Correlation of focal plane orientation and imaging of subcellular structures. Due to optical sectioning, images from confocal microscopes represent thin slices of a specimen with an axial resolution of ≈ 500 nm (indicated in gray). However, in many cases the image plane might not match the orientation of the canaliculi. Depending on the orientation of the hepatocyte, the image plane might not cut both tight junctions, which delimitate the canaliculus, in the same plane. Consequently, the corresponding Zo-1 intensity profile does not exhibit two symmetrical peaks. The automated profile selection algorithm eliminates Zo-1 intensity profiles with relative peak intensity discrepancy of more than 15%. The illustration gives two examples with representative microscopic images.