New versions of PyPTV and OpenPTV

[Alex Liberzon]

I'm glad to announce a couple of updates of PyPTV and OpenPTV:

- openptv segmentation.c now has an artificial single target added if no targets in the image is found. this workaround protects against segfaults when we play with the object detection parameters

- PyPTV has a new detection_gui.py that allows to load an image and create detection parameters dynamically, i.e. sliding threshold, min-max pixel size, etc.

- PyPTV works also with black-on-white objects, there is a checkbox "inverse" that automatically inverts the image. it works for the manual processing as well as for the sequence

OpenPTV can be installed using:

1. git clone https://github.com/openptv/openptv

2. cd openptv/py_bind

3. python setup.py prepare && python setup.py install

Then PyPTV can be installed by pip directly from git

pip install git+https://github.com/alexlib/pyptv --update

PyPTV does not require the update, but it's safer to play dynamically with the detection with this new workaround trick.

Good luck with 3D-PTV

Alex