I tried a few solutions to extract text out of a clear image containing alan0@hotmail.com:

Install with:

sudo apt-get install gocr tesseract ocrad  

Gocr

gocr -i email.png   
aIan0hdmaiI.com  

Tesseract

convert email.png email.tif # requires tif  
tesseract email.tif out  
cat out.txt  
Ina rrykeeg a  

Ocrad

convert email.png email.ppm # requires p[bgp]m  
ocrad email.ppm   
alano_no_mall.  

Upscaling the image slightly improved the results but still none were correct.
Disappointing ...