I’m looking for a program that creates a drawing (set of lines) for CAD from a picture.
I want quick drawing (I draw in a compass and rhino), so I’m looking for a program that creates contours from pictures (I just draw a sketch in a notebook along the X , Y and Z axes).
Have you encountered such programs?
An obvious candidate for me would be using an Edge Detection algorithm in something like GIMP, which has various inbuilt methods.
You can then open this image in something like Inkscape, and attempt to use the Trace Bitmap function to give you some editable SVG lines. How well it would work for you, I’m not sure. There is always an element of fuzzyness with images.
If your sketches are already somewhat skeletonised, you can just scan your image, open directly in Inkscape, and try Trace Bitmap.
go to the package manager and download the plugin Vectorize, that will let you find contours of images and redraws them with nurbs with some threshold settings
training use “Edge Detection” from GIMP. not this comand 
training use “Trace Bitmap” from Inkscape. not this comand
I don’t really know how to use these programs, but maybe the commands are called something else ? 
You’ll probably be better off with Vectorize as suggested above. I am not very knowledgeable on functional plug-ins.