img2tex

A simple program that converts images of LaTeX equations from https://main.mimuw.edu.pl to the LaTeX source code.

Dependencies

• A C++ compiler with C++17 support
• OpenCV library

Build

To build just run

make img2tex

Usage

generated_symbols.db and manual_symbols.db files are essential for the untexing to work -- they need to be placed in the working directory where the img2tex is run. Assuming you are satisfied this requirement (e.g. you are in the project directory) you can run:

./img2tex untex main/3896.png

to see decoded LaTeX of the file main/3896.png.

On success img2tex prints decoded LaTeX code and exits with 0. Otherwise, it exits with 1 if any error occurs or the image cannot be decoded. It also prints a lot of information about untexing process to stderr that can be simply ignored by redirecting it to /dev/null e.g.

./img2tex untex main/3896.png 2> /dev/null

There are also other commands you can learn about by running img2tex without arguments:

./img2tex

Helper scripts

Helper scripts like test_on are useful when you want to check that every image in a given set of images untexes correctly and if not, then teach img2tex how to untex the unrecognized symbols.

Examples using test_on:

# Selected images
./test_on main 3.png 4.png 1000.png
# All images
for a in $(ls main -1v); do ./test_on main $a; done

You press enter to go to the next symbol, or type "skip" to omit the current symbol if it is not untexable in any way. If it stops on an unrecognizable symbol you either teach img2tex to recognize one of symbols saved in files symbol_* or type "skip" to omit it. To make teaching easier you can use the below command to teach how to recognize symbol (here symbol_2):

read -r a && echo -E "$a" | ./img2tex learn symbol_2

And then type source Tex of symbol saved in file symbol_2.

It is also useful to look at comparison.png during usage of test_on as there are placed: original image and image generated form the result of untexing the original image -- it is easy to visually compare results this way.