Holographic projection device capable of forming a holographic image without misalignment

A holographic projection device includes an image display and a plurality of reflective projection panels. The plurality of reflective projection panels intersect one another at an vertex. A method for operating the holographic projection device includes receiving projection coordinates of the vertex on the image display, receiving a vector connecting coordinates of an image center of the image display and the projection coordinates of the vertex, and shifting a plurality of images displayed on the image display according to the vector to project the plurality of images onto the plurality of reflective projection panels to form a holographic image.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a holographic device, and more particularly, a holographic device that can align an image center with a vertex of a plurality of reflective projection panels to form a holographic image.

2. Description of the Prior Art

A holographic image is commonly formed by projecting different views of a three-dimensional object from their respective angles. After the holographic image is formed, it appears as the three-dimensional object floating in space. Due to the ability of creating a sense of reality, the holographic projection device can be used in augment reality applications. For example, the holographic image may be used on a theater stage to interact with real actors so that the audience can experience a fantasy between reality and illusion.

FIG. 1shows a holographic image of a duck formed by a holographic projection device100of prior art. Since the holographic image is composed of different views of the duck, it is crucial for the different views to be aligned accurately. InFIG. 1, the holographic image H0shows a front view H0fof the duck and a side view H0sof the duck. However, since the front view H0fof the duck is displayed higher than the side view H0sof the duck, the holographic image would be misaligned at the boundary of the portions formed by the front view H0fand the side view H0sof the duck. Therefore, it is critical to fix misalignment at the boundary of portions formed by different views in a holographic image.

SUMMARY OF THE INVENTION

One embodiment of the present invention discloses a method for operating a holographic projection device. The holographic projection device comprises an image display and a plurality of reflective projection panels. The plurality of reflective projection panels are intersecting one another at an vertex. The method comprises receiving projection coordinates of the vertex on the image display, receiving a vector connecting coordinates of an image center of the image display and the projection coordinates of the vertex, and shifting a plurality of images displayed on the image display according to the vector to project the plurality of images onto the plurality of reflective projection panels to form a holographic image.

Another embodiment of the present invention discloses a holographic projection device. The holographic projection device comprises a plurality of reflective projection panels, an image display, a position sensing module, and a processor. The plurality of reflective projection panels intersect one another at an vertex. The image display is used to project a plurality of images onto the plurality of reflective projection panels. The position sensing module is used to detect projection coordinates of the vertex on the image display. The processor is used to receive a vector connecting coordinates of an image center of the image display and the projection coordinates of the vertex, and shift the plurality of images displayed on the image display according to the vector to project the plurality of images onto the plurality of reflective projection panels to form a holographic image.

DETAILED DESCRIPTION

FIG. 2shows a holographic projection device200according to one embodiment of the present invention. The holographic projection device200may include a plurality of reflective projection panels210, an image display220, a position sensing module230, and a processor240. The plurality of reflective projection panels210may intersect one another at a vertex212and the image display220may project a plurality of images onto the plurality of reflective projection panels210.

InFIG. 2, the holographic projection device200may include four reflective projection panels210, and the four reflective projection panels210may intersect one another at the vertex212. In this case, the four reflective projection panels210may form a square base pyramid. In other embodiments of the present invention, the holographic projection device200may have a different number of reflective projection panels.

The vertex212may be disposed close to the image display220so the four images I1to I4displayed by the image display220may be projected onto the four reflective projection panels210respectively. The four images I1to I4projected by the image display220may be different views of an object so as to form a holographic image H1of the object.

The reflective projection panels210may be made of material that is both reflective and transparent, such as glass or acrylic, so the reflective projection panels210may generate virtual images V1to V4of the images I1to I4displayed by the image display220and the virtual images V1to V4may be seen through the reflective projection panels210. In some embodiments of the present invention, the angle between each of the reflective projection panels210and the image display220may be 45 degrees so the holographic image H1formed by the virtual images V1to V4may be perpendicular to the image display220. However, the angle is not limited to 45 degrees in the present invention.

In addition, the plurality of images I1to I4may be displayed with respect to an image center C1of the image display220, that is, the distances from the four images I1to I4to the image center C1are all the same. In some embodiments of the present invention, the image center C1of the image display220may be a geographic center of the image display220by default. For example, inFIG. 2, the image display220may display the plurality of images I1to I4with respect to the geographic center of the image display220. However, since the projection coordinates (xv, yv) of the vertex212on the image display220do not substantially overlap with the coordinates (xc, yc) of the image center C1of the image display220, the distances between the four images I1to I4and the vertex212may be different, causing the distances between the virtual images V1to V4and the image display220to be different. Consequently, the distances between the four sides of the holographic image H1and the image display220may be different, thus the four sides of the holographic image H1are misaligned.

