Raindrop sensor and wiper controller having the same
First Claim
1. A raindrop sensor for detecting a raindrop on a windshield of a vehicle, the raindrop sensor comprising:
- capturing means for capturing an image of the windshield from inside the vehicle;
high-frequency component determination means for performing a frequency analysis of the image and for determining based on a result of the frequency analysis whether the image has a high-frequency component;
gradation change detection means that operates when the image has the high-frequency component to detect a width of a change region where a change in gradation of the image occurs; and
raindrop determination means for determining that the raindrop is on the windshield when the width of the change region is within a predetermined range corresponding to a diameter of the raindrop.
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Accused Products
Abstract
A raindrop sensor includes an image sensor and an image processor. The image sensor captures an image of a windshield from inside a vehicle. The image processor performs a frequency analysis of the image to detect a high-frequency component in the image. When the high-frequency component is detected, the image processor detects a width of a change region where a change in gradation of the image occurs. When the width of the change region is within a predetermined range corresponding to a diameter of a raindrop, the image processor determines that the raindrop is on the windshield. Even when a foreign matter such as a water stain appears as the high-frequency component as a result of the frequency analysis, the raindrop and the foreign matter can be distinguished from each other based on the width of the change region.
26 Citations
14 Claims
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1. A raindrop sensor for detecting a raindrop on a windshield of a vehicle, the raindrop sensor comprising:
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capturing means for capturing an image of the windshield from inside the vehicle;
high-frequency component determination means for performing a frequency analysis of the image and for determining based on a result of the frequency analysis whether the image has a high-frequency component;
gradation change detection means that operates when the image has the high-frequency component to detect a width of a change region where a change in gradation of the image occurs; and
raindrop determination means for determining that the raindrop is on the windshield when the width of the change region is within a predetermined range corresponding to a diameter of the raindrop. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A wiper controller for controlling a windshield wiper of a vehicle, the wiper controller comprising:
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capturing means for capturing an image of a windshield of the vehicle from inside the vehicle;
high-frequency component determination means for performing a frequency analysis of the image and for determining based on a result of the frequency analysis whether the image has a high-frequency component;
gradation change detection means that operates when the image has the high-frequency component to detect a width of a change region where a change in gradation of the image occurs;
raindrop determination means determining that the raindrop is on the windshield when the width of the change region is within a predetermined range corresponding to a diameter of the raindrop; and
control means for controlling the windshield wiper in accordance with an amount of the raindrop on the windshield. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification