Matlab/Octave code/technique for making thin lines from thicker lines

[baby14]

I want to convert thick bold lines, curves e.g., letters and digits to their thinner possible form. These digits, curves are saved as images in thick black lines with white background.
The image is attached.

Thanks

[OReubens]

You're not really saying what kind of result you want, and/or how near to the ideal you want things to be.

Do you want an outer outline ? an inner outline ? An average ? A weighted curve ? Something else ?
are there guarantees/input about the size and slant of the used pen tip ? Do you know what they are ? Is it the Original "gesture path" you want to try to recreate ?
or do you just care about "recognizing" the input and converting it to tekst (OCR ?). I'm sort of assuming this because the thin and thick B in the provided image are not "the same", they're both B's, but they're written differently.