I have a scanned text document. After some pre-processing, I managed to get texts on a white background. However, some texts are in gray colour (faint/light gray) and some text in black. At least, the black text is darker than the gray text.
I tried using thresholding but the gray like didn't change much.
What is a good approach to make the gray text darker (or black) and not affecting the already black text and white surrounding.
I also attached a sample image. Basically I would like to make the string "This is a demonstration" in light gray darker or black will be ideal.
