Evaluation of image descriptors in subspace-based classifiers for traffic sign recognition

In this study, the performance of some image descriptors in traffic sign recognition is obtained using the subspace-based classifiers. The subspace methods make both dimension reduction in feature space and maximize the classification rate. The feature vectors are extracted from the images containing a traffic sign by image descriptors. Gray scale, Histogram of Oriented Gradients (HOG), Local Binary Patterns (LBP), and Local Phase Quantization (LPQ) are used as image descriptors in our study. The feature vectors are processed by the subspace methods, Principle Component Analysis (PCA), Linear Discriminant Analysis (LDA), and Discriminative Common Vector (DCV), for recognizing traffic signs. In the experimental study, the database containing triangular and circular signs was used. The database also includes shifted and rotated traffic signs. The recognition performances of the subspace-based classifiers were compared with the template matching method. The best classification performances are obtained for the HOG features and DCV method. The classification rates for triangular and circular signs are 98.38% and 99.25% respectively.