High Quality Color Estimation of Shine Muscat Grape Using Vision Transformer

Currently, skilled farmers judge the ripeness of the Shine Muscat grape variety by looking at the color on the surface of the grapes. However, the color of Shine Muscat grapes does not change much as they grow, and there are individual differences in the way the color is perceived. Furthermore, the same color can look very different depending on the exposure to sunlight and shadows. Therefore, there is a need for a system that can quantitatively determine the color of Shine Muscat grapes to pass on the harvesting techniques of experienced farmers to amateurs and inexperienced farmers. This research aims to improve the accuracy of the color estimation of Shine Muscat grapes using deep learning. We propose a method to estimate the color of individual grapes using a color estimation model with a self-attention mechanism, from which the color of the whole bunch is estimated. A Vision Transformer model with a self-attention mechanism was found to improve the color estimation accuracy to $96.9 \%$. Furthermore, by eliminating outliers using the interquartile range, a color estimation accuracy of $97.2 \%$ could be achieved, demonstrating the effectiveness of the new color estimation model.