The localization and recognition of key symbols in engineering drawings have long been essential applications in computer vision. Compared with traditional methods, deep learning-based text detection approaches offer higher detection efficiency and accuracy. It is therefore necessary to apply existing text detection algorithms to engineering drawing recognition tasks. This paper proposes a deep learning-based method for the localization and recognition of key symbols in engineering drawings, focusing on the detection and recognition of index symbols and dimension symbols. For index symbol localization, the drawings are cropped to a uniform size, and non-maximum suppression is used to remove redundant candidate boxes. For dimension symbol localization, a complete detection is performed on the masked drawings, and the intersection-over-union between each detected box and index symbol location is calculated to filter out partial data. Experimental results demonstrate that the proposed method achieves high precision and recall in both the localization and recognition of index and dimension symbols in engineering drawings.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |