my two cents
I feel your pain on scanning from raster to vector. I've had decent success with two methods:
Automatic CorelDraw Method
1) Scan image
2) edit in a photo editing software, remove anything you're not going to trace, reduce color depth, B&W if possible, keep resolution high.
3) import edited photo into CorelDraw
4) Use one of the tracing methods (Quick Trace, Outline Trace, or Centerline Trace)
5) adjust sensitivity and color picking settings.
6) save your vector image.
Von Glitschka Method (
http://www.amazon.com/Vector-Basic-Training-Systematic-Precision/dp/0321749596)
1) print your image to paper
2) use tracing paper to trace the geometry you want
3) ink in the hand traced geometry
4) scan tracing to raster file
5) import raster image to a unique layer in your vector software (AI, Corel, whatever)
6) adjust opacity to make image just barely visible and lock layer.
7) create new layer for vector work.
8) use standard vector tools (bezier, lines, arcs, etc) to create clean vector work on top of locked raster layer.
Personally I much prefer the manual method. At first glance you might think the manual method will take much longer, but it's actually faster when done right. The book in the link above has really helped me, especially with bezier point placement. I get much cleaner graphics with far fewer spline points using the manual method. Cheers.
