Abstract: Information having a hierarchical structure is appropriately selected and displayed in accordance with a change in a user. Provided are: a display unit; a storage unit configured to store information to be displayed on the display unit, the information having a plurality of hierarchical structures; and a display control unit configured to read information from the storage unit while selecting a level and display the read information on the display unit, based on a maximum viewing distance between the display unit and a viewer viewing the display unit at which the viewer is able to view the display unit while holding a device housing, and on a current viewing distance between the viewer and the device housing.

Abstract: A positioning assistance device that assists positioning between a content displayed on a display and an object transparently observed through the display is as follows. The positioning assistance device includes: a state calculation unit configured to calculate a supported state of the display relative to the object; an adjustment amount calculation unit configured to calculate, for the supported state, an adjustment amount related to a positioning operation for setting an appropriate positional relation between the content and the object; and a presentation information generation unit configured to generate and output presentation information including the adjustment amount. The adjustment amount calculation unit calculates the adjustment amount by using record data of a positioning operation performed by a user of the display in response to the presentation information output in advance.

Abstract: Provided is an image presentation system 10, including: a plurality of particle emission units 20 each of which emits particles; an image projection unit 30; and a control unit 50. The control unit 50 controls to cause collision of particles emitted from a first particle emission unit 20 (#1), out of the plurality of particle emission units 20, and particles emitted from a second particle emission unit 20 (#2), out of the plurality of particle emission units, so as to generate a retention field 60 that is used as a screen to which an image is project, and the image projection unit 30 projects an image to the retention field 60.

Abstract: A screen forming apparatus 20 includes: a particle source selecting unit 24 which selects a particle source to be used from a plurality of particle sources 22 having different characteristics regarding a viewing angle; a vaporizing unit 26 which vaporizes particles acquired from the particle source selected by the particle source selecting unit 24; and a screen forming unit 28 which forms a screen using the particles vaporized by the vaporizing unit 26.

Abstract: Provided is an image presentation system 10, including: a plurality of particle emission units 20 each of which emits particles; an image projection unit 30; and a control unit 50. The control unit 50 controls to cause collision of particles emitted from a first particle emission unit 20 (#1), out of the plurality of particle emission units 20, and particles emitted from a second particle emission unit 20 (#2), out of the plurality of particle emission units, so as to generate a retention field 60 that is used as a screen to which an image is project, and the image projection unit 30 projects an image to the retention field 60.

Abstract: A screen forming apparatus 20 includes: a particle source selecting unit 24 which selects a particle source to be used from a plurality of particle sources 22 having different characteristics regarding a viewing angle; a vaporizing unit 26 which vaporizes particles acquired from the particle source selected by the particle source selecting unit 24; and a screen forming unit 28 which forms a screen using the particles vaporized by the vaporizing unit 26.