OpenCV on N950

[blackcoder]

How can I install OpenCV on N950, it doesn't exist in the default repositories, I did a search on the community repositories without any luck. If it's not already packaged then I guess I can do it myself but I will have to install building tools and compiles such as cmake gcc which doesn't exist in the repositories either. Any ideas how I can do that ?

[gnuton]

Hi,
As far as I know OpenCV has not been packaged yet for Harmattan.
I think you need to package it by yourself.

In case you want to take care of it, I suggest you to start from the Maemo pkg [1] which depends on less packages than the
the Ubuntu/Debian ones.

[1] http://maemo.org/packages/source/vie...pencv/2.0.0-5/

[ohookins]

I'm the maintainer (only as of recently) of OpenCV on Maemo Fremantle and I'm also going to be building OpenCV for Harmattan. I've just started the project - https://projects.developer.nokia.com/opencv and will be starting work in the next couple of days on porting it and getting it built. Please keep an eye on the project for when I have something built.

[blackcoder]

ohookins, you are absolutely f**king awesome, please let me know when you have Opencv packed up. What version is it by the way ? I am currently using 2.3.1

[ohookins]

I am starting with 2.1.0 since that is what is available in Debian Squeeze, but if there is demand for later versions and it is not too hard to build I will try to add them.

[weiwei2]

thanks for the great work. i'm looking forward to it. it will be very good if there is a getting started guide on how to gets the camera running with OpenCV. Newbies in OpenCV like me will be much delighted to that. i've used other image processing libraries prior to this but i really see OpenCV is getting popular and useful

[ohookins]

A getting started guide is a bit out of scope for the package in the context of Meego, but there are plenty of good materials out there to you started. If OpenCV is actually working for the platform then usually a call to opencv.highgui.cvCreateCameraCapture is all that is needed to set up the capture object, then it's just a matter of calling opencv.highgui.cvQueryFrame on the capture object to grab a frame.

I can recommend "Learning OpenCV" by Gary Bradski and Adrian Kaehler (written for C++) and I have some worked examples from the book using Python which you can find here: https://github.com/ohookins/opencv-test

[blackcoder]

ohookins, I would really recommend opencv 2.3.1, opencv 2.1.0 is very buggy and the API was not finalized at that time. I've been using Opencv for more than 5 years and I have good experience in building it. Perhaps I can help you if you need, I have no experience in building packages for meamo/meego but I am willing to learn

[ohookins]

I've been using the version on Ubuntu Natty which is 2.1.0, and this is also what is available in Debian Squeeze (more or less the Harmattan 1.2 environment) hence it is easiest to build.

I'll certainly target 2.3.1 once I have 2.1.0 building and confirmed working, just so as to make incremental steps in the process. If you have experience building 2.3.1 on a standard Debian Squeeze tool chain I would be interested to know what changes you had to make if any.

[blackcoder]

I never build opencv in Debian Squeeze, I build it for Fedora, Kubuntu, Ubuntu and Windows. The building process for 2.1.0 is quite straight forward, it's been a while since I last built the 2.1.0 but I remember there was an annoying bug related to ffmpeg and I had to manually edit the cmake files to compile it properly. What is the process for building a Harmattan package by the way ? Do you have to package all the dependencies, because they might be a lot depending on which options u tick for the build ...

[ohookins]

Yes, that is the main problem. There aren't a lot of "standard" packages for Harmattan right now so I've had to build a lot of them. Where possible I've stripped out requirements (a lot of ffmpeg dependencies should be unnecessary, e.g. different codecs) but some things are just tricky no matter what. E.g. opencv -> python-numpy (at least for python bindings I guess) -> liblapack -> libblas -> gfortran -> gcc...

I'm getting closer though....

[blackcoder]

Yes, the list of dependencies is endless, you might end up having to build a lot of dependencies. I can't wait to test drive the package, just let me know as soon as you have it built

[ohookins]

@blackcoder: have you got any experiencing building the Atlas libraries? I cannot seem to get a stable build on my machine even with performance CPU settings and very high nflop settings.

[blackcoder]

Yes I did a while ago and I remember I had issues with the cpu throttling. Recently I just install the development package from the yum repository (Fedora). I don't think the new versions of opencv depend on it ? I can't remember being asked about atlas in any of my recent builds.

[ohookins]

I managed to get it built finally. For some reason python-numpy was complaining bitterly about not finding ATLAS libraries, and when I read the python-numpy documents it seems like ATLAS is the reference platform for building it.

If there is some magic to building python-numpy without ATLAS I'd love to know about it, but at least with ATLAS built I can proceed with debugging python-numpy.