Automatic detecting system of apple harvest season for robotic apple harvesting

Abstract

The objective of this research was to develop the automatic detecting system of apple harvesting season for the robotic apple harvest. The farmers check the fruit color, when they harvest the apple fruits. The fruit color is the most important function to decide the suitable fruit harvest time. This detecting system should be installed to the apple harvesting robot. The color of apples that were suitable season to harvest and earlier season to harvest, were measured and comp aired using the spectrophotometer. The harvest season apple showed chromatic red color, and the earlier apple fruit of harvest included the yellow portions on its surface. The harvest season apple’s color and earlier apple’s color were well separated based on the Munsell color system, the L*a*b* color space and XYZ color system. The threshloding which detect the apples at the harvest time would be produced based on the evaluation of these color system. In addition, the chlorophyll contents (SPAD values) of apple tree leaves were also investigated during the apple cultivation. The highest SPAD values showed in the beginning of September. This was the just after the fruition season. The values were, then, decreasing until the harvest season. The variance of chlorophyll contents of apple tree leaves was also used for detecting the suitable harvest season of apples.