JP2016186559A - Starry sky projection device, starry sky projection system, and starry sky projection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a starry sky projection device, a starry sky projection system, and a starry sky projection method that can delete or fade a freely selected range of stars by using an image element in a part of the passage of a projection optical system.SOLUTION: A light emitted from a light source 1 passes through a condenser lens 2 and is reflected (turned on and off) by a DMD element 3a in the unit of a micro fine element, and an image is formed at a stellar original plate 6 through an image-forming lens 4. The light having passed through the stellar original plate 6 is projected on a dome screen, for example, by a projection lens 7.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a starry sky projection device, a starry sky projection system, and a starry sky projection method constituting a planetarium device that projects a starry sky on a dome screen, a ceiling, a wall, and the like.

In a conventional optical planetarium, the light from a strong light source is passed through a stellar original plate that has a transmission hole equivalent to a stellar in a light-shielding substrate, and is projected into a dome screen with a projection lens. It was projected.
Conventionally, the optical planetarium has a plurality of projection units to project the starry sky over the entire surface of the dome-shaped ceiling. The mainstream method is to reproduce changes in date and time by rotating the whole projector having a plurality of projection units.

In recent years, there is a single projection unit that projects the starry sky only on the ceiling, and at this time, the stellar original plate is decentered from the optical axis and rotated to show the diurnal motion. Some exist (Patent Document 1). According to these, it is possible to appreciate a beautiful starry sky simply at home at a low price (Patent Document 3).
Optical planetariums using these stellar original plates have a feature that a beautiful starry sky can be projected by increasing the definition of the stellar original plates by precision processing. However, on the other hand, since the stellar original plate is a fixed pattern, it is not possible to display or hide only any of the stars.

This is enough if you just want to project a starry sky. In actual planetarium screenings, foregrounds such as clouds and terrain are projected on a beautiful starry sky using a slide projector or video projector, and a presentation is often made.
However, in these effects, the star is projected even in the portion where the starry sky overlaps the image, so that the star is projected through the foreground, giving an unnatural impression to the audience.
In order to solve this problem, a technique has been proposed in which an element having an electro-optic effect for obtaining an arbitrary transmission pattern is inserted into a projection optical path including a star original plate to shield an arbitrary range of the starry sky (Patent Document 2). ).

However, when an electro-optical element is inserted in the projection optical path, for example, an ECD (electro-optical element) is inconvenient in practice because the light shielding property of the light shielding portion is not sufficient and the response speed is slow. In addition, stellar original plates are mostly designed with dimensions of 50 mm or more, and the equivalent size is difficult to obtain in practice and is difficult to implement on a planetarium projector with a limited market scale. .
On the other hand, a variety of liquid crystal panels, DMD elements, and the like are commercially available for projectors, but the panel size is too small to be implemented in the form of Patent Document 2.

  In recent years, digital planetariums using computer graphics and video projectors have been utilized, and there are no restrictions on production. However, the resolution by a video projector is far from that of an optical planetarium using a stellar original plate manufactured by precision machining, and this problem cannot be solved by using only a digital planetarium.

  In order to eliminate the unnaturalness of the high-definition starry sky and image overlap, the starry sky is projected by projecting a star that is darker than the specified value with a digital projector using a video projector, and the optical planetarium with a star that is brighter than the specified value. At the same time, a device has been proposed that can individually turn on and off bright stars projected by an optical planetarium, which has achieved remarkable effects. For this purpose, a high-definition digital projection device, and from these, The projected star image is reproduced at the correct position on the dome screen, and precise installation adjustment is necessary to maintain the positional relationship with the star image projected from the optical planetarium correctly. In addition, there is a problem that the cost is increased because special installation work and maintenance are required.

Japanese Patent No. 5105917 JP-A-10-123939 JP 2006-308785 A

  In this way, when displaying the starry sky and the foreground at the same time, it is difficult to erase or diminish an arbitrary range of stars, resulting in unnatural effects. Further, when an optical projector and a digital projector are used together in order to solve this problem, it becomes expensive and installation adjustment becomes troublesome, and it is difficult to install and operate easily.

  The present invention realizes a starry sky projection apparatus that solves the above-described problems of the prior art, and an object of the present invention is to provide an image element having a plurality of pixels, a light source that illuminates the image element, and an image using light from this light source. By having an illumination optical system that illuminates the element and an imaging optical system that forms an image of the image element illuminated by the illumination optical system on the stellar original plate surface, by making the illuminance distribution on the stellar original plate variable, It is an object to provide a starry sky projection device, a starry sky projection system, and a starry sky projection method capable of erasing or dimming an arbitrary range of stars.

