5783001583" clear="none">
> <br class="yiv5783001583" clear="none">
> Oh! That's something I didn't understand about the mechanism at first.<br class="yiv5783001583" clear="none">
> I thought the vacuum was transmitted through the paper, so that you<br class="yiv5783001583" clear="none">
> would have one "transmitting" side and one receiving side. Instead, it<br class="yiv5783001583" clear="none">
> has constant pressure and relieves the vacuum pressure when a hole<br class="yiv5783001583" clear="none">
> passes over.<br class="yiv5783001583" clear="none">
> <br class="yiv5783001583" clear="none">
> So that gives me a different idea for a working principle based on<br class="yiv5783001583" clear="none">
> light: reflection. No hole=light reflects back. Only one side of the<br class="yiv5783001583" clear="none">
> paper has electronics. This could be done with either a visible LED<br class="yiv5783001583" clear="none">
> (for an additional visualizer effect) or an IR LED (for<br class="yiv5783001583" clear="none">
> authentic-looking operation). This method might be susceptible to<br class="yiv5783001583" clear="none">
> light interference through the holes though... Probably not a good<br class="yiv5783001583" clear="none">
> idea, just throwing ideas out there.<br class="yiv5783001583" clear="none">
> <br class="yiv5783001583" clear="none">
> /Didrik<br class="yiv5783001583" clear="none">
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