Exercise: Detect Edges of an Electronic Board

Problem statement

We want to inspect the two rows of small solder cones highlighted by the blue rectangle in the image below.

We know the distance between the northwest golden fiducial and the left border of the white rectangle around the zone to inspect. In a previous exercise, we located the three golden fiducials, so we have a good approximation of the zone to inspect. Your task is to precisely locate the four white segments i.e., the long white rectangle inside the annotated blue rectangle in the image below that delimitates our zone to inspect.