Automatic Vehicle License Plate Extraction Using Region-Based Convolutional Neural Networks and Morphological Operations
Abstract
1. Introduction
2. Related Works
3. Proposed Methods
3.1. Vehicle Detection
3.2. Vehicle Tracking
3.3. License Plate Extraction
4. Experimental Results
5. Conclusions
Funding
Conflicts of Interest
References
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1. Convert the detected vehicle region into gray. |
2. Select the lower half region of the detected vehicle region. |
3. Calculate vertical edge pixels using a Sobel edge mask [−1 0 1; −2 0 2; −1 0 1]. |
4. Normalize the vertical edge pixels to [0 1]. |
5. Obtain the binary image using Otsu’s threshold method. |
6. Calculate the horizontal edge histogram. |
7. Set a threshold if (horizontal edge histogram >= 0.7) to 1 otherwise 0. |
8. Apply the vertical and horizontal dilation morphological operation using [80, 4] and [4, 80] rectangle mask |
9. Extract overlapped region from the morphological operation results. |
10. Fill holes using dilation with [4, 10] rectangle mask and erosion with [20] line mask. |
11. Extract the biggest binary region. |
12. Extend the region by 5 pixels. |
Image | VD Rate (%) | LPE Rate (%) | Time (sec.) | ||
---|---|---|---|---|---|
Success | Miss | Success | Miss | ||
Highway | 94 | 12 | 85 | 15 | 0.89 |
City road | 91 | 18 | 83 | 19 | 0.91 |
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Kim, J. Automatic Vehicle License Plate Extraction Using Region-Based Convolutional Neural Networks and Morphological Operations. Symmetry 2019, 11, 882. https://doi.org/10.3390/sym11070882
Kim J. Automatic Vehicle License Plate Extraction Using Region-Based Convolutional Neural Networks and Morphological Operations. Symmetry. 2019; 11(7):882. https://doi.org/10.3390/sym11070882
Chicago/Turabian StyleKim, JongBae. 2019. "Automatic Vehicle License Plate Extraction Using Region-Based Convolutional Neural Networks and Morphological Operations" Symmetry 11, no. 7: 882. https://doi.org/10.3390/sym11070882
APA StyleKim, J. (2019). Automatic Vehicle License Plate Extraction Using Region-Based Convolutional Neural Networks and Morphological Operations. Symmetry, 11(7), 882. https://doi.org/10.3390/sym11070882