What is p-tracker?

p-tracker is a framework for Digital Image Correlations (DIC) written in C++. The project was initiated by vincent.richefeu@univ-grenoble-alpes.fr and gael.combe@grenoble-inp.fr under the name of tracker (without the p- before). The special feature of the code is that it can follow the 2D positions of the particles on the photographs without losing the thread with any of them. This is not possible with a conventional correlation tool, no matter well-performing it may be. This focus on the discrete nature of tracking explains why the method is referred to as Particle Image Tracking (PIT) rather than DIC. However, the tool is still capable of performing DIC.

In its history, p-tracker is closely linked to a laboratory device called 1γ2ε, which consists of Schneebeli rolls assembled in a frame allowing solicitations in stress and/or strain as complex as desired.

Source tree

• sphinxdoc: user documentation (sphinx with ReStructuredText)
• examples: examples for usage tutorials or for testing features
• src: C++ source files

Credits

Features

How to install

The source code can be cloned from github repository:

git clone https://github.com/richefeu/p-tracker.git

For reading digital images, two libraries are required: libtiff and libraw. On an apple OS, you can install them via homebrew:

brew update
brew install libtiff
brew install libraw

On an unix OS, use the package managelent tool to install them. For example, on ubuntu, you can make:

sudo apt-get update -y
sudo apt-get install -y libtiff4-dev
sudo apt-get install -y libraw-dev

Then, the compilation should be as simple as typing make from the src folder:

cd src
make

How to perform a particle image tracking

File format

Column	Description
1	Reference x-position, in pixel (integer number)
2	Reference y-position, in pixel (integer number)
3	Reference rotation with respect to horizontal, in radian (decimal number, generally 0)
4	Radius in pixel (decimal number, not-usefull for non circular particles)
5	Cumulated displacement, with respect to the reference x-position, in pixel (decimal number)
6	Cumulated displacement, with respect to the reference y-position, in pixel (decimal number)
7	Cumulated rotation, with respect to the reference rotation (generally horizontal), in radian (decimal number)
8	Last displacement increment, with respect to the previous cumulated x-position, in pixel (decimal number)
9	Last displacement increment, with respect to the previous cumulated y-position, in pixel (decimal number)
10	Last rotation increment, with respect to the previous cumulated rotation (generally horizontal), in radian (decimal number)
11	NCC
12	NCC_rescue
13	NCC_subpix