An image of a space in which a mobile robot travels may be captured, and, in the case in which personal information is included in the captured image, the image including the personal information may be covered with a specific color such that the personal information is not visible, and the image may be replaced with an image including no personal information. As a result, it is possible to prevent the personal information from being exposed. In order to determine whether personal information is included in an image and to replace the image including the personal information with an image including no personal information, an object detection neural network and a frame prediction neural network may be used. In addition, input and output of an image may be performed in an Internet of Things (IoT) environment using a 5G network.