The video image flow monitoring technology has been applied in hydrological monitoring and irrigation area monitoring. Due to the limitation of received light, video image flow monitoring method has limitations in monitoring at conditions of night and low light. The thermal imaging was used to increase the spectral applicability of video flow measurement and compensate for the low applicability of video flow measurement under night conditions. By using a visible light and thermal imaging double-sided camera device mounted on a drone, the flow velocity field inversion results of visible light and thermal imaging camera devices under conditions of visible light and night were compared with the flow velocity monitoring data. The results show that under the condition of sufficient visible light during the day, the inversion effect of visible light video image flow velocity is better, and the accuracy error can reach within -5% except for a few monitoring points; Due to the limitation of its resolution, thermal imaging camera has a certain ability to capture natural tracers on the river surface, and has the ability and potential to invert the flow velocity field on the river surface. If missing particles of cold ice are added to the river section, the monitoring accuracy of thermal imaging at night can be significantly improved. Except for one monitoring point, the relative error of monitoring accuracy is 8.4%, and the accuracy of the other three monitoring points is relatively high, all around -1%. The research results can provide important references for improving the monitoring accuracy of video velocity measurement under conditions of nighttime and low light.
| 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 |