Abstract
The removal of Coreopsis lanceolate that was designated an invasive alien species have been attempted in river levees. However, in some cases, due to that it is not the best timing to perform the herbicide, there is also a risk of spreading the habitat not only to achieve the effect of the control. For full effectiveness, it is necessary to know the exact timing of flowering and fruiting of C. lanceolate in the region. Therefore, we have studied a method to understand quantitatively the amount of flowering, by analyzing the images captured using a time-lapse camera. Image analysis was performed in two ways, bloom color extraction and calculation of GRVI(Green-Red ratio Vegetation Index). Flowering color extraction results were in good agreement with the trends in the number of flower heads. As a result, we have confirmed that to shoot consecutive images by time-lapse camera, is an effective technique that can substitute for field measurement of the number of flowering.
