1. An information processing apparatus comprising: circuitry configured to acquire a real-world image; analyzing analyze a three-dimensional space structure of the real-world image; detect a length, in a three-dimensional space, of an object included in the real-world image to be a scale reference; determine, from the detected length of the object, a scale of the three-dimensional space; store virtual information to be displayed by being overlaid on the real-world image and a real size of the virtual information in association with each other; adjust a size of the virtual information according to the determined scale of the three-dimensional space of the real-world image; and generate an output image including the object and the virtual information whose size has been adjusted overlaid on the real-world image, the object being at least partially visible in the output image.