title: Opencv-python detect yellow highlighted text contour from page image
body: <p>I'm trying to detect (and then do ocr) on ONLY the physically yellow-highlighted text from the image of a page. I want to essentially digitize my highlights in a physical book to store them. I'm using opencv python and have tried some basic contour detection and thresholds with no luck...</p>
  
  <p>I think once I can get the contour of the highlighter, I can crop that portion of the image and then do OCR? But not sure how to extract the contour</p>