In order to achieve the above object, a starry sky projection device according to claim 1 of the present invention has a stellar original plate having a transmission hole pattern corresponding to a stellar on a light-shielding substrate, a plurality of pixels, and each pixel An image element that is turned on and off by independently controlling each time, a light source that illuminates the image element, an illumination optical system that illuminates the image element with light of the light source, and the illumination optical system that is illuminated by the illumination optical system And an imaging optical system that forms an image of an image element on the surface of the stellar original plate, wherein the illuminance distribution on the stellar original plate is variable.
A starry sky projection apparatus according to a second aspect of the present invention is the starry sky projection apparatus according to the first aspect, wherein the image element uses a DMD element.
A starry sky projection apparatus according to a third aspect of the present invention is the starry sky projection apparatus according to the first aspect, wherein the image element uses a liquid crystal panel.
A starry sky projection device according to a fourth aspect of the present invention is the starry sky projection device according to the first, second, or third aspect, wherein the stellar original plate is movable with respect to the optical system, and the positional information of the stellar original plate is referred to. And an image element control circuit for controlling a signal applied to the image element, and displays, erases, or emphasizes an arbitrary range of the starry sky.
In other words, the image element control circuit displays a plurality of stars (such as solar system celestial bodies) independently at a predetermined position of the starry sky by the user's operation, erases specific stars independently, and further selects specific stars. It works to brighten and emphasize etc.
A starry sky projection system according to a fifth aspect of the present invention is characterized in that the starry sky is projected by using the starry sky projection device according to the first, second, third or fourth aspect alone.
A starry sky projection system according to a sixth aspect of the present invention is characterized by using a plurality of starry sky projection devices according to the first, second, third, or fourth aspect to divide and project a star to complete the starry sky.
According to a seventh aspect of the present invention, there is provided a starry sky projection system, wherein the starry sky projection device according to the first, second, third or fourth aspect is provided with a digital video projection device, and an image element is provided in accordance with the image of the digital video projection device. It has an image element control circuit to control, and masks the starry sky at the overlapping part with the image.
The starry sky projection method according to claim 8 of the present invention is a starry sky projection method in a starry sky projection system in which an image element for individually controlling the brightness of bright stars is inserted into the projection lens optical system to project the starry sky on a dome screen or the like. A mask video signal generating step of processing a video signal for projecting a starry sky and extracting a region that projects only the starry sky within a projected image range as a transparent portion to generate a mask video signal; A corrected mask video signal generating step for generating a corrected mask video signal for correcting and matching the deviation between the transparent area and the star display area in the digital video; and Image element driving step for driving, and depending on the difference in the position of the projection lens of the projection image from both the starry sky projection device and the digital video projection device In order to correct Lalux, coordinates are converted and corrected to correlate the position of the star projected from the starry sky projection device and the coordinates on the digital image projection device, and includes the bright star projected from the starry sky projection device. Each star is projected onto a dome screen.
A starry sky projection method according to a ninth aspect of the present invention is the starry sky projection method according to the eighth aspect, wherein the image element is a DMD element or a liquid crystal panel.
A starry sky projection method according to a tenth aspect of the present invention is the starry sky projection method according to the eighth or ninth aspect, wherein the starry sky projection device is an optical starry sky projector, and the digital image projection device is a video projector. Features.
The starry sky projection method according to an eleventh aspect of the present invention is the starry sky projection method according to the tenth aspect, wherein the video projector includes an imaging auxiliary lens, a condenser lens, and a stellar on a main body constituting a video projector for projecting a video signal. An original plate is arranged, and a projection image emitted from the star original plate is projected.
A starry sky projection method according to a twelfth aspect of the present invention is the starry sky projection method according to the tenth aspect, wherein the optical starry projector decenters the star original plate with respect to the optical axis of the optical lens system that projects the starry sky. It is characterized by realizing a starry sky that rotates and moves daily.

According to the above configuration, the starry sky projection device and the starry sky projection system can change the illuminance distribution on the star original plate, and can extinguish or diminish an arbitrary range of stars. Therefore, the brightness can be increased or decreased by adjusting the luminous intensity in units of stars, and a natural rendering effect can be obtained.
The starry sky projection system also erases the star that overlaps the foreground position, such as when displaying the starry sky and the foreground at the same time. For example, when the starry sky is visible from between the trees in the forest, the stars appear and disappear according to the shaking of the leaves of the trees. When there is a foreground (such as a cloud or other natural phenomenon) that can produce an effect and is slightly transmitted even with the brightness of the stars, it will be dimmed according to the degree and realize a starry sky close to nature Is possible.

