clean noise from an image

Question

I need to know how to clean noise from an image with Matlab.

lets look at this example:

Answer 1

Let's do it step by step in Mathematica:

(*first separate the image in HSB channels*)
i1 = ColorSeparate[ColorNegate@yourColorImage, "HSB"]

(*Let's keep the B Channel*)
i2 = i1[[3]]

(*And Binarize it *)
i3 = Binarize[i2, 0.92]

(*Perform a Thinning to get the skeleton*)
i4 = Thinning[i3]

(*Now we cut those hairs*)
i5 = Pruning[i4, 10]

(*Remove the small lines*)
i6 = DeleteSmallComponents[i5, 30]

(*And finally dilate*)
i7 = Dilation[i6, 3]

(*Now we can perform an OCR*)
TextRecognize@i7
-->"93 269 23"  

Done!