KR20050093930A - Three-dimensional display system using lens array - Google Patents

Abstract

The present invention relates to a stereoscopic display system using a lens array.

In the present invention, the image processing unit generates a plurality of base images for reproduction of the 3D image, and these base images are transferred to the image display unit for display. The base image displayed on the image display unit is imaged by a plurality of base lenses arranged in a matrix of lens arrays, and reproduced as a 3D image. In particular, since the lens array has a predetermined curvature so that the center of the lens array is bent in the first direction or the second direction, the radius of curvature of the lens array is defined by the boundary of the base image area in which the respective base images are displayed on the image display unit. The line of view is redefined to a point where a straight line connecting both ends of each elementary lens meets the image display part at the center of, thereby increasing the viewing angle.

In addition, a partition wall may be positioned between the lens array and the image display unit to remove a flipped image, that is, an unwanted image viewed through a neighboring lens, thereby displaying a stereoscopic image having a significantly increased viewing angle.

Description

Three-dimensional display system using lens array}

The present invention relates to a stereoscopic display system, and more particularly, to a stereoscopic display system and a method for displaying a three-dimensional image using Integrated Photography (hereinafter referred to as IP).

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.

The entire system for implementing the IP scheme is largely composed of two functional units, namely, the photographing unit 100 and the display unit 200, as shown in FIG. The photographing unit 100 includes a lens array 110 forming an image of an object having a three-dimensional shape, and a photographing element 120 storing a basic image formed by the lens array 110, and the display unit 200. ) Includes a display element 210 for displaying a base image stored in the photographing element, and a lens array 220 for forming a 3D image by forming an image of the base image displayed on the display element. Each lens array 110, 220 is composed of a plurality of unit lenses.

 In the photographing unit 100, a basic image in various directions of a 3D object is formed in the photographing element 120 by the unit lens of the lens array 110. In the display unit 200, the base images stored in the reverse process of the photographing unit 100 are displayed by the display element 210, and the base images are combined while passing through the lens array 220 (this is called an aggregate image). ) 3D video is played back from the original 3D object location.

In this case, CGIP (Computer-Generated Integral Photography), a method of producing basic images with computer graphics, has been proposed to solve problems such as depth inversion during the shooting process and to simplify the structure of the system.

The structure of the CGIP system is shown in FIG. As shown in FIG. 1B, a simple method of generating a basic image of a virtual three-dimensional object using a computer, transferring it to a display element (for example, a liquid crystal display (LCD) panel), and then implementing a stereoscopic image through a lens array. Structure. At this time, the position where the aggregated image is formed varies depending on the distance between the lens array and the display element, for example, the LCD panel. This can be easily seen from the following equation.

1 / z + 1 / g = 1 / f

Where z is the position from the lens array of the aggregated image, g is the distance between the lens array and the LCD panel, and f is the focal length of the base lens (unit lens) constituting the lens array.

In other words, if the distance between the lens array and the LCD panel is larger than the focal length of the base lens, the distance between images is positive and the aggregated image is actually formed on the front of the lens array (actual IP). If the distance from the panel is smaller than the focal length of the basic lens, the distance between the images becomes negative, which means that the aggregated image is formed as a virtual image on the back of the lens array (virtual IP).

In FIG. 2, the two IP display methods, real IP and virtual IP, are compared and shown. In the case of the virtual IP, the location where the aggregated image is formed is farther from the viewer than the actual IP, so that the observer can see the stereoscopic image even slightly closer to the lens array and the LCD panel. Also, as can be seen from FIG. 2, the basic video of the virtual IP is similar to the actual IP implementation except for the fact that the basic video of the virtual IP is upright.

One of the problems in the stereoscopic display system by the IP method is the viewing angle. In the IP method, in order to eliminate the phenomenon in which three-dimensional images to be reproduced at the same time are not displayed on the display element among the respective basic images out of the area of the corresponding basic lens, which limits the basic viewing angle of the IP method. do. As a result, the limited viewing angle is expressed as follows.

Θ is the viewing angle, L is the width of the base lens, g is the distance between the lens array and the display element.

As shown in Equation 2 above, the viewing angle is inversely proportional to the distance between the lens array and the display element and is proportional to the size of the elementary lens. Therefore, in order to increase the viewing angle, the distance between the lens array and the display element must be narrowed or the width of the elementary lens must be widened. do. However, the distance between the lens array and the display element cannot be narrowed beyond a certain limit due to the limitation of the focal length of the base lens and the resolution of the reproduced base image, and if the width of the base lens becomes too wide, the thickness of the stereoscopic image that can be expressed is increased. Thinner. In addition, the stereoscopic image to be reproduced should be able to enjoy a wide range of people together, due to this limited viewing angle there is a problem that several people can not enjoy the stereoscopic image together.

Therefore, the technical problem to be solved by the present invention is to solve the conventional problems, to provide a stereoscopic display system capable of observing a stereoscopic image in a wider range.

Another object of the present invention is to provide a three-dimensional display system having a wider viewing angle by using a lens array having a predetermined curvature and a partition wall.

