Can I get bold text from image using Tesseract for Java

Question

I would like to take only bold text from image using Tesseract and Java.

Example:

Thanksgiving day

I need "Thanksgiving" as text from image.

Answer 1

Tesseract does not provide this information. But there might be some things, you can look into:

A) In Tesseract 3 there is a metadata result which contains a recognized font. Probably it is not super reliable, but it might work for basic fonts and detect bold and non-bold fonts.

• Get font of recognized character with Tesseract-OCR
• https://github.com/tesseract-ocr/tesseract/issues/1074

B) In Tesseract 4 you can export HOCR output and configure it in a way to get boxes around each character (not sure about Tesseract 3). I am not sure how reliable these boxes are either, but if it is okay, you could use them to have a second algorithm (e.g. small Convolutional Neural Network) which just classifies whether a single character is bold or not and remove non-bold text from the tesseract output.

• How to get character wise confidence in tesseract using command line?
• https://www.baeldung.com/java-ocr-tesseract#tess4j (tess4j has HOCR support)

C) In case you have precise line boxes before using tesseract, you could also look into training an algorithm (Fully Convolutional Neural Network) which segments the part of the line which is bold, then crop the image and use tesseract only for the bold parts. This would probably the most technical solution, but I think it could work as well.