To align the four sides of the holographic image H1, the coordinates (xc, yc) of the image center C1of the image display220should substantially overlap with the projection coordinates (xv, yv) of the vertex212on the image display220. The position sensing module230and the processor240may be used to align the projection coordinates (xv, yv) of the vertex212on the image display220and the coordinates (xc, yc) of the image center C1of the image display220.

The position sensing module230may be used to detect projection coordinates (xv, yv) of the vertex212on the image display220. The projection coordinates (xv, yv) of the vertex212on the image display220may be coordinates of the orthogonal projection of the vertex212on the image display220. In some embodiments of the present invention, the vertex212may directly contact with the image display220. In this case, the projection coordinates (xv, yv) of the vertex212on the image display220may be coordinates of a point on the image display220that the vertex212contacts with.

InFIG. 2, the position sensing module230may include two image sensors231and232to derive the projection coordinates (xv, yv) of the vertex212. For example, the image sensor231may detect an angle θ between an edge W of the image display220and the contact point of the vertex212on the image display220with respect to the image sensor231and the image sensor232may detect an angle Ø between the edge W of the image display220and the contact point of the vertex212on the image display220with respect to the image sensor232. Since the length LWof the edge W is a known factor, the projection coordinates (xv, yv) of the vertex212on the image display220may be derived as

Once the projection coordinates (xv, yv) of vertex212on the image display220is derived, a vector (Δx, Δy) connecting the coordinates (xc, yc) of the image center C1of the image display220and the projection coordinates (xv, yv) of the vertex212on the image display220may be generated as

(xv-Lw2,yv-LL2)
where LLis a length of an edge L of the image display212, and the coordinates (xc, yc) of the image center C1of the image display220is at the geographic center of the image display220with coordinates of

(Lw2,LL2),
which are both known factors.

The processor240may receive the vector (Δx, Δy), and shift the plurality of images I1to I4displayed on the image display220according to the vector (Δx, Δy), that is to shift the image center C1of the image display220. InFIG. 3, the coordinates (xc′, yc′) of the shifted center C1′ of the image display220are shifted to overlap with the projection coordinates (xv, yv) of vertex212so the distances from the four images I1to I4to the projection coordinates (xv, yv) of the vertex212are the same and the four images I1to I4may be projected onto the four reflective projection panels210to form the holographic image H2without any misalignment.

Moreover, after the processor240shifts the images I1to I4according to the vector (Δx, Δy), the vertex212may be changed by the user again. In this case, the processor240may further shift the images I1to I4again with respect to a vector connecting the coordinates (xc′, yc′) of the shifted center C1′ of the image display220and new projection coordinates of the vertex212that was changed by the user to align the coordinates (xc′, yc′) of the shifted center C1′ of the image display220and new projection coordinates of the vertex212.

Although, inFIG. 2, the position sensing module230includes two image sensors, the present invention is not limited to apply two image sensors in the position sensing module. In other embodiments of the present invention, the position sensing module may include even more image sensors for detecting the projection coordinates of the vertex when the vertex does not contact with the image display directly. Also, in other embodiments of the present invention, the position sensing module may include a touch sensor instead of image sensors to detect projection coordinates of the vertex on the image display when the vertex contacts with the image display directly.

Furthermore, the processor240may increase distances D1to D4between the plurality of images I1to I4and the projection coordinates (xv, yv) of the vertex212to increase a distance D5between the holographic image H2and the image display220.FIG. 4shows the holographic image H3projected by the holographic projection device200according to one embodiment of the present invention. The distances D1′ to D4′ between the plurality of images I1to I4and the projection coordinates (xv, yv) of the vertex212inFIG. 4are greater than the distances D1to D4between the plurality of images I1to I4and the projection coordinates (xv, yv) of the vertex212inFIG. 3. Consequently, the distance D5′ between the holographic image H3and the image display220is greater than the distance D5between the holographic image H2and the image display220. In some embodiments of the present invention, the distance between the holographic image and the image display may be seen as a height of the holographic image from the image display. In this case, by increasing the distances between the plurality of images I1to I4and the projection coordinates (xv, yv) of the vertex212, the height of the holographic image is raised.

