Depth estimation based on object bottom position

A method may include receiving, from a camera, image data representing an object in an environment and determining, based on the image data, a vertical position within the image data of a bottom of the object. The method may also include determining an object bottom ratio between the vertical position and a height of the image data and determining, by way of a distance projection model and based on the object bottom ratio, an estimate of a physical distance between the camera and the object. The distance projection model may define, for each respective candidate object bottom ratio of a plurality of candidate object bottom ratios, a mapping between (i) the respective candidate object bottom ratio and (ii) a corresponding physical distance in the environment. The method may additionally include generating an indication of the estimate of the physical distance between the camera and the object.