Image Correction for Proper Time of Harvesting Fruit Outdoors

摘要

Reduction in the number of farmers and aging of workers have recently become a problem in Japan. Thus, agriculture and industry cooperation is actively performed. One example showing this cooperation is the utilization of a plant factory and harvesting robot for agricultural crops. However, using this type of robots makes it difficult to retain farms and trees, hence the need for a method to produce high-value fruits without requiring intuition and experience. The proper harvest time for high-quality and -value fruits is decided upon by comparing tree fruits using a color chart defined for each breed. The assessment standard is not unified because this is a sensory exam based on sensibility information. This study aims to develop a system that would decide on the proper time of harvesting fruits from the tree. Previous studies were able to decide on the proper time of fruit harvest indoors. However, the outdoor lighting conditions change according to time and weather. Therefore, directly applying this method is difficult. In this paper, we introduce the image correction method to reduce the influence of lighting conditions. The proposed method is performed using a color chart taken together with fruit. First, we analyzed the color chart for fruit colors taken outdoors and confirmed that the influence of illumination change reduces. Second, we analyzed the fruit color. The fruit color was confirmed to have values along the breeding status. We also proposed image correction without the use of the color chart and acquired a useful feature. The results of the procedure show that quantitatively determining the proper harvesting time of fruit outdoors is possible.