In order to achieve this technical problem, the present invention manufactures the flat lens array bent to have a constant curvature in the horizontal or vertical direction. According to the structure of the bent lens array, the area in which the base image is displayed is redefined to display the base images on the display device, and a partition is provided between the lens array and the display device to effectively remove the flipped image.

According to an aspect of the present invention, a stereoscopic display system using a lens array includes: an image processor configured to generate a plurality of basic images for reproducing a 3D image; An image display unit which displays a basic image generated by the image processor; And a lens array configured to form a plurality of elementary lenses arranged in a matrix, and to form an image of the elementary image displayed on the image display unit to reproduce a corresponding three-dimensional image, wherein the lens array is arranged in a first direction or a second direction. It has a predetermined curvature so that the center of the lens array is bent.

In particular, the boundary of the base image area in which each base image is displayed on the image display unit is a point where a straight line connecting both ends of each base lens meets the image display unit at the center of the radius of curvature of the lens array.

In addition, a plurality of barrier ribs may be positioned between the lens array and the image display unit, and the barrier ribs may be positioned along line segments connecting both ends of each elementary lens of the lens array and a corresponding base image region. do.

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present disclosure. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

3 is a block diagram of a stereoscopic display system according to a first exemplary embodiment of the present invention. As shown in FIG. 3, the stereoscopic display system according to the first embodiment of the present invention includes an image display unit 10, an image processing unit 20, and a lens array 30.

The image display unit 10 may receive a video signal from the image processor 20 and display the image signal. For example, a conventional display device such as a liquid crystal display (LCD) or a flat panel CRT may be used. In this embodiment, the liquid crystal display device is shown as an example of the image display unit.

The image processor 20 generates an image signal for a basic image to be displayed on the image display unit 10 to display a stereoscopic image, and transmits the image signal to the image display unit 10.

The lens array 30 is composed of a plurality of lenses arranged in a matrix corresponding to the display area of the image display unit, and the lenses constituting the lens array 30 are called base lenses. In particular, the lens array 30 according to the embodiment of the present invention is formed to have a predetermined curvature. That is, as shown in FIG. 3, the lens array 30 is bent to have a constant curvature in the first direction (eg, horizontal direction) or the second direction (eg, vertical direction).

Next, the operation of the image display system according to the first embodiment of the present invention will be described based on the structure.

In the first embodiment of the present invention, the viewing angle is further improved by using the lens array 30 having the curvature.

4 illustrates a structure representing a viewing angle limitation when displaying a stereoscopic image by using an existing flat lens array, and FIG. 5 illustrates an IP using a curved lens array according to the first embodiment of the present invention. A structure showing an increase in viewing angle when displaying a stereoscopic image by the method is illustrated.

Since a conventional image display system uses a flat lens array, as shown in the base image displayed on the image display unit 10 of FIG. 4, the base image may exceed an area of the corresponding base lens. . That is, a phenomenon in which the base image is not displayed only in an area corresponding to the base lens of the lens array 30 but also up to an area corresponding to another base lens (see arrow shown in FIG. 4) occurs. In order to prevent such a phenomenon, conventionally, the base images out of the corresponding area are not displayed on the image display unit 10, but the base images are displayed only in an area corresponding to the base lens.

However, in the first embodiment of the present invention, as shown in FIG. 5, the case where the base image does not exceed the area of the corresponding base lens does not occur. This is due to the lens array bent to have a constant curvature in the horizontal or vertical direction. Specifically, unlike the conventional stereoscopic display system, the lens array bent in a form surrounding the center of curvature increases the area for displaying the base image. In other words, all of the base images corresponding to each base lens are displayed in a direction having a predetermined curvature in the redefined base image region. For example, in the case of having curvature in the horizontal direction, only the basic image corresponding to some basic lenses among the basic lenses arranged in the vertical direction is displayed, and in the horizontal direction, the same number as the number of the basic lenses arranged in the horizontal direction. Display the basic video. This principle is explained in more detail as follows.

First, a method of producing a basic video of the existing real IP and the basic video of the virtual IP will be described.

The position on the plane of a point P constituting the stereoscopic image to be reproduced is (x, y) in Cartesian coordinates, the depth information, that is, the distance z from the lens array to where the image of the point is formed, the left of each elementary lens of the lens array. The coordinates of the center lens of the base lens positioned i th from the top and j th from above (lens_x [i] [j], lens_y [i] [j]), and the x direction size of the base lens L_x and the y direction size L_y Let f be the focal length.

At this time, the base image corresponding to the base lens located at the i th from the i 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.

In the case of the actual IP, the base image may be represented as follows.

In the case of the virtual IP, the base image may be represented as follows.

However, according to the existing IP basic image production method, the point E_ij calculated by Equations 3 and 4 or Equations 5 and 6 must be the basic image by the elementary lens located at the j th from the i th from the left. It is not a basic image only when the following two conditions are satisfied at the same time.

