CMake tips

CMake is a cool tool to perform cross-platform system for build automation. But sometime you want a better control through the command line. For example you are on a linux 64 bit machine and by default you will compile 64 bits binaries. So if you want to compile 32 bits binaries on a 64 bits machine you have to use some parameters to configure CFLAGS, CXXFLAGS:

How to control compiler flags :

If you want to specify your own compiler flags, you can
Set environent variable CFLAGS, CXXFLAG

or
cmake . -DCMAKE_C_FLAGS= -DCMAKE_CXX_FLAGS=

When providing own compiler flags, you might want to specify CMAKE_BUILD_TYPE as well.

 For example if you want to do release build for 32 bit on 64 bit Linux machine ,you do cmake -DCMAKE_C_FLAGS=-m32 --DCMAKE_CXX_FLAGS=-m32

Additionally you could use the -DCMAKE_BUILD_TYPE keyword.

Tips found here. 

Geometric Computer Vision courses

Here a course on geometric computer vision from Dr Marc Pollefeys

Course Objectives

After attending this course students should:
Understand the concepts that allow recovering 3D shape from images.
Have a good overview of the state of the art in geometric computer vision.
Be able to critically analyze and asses current research in the area
Implement components of a 3D photography system.



Course Topics
The course will cover the following topics a.o. camera model and calibration, single-view metrology, triangulation, epipolar and multi-view geometry, two-view and multi-view stereo, structured-light, feature tracking and matching, structure-from-motion, shape-from-silhouettes and 3D modeling and applications.



Target Audience
The target audience of this course are Master or PhD students, or advanced Bachelor students, that are interested in learning about geometric computer vision and related topics.

Panorama Tracking and Mapping on Mobile Phones

For the tech side :
http://studierstube.icg.tu-graz.ac.at/handheld_ar/naturalfeature.php

Related paper :
Real-time Panoramic Mapping and Tracking on Mobile Phones


Online Creation of Panoramic Augmented Reality Annotations on Mobile Phones

Authors: Tobias Langlotz, Daniel Wagner, Alessandro Mulloni, Dieter Schmalstieg

Details:Accepted for IEEE Pervasive Computing

We present a novel approach for creating and exploring annotations in place using mobile phones. The system can be used in large-scale indoor and outdoor scenarios and offers an accurate mapping of the annotations to physical objects. The system uses a drift-free orientation tracking based on panoramic images, which can be initialized using data from a GPS sensor. Given the current position and view direction, we show how annotations can be accurately mapped to the correct objects, even in the case of varying user positions. Possible applications range from Augmented Reality browsers to pedestrian navigation.

Unreal Engine 3 on Ipad, Itouch, I

Epic Citadel is an application that showcases the technical capabilities of the Unreal Engine 3 on iOS devices like iPad and iPhone.

http://epicgames.com/technology/epic-citadel

It looks good !

Kmeans a tutorial

Here you will find a short tutorial of the process of the KMean algorithm.

K-Means is a clustering algorithm. That means you can “group” points based on their neighbourhood. When a lot of points a near by, you mark them as one cluster. With K-means, you can find good center points for these clusters.

SIFT an illustrated tutorial

On the web we found a bunch of things... and sometimes interesting things.

http://www.aishack.in/2010/05/sift-scale-invariant-feature-transform/

Here a point per point study of the SIFT process. (I'm not agree with all the illustration, but the idea is here and could help people to understand the meaning of each process).

1. Constructing a scale space
2. LoG Approximation
3. Finding keypoints
4. Get rid of bad key points
5. Assigning an orientation to the keypoints
6. Generate SIFT features

Popcode AR for mobile phone

"Popcode is what is known in the trade as a Markerless Augmented Reality platform. That means you can add additional content onto any image (providing it has enough texture). You do not need to print large black-and-white markers to be able to add Augmented Reality (AR) content to the world using Popcode." The product was realized by Extra Reality Ltd.



For the tech side :
The founder are Simon Taylor, Dr. Tom Drummond (The thesis supervisor of Simon) and Connell Gauld (Mobile platform coder expert).

=> They used Fast corder detector, HIPS matching.
I let you see the SDK !

And the demos :