Determination procedure of the luminance of traffic signs and device for its embodiment
First Claim
1. A luminance detection system connectable to a vehicle and operable while the vehicle is moving along a roadway, the luminance detection system comprising:
- a light source configured to illuminate a road marking positioned along the roadway, the light source being separate and distinct from a pair of headlights of the vehicle;
a first camera configured to obtain first image data, the first image data including the road marking, the first image data having first color characteristics;
a second camera configured to obtain second image data, the second image data including the road marking also included in the first image data, the second image data having second color characteristics, wherein the first color characteristics are separate and distinct from the second color characteristics;
a processor configured to;
calculate a distance between the vehicle and the road marking based on the first image data and the second image data;
apply one or more luminance transforms to convert one or more pixel values of the first image data and the second image data to obtain corresponding luminance levels representative of at least a portion of the road marking;
after applying the one or more luminance transforms, compare the first image data, and the second image data to minimize ambient light information; and
calculate a luminance value representative of a luminance of the road marking based on (i) the distance between the vehicle and the road marking (ii) the luminance levels representative of the road marking and (iii) the comparison of the first image data, after applying the luminance transform, and the second image data to minimize ambient light information.
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Abstract
The method of the invention comprises: obtaining a sequence of at least two images, with different levels of illumination; extracting the region containing the sign in the image; calculating the luminance values of the signs; and obtaining the difference in luminance of the sign corresponding to the two levels of illumination. The value obtained is the luminance of the sign (11) corresponding to an illumination equal to the difference between the illuminations, or additional illumination. This result is based on the additive property of luminance, according to which the luminance of a sign is the sum of the luminance produced by each source of illumination. A basic illumination device (5), an additional illumination device (7), at least one camera for taking images, and image recording, positioning and synchronism systems are required to implement the method.
169 Citations
7 Claims
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1. A luminance detection system connectable to a vehicle and operable while the vehicle is moving along a roadway, the luminance detection system comprising:
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a light source configured to illuminate a road marking positioned along the roadway, the light source being separate and distinct from a pair of headlights of the vehicle; a first camera configured to obtain first image data, the first image data including the road marking, the first image data having first color characteristics; a second camera configured to obtain second image data, the second image data including the road marking also included in the first image data, the second image data having second color characteristics, wherein the first color characteristics are separate and distinct from the second color characteristics; a processor configured to; calculate a distance between the vehicle and the road marking based on the first image data and the second image data; apply one or more luminance transforms to convert one or more pixel values of the first image data and the second image data to obtain corresponding luminance levels representative of at least a portion of the road marking; after applying the one or more luminance transforms, compare the first image data, and the second image data to minimize ambient light information; and calculate a luminance value representative of a luminance of the road marking based on (i) the distance between the vehicle and the road marking (ii) the luminance levels representative of the road marking and (iii) the comparison of the first image data, after applying the luminance transform, and the second image data to minimize ambient light information. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification