Hi there,
since you ask.. Win Topo is a "one touch vectorization" tool... theres a FREE fully functional version.
once you have it set to suit a certain type of image you can fire those kind of images at it all day and it will spit out .DXF
you have to know a little bit about raster thinning and polyline reduction to set the options up correctly... and generate the best .DXF.... i.e a low entity count with mostly closed polylines... those criticising .DXF conversions of bitmaps forget 1 thing... the content has a lot to do with it. the image may contain lines that do not close and conversion can only represent the data in the image...
I've added and image I converted with wintopo.. the FREE version...and the resultant .DXF for comparison. The .DXF is as WinTopo spat it out... I haven't tweaked it or anything... for an honest assessment.
hope it helps
Danny