OpenCV - Removal of noise in image

Question

I have an image here with a table.. In the column on the right the background is filled with noise

How to detect the areas with noise? I only want to apply some kind of

Answer 1

As I know the median filter is the best solution to reduce noise. I would recommend to use median filter with 3x3 window. See function cv::medianBlur().

But be careful when use any noise filtration simultaneously with OCR. Its can lead to decreasing of recognition accuracy.

Also I would recommend to try using pair of functions (cv::erode() and cv::dilate()). But I'm not shure that it will best solution then cv::medianBlur() with window 3x3.