Hmmm. super unusual actually; your results are sort of the opposite of most (many people report excessive smoothing in the final results). Unfortunately, though, no, there are no "settings" at this point. We do get a lot of requests for a more hands-on function to editing the final result so... maybe in an update.
One thought: Could it be the angle at which you're capturing the image?
Thanks for the screen shots. I'll pass them along to the Capture team along with your comments. Sorry I couldn't be more helpful. I'm glad you're liking the app.
I usually hold it right above the drawing and in good light. Maybe I'll try uninstalling and reinstalling the app.
Just make sure to sync anything you're working on over a wi-fi connection before deleting the app.
And let me know if reinstalling helps.