Fig. 3.

Error in orientation detection using the vector summation method for a simulated image containing regions with diverging orientations. (a) The average absolute value of the difference between measured and actual pixel-wise orientations noticeably decreases with increasing window sizes of $3\times 3$ to $11\times 11$ using a simulated image (b) of circles at different locations, diameters, and thicknesses. (c) With increasing window size, error initially decreases and then becomes localized to regions where fibers are in close proximity to each other. (d) A magnified view of the error in the area indicated by red outline in (b) demonstrates an increase in error between $11\times 11$ and $25\times 25\text{\hspace{0.17em}\hspace{0.17em}pixel}$ windows for specific regions with multiple nearby fibers.