Rain detection apparatus and method

摘要

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.

主权项

1. A mist detection apparatus comprising:
a camera adapted to view a surface; a processor adapted to capture at least one image from the camera and generate at least one signal indicative of the presence of mist on the surface from information contained in the at least one captured image, and a backlight adapted to illuminate the surface, wherein the processor is arranged to (1) distinguish a first area of the image, in which a specular reflection of the backlight is not found, from a second area of the image, in which a specular reflection of the backlight on the surface is found, (2) calculate a difference in intensity in the first area of the image between captured images in which the backlight is illuminated and in which the backlight is not illuminated, and (3) generate the at least one signal based upon the difference in intensity.