Abstract: A projector includes an image acquiring unit that acquires an image including the projection image captured by the image-capturing device during image projection, an image region separating unit that separates a projection image region and a background image region from the acquired image, a background image time-lapse change storage unit that stores a time-lapse change of the background image acquired by a background time-lapse change acquiring unit, a projection image time-lapse change storage unit that stores a time-lapse change of the projection image acquired by a projection image time-lapse change acquiring unit, an tendency-of-use judging unit that judges a tendency of use of the projector on the basis of the stored time-lapse change of the background image and the stored time-lapse change of the projection image, and a light quantity adjusting unit that adjusts a light quantity of the light source on the basis of the judgment result.

Abstract: In a virtual LAN, a packet forwarding apparatus forwards IP packets and L2 packets using a single switch. The packet forwarding apparatus includes a switch that switches a media access control (MAC) packet using a MAC address of the MAC packet, and a packet format converter. The packet format converter converts a packet from an input and output unit into a packet having a MAC address according to information from the input and output unit, and converts a packet output from the switch to the input and output unit to a packet format compatible with the input and output unit according to the information of the input and output unit.

Abstract: A projector that includes: a projector body including an image optical system for image creation and projection, and an image circuit that operates the image optical system; an auxiliary input unit that forms an auxiliary signal for exercising control over an operating state of the projector body; and a distribution unit that transfers the auxiliary signal formed by the auxiliary input unit to the image circuit and an external display unit.

Abstract: To automatically adjust the quality of a projection image commensurate with the performance in-time deterioration and aging of projector component parts in an image projection system, each projector detects an integrated service time of its own light-source lamp and a service time and temperature of a liquid-crystal panel, and sends a detection result thereof to a control unit in compliance with a request from the control unit. These parameter values are parameter values having an effect upon the quality of a projection image and varying with time. The control unit copes with the projectors depending upon the detection result received from the projectors, to set predetermined control data for use in image-quality adjustment and send the control data respectively to the projectors. Each projector controls the driving to its light-source lamp and liquid-crystal panel, depending upon the control data received from the control unit.

Abstract: The two-way communication system which provides program information distributed in a predetermined broadcasting system from a program information provider for a CATV subscriber through a CATV network, processes return information returned from the CATV subscriber, and transmits the processed information to the program information provider is disclosed.