Similarly, the processor240may decrease the distances D1to D4between the plurality of images I1to I4and the projection coordinates (xv, yv) of the vertex212to decrease the distance D5between the holographic image H2and the image display220.FIG. 5shows the holographic image H4projected by the holographic projection device200according to one embodiment of the present invention. The distances D1″ to D4″ between the plurality of images I1to I4and the projection coordinates (xv, yv) of the vertex212inFIG. 5are smaller than the distances D1to D4between the plurality of images I1to I4and the projection coordinates (xv, yv) of the vertex212inFIG. 3. Consequently, the distance D5″ between the holographic image H4and the image display220is smaller than the distance D5between the holographic image H2and the image display220. In other words, the height of the holographic image H4is lowered by decreasing the distances between the plurality of images I1to I4and the projection coordinates (xv, yv) of the vertex212.

In addition, the processor240may rotate the plurality of images I1to I4with respect to the projection coordinates (xv, yv) of the vertex212on the image display220so that the position of the holographic image H2on the plurality of reflective projection panels210may be adjusted.FIG. 6shows a holographic image H5projected by the holographic projection device200according to one embodiment of the present invention. InFIG. 6, the images I1to I4are rotated with respect to the projection coordinates (xv, yv) of the vertex212by a degree α on the image display220so as to rotate the holographic image H5by a degree α.

Since the processor240may shift the plurality of images I1to I4displayed on the image display220according to the vector (Δx, Δy) when the projection coordinates (xv, yv) of the vertex212on the image display220do not substantially overlap with the coordinates (xc, yc) of the image center C1, the holographic projection device200is able to project the plurality of images I1to I4onto the plurality of reflective projection panels210to form the holographic image H2without misalignment. Furthermore, the processor240may adjust the distances D1to D4between the plurality of images I1to I4and the projection coordinates (xv, yv) of the vertex212and/or rotate the plurality of images I1to I4with respect to the projection coordinates (xv, yv) of the vertex212to adjust the position of the holographic image H2on the plurality of reflective projection panels210. Therefore, the holographic projection device200is not only able to fix misalignment but is also able to adjust the position of the holographic image according to various application requirements.

FIG. 7shows a method700for operating a holographic projection device200according to one embodiment of the present invention. The method700includes steps S710to S730:

S710: receiving the projection coordinates (xv, yv) of the vertex212on the image display220;

S720: receiving the vector (Δx, Δy) connecting the coordinates (xc, yc) of an image center C1of the image display220and the projection coordinates (xv, yv) of the vertex212; and

S730: shifting the plurality of images I1to I4displayed on the image display220according to the vector (Δx, Δy) to project the plurality of images I1to I4onto the plurality of reflective projection panels210to form the holographic image.

In some embodiments of the present invention, after the processor240receives the projection coordinates (xv, yv) of the vertex212on the image display220in step S710, the processor240may further determine if the projection coordinates (xv, yv) of the vertex212substantially overlap with the coordinates (xc, yc) of the image center C1. If the projection coordinates (xv, yv) of the vertex212do not substantially overlap with the coordinates (xc, yc) of the image center C1, a misalignment may occur. Consequently, the processor240may receive the vector (Δx, Δy) connecting coordinates (xv, yv) of the image center C1of the image display220and the projection coordinates (xv, yv) of the vertex212in step S720and shift the plurality of images I1to I4according to the vector (Δx, Δy) in step S730. However, if the projection coordinates (xv, yv) of the vertex212overlap with the coordinates (xc, yc) of the image center C1, then the processor doesn't shift the images.

Furthermore, in some embodiments of the present invention, the method700may further include steps S740to S760:

S740: increasing the distances between the plurality of images I1to I4and the projection coordinates (xv, yv) of the vertex212to increase the distance between the holographic image and the image display220;

S750: decreasing the distances between the plurality of images I1to I4and the projection coordinates (xv, yv) of the vertex212to decrease the distance between the holographic image and the image display220; and

S760: rotating the plurality of images I1to I4with respect to the projection coordinates (xv, yv) of the vertex212on the image display220.

By operating steps S740and S750, a height of the holographic image can adjusted as the system need. Also, steps S740to S760may be operated more than one time in any sequence according the application needs. For example, the processor240may increase distances between the plurality of images I1to I4and the projection coordinates (xv, yv) of the vertex212firstly, then rotate the plurality of images I1to I4with respect to the projection coordinates (xv, yv) of the vertex212on the image display220, and then increase distances between the plurality of images I1to I4and the projection coordinates (xv, yv) of the vertex212again to project the holographic image at a proper position. In some embodiment of the present invention, steps S710to S760may be done by the processor240.

According to the holographic projection device and the method for operating the holographic projection device provided by the embodiments of the present invention, the problem of misaligning the holographic image can be solved. Furthermore, the position of the holographic image can be adjusted easily.