2 deleted 9 characters in body edited Jun 20 '15 at 10:35 bill s 56.4k33 gold badges8080 silver badges161161 bronze badges If you are looking for a quick estimate, you can erode the line until it disappears. The point at which it is gone gives an estimate of the original thickness of the original line. In this implementation, adjust the slider until the line is just barely visible, the. The t parameter is the maxnumber of pixels eroded, and so corresponds to the thickness of the line. When I do it, I see it separating into multiple components by the 12th or 13th erosion and disappearing after the 14th or 15th. Manipulate[Erosion[img, t], {t, 0, 30, 1}]  If you are looking for a quick estimate, you can erode the line until it disappears. The point at which it is gone gives an estimate of the original thickness of the original line. In this implementation, adjust the slider until the line is just barely visible, the t parameter is the max thickness of the line. When I do it, I see it separating into multiple components by the 12th or 13th erosion and disappearing after the 14th or 15th. Manipulate[Erosion[img, t], {t, 0, 30, 1}]  If you are looking for a quick estimate, you can erode the line until it disappears. The point at which it is gone gives an estimate of the thickness of the original line. In this implementation, adjust the slider until the line is just barely visible. The t parameter is the number of pixels eroded, and so corresponds to the thickness of the line. When I do it, I see it separating into multiple components by the 12th or 13th erosion and disappearing after the 14th or 15th. Manipulate[Erosion[img, t], {t, 0, 30, 1}]  1 answered Jun 20 '15 at 8:49 bill s 56.4k33 gold badges8080 silver badges161161 bronze badges If you are looking for a quick estimate, you can erode the line until it disappears. The point at which it is gone gives an estimate of the original thickness of the original line. In this implementation, adjust the slider until the line is just barely visible, the t parameter is the max thickness of the line. When I do it, I see it separating into multiple components by the 12th or 13th erosion and disappearing after the 14th or 15th. Manipulate[Erosion[img, t], {t, 0, 30, 1}]