如何将背景颜色的一部分（黑色）更改为白色？

Question

I have been working on PyTesseract OCR and converting PDF to JPEG inorder to OCR the image. A part of the image has a black background and white text, which Tesseract is unable to identify, whereas all other parts of my image are being read perfectly well. Is there a way to change a part of the image that has black background? I tried a few SO resources, but doesn't seem to help. I am using Python 3, Open CV version 4 and PyTesseract

Answer 1

opencv has a bitwise not function wich correctly reverses the image

you can put a mask / freeze on the rest of the image (the part that is correct already) and use something like this:

imageWithMask = cv2.bitwise_not(imageWithMask)

alternatively you can also perform the operation on a copy of the image and only copy over parts / pixels / regions you need....