Threshold of blurry image - part 2

Question

How can I threshold this blurry image to make the digits as clear as possible?

In a previous post, I tried adaptively thresholding a blurry image (left)

Answer 1

I've tried thresholding each 3x3 box separately, using Otsu's algorithm (CV_OTSU - thanks remi!) to determine an optimal threshold value for each box. This works a bit better than thresholding the entire image, and is probably a bit more robust.

Better solutions are welcome, though.