It is a figure which shows embodiment of the projection unit which comprises the starry sky projection apparatus by this invention, and is the example using a DMD element as an image element which has a some pixel. It is a figure for demonstrating that a DMD element surface and a star original plate surface have a conjugate relation. It is a figure which shows other embodiment of the projection unit which comprises the starry sky projection apparatus by this invention, and is the example using a transmissive liquid crystal panel as an image element which has a some pixel. It is a figure for demonstrating the structural example of the simple planetarium apparatus which projects a starry sky using the single optical system of the projection unit of FIG. It is a figure which shows embodiment of the complex type planetarium comprised combining the projection unit and video projector by this invention. It is a figure which shows embodiment which used the projection unit shown in FIG. 3 for an off-the-shelf video projector. It is a figure which shows the example of the image | video projected with a video projector, and shows the night sky seen from between high-rise buildings. It is a figure which shows the example of the mask image | video which is the image | video which extracted only the sky part of FIG. It is a figure for demonstrating the illumination range on a stellar original plate, and has shown the state in which light is irradiated only to the part of the projection range on a stellar original plate. It is a figure for demonstrating the flow of the video signal process for correct | amending the positional relationship of the projection image of both an optical starry sky projector and a video projector. It is a figure which shows an example of the image | video pattern which sends and inputs the image | video of random noise to a DMD element.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an embodiment of a projection unit constituting a starry sky projection apparatus according to the present invention, and is an example in which a DMD element is used as an image element having a plurality of pixels.
The DMD element 3a is a known image element for a projector, and is an element in which a large number of fine reflecting mirrors whose angles can be electrically controlled are arranged in a grid pattern. The size of one fine reflector is approximately 10 μm, and each angle has a function that can be varied within a range of approximately ± 10 ° by electrical control.

The light emitted from the light source 1 is condensed on the surface of the DMD element 3 a by the condenser lens 2. The DMD element 3a is also called a micromirror device, and is an assembly of a large number of fine reflecting mirrors. The reflecting mirrors can be individually controlled in angle by electric signals.
The angle of the reflecting mirror of the DMD element 3a changes approximately 40 ° between the on direction and the off direction. At this time, the light reflected when the reflecting mirror of the DMD element 3a is in the ON direction is exactly incident on the condenser lens 5 and the star original plate 6 through the imaging lens 4. On the other hand, when the reflecting mirror of the DMD element 3a is in the off direction, the reflected light is scattered in another direction without passing through the imaging lens, or is absorbed by an appropriate light absorbing material or the like.

At this time, when the imaging lens 4 has a conjugate relationship between the DMD element 3a surface and the stellar original plate 6 surface, an image 8 of the DMD element 3a is formed on the stellar original plate 6 as shown in FIG. The image 8 of the DMD element 3 a covers the effective range of the stellar original plate 6. At this time, illumination in an arbitrary range on the surface of the stellar original plate 6 is turned on / off by turning on / off an arbitrary pixel of the DMD element 3a.
When the imaging lens 4 enlarges the DMD element 3a to a predetermined magnification and forms an image on the surface of the stellar original plate 6, the stellar original plate 6 can be used in a large size without being limited by the size of the DMD element 3a.
The light that has passed through the star original plate 6 is projected onto a projection surface such as a dome screen by the projection lens 7 in the same manner as a conventional projection unit, and can project the starry sky.

FIG. 3 is a diagram showing another embodiment of the projection unit constituting the starry sky projection apparatus according to the present invention, which is an example in which a transmissive liquid crystal panel is used as an image element having a plurality of pixels.
As the liquid crystal panel, a high-temperature polysilicon transmission type liquid crystal panel suitable for a projector is preferably used. The transmissive liquid crystal panel 13 is a transmissive element and can electrically control the polarization characteristics of the liquid crystal elements corresponding to individual pixels. When this is irradiated with predetermined polarized light, the amount of transmitted light changes due to the change in the polarization characteristics of the liquid crystal element.
The implementation principle using this liquid crystal element is almost the same as that of the DMD element 3a, but since it is a transmissive element, its optical axis is in a straight line.
The light source 11, the condensing lens 12, the imaging lens 14, the condenser lens 15, the stellar original plate 16 and the projection lens 17 are the light source 1, condensing lens 2, imaging lens 4, condenser lens 5, stellar original plate 6 and Each of the projection lenses 7 corresponds to the same configuration.

The transmissive liquid crystal panel 13 plays the same role as the DMD element of FIG. Actually, since the transmissive liquid crystal panel 13 is a polarizing element, a polarizing plate or a polarizing beam splitter is required in the front and rear, but these are well known and are omitted in the figure.
Although not shown as an embodiment, the same implementation is possible even when a reflective liquid crystal panel (L-COS) element is used. The implementation configuration in the case of using the L-COS element conforms to the usage example of the DMD element.
In this embodiment, an example in which an image element is used alone is shown. However, an embodiment as shown in FIGS. 1 and 3 is applied to an off-the-shelf projector using a DMD element or a liquid crystal panel. Even in the case of a configuration corresponding to the above, it is a matter of course that the present invention is included in the scope of the present invention as long as it is a principle of forming an image of an image element on a stellar original plate.

FIG. 6 is a diagram showing an embodiment in which the projection unit shown in FIG. 3 is used in an off-the-shelf video projector.
The projection light emitted from the off-the-shelf video projector 34 forms an image on the stellar original plate 36 through the condenser lens 35 by the projection lens 34a and the imaging auxiliary lens 34b of the projector itself. The light that has passed through the star original plate 36 projects the starry sky on the dome screen or ceiling through the projection lens 38. Only an arbitrary range of the stellar original plate 36 can be projected by a video signal input to the off-the-shelf video projector 34.
By combining a plurality of such projection units into a stellar projector as in the past, a starry sky projection system capable of turning on and off a starry sky in an arbitrary range can be configured.

FIG. 4 is a diagram for explaining a configuration example of a simple planetarium device that projects a starry sky using a single optical system of the projection unit of FIG. 1.
The light emitted from the light source 1 is condensed on the DMD element 3 a by the condenser lens 2. The light reflected by the DMD element 3a has a configuration in which the reflected light is directed toward the imaging lens 4 when the mirror of the DMD element 3a is at the ON state, and the DMD element 3a and the stellar original plate 6a are Because of the conjugate relationship, the light reflected from the arbitrary pixel 3b on the DMD element 3a forms an image at a predetermined position 19 on the stellar original plate 6a by the imaging lens 4 along the optical path 18. With such a structure and function of the DMD element 3a, light from the light source can be guided only to an arbitrary range (in this example, within a predetermined position 19) on the stellar original plate 6a by turning on / off each pixel of the DMD element 3a. .

The stellar original plate 6a is supported by an annular ring 9 having a gear 9a on the outer periphery, and is configured to be rotatable about a rotation shaft 21. The gear 9a meshes with the gear 10a of the output shaft of the motor 10, and the rotation output of the motor 10 is transmitted to the ring 9 via the gear 10a by driving the motor 10 under the control of a control circuit (not shown). . The stellar original plate 6a is brought to an arbitrary angular position at an arbitrary speed around the rotation axis 21. Since the rotation axis 21 is set to a position that is deviated from the optical axis 22 by a predetermined distance within a predetermined position 19 that is a projectable range, the starry sky to be projected on the star original plate 6a is controlled by the rotation control of the motor 10. Can move to the predetermined position 19 to realize movement like a constellation quick-view board. The starry sky projected onto the ceiling or the dome through the projection lens 7 by the configuration and control of the rotating mechanism portion of the star original plate 6a can realize a transition such as a diurnal motion.
This principle and details are described in Patent Document 3.

A control method for displaying a specific star in the simple planetarium apparatus will be described.
Since the position of a specific star on the stellar original plate 6a is known, naturally, the position of the specific star and the rotation angle are given, so that the position of the DMD element corresponding to the star is determined by coordinates such as a coordinate conversion circuit (not shown). It can be easily obtained by conversion processing. Therefore, if only the DMD element in this range is turned on by an image element control circuit (not shown) in FIG. 4 corresponding to the image element control circuit 25 incorporated in the optical starry projector 26 in FIG. It can be displayed and the other areas can be shielded.

