Rodrigo, that's really cool! Thanks for sharing
I added color, first with ColorNegate@image and then using ImageSubtract:
char=CharacterRange[" ","~"]~Join~Map[Style[#,Bold]&,CharacterRange[" ","~"]];
w=N@Mean@Flatten@ImageData@Binarize@Rasterize@#->#&/@char;
w[[All,1]]=#~Rescale~{Min[#],Max[#]}&@w[[All,1]];
findChar=Nearest[w];
asciiIt[image_]:=Module[{img},
img=ImageAdjust@ColorConvert[ColorNegate@image,"Grayscale"];
img=ImageData@ImageResize[img,50];
img=Map[First@findChar[#,1]&,img,{-1}];
Grid[img,Spacings->{0.2,-0.2},ItemSize->{0.4,0.4}]
]
width=ImageDimensions[Rasterize[asciiIt@CurrentImage[]]][[1]];
Dynamic[ImageSubtract[ImageResize[CurrentImage[], width], Rasterize[asciiIt@CurrentImage[]]]]
Spacings->{0.2,-0.2} gives you the right AspectRatio.
