Trw Limited

Alastair James Buchanan

Martin John Thompson

Adam John Heenan

Roger John Hazelden

A rain detection apparatus includes a camera that views a surface and a processor that captures an image from the camera. The processor generates a signal indicative of rain on the surface from information contained in the captured image and optionally drives a surface cleaning apparatus in response thereto. The apparatus captures images focused at a plurality of distances. The processor includes an edge detector that detects edges visible in the captured image and a difference structure that calculates the difference between the number of edges visible between differing images. The edge detector disregards edges close to areas of light larger than the largest raindrop that is desired or expected to be detected. The apparatus optionally includes a backlight, and the difference in numbers of edges between frames with and without the backlight illuminated are used to distinguish between background features and rain on the surface.

Rain detection apparatus and method

A rain detection apparatus and method, comprising a camera adapted to view a surface and a processor adapted to capture at least one image from the camera, in which the processor is further adapted to generate at least one signal indicative of the presence of rain on the surface from information contained in the at least one captured image and to, optionally drive surface cleaning apparatus in response thereto, in which the apparatus is adapted to capture images focused at a plurality of distances; in which the processor includes edge detection means adapted to detect edges visible in the at least one captured image and difference means adapted to calculate the difference between the number of edges visible between differing images; and in which the edge detection means is further adapted to disregard edges close to areas of light larger than the largest raindrop that is desired or expected to be detected. The apparatus and method optionally includes a backlight, which the difference in numbers of edges between frames with and without the backlight illuminated being used to distinguish between background features and rain on the surface. The surface may be a vehicle windscreen, windshield or the cover or lens of a vehicle lamp, in which case the cleaning apparatus may be one or more wipers or washers.

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Sutton Coldfield, United Kingdom

Alastair James Buchanan