FIG. 5 is a diagram showing an embodiment of a composite planetarium configured by using a projection unit according to the present invention and a video projector in combination.
The image of the video projector 37 installed toward the ceiling and the starry sky by the optical starry projector 26 are projected on the dome screen or the ceiling.
The video projector 37 is equipped with a fisheye lens 38a, and a video signal is input from the video reproduction device 32 through the video cable 23, and a video can be projected on the entire area of the dome screen or the ceiling. For example, when the image projected from the video projector 37 is a night sky image of a skyscraper city, a projected image 39 of the night view of the skyscraper city as shown in FIG. 7 is observed on the spot on the dome screen or ceiling. It is reproduced like this.

FIG. 8 is a diagram illustrating an example of a mask image that is an image obtained by extracting only the empty portion of FIG.
The video shown in FIG. 7 is processed in advance or processed in real time, and only the empty part is extracted. This is called a mask video. A white portion 41 of the mask image 40 in FIG. 8 is a transparent range corresponding to the sky.
The process of forming the mask video 40 is performed by the video playback device 32.
The video signal output from the video playback device 32 is input to the image element control circuit 25 in the optical starry projector 26 through the video cable 24, and the DMD element 3a which is an image element follows the mask video signal on the stellar original plate. Control the lighting range.

FIG. 9 is a diagram for explaining the illumination range on the stellar original plate, and shows a state where light is irradiated only on a portion of the projection range on the stellar original plate.
Light hits only the portion of the projection range 47 on the star original plate 46. Therefore, the star only in the projection range 47 is projected, and the other stars are not projected.

FIG. 10 is a diagram for explaining the flow of video signal processing for correcting the positional relationship between the projection images of both the optical starry sky projector and the video projector.
The positional relationship between the projection images from both the optical starry sky projector and the video projector causes parallax due to the difference in the position of the projection lens. However, by correcting by coordinate transformation, the relationship between the position of the star projected from the projection unit of the optical starry sky projector and the coordinates on the video projector is obtained.

The video signal output from the video processing device 32a is sent to the video projector 37 via the video cable 23 and simultaneously converted into a mask video signal in which only the transparent portion is white by the transparent portion extraction device 32b. The mask video signal is deformed and corrected by the parallax correction device 32c to become a corrected mask video signal. The corrected mask video signal drives the DMD element 3a via the DMD driving device 26a. Therefore, a star can be projected only in a sky range that does not overlap the foreground such as a skyscraper city projected from a video projector, and as a result, a beautiful starry sky in harmony with the foreground can be reproduced. In this embodiment, the parallax correction is performed on the video signal on the optical starry projector side. However, the parallax correction may be performed on the video signal sent to the video projector 37.
Moreover, although the transparent part extraction apparatus 32b and the parallax correction apparatus 32c were provided in the video reproduction apparatus 32, and the DMD drive apparatus 26a was provided in the optical starry projector 26, the transparent part extraction apparatus 32b and the parallax correction apparatus 32c were shown. The DMD driving device 26a is not limited to the image reproducing device 32 or the optical starry projector 26, but may be provided externally to other devices, the image reproducing device 32, or the optical starry projector 26.
When performing parallax correction on the video signal sent to the video projector 37, it is also possible to provide the transparent portion extraction device 32b and the parallax correction device 32c on the video projector 37 side.

The mask image 40 (see FIG. 8) is hidden by the transparent area of the mask image and the skyscraper group assuming that the skyscraper group clearly separates the part where the starry sky is not visible and the part where the starry sky is visible. For example, the forest part where there are many trees occupies most of the background, and there are many small area parts where the starry sky can be seen in the background. When the position is shifted, it is difficult to produce the effect of making the mask image visible or invisible by turning on / off the star by controlling the image element even in a large number of minute areas.
Therefore, for the part where the starry sky and the part where trees stand are overlapped, the minute area part is set as the transparent range, and the transparent range moves slightly to the left and right in time series, and the time of the wind movement is assumed. Then, a more realistic starry sky can be realized by controlling the starry sky where the star is present.

  In order to bring about the above-mentioned effect, a mask image having a small area portion as a transparent range is created in a portion of the mask image that overlaps, for example, a forest portion, and a mask image in which the minute area portion is moved is created. A transparent part extraction device and a parallax correction device for performing processing of sequentially switching to a mask image corresponding to an image generated by a video projector having a motion in a grove and changing in time series due to the influence of wind Can be used to construct a device that is unique to a circuit that controls on / off of a star with an image element to express the starry sky.

