KR20030088649A - Three-dimensional display - Google Patents

Abstract

PURPOSE: A stereoscopic display apparatus is provided to prevent the integrated image overlapping effect by opening and closing in turns a basic lens through a cross orthogonal polarized mask and a polarization modulator . CONSTITUTION: An image processor generates a basic image for generating three-dimensional image. An image display displays the basic image generated in the image processor. A lens array is comprised of plural basic lenses and images the basic image displayed through the image display to regenerate a corresponding three-dimensional image. A polarization modulator switches in turns so that a polarized direction of the basic image displayed by the image display has one of polarized directions of a cross orthogonal polarized mask.

Description

Stereoscopic display device {Three-dimensional display}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stereoscopic image display apparatus, and more particularly, to a stereoscopic image display apparatus for displaying a 3D image using integrated photography (hereinafter referred to as IP). will be.

The IP method using the lens array among 3D image realization techniques has been gradually improved since it was first proposed by Lippmann in 1908, but it has not received much attention due to the limitations of the imaging device or display device technology. In recent years, with the development of high-resolution imaging devices and high-resolution display devices, research has been actively conducted.

The basic principle of the conventional IP scheme is shown in FIG.

As shown in FIG. 1, the entire system for implementing the IP scheme is largely composed of two functional units, that is, a photographing unit and a display unit. The photographing unit includes a lens array forming an image of an object having a three-dimensional shape, and a photographing element storing a basic image formed by the lens array. The display unit includes a display element displaying a basic image stored in the photographing element, and a display. It includes a lens array for forming a three-dimensional image by forming the base image displayed on the device. Each lens array consists of a plurality of unit lenses.

In the image capturing unit, the basic image in various directions of the 3D object is stored in the image capturing device by the unit lens of the lens array. In the display unit, the basic images stored in the reverse process of the photographing unit are displayed by the display element, and these basic images are then merged through the lens array (referred to as an aggregate image) to a three-dimensional image from the position where the original three-dimensional object was located. Is played.

However, one of the problems in the stereoscopic image display device by the IP method is a limited viewing angle. In order to eliminate the phenomenon that several stereoscopic images reproduced by the IP method are displayed at the position beyond the corresponding basic lens area among the respective basic images, it is not displayed on the image display device, which limits the basic viewing angle of the IP method. do. As a result, the limited viewing angle is expressed as follows.

Where θ is the viewing angle, φ is the width of the underlying lens, and g is the distance between the lens array and the image display element.

In detail, when an observer observes a stereoscopic image at a location outside the viewing angle as shown in FIG. 2, the overlapping integrated image overlapping with the original integrated image is observed. The overlapping phenomenon of the integrated image is basically because each base image passes through the corresponding base lens and the adjacent base lens. In an ideal stereoscopic image system, the stereoscopic image to be reproduced should be viewed by a wide range of people together, and this limited viewing angle has been pointed out as a problem far less than that.

An object of the present invention is to provide a three-dimensional image display device having a wider viewing angle.

1 is a diagram illustrating the basic concept of general integrated photography (IP).

FIG. 2 is a view illustrating a limitation of a viewing angle due to overlapping of integrated images in a conventional IP.

3 is a block diagram of a viewing angle enhanced IP stereoscopic image display apparatus using a base lens opening and closing according to a first embodiment of the present invention.

FIG. 4 is a diagram illustrating an embodiment of a viewing angle enhanced IP stereoscopic image display apparatus using opening and closing a basic lens illustrated in FIG. 3.

5 is a conceptual diagram for generating a base image according to an embodiment of the present invention.

6 is a block diagram illustrating an operating principle of a stereoscopic image display device according to a second embodiment of the present invention.

7A and 7B are diagrams showing an example of the opening and closing role of the base lens as the polarization state after passing through the cross-orthogonal polarization mask when the polarization states of the polarization modulators are switched to be orthogonal in the second embodiment.

8 is a block diagram illustrating an operating principle of a stereoscopic image display device according to a third embodiment of the present invention.

In order to achieve the technical problem, the present invention uses a method of placing an orthogonal polarization mask between the lens array and the image display device and changing the base image displayed on the image display device into two polarization states.

