  A novel method for automated assessment of directions of collagen fibers in
soft tissues is presented. It is based on multiple rotated images obtained via
polarized light microscope with perpendicular and inclined polarizers and thus
it breaks the limitation of 90{\deg} periodicity of polarized light intensity
and evaluates the fiber orientation over the whole 180{\deg} range accurately
and quickly. After having verified the method, we used histological specimens
of porcine Achilles tendon and aorta to validate the proposed algorithm and to
lower the number of rotated images needed for evaluation. Our algorithm is
capable to analyze 5.10^5 pixels in one micrograph in a few seconds and is thus
a powerful and cheap tool for histological image analysis of such samples
promising a broad application.
