I am involved in a project for which it is required to measure amount of the food in photograph. Especially, I would like to capture an image of a dish, e. g. cup of tea or let’s say biryani and get the approximate occupied volume of the teal liquid in milliliters (ml) and biryani in gm. From this perspective, I understand that there must be difficulties such as perspective and the use of a reference object to address the scale issue.