# Reduce the acquisition frequency of a recorded sequence

**URL:** <https://discourse.slicer.org/t/reduce-the-acquisition-frequency-of-a-recorded-sequence/17437>\
**Category:** Support\
**Tags:** sequences, ultrasound\
**Created:** [May 4, 2021, 8:23am UTC](https://discourse.slicer.org/t/reduce-the-acquisition-frequency-of-a-recorded-sequence/17437 "2021-05-04T08:23:20Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![AurelieS](https://avatars.discourse-cdn.com/v4/letter/a/87869e/32.png) [@AurelieS](https://discourse.slicer.org/u/AurelieS)\
**Post date:** [May 4, 2021, 8:23am UTC](https://discourse.slicer.org/t/reduce-the-acquisition-frequency-of-a-recorded-sequence/17437/1 "2021-05-04T08:23:21Z")

</div>

Operating system: win10  
Slicer version: 4.11.20200930

Dear 3D Slicer team,

We did a number of freehand 3D ultrasound using 3D Slicer (and PlusServer with ultrasound video acquisition and streaming of Optitrack data).  
All is working fine but we believe we may have used too high of an acquisition frequency while recording with the module ‘sequences’, leading to very heavy acquisitions (more than 20Go for a muscle acquisition), and not so well defined volume reconstructions (maybe due to the excessive amount of video data, especially since the video feed had a maximal frequency of 32Hz so we have image duplicates for different probe tracking data … ). The time of reconstruction is also very high for our computer with 64Go RAM and 150Go virtual RAM …  
All sequences recorded both the image from the ultrasound and the tracker position of the probe (2 nodes) at 50Hz.  
Is it possible, one way or another, to lower the sampling frequency of our sequence, meaning for example to take one sample every of 5 samples of our recorded sequence ?

Thank you in advance,  
Cheers,  
Aurélie

---

<div class="post-metadata">

**Author:** ![AurelieS](https://avatars.discourse-cdn.com/v4/letter/a/87869e/32.png) [@AurelieS](https://discourse.slicer.org/u/AurelieS)\
**Post date:** [May 7, 2021, 11:16am UTC](https://discourse.slicer.org/t/reduce-the-acquisition-frequency-of-a-recorded-sequence/17437/2 "2021-05-07T11:16:34Z")

</div>

Please find here some raw data, for example S1\_BF\_1.1 that we do not find of very good reconstruction quality :

> **[Share Anything with pCloud](https://e.pcloud.link/publink/show?code=kZwTIXZmdvDd9EGDB0iGkqHMvEjAkuVWttV)**
>
> With pCloud's unique Download Link feature you can share files with everyone. Click to download. 
> Join pCloud.com and get up to 20GB FREE cloud storage.

Password : 3Dslicer

Cheers,  
Aurélie