training and synthetic data generation code

manga_ocr_dev/synthetic_data_generator/README.md

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+# Synthetic data generator
+
+Generation of synthetic image-text pairs imitating Japanese manga for the purpose of training OCR.
+
+Features:
+- using either text from corpus or random text
+- text overlaid on background images
+- drawing text bubbles
+- various fonts and font styles
+- variety of text layouts:
+  - vertical and horizontal text
+  - multi-line text
+  - [furigana](https://en.wikipedia.org/wiki/Furigana) (added randomly)
+  - [tate chū yoko](https://www.w3.org/International/articles/vertical-text/#tcy)
+
+
+Text rendering is done with the usage of [html2image](https://github.com/vgalin/html2image),
+which is a wrapper around Chrome/Chromium browser's headless mode.
+It's not too elegant of a solution, and it is very slow, but it only needs to be run once,
+and when parallelized, processing time is manageable (~17 min per 10000 images on a 16-thread machine).
+
+The upside of this approach is that a quite complex problem of typesetting and text rendering
+(especially when dealing with both horizontal and vertical text) is offloaded to
+the browser engine, keeping the codebase relatively simple and extendable. 
+
+High-level generation pipeline is as follows:
+1. Preprocess text (truncate and/or split into lines, add random furigana).
+2. Render text on a transparent background, using HTML engine.
+3. Select background image from backgrounds dataset.
+4. Overlay the text on the background, optionally drawing a bubble around the text.
+
+# Examples
+
+## Images generated with text from [CC-100 Japanese corpus](https://data.statmt.org/cc-100/)
+![](../../assets/examples/cc-100.jpg)
+
+## Images generated with random text
+![](../../assets/examples/random.jpg)