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 seasonfor the robotic apple harvest. The farmers check the fruit color, when they harvest the apple fruits. The fruit color isthe most important function to decide the suitable fruit harvest time. This detecting system should be installed to theapple harvesting robot. The color of apples that were suitable season to harvest and earlier season to harvest, weremeasured and comp aired using the spectrophotometer. The harvest season apple showed chromatic red color, andthe earlier apple fruit of harvest included the yellow portions on its surface. The harvest season apples color andearlier apples color were well separated based on the Munsell color system, the L*a*b* color space and XYZ colorsystem. The threshloding which detect the apples at the harvest time would be produced based on the evaluation ofthese color system. In addition, the chlorophyll contents (SPAD values) of apple tree leaves were also investigatedduring the apple cultivation. The highest SPAD values showed in the beginning of September. This was the just afterthe fruition season. The values were, then, decreasing until the harvest season. The variance of chlorophyll contentsof apple tree leaves was also used for detecting the suitable harvest season of apples.