Patent ID: 7718943

Claim:
An apparatus, comprising: a target generating means for projecting a predetermined pattern of illumination toward a substantially transparent substrate comprising an interior surface and an exterior surface; an optical sensing means comprising a first lens and an image sensor having a primary optical axis that is optically aligned with said first lens, such that said optical sensing means is configured to detect reflection of said illumination of said target generating means from said interior surface and to detect reflection of said illumination of said target generating means from said exterior surface such that said interior reflection is separate from said exterior reflection to detect moisture on at least one of said exterior surface and said interior surface based upon said detected reflection and said predetermined pattern of illumination of said target generating means; a transparent diffuse surface configured to allow said optical sensing means to obtain information about ambient light that has first transmitted through said interior and exterior surfaces of said substantially transparent substrate; and a means for analyzing said interior and said exterior reflection to detect a presence of moisture on at least one surface of said substantially transparent substrate based upon said illumination of said target generating means that is reflected from said interior and exterior surfaces, respectively, and received by said optical sensing means, and said obtained information about ambient light.