New paper: Test–retest reliability of computer-based video analysis of general movements in healthy term-born infants

Screenshot from 2015-08-03 22:10:06I have for several years been collaborating with researchers at NTNU in Trondheim on developing video analysis tools for studying the movement patterns of infants. This has resulted in several papers, international testing (and a TV documentary). Now there is a new paper out, with some very successful data testing the reliability of the video analysis method:

Reference:

Valle, Susanne Collier, Ragnhild Støen, Rannei Sæther, Alexander Refsum Jensenius, and Lars Adde.
Test–retest Reliability of Computer-Based Video Analysis of General Movements in Healthy Term-Born Infants.
Early Human Development 91, no. 10 (October 2015): 555–58. doi:10.1016/j.earlhumdev.2015.07.001.

Highlights:

  • Test–retest reliability of computer-based video analysis of general movements.
  • Results showed high reliability in healthy term-born infants.
  • There was significant association between computer-based video analysis and temporal organization of fidgety movements.

Add date to files in Ubuntu

Even though I have been running Ubuntu as my main OS for more than a year now, I am still trying to figure out a good workflow. One thing I have been missing from my former OSX setup was the ability to quickly and easily prepend the date to a number of files. Having moved my files between many different OSes, hard drives, network drives, etc. over many years, I know that the files’ creation dates will break at some point. For that reason, I prefer to prepend the date to filenames of photos, random text files, etc. That way I am able to quickly search through the files easily.

On OSX I have made a small Automator script called add-date that does exactly this: prepends a file’s creation date to the filename. It has worked like a charm for many years, and still works, so feel free to try it out if you are on OSX.

In Ubuntu there are, of course, numerous terminal based methods to do something like this. But I haven’t really been that eager to mess around with mv, rename and regexp just to rename a bunch of files once in a while. In the quietness of the Norwegian summer I finally got around to look a little more into how to do this in Ubuntu, and it turned out to be very easy. Nautilus, the file manager on Ubuntu, actually sports the ability to run scripts from the GUI. The scripts, of any programming flavor (python, perl, etc.) just need to be put in the folder:

 ~/.local/share/nautilus/scripts

There are many examples of adding today’s date to the files, such as this python example, but it took a little while to figure out how to do it using the modification date of the file. I finally got this to work as a little bash script:

#!/bin/sh
mv -- "$@" "$(date -d@$(stat -c %Y "${@}") +%Y_%m_%d)-$@"

Save this as a file in the scripts folder, make it executable (chmod a+x), and restart nautilus. Then I can easily add the date to all files I want directly from the GUI.

Screenshot from 2015-08-03 21:53:02

New paper: MuMYO – Evaluating and Exploring the MYO Armband for Musical Interaction

usertest3Yesterday, I presented my microinteraction paper here at the NIME conference (New Interfaces for Musical Expression), organised at Louisiana State University, Baton Rouge, LA. Today I am presenting a poster based on a paper written together with two of my colleagues at UiO.

Title
MuMYO – Evaluating and Exploring the MYO Armband for Musical Interaction

Authors
Kristian Nymoen, Mari Romarheim Haugen, Alexander Refsum Jensenius

Abstract
The MYO armband from Thalmic Labs is a complete and wireless motion and muscle sensing platform. This paper evaluates the armband’s sensors and its potential for NIME applications. This is followed by a presentation of the prototype instrument MuMYO. We conclude that, despite some shortcomings, the armband has potential of becoming a new “standard” controller in the NIME community.

Files

BibTeX

@inproceedings{nymoen_mumyo_2015,
    address = {Baton Rouge, LA},
    title = {{MuMYO} - {Evaluating} and {Exploring} the {MYO} {Armband} for {Musical} {Interaction}},
    abstract = {The MYO armband from Thalmic Labs is a complete and wireless motion and muscle sensing platform. This paper evaluates the armband's sensors and its potential for NIME applications. This is followed by a presentation of the prototype instrument MuMYO. We conclude that, despite some shortcomings, the armband has potential of becoming a new ``standard'' controller in the NIME community.},
    booktitle = {Proceedings of the International Conference on New Interfaces For Musical Expression},
    author = {Nymoen, Kristian and Haugen, Mari Romarheim and Jensenius, Alexander Refsum},
    year = {2015}
}

New publication: Microinteraction in Music/Dance Performance

2012-10-26-dsc_0014b-640This week I am participating at the NIME conference (New Interfaces for Musical Expression), organised at Louisiana State University, Baton Rouge, LA. I am doing some administrative work as chair of the NIME steering committee, and I was  happy to present a paper yesterday:

Title
Microinteraction in Music/Dance Performance

Abstract
This paper presents the scientific-artistic project Sverm, which has focused on the use of micromotion and microsound in artistic practice. Starting from standing still in silence, the artists involved have developed conceptual and experiential knowledge of microactions, microsounds and the possibilities of microinteracting with light and sound.

Links
Paper (PDF)
Project page

BibTeX

@inproceedings{jensenius_microinteraction_2015,
address = {Baton Rouge, LA},
title = {Microinteraction in {Music}/{Dance} {Performance}},
url = {https://nime2015.lsu.edu/proceedings/178/index.html},
abstract = {Abstract: This paper presents the scientific-artistic project Sverm, which has focused on the use of micromotion and microsound in artistic practice. Starting from standing still in silence, the artists involved have developed conceptual and experiential knowledge of microactions, microsounds and the possibilities of microinteracting with light and sound.},
booktitle = {Proceedings of the International Conference on New Interfaces For Musical Expression},
author = {Jensenius, Alexander Refsum},
year = {2015}
}

Simple video editing in Ubuntu

I have been using Ubuntu as my main OS for the past year, but have often relied on my old MacBook for doing various things that I haven’t easily figured out how to do in Linux. One of those things is to trim video files non-destructively. This is quite simple to do in QuickTime, although Apple now forces you to save the file with a QuickTime container (.mov) even though there is still only MPEG-4 compression in the file (h.264).

There are numerous linux video editors available, but most of these offer way too many features and hence the need to re-compress the files. But I have found two solutions that work well.

The first one, ffmpeg, should be obvious, although I hadn’t thought that it could also do trimming. However, I often like GUI software, and I have found that Avidemux can do what I need very easily. Just open a file, add start and stop markers for the section to be trimmed, and click save. As opposed to QuickTime, it also allows for saving directly to MPEG-4 files (.mp4) without recoding the file.

There was only one thing that I had to look up, and that was the need for starting the trim section on a keyframe in the video. This is quite obvious when wanting to avoid re-encoding the file, but unfortunately Avidemux doesn’t help in explaining this but only gives an error message. The trick was to use the >> arrows to jump to the next keyframe, and then the file saved nicely.