Abstract: Navigational systems and methods include building a topological graph of an environment using nodes that represent locations in the space and associated directions, with frontiers associated with particular nodes and directions within the topological graph. An action is determined using a policy trained with an action reward function that weighs exploration to find new objects and moving objects to a goal. An agent navigates within the environment in accordance with the determined action.

Abstract: Disclosed is a device for extracting depth information using infrared light which can be provided at low cost in such a way to apply a nonlinear crystal and a photonic crystal to a depth camera and comprises infrared light emission unit which emits a first infrared light toward a subject; a wavelength conversion unit which concerts the first infrared light reflected from the subject into a second infrared light having a wavelength shorter than the wavelength of the first infrared light; and depth information extraction unit which detects the converted second infrared light and extracts depth information of the subject, wherein the wavelength conversion unit is formed of a crystal capable of concerting the length of the wavelength. The wavelength conversion unit is formed of a crystal which is capable of converting the length of wavelength.