| 研究開始時の研究の概要 |
Sugarcane has been cultivated worldwide to produce sugar, ethanol and electricity. In the sugarcane industries, the quality and yield information of sugarcane in growth stages might be the key to reduce the loss and reaching the maximum yield of production. Recently, optical sensing devices such as benchtop NIR, portable NIR and UAV equipped with optical sensing devices has been reported to get the information in sugarcane agriculture. In this study, a combination system of optical sensors will be developed and investigated to maximize the quality and yield.
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| 研究実績の概要 |
In 2022, we conducted experiments on Minamidaito Island in Okinawa, Japan during the growth or ripening stage of sugarcane (October-December 2022). We measured sugar quality and absorbance spectra of sugarcane stalks in the sugarcane field using a portable Vis-NIR spectrometer. Additionally, we collected multispectral images of sugarcane leaves using an unmanned aerial vehicle equipped with a multispectral camera. We evaluated the effectiveness of the multispectral images in estimating sugar quality by checking the correlation between sugar quality measured by the portable Vis-NIR spectrometer and vegetation indices.
Furthermore, we investigated the effect of sugarcane skin on Minamidaito (Jan-Mar 2023). We scanned normal sugarcane stalks and peeled sugarcane stalks from different fields and varieties, then harvested the sugarcane and brought it back to the laboratory to measure sugar quality and develop a new calibration model. After developing models using the multiple linear regression method, we found that the peeled sugarcane spectra showed lower noise than the non-peeled spectra, which had higher noise caused by sugarcane wax. The results reveal that the peeled spectra model provides more accurate results than the non-peeled sugarcane spectra model, as the top two wavelengths with the highest correlation coefficient of the peeled sugarcane spectra model contain the sugar content absorption band (900-910 nanometers), whereas the normal sugarcane stalk spectra model had to select at least four wavelengths to find the sugar content absorption band.
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