texify 0.1.2

OCR for latex images

Texify

Texify converts equations and surrounding text into markdown with LaTeX math that can be rendered by MathJax ($$ and $ are delimiters). It will work with images or pdfs, and can run on CPU, GPU, or MPS.

Detected Text The potential $V_{i}$ of cell $\mathcal{C}{j}$ centred at position $\mathbf{r}{i}$ is related to the surface charge densities $\sigma_{j}$ of cells $\mathcal{E}_{j}$ $j\in[1,N]$ through the superposition principle as:

$$V_{i},=,\sum_{j=0}^{N},\frac{\sigma_{j}}{4\pi\varepsilon_{0}},\int_{\mathcal{E}{j}}\frac{1}{\left|\mathbf{r}{i}-\mathbf{r}^{\prime}\right|},\mathrm{d}^{2}\mathbf{r}^{\prime},=,\sum_{j=0}^{N},Q_{ij},\sigma_{j},$$

where the integral over the surface of cell $\mathcal{C}{j}$ only depends on $ \mathcal{C}{j} $ shape and on the relative position of the target point $\mathbf{r}{i}$ with respect to $\mathcal{C}{j}$ location, as $\sigma_{j}$ is assumed constant over the whole surface of cell $\mathcal{C}_{j}$.

The closest open source comparisons to texify are pix2tex and nougat, although they're designed for different purposes:

• Compared to pix2tex, texify can detect text and inline equations. Pix2tex is designed for block LaTeX equations, and hallucinates more on text.
• Compared to nougat, texify is optimized for equations and small page regions. Nougat is designed to OCR entire pages, and hallucinates more on small images.

See more details in the benchmarks section.

Community

Discord is where we discuss future development.

Demo

https://github.com/VikParuchuri/texify/assets/913340/882022a6-020d-4796-af02-67cb77bc084c

Examples

Image	OCR Markdown
1	1
2	2
3	3
4	4

Installation

This has been tested on Mac and Linux (Ubuntu and Debian). You'll need python 3.10+ and poetry.

pip install texify

Model weights will automatically download the first time you run it.

Note You will need to have PyTorch properly setup for this to work. You may need to install the CPU version of torch first if you're not using a Mac or a GPU machine. See here for more details.

Usage

• Inspect the settings in texify/settings.py. You can override any settings with environment variables.
• Your torch device will be automatically detected, but you can override this. For example, TORCH_DEVICE=cuda or TORCH_DEVICE=mps.

App for interactive conversion

I've included a streamlit app that lets you interactively select and convert equations from images or PDF files. Run it with:

texify_gui

The app will allow you to select the specific equations you want to convert on each page, then render the results with KaTeX and enable easy copying.

Convert images

You can OCR a single image or a folder of images with:

texify /path/to/folder_or_file --max 8 --json_path results.json

• --max is how many images in the folder to convert at most. Omit this to convert all images in the folder.
• --json_path is an optional path to a json file where the results will be saved. If you omit this, the results will be saved to data/results.json.

Manual install

If you want to develop texify, you can install it manually:

• git clone https://github.com/VikParuchuri/texify.git
• cd texify
• poetry install # This skips the dev dependencies

Limitations

OCR is complicated, and texify is not perfect. Here are some known limitations:

• Texify will OCR equations and surrounding text, but is not good for general purpose OCR. Think sections of a page instead of a whole page.
• Texify was mostly trained with 96 DPI images, and only at a max 420x420 resolution. Very wide or very tall images may not work well.
• It works best with English, although it should support other languages with similar character sets.
• The output format will be markdown with embedded LaTeX for equations (close to Github flavored markdown). It will not be pure LaTeX.

Benchmarks

Benchmarking OCR quality is hard - you ideally need a parallel corpus that models haven't been trained on. I've sampled some images from across a range of sources (web, arxiv, im2latex) to create a representative benchmark set.

Of these, here is what is known about the training data:

• Nougat was trained on arxiv.
• Pix2tex was trained on im2latex and web images.
• Texify was trained on im2latex and web images.

Running your own benchmarks

You can benchmark the performance of texify on your machine.

• Follow the manual install instructions above.
• If you want to use pix2tex, run pip install pix2tex
• If you want to use nougat, run pip install nougat-ocr
• Download the benchmark data here and put it in the data folder.
• Run benchmark.py like this:

python benchmark.py --max 100 --pix2tex --nougat --data_path data/bench_data.json --result_path data/bench_results.json

This will benchmark marker against Latex-OCR. It will do batch inference with texify, but not with Latex-OCR, since I couldn't find an option for batching.

• --max is how many benchmark images to convert at most.
• --data_path is the path to the benchmark data. If you omit this, it will use the default path.
• --result_path is the path to the benchmark results. If you omit this, it will use the default path.
• --pix2tex specifies whether to run pix2tex (Latex-OCR) or not.
• --nougat specifies whether to run nougat or not.

Training

Texify was trained on latex images and paired equations from across the web. It includes the im2latex dataset. Training happened on 4x A6000 GPUs for 3 days.

Commercial usage

This model is trained on top of the openly licensed Donut model, and thus can be used for commercial purposes.

Thanks

This work would not have been possible without lots of amazing open source work. I particularly want to acknowledge Lukas Blecher, whose work on Nougat and Latex-OCR was key for this project. I learned a lot from his code, and used parts of it for texify.

• im2latex - one of the datasets used for training
• Donut from Naver, the base model for texify
• Nougat - I used the tokenized from Nougat
• Latex-OCR - The original open source Latex OCR project