Smart peak detection

Hello,
I have signal of valve acceleration. My present task is to detect all important peaks for other calculation. At firs I tried to use derivative and look for points where it crosses zero (local extreme - relative extreme), but this is not useful because it detects all even the smallest one. I think about any kind of filtration but I don’t know any.
Does anybody know how to at least smooth the line to eliminate no important peaks? Or any other advices?
I marked all important peaks in signal (peaks2.png) and attached VI with the signal.
Thanks, I appreciate all comments.
LV 2011, Win7
Attachments:
peaks.vi ‏31 KB
peaks.PNG ‏68 KB

I know that this is very subjective. I want to chose these peaks that are big and "keen" (acute). In the light of these facts I changed the picture with the important peaks. In addition I care only about the peaks that are between 200 and 300 (x axis) and theit direction is up (peaks4.png).
My main problem is how to eliminate small deviation like in the picture peaks4 - with red colour is highlight area, that is considered to be one peak. But when using derivative it will find many small extrems.
Thanks for all ideas.Message Edited by ceties on 02-21-2006 03:01 AM
LV 2011, Win7
Attachments:
peaks5.PNG ‏60 KB
peaks4.png ‏65 KB

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