Is there any way to thin out the characters after Otsu thresholding?

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Hi

I am trying to segment all the characters (see the image below) and there is one issue I still can't solve. THRESH_OTSU works the best with the only exception that it merges some characters.

When I tried to use adaptive thresholding, there was no problem with character merging but I was unable to control the parameters so that it could work for most images.

I know that some combinations of erosion and dilation might work in such cases. Trouble is, even though the characters get thinner as a result of erosion, the areas between the characters only increase. Probably, I am misusing/misunderstanding erosion.

Thanks in advanced for any suggestions.

Here's the source image.

Unlike the more classical case of car number plates, the font is often black on a light background. This is why I have to count the number of contours or rects returned by minAreaRect to invert the image in such cases.