TsumeColorGram: A Method of Estimating an Object's Weight Based on the Thumb's Nail Color

Measuring the weight or amount of ingredients is necessary when cooking but it requires tools and can often feel burdensome to the cook. This study developed a method to estimate the weight of an object without special tools by observing the change in fingernail color when holding an object (the color of human fingernails changes when force is applied to the fingertips). We constructed a dataset of nail images with varying weights of held objects. Our analysis revealed a tendency for the values of G and B in the nail's RGB color and H and S in HSV to be related to the object's weight. Linear regression was used for the estimation, and it was found that, although there were individual differences, estimation was possible with an error of 20.99 g in the most accurate case.