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