endocal 16.7rc1

A compact GUI application for optical distortion calibration of endoscopes

endocal is a compact GUI application for optical distortion calibration of endoscopes.

endocal was developed as part of the [GIFT-Surg project](http://www.gift-surg.ac.uk/). It uses the [OpenCV camera calibration module](http://docs.opencv.org/2.4/doc/tutorials/calib3d/camera_calibration/camera_calibration.html) under the hood, and was developed by Dzhoshkun I. Shakir at the [Translational Imaging Group](http://cmictig.cs.ucl.ac.uk/) in the [Centre for Medical Image Computing](http://www.ucl.ac.uk/cmic/homepage) at [University College London (UCL)](http://www.ucl.ac.uk/).

# System requirements
* [OpenCV 2.4](http://docs.opencv.org/2.4/doc/tutorials/introduction/table_of_content_introduction/table_of_content_introduction.html)
* [pip](https://pip.pypa.io/en/stable/installing/)
* For online calibration, frame-grabber hardware supported by [OpenCV](http://docs.opencv.org/2.4/modules/highgui/doc/reading_and_writing_images_and_video.html#videocapture)

# Installation
1. Install endocal by running `pip install endocal`.
1. Test your installation by running `endocal-test`:
* See [this screenshot](endocal/res/screenshot-start.png) for what to expect on launching the application.
* To perform an optical distortion calibration, follow the instructions shown in red on top of the window. While acquiring calibration data, detected calibration pattern blobs will be emphasized with a virtual overlay as in [this screenshot](endocal/res/screenshot-detection.png).
* All data for each calibration will be saved in the sub-folder of a folder called `tmp-sample_001`, created within the current folder. These include:
* Calibration parameters saved as `calibration.yml`
* Frames used for calibration saved as indexed image files, e.g. `frame_009.jpg`
* After performing a calibration, the application will automatically show the undistorted images to the right as shown in [this screenshot](endocal/res/screenshot-undistort.png).

# How to use
`endocal --help` will show details of what input parameters are expected. Examples include:

* Using all frames stored as indexed files e.g. `frame_009.jpg`:
```
endocal --pattern-specs 3 11 3 1 --output-folder ./calibration-results --input /home/dzhoshkun/offline-calibration-data/frame_%3d.jpg
```

* Using online video stream from a frame-grabber (attached to an endoscope) that is mounted as `/dev/video0` on Linux:
```
endocal --input 0 --pattern-specs 3 11 3 1 --output-folder ./calibration-results
```

* Using a `700 x 700` sub-frame of the whole endoscopic video frame (`1920 x 1080`):
```
endocal --input 0 --pattern-specs 3 11 3 1 --output-folder ./calibration-results --roi 620 200 700 700
```

# Supported platforms
endocal was tested only on Linux (Ubuntu 14.04 LTS) so far. However it is highly likely that it will work on other platforms as well, due to the small number of dependencies.

# License
Copyright (c) 2016, [University College London](http://www.ucl.ac.uk/). endocal is available as free open-source software under a BSD 3-Clause Licence.