Module 04 Summary

What this module established

Edges are gradients: a shadow and a printed line produce them exactly as an object boundary does. Contours find connected regions, not objects - touching objects merge, and the information needed to split them is not in the mask.

Carry forward

• Otsu automates the choice of a global threshold; it does not make one appropriate. Uneven lighting needs a local comparison.
• Classical methods assume a consistent describable appearance. Where that fails, tuning is time spent on a wrong assumption.
• Report IoU with precision and recall - the direction of the error is what you act on.

Before moving on

Move on when you have answered honestly whether your target has a consistent describable appearance, with IoU, precision and recall against hand-drawn masks.

Mark complete