Added opencv to README

Author: raaj-akshar

README.md

@@ -70,4 +70,8 @@ It is being used to perform Natural Language Processing. We have the ability to
 For advanced purposes, we might explore using spaCy.
 
 ### rq
-rq(Redis Queue) is being used to enqueue the OCR extraction tasks on a Redis List. Workers running in the background dequeue from this list and invoke the service functions to perform actual OCR.
+rq(Redis Queue) is being used to enqueue the OCR extraction tasks on a Redis List. Workers running in the background dequeue from this list and invoke the service functions to perform actual OCR.
+
+### opencv-contrib-python
+Provides Computer Vision and Image processing capability. We preprocess the image before performing recognition and detection.
+We apply grayscaling, smoothing and denoising, and thresholding and binarisation.