Patent ID: 9187063
Filing Date: 2015-11-17
Classification: B60S,G01N,G06K

Abstract:
1. A substance detection apparatus, comprising: a light source to emit light to a planar transparent member, having a proximal first face and a distal second face opposite the first face, the light from the light source first striking the first face of the planar transparent member; an image capture lens; a polarization filter including a two-dimensional array of polarization filter areas that are adjacent to each other, each dimension of the two-dimensional array having more than two polarization filter areas; an image sensor; and a substance detection processor that executes a detection process to detect a substance present on the second face of the planar transparent member based on an image of the substance captured by the image sensor, wherein the polarization filter, disposed after the image capture lens and before the image sensor with respect to a direction of the light entering the image sensor, passes only a polarized light component having a polarized light direction substantially parallel to a virtual plane including an optical axis of the light source that emits the light to the planar transparent member and an optical axis of the image capture lens, wherein the image sensor is composed of a two-dimensional array of pixels having a plurality of light receiving elements, wherein the light emitted from the light source is reflected at the substance present on the second face of the planar transparent member, the image sensor receives a light reflected from the substance, via the image capture lens and the polarization filter, to capture an image of the substance present on the second face of the planar transparent member; and wherein the focus of the image capture lens is set at a point in a distance beyond the planar transparent member and less than infinity.