Traffic sign recognition plays a crucial role in the development of autonomous cars to reduce the accident rate and promote road safety. It has been a necessity to address traffic signs that are affected significantly by the environment as well as poor real-time performance for deep-learning state-of-the-art algorithms. In this paper, we introduce Real-Time Image Enhanced CNN ({\our}) for Traffic Sign Recognition. {\our} is a real-time, novel approach that tackles multiple, diverse traffic sign datasets, and out-performs the state-of-the-art architectures in terms of recognition rate and execution time. Experiments are conducted using the German Traffic Sign Benchmark (GTSRB), the Belgium Traffic Sign Classification (BTSC), and the Croatian Traffic Sign (rMASTIF) benchmark. Experimental results show that our approach has achieved the highest recognition rate for all Benchmarks, achieving a recognition accuracy of 99.75% for GTSRB, 99.25% for BTSC and 99.55% for rMASTIF. In terms of latency and meeting the real-time constraint, the pre-processing time and inference time together do not exceed 1.3 ms per image. Not only have our proposed approach achieved remarkably high accuracy with real-time performance, but it also demonstrated robustness against traffic sign recognition challenges such as brightness and contrast variations in the environment.
Figures & tables
Figure 1: Sample of GTSRB traffic signs after pre-processing, left images are original unprocessed ones and the next images to the right display the result after each stage of pre-processing in order: 1) Image contrast enhancement, 2) Retinex algorithm, 3) Histogram equalization, and 4) Edge enhancement with gray-scale conversion
Figure 11: Contribution of each pre-processing method to the performance of the GTSRB
Figure 12: Pre-processed sample image after applying 1-stage versus 4-stages of pre-processing techniques
Figure 13: Feature maps for figure 12(a)
Figure 14: Feature maps for figure 12(b)
Figure 15: Prediction of RIECNN model on the three datasets, focusing on challenging test set images. Green background indicates correct prediction, purple background indicates miss-classification
The Hong Kong University of Science and Technology (Guangzhou), Guangzhou 511453, China · Lingnan University, Hong Kong SAR, China · Shenzhen Unity Drive Innovation Technology Co., Ltd., Shenzhen 518063, China +1