I'm trying to convert raster to vector from a scanned pdf file. Have converted the pdf to a bitonal (black & white) tiff image using Adobe Acrobat and IrfanView. The tiff image inserts into Map3D 2011 without a problem, but when I try to run the Raster Design contour follower, CAD says "no bitonal image recognized". My image is 300 dpi (within the 200-400 recommended) and is definitely B&W, not grayscale.
Then if I use the AutoCAD tools to convert the image to bitonal, CAD changes the background to BLACK and the contours to WHITE. Then the contour follower will not work. Sometimes it starts, takes forever, and makes a few strange lines that don't track with the contours at all.
The tutorial for contour follower works perfectly on my PC. But it isn't working with my tiff. Any suggestions would be appreciated.