Specifically, an image processor for generating a base image for reproducing a 3D image, an image display unit for displaying a base image generated by the image processor, a polarization modulator for switching polarization states of the base image, and polarization states orthogonal to each other A stereoscopic image display device including a polarization mask portion to be alternately provided and a lens array portion including a plurality of elementary lenses is provided.

At this time, it is preferable that the basic image displayed on the image display unit is synchronized with the polarization state switching of the polarization modulator to change its shape and polarization state.

An embodiment of the present invention will now be described with reference to the drawings.

3 illustrates a stereoscopic image display apparatus using a viewing angle enhancement method by opening and closing a lens according to a first embodiment of the present invention.

The stereoscopic image display device according to the first embodiment of the present invention includes an image processing unit, an image display unit, a lens array, and a basic lens opening and closing unit as shown in FIG. 3.

The image processor produces a base image, and the base lens opening and closing part serves to allow only the base lens to pass through the base lens, so that an integrated image superimposition phenomenon does not occur, thereby improving the viewing angle.

Here, the base lens opening and closing part is positioned between the lens array and the image display part and selectively covers the light directed from the image display part to any elementary lens according to the control signal of the image processor. Specifically, an LCD shutter, a spatial light modulator, a mechanical shutter, and the like may be used as the basic lens opening and closing portion.

4 is an embodiment of a viewing angle enhancement CGIP (Computer Generated Integral Photography) method by opening and closing a lens according to the first embodiment of the present invention. Here, the basic images corresponding to the basic lenses in the vertical direction or the horizontal direction by one line are displayed on the image display unit, and at the same time, the basic lenses in the vertical direction or the horizontal direction by the basic lens opening / closing unit by the basic lens opening and closing unit. Are opened. Then, the currently opened basic lenses are closed, and the basic lenses in the vertical direction or horizontal direction are opened one by one over the other row that was closed by the basic lens opening and closing, and the corresponding basic images are displayed on the image display unit to perform one cycle of operation. And repeat quickly. As described above, the basic image of the two states is displayed on the image display unit, and the basic lens opening and closing unit is operated in synchronization with the basic image.

The basic image generated in the stereoscopic image display device according to the first embodiment of the present invention operating as described above is produced as follows.

In an embodiment of the present invention, in order to solve problems such as a depth reversal phenomenon occurring in the photographing process and to simplify the structure of the system, a basic image is produced by computer graphics. Accordingly, the stereoscopic image display device according to the present invention is a CGIP. It can be called a device.

Here, the object may be assumed to be a virtual three-dimensional object, and the information may be directly produced, or three-dimensional object source information used in general three-dimensional computer graphics may be used as it is.

In general 3D image, depth information is added to 2D image information, and in order to implement it on a display panel, which is a 2D medium, a 3D image needs to be changed into a set of basic images containing information in various directions.

In the 3D image display device according to the present invention, the 3D information of the virtual object to be displayed is mapped into a set of base images according to the characteristics of the lens array used, and in particular, the 3D image information is mapped to the base image. Is independently performed for each point constituting the 3D image information.

One point of the three-dimensional image information, or a randomly selected depth information (z value), the focal length of the lens array used, the size of the base lens, and the positional information on the plane of the point (x, y value) In consideration of such a situation, if the basic image is changed and the process is performed for all points forming the 3D image information, the entire 3D image information is changed to the basic image.

5 is a conceptual diagram for generating a base image.

The position on the plane of a point P constituting the three-dimensional image information is (x, y) in Cartesian coordinates, and the depth information, i.e., the distance from the lens array to the place where the image of the point is formed, z, of each elementary lens of the lens array. The coordinates of the center of the base lens positioned i-th from the left and j-th from the top (lens_x [i] [j], lens_y [i] [j]), and the x-direction size of the base lens is L_x, the y-direction size. L_y, let's say f is the focal length.

At this time, the base image by the base lens positioned from the i th to the j th from the left among the base images of the point P as the virtual object point becomes the point E_ij having the coordinate value according to the following equation.

