DrawInput

DrawInput - Handwrinting input method for Android.

This app was born after my Master's thesis, where I researched handwriting
recognition algorithms. Having a decent background knowledge, I tried to
implement a handwriting input mode for Android.


Features:
* Simple and easy to use
* Supports all English letters, numbers and many special characters
- numbers, [0-9]
- small letters, [a-z]
- big letters, [A-Z]
- special characters, .,:;!?()[]{}<>/'"^-_+*=@$#%
* Source code available at: https://github.com/joonazzz/drawinput.git


About security:
* User should always be cautious when installing 3rd party text input methods,
. as they could be used for example recording all text inputs. This is why
. Android will warn you when you enable any 3rd party text input method
* To make user more comfortable, I want to highlight that this app does not
. require Internet permission, and cannot upload any data back to developers.

About technologies:
* Simple character preprocessing
- duplicate point removal
- resampling to 12 points / char
- normalization of coordinates to [0,1]
* Simple features
- 4 features
- normalized x
- normalized y
- sin(dx/dy)
- cos(dx/dy)
* Two recognition strategies: by custom logic and rbf svm
- Custom logic
- some characters are easy to recognize by logic
- Numbers: 1
- Small letters: i, l, t, x
- Big letters: E, F, H, I, T, X
- Special chars: .,:;!/-_+='"#
- looks for stroke count, vertical, horizontal and diagonal lines, line
. crossings (X, T-junctions), line alignments, line width, line curvature,
. special points, etc...
- RBF SVM
- trained with UNIPEN- database
- 15 training samples / char