The invention relates to an optical system for restoring a natural image combined with a digital image, in order to characterise and highlight the objects represented on the natural image. The optical system includes an objective lens, an eyepiece, a semi-reflective plate, a processing unit, capturing means and restoring means. The invention also relates to a method for producing such a digital image.

A starry sky reproducing device contains: a ceiling section an inner surface of which has a semi-spherical surface on which a starry sky can be projected; a wall section which has a nearly vertical wall surface contiguous to a lower end section of the semi-spherical surface of the ceiling section; a floor section on which the wall section is installed; starry sky projection means for projecting a starry sky on the semi-spherical surface of the ceiling section, the starry sky projection means being installed near a center of the floor section and near a center of the semi-spherical surface of the ceiling section; a plurality of seats which are installed on the floor section; one or more partial starry sky reproducing means for reproducing details of a part of a starry sky, the partial starry sky reproducing means being installed between the seats and the wall surface, preferably at positions in a proximity of the wall surface; and one or more telescopes through which a detailed image of a part of a starry sky which the partial starry sky reproducing means reproduces can be observed, the telescopes being installed at positions between the seats and the wall surface opposing the partial starry sky reproducing means across the starry sky projection means.

A starry sky reproducing device contains: a ceiling section an inner surface of which has a semi-spherical surface on which a starry sky can be projected; a wall section which has a nearly vertical wall surface contiguous to a lower end section of the semi-spherical surface of the ceiling section; a floor section on which the wall section is installed; starry sky projection means for projecting a starry sky on the semi-spherical surface of the ceiling section, the starry sky projection means being installed near a center of the floor section and near a center of the semi-spherical surface of the ceiling section; a plurality of seats which are installed on the floor section; one or more partial starry sky reproducing means for reproducing details of a part of a starry sky, the partial starry sky reproducing means being installed between the seats and the wall surface, preferably at positions in a proximity of the wall surface; and one or more telescopes through which a detailed image of a part of a starry sky which the partial starry sky reproducing means reproduces can be observed, the telescopes being installed at positions between the seats and the wall surface opposing the partial starry sky reproducing means across the starry sky projection means.

The present invention addresses the problem of providing a video display device that projects and displays video including starry sky images onto a target surface, that can reproduce the twinkling of stars and that can more faithfully reproduce an actual starry sky. Provided are a light source, a projection lens, a starry-sky projection negative plate, a twinkling negative plate with uneven light-transmitting properties, a starry-sky-end support unit that supports the starry-sky projection negative plate in a location onto which light from the light source is radiated, a twinkling-end support unit that supports the twinkling negative plate between the starry-sky projection negative plate and the projection lens or between the light source and the starry-sky projection negative plate, and an actuation mechanism that rotationally actuates, by power from an actuator, the starry-sky projection negative plate in a state of being supported by the starry-sky-end support unit and the twinkling negative plate in a state of being supported by the twinkling-end support unit. Light that has penetrated the starry-sky projection negative plate and the twinkling negative plate is radiated onto the target surface via the projection lens.

The present invention addresses the problem of providing a video display device that projects and displays video including starry sky images onto a target surface, that can reproduce the twinkling of stars and that can more faithfully reproduce an actual starry sky. Provided are a light source, a projection lens, a starry-sky projection negative plate, a twinkling negative plate with uneven light-transmitting properties, a starry-sky-end support unit that supports the starry-sky projection negative plate in a location onto which light from the light source is radiated, a twinkling-end support unit that supports the twinkling negative plate between the starry-sky projection negative plate and the projection lens or between the light source and the starry-sky projection negative plate, and an actuation mechanism that rotationally actuates, by power from an actuator, the starry-sky projection negative plate in a state of being supported by the starry-sky-end support unit and the twinkling negative plate in a state of being supported by the twinkling-end support unit. Light that has penetrated the starry-sky projection negative plate and the twinkling negative plate is radiated onto the target surface via the projection lens.

Disclosed is a starry sky reproducing sheet containing: N laminated light reducing sheets stuck together, each of which has homogeneous light reducing effects (where N is two or larger); the starry sky reproducing sheet containing, with M and L being two mutually different integers that are one or larger and N or smaller (M>L): L-layer transmission holes that are formed through L light reducing sheets stuck together, so that light beams pass therethrough; and M-layer transmission holes that are formed, through M light reducing sheets stuck together including the L light reducing sheets, at different positions from those of the L-layer transmission holes; wherein light beams incident on one face of the starry sky reproducing sheet pass through the L- and M-layer transmission holes while being attenuated at mutually different light reduction ratios to become L- and M-layer transmitted beams respectively which are visibly recognizable as transmitted-light stars having mutually different brightnesses.

Disclosed is a starry sky reproducing sheet containing: N laminated light reducing sheets stuck together, each of which has homogeneous light reducing effects (where N is two or larger); the starry sky reproducing sheet containing, with M and L being two mutually different integers that are one or larger and N or smaller (M>L): L-layer transmission holes that are formed through L light reducing sheets stuck together, so that light beams pass therethrough; and M-layer transmission holes that are formed, through M light reducing sheets stuck together including the L light reducing sheets, at different positions from those of the L-layer transmission holes; wherein light beams incident on one face of the starry sky reproducing sheet pass through the L- and M-layer transmission holes while being attenuated at mutually different light reduction ratios to become L- and M-layer transmitted beams respectively which are visibly recognizable as transmitted-light stars having mutually different brightnesses.

A dome screen projection system includes a dome screen unit and two sets of projectors. The dome screen unit includes a top side, two opposite lateral sides extending downward from two opposite ends of the top side, and a curved projection surface extending downwardly from the top side between the opposite lateral sides. Each of the two sets of projectors are disposed on the top side proximally to one of the lateral sides. The two sets of projectors are directed toward the curved projection surface.

A dome screen projection system includes a dome screen unit and two sets of projectors. The dome screen unit includes a top side, two opposite lateral sides extending downward from two opposite ends of the top side, and a curved projection surface extending downwardly from the top side between the opposite lateral sides. Each of the two sets of projectors are disposed on the top side proximally to one of the lateral sides. The two sets of projectors are directed toward the curved projection surface.

In an image projection device including a laser beam source and a diffractive optical element provided on an optical path of a laser beam L from the laser beam source, a transparent member having a refractive index higher than that of an area ahead of an emission surface on the optical path of the laser beam L and a diffractive optical element is formed on an emission surface of the transparent member. The laser beam L is obliquely incident on the diffractive optical element. The diffractive optical element generates a diffraction image in an area which is not overlapped with zeroth order light LR of the laser beam L and an area occupied by a conjugate image, and is arranged in a direction to irradiate a screen with diffracted light forming the diffraction image while substantially eliminating the zeroth order light and the diffracted light forming the conjugate image.