Elemental_image_x [i] [j] = lens_x [i] [j] + (f / z) * (lens_x [i] [j] x)

Elemental_image_y [i] [j] = lens_y [i] [j] + (f / z) * (lens_y [i] [j] y)

The above equations can be easily obtained by the proportional relationship of two similar triangles from the conceptual diagram of basic image production of FIG. 5. However, in the exemplary embodiment of the present invention, the point E_ij calculated by the above Equations 1 and 2 does not necessarily become the base image by the base lens located at the i th from the i th top from the left, and the base image when the following conditions are satisfied. Becomes

More specifically, when the base lenses in the horizontal direction are operated in units of one line across one of the points E_ij calculated by Equation 1 and Equation 2 above, only the following condition 3 and one line are crossed vertically When the basic lenses are operated in units, only the points satisfying condition 4 become the basic images.

(Condition 3) -Lx <Elemental_image_x [i] [j]-lens_x [i] [j] <Lx

(Condition 4) -Ly <Elemental_image_y [i] [j]-lens_y [i] [j] <Ly

Base images are obtained by applying the above method to all points of the 3D image information, and the set of the base images becomes the entire base image of the 3D image information.

As described above, the basic image obtained for all points of the 3D image information is obtained. As shown in FIG. 3, the basic image of the two states is displayed on the image display unit, and the basic lens opening and closing unit operates in synchronization therewith.

In this way, the overlap angle of the integrated image is prevented, and the viewing angle of the system is doubled compared with the conventional method. In this method, the speed at which the primary lens opens and closes should be fast enough for the human eye to accept the afterimage effect without difficulty.

Next, a second exemplary embodiment in which a viewing angle may be improved, as in the stereoscopic image display apparatus according to the first exemplary embodiment, will be described.

In the second embodiment of the present invention, by using a polarization mask that is crossed orthogonally polarized one by one in a vertical or horizontal direction, and displaying basic images of different states on the image display device to be orthogonally polarized with each other, Similarly, a stereoscopic image display device having a wider viewing angle is provided.

6 is a block diagram of a stereoscopic image display device according to a second embodiment of the present invention.

As shown in FIG. 6, the stereoscopic image display apparatus according to the second embodiment of the present invention includes an image display unit, an image processing unit, a polarization modulator, a cross-orthogonal polarization mask unit, and a lens array unit, which are image display elements.

Here, the image display unit is a device for receiving an image signal from the image processor and displaying the liquid crystal display (LCD) or a flat panel CRT.

The image processor generates an image signal to be displayed on the image display unit and displays the stereoscopic image to the image display unit. The image processing unit basically produces two types of basic images according to the viewing angle enhancement method using the lens opening and closing as in the first embodiment.

Cross-orthogonal polarization masks are masks configured such that polarization states are orthogonal to one another in a horizontal or vertical direction one by one, where the spacing between the lines in which the polarizations are alternated is equal to the size of each elementary lens.

In addition, the polarization modulator modulates the polarization state of the base image displayed on the image display unit, and a variable polarizer or a polarization shutter screen may play a role. In this case, the modulated polarization state is one of two polarization states constituting the cross-orthogonal polarization mask. For example, if the cross-orthogonal polarization masks are arranged so that the polarization direction is 45 degrees and 135 degrees one by one, the polarization modulator switches the intersection so that the polarization direction of the base image is 45 degrees and 135 degrees. Therefore, the combination of the orthogonal polarization mask and the polarization modulator serves to open and close the lenses one by one across a line, and FIGS. 7A and 7B illustrate this example.

Here, assuming that the polarization direction of the orthogonal polarization mask is 45 degrees and 135 degrees, FIGS. 7A and 7B are diagrams illustrating the polarization direction of the orthogonal polarization mask after passing through the cross orthogonal polarization mask when the polarization states of the polarization modulators are switched to be orthogonal. An example of the opening and closing role of the base lens as the polarization state is shown. That is, FIG. 7A shows the case where the polarization direction of the polarization modulator is 45 degrees, and FIG. 7B shows the state when the polarization direction of the polarization modulator is 135 degrees. It should be noted that the polarization modulation in the polarization modulator must be synchronized with the base image of the corresponding state, and the speed at which the polarization is modulated should be fast enough for the human eye to feel the afterimage effect without difficulty.

