Development of Image Data Acquisition System with Unmanned Radio Controlled Helicopter-Mounted Low-Altitude Remote Sensing (LARS) Platform for Disease Infestation Monitoring in Cassava Plantation

บทคัดย่อ

 The developed unmanned radio controlled helicopter mounted with RGB and NIR band digital cameras can offer near real-time results upon user demand for timely detection of disease infections in cassava plantation which is extremely important for controlling the spread of disease and preventing crop productivity losses. This system is capable of acquiring images at altitudes ranging from 10 to 30 m, and the acquired LARS images were processed to estimate vegetative-indices with MATLAB program (Red=650 nm and NIR=800 nm band center) and thereby detecting diseases in both young and mature cassava plants. Good correlations and clear data clusters were obtained in characteristic plots of NDVI and various altitude levels, by which infested plants were discriminated from healthy plants in both young and mature crops. The correlation coefficients (R2) were in an acceptable range (0.978-0.988). Furthermore, good correlationswere obtained in characteristic plots of NDVI and GNDVI against chlorophyll content, the chlorophyll content values (μmol m-2) according to t-test showed notable differences among clusters for healthy young (R2=0.780-0.954), for infested young (R2=0.877-0.930), for healthy mature (R2=0.860-0.931), and for infested mature (R2=0.725-0.907) cassava plantation, respectively. The vegetation indices based on LARS images processed, provided satisfactory results comparing with a manual measurement.