植基於尺度不變性特徵轉換之交通號誌偵測與辨識

Detection and Recognition of Road Signs Using Scale Invariant Feature Transform

陳寶鳳(Pao-Feng Chen)

指導教授 ： 郭文嘉

元智大學/資訊學院/資訊管理學系/碩士(2005年)

摘要

本論文提出一個植基於尺度不變性特徵轉換(Scale Invariant Feature Transform,SIFT)之自動化交通號誌偵測與辨識方法，主要可分成兩個階段。首先利用交通號誌色彩的特殊性與區域投影法，從輸入影像中切割出可能包含號誌的候選區，並利用形狀特徵重建候選區。其次使用尺度不變特徵轉換萃取候選影像的特徵點，利用最近鄰居演算法尋找各特徵點與標準圖庫特徵點之配對、哈夫轉換尋找特徵點叢集與最小平方法檢驗仿射扭曲，以達交通號誌偵測與辨識目的。實驗結果顯示，大部份的交通號誌均可被成功的偵測與辨識，辨識率可高達95.37%，同時針對受外界特殊狀況如尺度改變、旋轉、明暗及色調改變、部份遮擋、扭曲變形等影響之號誌，亦均能成功有效地完成偵測與辨識。本論文所提之方法將有助於駕駛輔助系統及智慧型監控系統之發展，並提供即時各種有效之駕駛輔助訊息。

關鍵字

交通號誌 ； 尺度不變性特徵轉換 ； 哈夫轉換

並列摘要

This study describes an automatic road sign detection and recognition system by using scale invariant feature transform (SIFT). The method consists of two stages. In the detection stage, the relative position of road sign is located by using a priori knowledge, shape and specific color information. The shape feature is then used to reconstruct the road sign in the candidate region, and the road sign image is fully extracted from the original image for further recognition. In the recognition stage, distinctive invariant features are extracted from the road sign image by using SIFT to perform reliable matching. The recognition proceeds by matching individual features to a database of features from known road signs using the fast nearest-neighbor algorithm, a Hough transform for identifying clusters that agree on object pose, and finally performing verification through least-squares solution for consistent pose parameters. Experimental results demonstrate that most road signs can be correctly detected and recognized with an accuracy of 95.37%. Moreover, the extensive experiments have also shown that the proposed method is robust against the major difficulties of detecting and recognizing road signs such as image scaling and rotation, illumination change, partial occlusion, deformation, perspective distortion, and so on. The proposed approach can be very helpful for the development of Driver Support System and Intelligent Autonomous Vehicles to provide effective driving assistance.

並列關鍵字

Road signs recognition ； Scale Invariant Feature Transform ； Hough transform.

參考文獻

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