Method for measuring visibility from a moving vehicle
First Claim
1. A method of measuring visibility to an operator of a vehicle in motion while the vehicle is in motion comprising producing a plurality of images of a scene viewed by an operator of the vehicle in the direction of the visibility to be measured using optical-electronic camera means, comprising the loci in successive images of the plurality of selected image features of defined local brightness contrast in stationary objects in the images, determining the ranges of distances of the selected image features in the scene relative to the optical-electronic camera means, and determining the visibility to an operator of the vehicle based upon the ranges of the selected image features in the scene by way of a maximum range filtration using a threshold value for the brightness contrast of the selected image features.
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Abstract
In a method of measuring visibility from a vehicle in motion, images taken by an optical-electronic camera are transformed into selected image features establishing the loci of defined brightness variations in the images. A range determination of the selected features relative to the optical-electronic camera is carried out followed by filtration of the range readings to establish the prevailing visibility for a vehicle operator or a sensor system based on image processing. The advantage over conventional active methods is that, without requiring an active transmitter, the true visual object contrast as well as the atmospheric transmission enters into the visibility determination.
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15 Claims
- 1. A method of measuring visibility to an operator of a vehicle in motion while the vehicle is in motion comprising producing a plurality of images of a scene viewed by an operator of the vehicle in the direction of the visibility to be measured using optical-electronic camera means, comprising the loci in successive images of the plurality of selected image features of defined local brightness contrast in stationary objects in the images, determining the ranges of distances of the selected image features in the scene relative to the optical-electronic camera means, and determining the visibility to an operator of the vehicle based upon the ranges of the selected image features in the scene by way of a maximum range filtration using a threshold value for the brightness contrast of the selected image features.
Specification