An information processing device includes a picture image inputter configured to acquire a picture image imaged by a camera and at least one processor configured to execute a program stored in a memory. The at least one processor detects, from the picture image acquired by the picture image inputter, light emitted by a light-emission device, acquires, based on brightness of the detected light emitted by the light-emission device, set brightness information indicating an appropriate brightness for light to be emitted by the light-emission device, and transmits the acquired set brightness information to the light-emission device.