Q: “Interested in assessing whether your software could be used to determine the quality of a solder joint… Joint is composed of an aluminum tube and a copper pipe… The area of the copper pipe that overlaps or contacts the aluminum tube is the area that needs assessment. Would like to determine what percent of this area has a solder coating. The solder is a zinc78%/alum22% alloy… the copper pipe section could be flattened to a greater degree if this to would help with accuracy.”

As it has been suggested, it is a good idea to outline what is to be measured manually so that we can see if automatic analysis produces reasonable results:

In the screenshot the two numbers are at the top.

The area inside the red contour (i.e., inside your red line) is 140,582 pixels.
The area inside the green contour (i.e., gray region) is 106,787 pixels.

So the proportion of gray inside the red line is
106,787 / 140,582 = 76%.

By moving the sliders one can make the contours to fit better and improve the accuracy.

More here…