FIG. 11 is a diagram illustrating an example of a video pattern in which a random noise-like video is sent to the DMD element and input.
If the brightness of each pixel changes randomly due to such random noise, the brightness of the stars on the stellar original plate will change randomly within a fine range. Thereby, the effect that individual stars blink arbitrarily is obtained. In addition, since the blink pattern is generated by a digital image, it is also possible to change the intensity of the flicker, and it is also possible to change the intensity of the flicker near the night sky zenith and the horizon. Therefore, an optical planetarium in which all stars blink naturally can be realized.
According to the present invention, an optical planetarium capable of finely shielding an arbitrary range and projecting a starry sky in harmony with an image can be realized.

  A starry sky projection device, a starry sky projection system, and a starry sky projection method constituting a planetarium device that projects a starry sky on a dome screen, a ceiling, or the like.

DESCRIPTION OF SYMBOLS 1,11 Light source 2,12 Condensing lens 3a DMD element 3b Arbitrary pixel 4,14 Imaging lens 5,15,35 Condenser lens 6,6a, 16,36,46 Stellar original plate 7,17,34a, 38 Projection lens 8 Image of DMD element 9 Ring 9a, 10a Gear 10 Motor 13 Transmission liquid crystal panel 17 Projection range 18 Optical path 19 Predetermined position 21 Rotating axis 22 Optical axis 23, 24, 33 Video cable 25 Image element control circuit 26 Optical starry sky projector 32 Video playback device 34, 37 Video projector 34b Imaging auxiliary lens 39 Projected image of video projector 40 Mask video 41 Transparent range corresponding to the sky 42 Random noise video pattern 47 Projection range on stellar original plate

Claims (12)

A stellar original plate having a transmission hole pattern corresponding to a stellar on a light-shielding base material,
An image device having a plurality of pixels and independently turning on and off the light for each pixel;
A light source that illuminates the image element;
An illumination optical system that illuminates the image element with light from the light source;
An imaging optical system that forms an image of the image element illuminated by the illumination optical system on the stellar original plate surface;
A starry sky projection device characterized in that the illuminance distribution on the star original plate is variable.   2. The starry sky projection device according to claim 1, wherein the image element is a DMD element.   2. The starry sky projection device according to claim 1, wherein a liquid crystal panel is used as the image element. The stellar original plate is movable with respect to the optical system, and has an image element control circuit that controls a signal applied to the image element with reference to positional information of the stellar original plate,
4. The starry sky projection device according to claim 1, wherein an arbitrary range of the starry sky is displayed, erased or emphasized.   A starry sky projection system, wherein the starry sky projection device according to claim 1 is used alone to project the starry sky.   A starry sky projection system using a plurality of the starry sky projection devices according to claim 1, 2, 3 or 4 to divide and project a star to complete a starry sky. The starry sky projection device according to claim 1, 2, 3 or 4, further comprising an image element control circuit for controlling an image element in accordance with an image of the digital image projection device,
A starry sky projection system that masks the starry sky that overlaps the image. A starry sky projection method in a starry sky projection system for projecting a starry sky onto a dome screen or the like by inserting an image element for individually controlling the brightness of a bright star into a projection lens optical system,
A mask video signal generation step of processing a video signal for projecting the starry sky to extract a region that projects only the starry sky within the projected image range as a transparent portion and generating a mask video signal;
A corrected mask video signal generating step for generating a corrected mask video signal for correcting and matching the deviation between the extracted transparent region and the region displaying the starry sky in the digital video;
An image element driving step of driving an image element by the corrected mask video signal;
Consists of
In order to correct the parallax due to the difference in the position of the projection lens of the projection image from both the starry sky projection device and the digital video projection device, the coordinates of the star projected from the starry sky projection device and A starry sky projection method characterized by correlating coordinates on a digital video projector and projecting each star including bright stars projected from the starry projector onto a dome screen or the like.   9. The starry sky projection method according to claim 8, wherein the image element is a DMD element or a liquid crystal panel. The starry sky projection device is an optical starry sky projector,
10. The starry sky projection method according to claim 8, wherein the digital image projection device is a video projector.   The video projector is characterized in that an imaging auxiliary lens, a condenser lens, and a star original plate are arranged on a main body constituting a video projector for projecting a video signal, and a projection image emitted from the star original plate is projected. Item 11. The starry sky projection method according to Item 10.   11. The starry sky projection according to claim 10, wherein said optical starry sky projector realizes a starry sky moving in a diurnal motion by decentering and rotating a star original plate with respect to an optical axis of an optical lens system for projecting the starry sky. Method.