In optics, the image of an object is defined as the collection of focus points of light rays coming from the object. A real image is the collection of focus points made by converging rays, while a virtual image is the collection of focus points made by extensions of diverging rays. In other words, a virtual image is found by tracing real rays that emerge from an optical device backward to perceived or apparent origins of ray divergences. Simply speaking, an image is virtual when rays diverge from it. There is also a concept virtual object; an object is virtual when rays converge toward it.