System for detecting droplets on a translucent surface
AssigneeHitachi, Ltd.
InventorsGeorge Saikalis, Shigeru Oho
Life of this patent
Estimating the term…
Abstract
A system which detects droplets on a translucent surface having a camera which, upon activation, acquires an image of a portion of the surface. A radiation source, upon activation, illuminates the portion of the translucent surface while a control circuit selectively activates both the camera and the radiation source. A processor receives a captured image from the camera and, through image processing, generates an output signal representative of the number of droplets on the portion of the translucent surface.
Claims27
A system for detecting droplets on a translucent surface comprising:
- a camera which, upon activation, acquires an image of at least a portion of the translucent surface and generates an output signal representative of said image,
- a radiation source which, upon activation, illuminates the at least a portion of the translucent surface,
- a control circuit which selectively activates said camera and said radiation source,
- a processor which receives said camera output signal and, through image processing, generates an output signal representative of the magnitude of droplets on the at least a portion of the translucent surface,
- wherein said radiation source comprises a visible light source, and
- wherein during activation of said radiation source, said control circuit activates said radiation source for a sufficiently short period of time so as to be undetectable to a human eye.
For use in conjunction with a translucent windshield and a variable speed windshield wiper which, when activated, wipes droplets from the windshield, a system for detecting droplets on the windshield comprising:
- a camera which, upon activation, acquires an image of at least a portion of the windshield and generates an output signal representative of said image,
- a visible light radiation source which, upon activation, illuminates the at least a portion of the windshield,
- a control circuit which selectively activates said camera and said radiation source,
- a processor which receives said camera output signal and, through image processing, generates an output signal representative of the magnitude of droplets on the at least a portion of the translucent surface,
- a wiper speed control circuit which receives said processor output signal and varies the speed of the windshield wiper as a function of said processor output signal,
- wherein said control circuit comprises a brightness control circuit which varies the brightness of the radiation source, and
- wherein during activation of said radiation source, said control circuit activates said radiation source for a sufficiently short period of time so as to be undetectable to a human eye.
A method for detecting droplets on a translucent surface comprising the steps of:
- acquiring an image of at least a portion of the translucent surface,
- generating an output signal representative of said image,
- illuminating the at least a portion of the translucent surface with a pulse of visible light having a duration undetectable to a human eye,
- image processing said image to generate an output signal representative of the magnitude of droplets on the at least a portion of the translucent surface.
Dependencies are inferred from the claim text.