The present invention can be similarly applied to the case of using a projection image display element, and FIG. 8 is a block diagram of a stereoscopic image display device according to a third embodiment of the present invention.

As shown in FIG. 8, the stereoscopic image display apparatus according to the third embodiment of the present invention includes an image display unit, an image processing unit, a cross orthogonal polarization mask unit, and a lens array unit.

The image display unit is composed of two beam projectors to which a polarizing film having polarization directions perpendicular to each other are attached, and a polarization maintaining screen. In the second embodiment, the image display unit is a CRT or panel-type display element and switches the polarization state orthogonal in the polarization modulator, while in the third embodiment, the image display unit is connected to two beam projectors (beam projector A and beam projector B). Polarizing films (polarizing film A, polarizing film B) having polarization directions orthogonal to each other are attached so that base images of two states with polarization orthogonal to each other are spatially merged on the polarization maintaining screen.

Therefore, in this case, it is not necessary to modulate the polarization fast enough to feel the afterimage effect or display the base image in synchronization with the modulation of the polarization.

Although this invention has been described with reference to the most practical and preferred embodiments, the invention is not limited to the embodiments disclosed above, but also includes various modifications and equivalents within the scope of the following claims.

As described above, in accordance with the above-described embodiment of the present invention, basic images having different shapes and polarization directions are displayed, and a cross-orthogonal polarization mask serves to open and close the base lens at an intersection, thereby reducing the viewing angle than the conventional IP method. You can double it. In particular, since the present invention is not a method that requires mechanical movement in the opening and closing method of the basic lens, it is easy to utilize the afterimage effect, and thus, there is an advantage of implementing a more practical viewing angle enhancement IP system.

Claims (5)

An image processor which generates a basic image for reproducing a 3D image; An image display unit displaying a basic image generated by the image processor; A lens array formed of a plurality of elementary lenses, for forming an elementary image displayed on the image display unit to reproduce a corresponding 3D image; A cross orthogonal polarization mask unit having a polarization direction orthogonal to each other one by one at intervals of the base lens in a vertical or horizontal direction, The polarization modulator alternately switching so that the polarization direction of the base image displayed from the image display unit has one of the polarization directions of the cross-orthogonal polarization mask unit. Stereoscopic image display device comprising a. The method of claim 1, And the image processor is configured to display two types of base images on the image display unit in synchronization with a change in the polarization direction of the polarization modulator. An image processor which generates a basic image for reproducing a 3D image; A cross orthogonal polarization mask unit having a polarization direction orthogonal to each other one by one at intervals of the base lens in a vertical or horizontal direction, An image display unit including two beam projectors each having two polarization films having two polarization directions and a polarization maintaining screen on which an image is projected from the beam projector, and displaying a basic image generated by the image processor; A lens array composed of a plurality of elementary lenses and forming an elementary image displayed on the image display unit to reproduce a corresponding 3D image. Stereoscopic image display device comprising a. The method according to any one of claims 1 to 3, When the coordinate of the point P which is an object point of 3D image information is (xy) and the distance from the lens array to where the image of the point P is formed is z, The basic image is calculated according to the following equation. Elemental_image_x [i] [j] = lens_x [i] [j] + (f / z) * (lens_x [i] [j] x) Elemental_image_y [i] [j] = lens_y [i] [j] + (f / z) * (lens_y [i] [j] y) (lens_x [i] [j], lens_y [i] [j]): center coordinates of the elementary lens located at an i th from the left and a j th from the top of the elementary lenses of the lens array. f: focal length) The method of claim 4, wherein And the image processor extracts only a value satisfying any one of the following conditions from the base image of the point P calculated by the equation and sets the base image of the point P as the base image. -Lx <Elemental_image_x [i] [j]-lens_x [i] [j] <Lx -Ly <Elemental_image_y [i] [j]-lens_y [i] [j] <Ly (Lx: size of the base lens in the x direction Ly ,: y-direction size of the base lens)