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Short Time Fourier Transform using the Accelerate framework

Parag K Mital — Thu, 14 Apr 2011 11:06:55 +0000

Using the libraries pkmFFT and pkm::Mat, you can very easily perform a highly optimized short time fourier transform (STFT) with direct access to a floating-point based object.

Get the code on my github:
http://github.com/pkmital/pkmFFT
Depends also on: http://github.com/pkmital/pkmMatrix… Continue reading...

The post Short Time Fourier Transform using the Accelerate framework first appeared on http://archive.pkmital.com.

Real FFT/IFFT with the Accelerate Framework

Parag K Mital — Wed, 13 Apr 2011 23:05:05 +0000

Apple’s Accelerate Framework can really speed up your code without thinking too much. And it will also run on an iPhone. Even still, I did bang my head a few times trying to get a straightforward Real FFT and IFFT working, even after consulting the Accelerate documentation (reference and source code), stackoverflow (here and here), and an existing implementation (thanks to Chris Kiefer and Mick Grierson). Still, the previously mentioned examples weren’t very clear as they did not handle the case of overlapping FFTs which I was doing in the case of a STFT or they did not recover the power spectrum, or they just didn’t work for me (lots of blaring noise).

Get the code on my github:
http://github.com/pkmital/pkmFFT… Continue reading...

The post Real FFT/IFFT with the Accelerate Framework first appeared on http://archive.pkmital.com.

Streaming Motion Capture Data from the Kinect using OSC on Mac OSX

Parag K Mital — Mon, 24 Jan 2011 23:43:59 +0000

This guide will help to get you running PrimeSense NITE’s Skeleton Tracking inside XCode on your OSX. It will also help you stream that data in case you’d like to use it in another environment such as Max. An example Max patch is also available.

PrimeSense NITE Skeletonization and Motion Capture to Max/MSP via OSC from pkmital on Vimeo.

Prerequisites:

0.) 1 Microsoft Kinect or other PrimeSense device.

1.) Install XCode and Java Developer Package located here: https://connect.apple.com/cgi-bin/WebObjects/MemberSite.woa/wa/getSoftware?bundleID=20719 – if you require a Mac OSX Developer account, just register at developer.apple.com since it is free.

2.) Install Macports: http://www.macports.org/

3.) Install libtool and libusb > 1.0.8:

$ sudo port install libusb-devel +universal

4.) Get the OpenNI Binaries for Mac OSX: http://www.openni.org/downloadfiles

5.) Install OpenNI by unzipping the file OpenNI-Bin-MacOSX (-v1.0.0.25 at the time of writing) and running,

$ sudo ./install.sh

6.) Get SensorKinect from avin2: https://github.com/avin2/SensorKinect/tree/unstable/Bin

7.) Install SensorKinect by unzipping and running

$ sudo ./install.sh

8.) Install OpenNI Compliant Middleware NITE from Primesense for Mac OSX: http://www.openni.org/downloadfiles

9.) Install NITE by unzipping and running

$ sudo ./install.sh

When prompted for a key, enter the key listed on the openni website.

Getting it up and running:

1.) Download the … Continue reading...

The post Streaming Motion Capture Data from the Kinect using OSC on Mac OSX first appeared on http://archive.pkmital.com.