opencv cutting out letters from image with much noise (java)

Question

i have the following picture of which i want to crop out all letters in to new images.

http://imgur.com/N2JqmFi

The result of each letter should look like this for example:

http://imgur.com/LvjdZh1

I have had troubles achieving this, i have used thresholding, findContours, and many other things. I just cannot seem to cut out the letters since the image contains very much noise.

Can someone please provide some help and information?

Answer 1

if it did not find any contours in your img, rect_min will contain invalid negative numbers, and submat will crash.

you'll have to add some logic, that cares for that.