Patent ID: 8077921

Claim:
An apparatus that detects the presence of fog which is present ahead of a vehicle comprising: means for capturing an image of space, the image being viewed from the vehicle and comprising arrays of pixels having luminance values; means for extracting a reference image from the image captured by the capturing means, the reference image including a portion of the image of the space located a predetermined distance from the vehicle; means for estimating the luminance values of the arrays of the pixels in the reference image; means for detecting an obstacle from the reference image to obtain a contour of the obstacle in the reference image; means for masking a region including a picture of the obstacle in the reference image in accordance with a contour of the obstacle detected by the means for detecting the obstacle to produce a masked reference image; means for calculating a reliability of determining the presence of the fog based on the region which is masked in producing the masked reference image; means for calculating a total luminance intensity as a function of the luminance values of the arrays of the pixels in the masked reference image to obtain a total luminance intensity; and means for determining the presence of the fog in accordance with the total luminance intensity calculated by the means for calculating the total luminance intensity and the reliability of determining the presence of the fog calculated by the means for calculating the reliability; wherein the means for calculating the reliability calculates a first reliability of determining the presence of the fog based on a shape of the contour of the obstacle in the reference image which relates to each individual number of unmasked continuous parts of the corresponding array of the pixels, the arrays of the pixels constituting the masked reference image, and the means for determining determines the presence of the fog in the environmental atmosphere around the vehicle in accordance with both the total luminance intensity and the first reliability of determining the presence of the fog.