Online tool for auto pen alignment. Drawing can be automatically aligned with the edges, either in realtime or when you release your mouse. It is similar to the magnetic lasso feature but has many more options to draw smooth computer aided traces online. Additionally, Image enhancements such as Canny Edge detection, CLAHE, Sharpening can also be done.

If you don't get the desired result try adjusting Radius and Threshold and try to Smoothen, or also try Image Enhancements

Right click to undo, Turn-on realtime to align in real time, Change radius for stronger results, Use reset to reset the drawing