SYSTEM AND METHOD FOR TRAFFIC SIGN RECOGNITION
First Claim
1. A vehicle-mounted traffic sign recognition system comprising:
- a forward-looking camera configured to capture stream data of imagery containing image frames having traffic sign images therein; and
a rotation and scale-invariant geometric pattern-matching process constructed and arranged to identify traffic sign candidates in the stream data, the geometric pattern-matching process including a pre-training mechanism to pre-train with predetermined traffic sign models having exterior geometric features and to classify each of the traffic sign candidates as either an unrecognized object or as a sign of a predetermined type upon a high-confidence match between each of the traffic sign candidates and at least one of predetermined traffic sign models.
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Abstract
This invention provides a vehicle-borne system and method for traffic sign recognition that provides greater accuracy and efficiency in the location and classification of various types of traffic signs by employing rotation and scale-invariant (RSI)-based geometric pattern-matching on candidate traffic signs acquired by a vehicle-mounted forward-looking camera and applying one or more discrimination processes to the recognized sign candidates from the pattern-matching process to increase or decrease the confidence of the recognition. These discrimination processes include discrimination based upon sign color versus model sign color arrangements, discrimination based upon the pose of the sign candidate versus vehicle location and/or changes in the pose between image frames, and/or discrimination of the sign candidate versus stored models of fascia characteristics. The sign candidates that pass with high confidence are classified based upon the associated model data and the drive/vehicle is informed of their presence. In an illustrative embodiment, a preprocess step converts a color image of the sign candidates into a grayscale image in which the contrast between sign colors is appropriate enhanced to assist the pattern-matching process.
196 Citations
26 Claims
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1. A vehicle-mounted traffic sign recognition system comprising:
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a forward-looking camera configured to capture stream data of imagery containing image frames having traffic sign images therein; and a rotation and scale-invariant geometric pattern-matching process constructed and arranged to identify traffic sign candidates in the stream data, the geometric pattern-matching process including a pre-training mechanism to pre-train with predetermined traffic sign models having exterior geometric features and to classify each of the traffic sign candidates as either an unrecognized object or as a sign of a predetermined type upon a high-confidence match between each of the traffic sign candidates and at least one of predetermined traffic sign models. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for recognizing traffic signs from a vehicle comprising the steps of:
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capturing stream data of imagery containing image frames having traffic sign images therein; and identifying, with a rotation and scale-invariant geometric pattern-matching process, traffic sign candidates in the stream data, the geometric pattern-matching process including a pre-training mechanism to pre-train with predetermined traffic sign models having exterior geometric features and classifying each of the traffic sign candidates as either an unrecognized object or as a sign of a predetermined type upon a high-confidence match between the each of the traffic sign candidates and at least one of predetermined traffic sign models. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification