Food volume estimation using a circular reference in image-based dietary studies

Accurate estimation of food volume plays an important role in dietary assessment using digital photographs. In this paper, we present a new approach based on a circular object (e.g., a dining plate or a coin) as a physical reference to determine food portion size. A geometrical model relating the circular object and its image is built. An algorithm to estimate food volume using the geometric model is developed. Experimental results have shown high reliability and accuracy of this approach.