Patent ID: 8466960

Claim:
A liquid droplet recognition apparatus for detecting a liquid droplet attached to a front surface of a transparent member, the apparatus comprising: an image pickup apparatus that picks up a vertically polarized light image and a horizontally polarized light image at the front surface of the transparent member from a side of a rear surface of the transparent member; and a signal processing unit that determines whether the liquid droplet is attached to the front surface of the transparent member based on a polarized-light image ratio composed of the vertically polarized light image and the horizontally polarized light image picked up by the image pickup apparatus, wherein the image pickup apparatus includes a lens array having a plurality of image pickup lenses on a same substrate, a filter that is separated into two polarizer regions with transmission axes orthogonal to each other so as to correspond to light fluxes passing through the plurality of image pickup lenses of the lens array, and an image pickup unit having a plurality of image pickup regions that pick up an image of a subject by receiving light passing through the respective polarizer regions of the filter, wherein the vertically polarized light image is picked up by any of the plurality of image pickup regions of the image pickup unit and the horizontally polarized light image is picked up by another of the plurity of image pickup regions thereof, and wherein the signal processing unit includes an image position correction unit that corrects a parallax positional shift between the vertically polarized light image and the horizontally polarized light image picked up by the plurality of image pickup regions.