(Condition 1)

(Condition 2)

It is not necessary to use both the point E_ij calculated by Equation 3 and Equation 4 or Equation 5 and Equation 6 as the base image, and to set only the point that satisfies Condition 1 and Condition 2 simultaneously as the base image. Irrespective of whether or not the satisfaction of the Equation Equation 1 and Equation (2) or Equation 5 calculated by Equation 6 as the base image, the three-dimensional images to be reproduced is observed because the disadvantage that several stereo images are reproduced at the same time Because of poor quality. However, since only the points satisfying condition 1 and condition 2 are used as the base image, the viewing angle of the reproduced stereoscopic image is limited. As a result, an observer outside the viewing angle cannot see the base image any more as shown in FIG. 4. . As a result, the location where the viewer can see the image is basically limited within the left and right viewing angle range in front of the lens array.

However, in the first embodiment of the present invention, since the base images are formed by using the bent lens array, the position of the base image for each base lens is different from the conventional one. First, as shown in FIG. 3, the point where a straight line connecting both ends of each elementary lens meets the image display unit 10 at the center of the curvature radius of the lens bent in the horizontal direction is defined as the boundary of the elementary image area of each lens. . The stereoscopic image to be reproduced is positioned at or near the center of the radius of curvature of the lens as shown in FIG. 5.

Specifically, the Cartesian coordinates, depth information, etc. according to the position on the plane of the point P forming the stereoscopic image to be reproduced as described above are referred to as (x, y) and z, respectively, and from the left of each elementary lens of the lens array. Let the center coordinates of the elementary lens located at the i-th and j-th be (lens_x [i] [j], lens_y [i] [j], lens_z [i] [j]).

FIG. 6 illustrates a Cartesian coordinate system used when calculating the position of each elementary lens and the elementary image in the first embodiment of the present invention.

Referring to FIG. 6, the x-direction size of the base lens is L_x, the y-direction size is L_y, the focal length f, the distance between the base lens positioned at the center of the bent lens array and the image display unit 10, and the lens array ( When the radius of curvature in the horizontal direction of 30) is r, the base image corresponding to the base lens located in the j th from the i th to the left from the left of the base image of the point P which is the virtual object point is represented by the following equation. It becomes point E_ij which has coordinate value by.

In the case of the actual IP, the base image may be represented as follows.

In the case of the virtual IP, the base image may be represented as follows.

And as in the existing IP basic video production method, the point E_ij calculated by the above Equations 7 and 8 or 9 and 10 is necessarily the base image by the base lens located from the i th to the j th from the left. It is not a basic image only when the following two conditions are satisfied at the same time.

However, in this case, the points E_ij calculated by Equations 7 and 8 or 9 and 10 satisfy most of the above conditions 3 and 4, so that all the elementary lenses have a corresponding elementary image as shown in FIG. That is, all the basic images corresponding to the basic lens area are displayed, thereby increasing the viewing angle.

This is due to the geometry of the lens array having a shape that wraps around the center of the radius of curvature, which is different from the conventional flat lens array, where the basic image is no longer present because the basic image is no longer present. As long as the lens exists, the basic image continues to exist, thereby increasing the viewing angle of the stereoscopic image.

Therefore, in view of the existence of the base image of all the lenses in the horizontal direction, the present invention is not limited to the conventional viewing angle.

On the other hand, in the stereoscopic display system using the bent lens array as in the first embodiment of the present invention may cause other factors that limit the viewing angle. In the present invention, this is referred to as a gap mismatch, and the gap mismatch refers to the following phenomenon.

In general, the focal length of each elementary lens of the lens array is constant f, and satisfies Equation 1, that is, the law of the lens. In the embodiment of the present invention, since the lens array is bent, the distance g between the centers of the respective base lenses and the image display unit 10 differs from the position of the base lens unlike the case of the flat lens array. As shown in FIG. 5, when the elementary lens is far from the center of the lens array, the change range of g becomes large, and the difference of each g value can be expressed as follows.

, At this time

Here, G [n] is the difference between the respective g values of the center base lens and the lens n-th separated from the center base lens when n, which is the order of the center base lens, is 0.

When the value of g changes, d is influenced by the law of the lens so that each basic image is no longer integrated and formed. Although the viewing angle may be limited by the gap mismatch phenomenon, the integrated stereoscopic image may be optimally viewed within the range in which the gap mismatch may be tolerated. Determine the maximum allowable G [n], the maximum integer value Can be calculated. The viewing angle Ω of the reproduced stereoscopic image is widened in a bent direction, that is, in a horizontal direction, and can be expressed as follows.

As described above, in the first embodiment of the present invention, the lens array 30 is bent in the horizontal direction to increase the viewing angle in the horizontal direction.

Next, a stereoscopic display system according to a second embodiment of the present invention will be described. The stereoscopic display system according to the second embodiment of the present invention has the same structure as the first embodiment, and detailed structure description thereof will be omitted.

Unlike the first embodiment, the second embodiment provides a method of increasing the viewing angle in the vertical direction by bending the lens in the vertical direction instead of bending the lens array in the horizontal direction.

At this time, the base image generated by the image processor 20 is generated as many as the number of base lenses constituting the lens array in the vertical direction. At this time, the base image is generated in the same manner as in the first embodiment by the above Equations 7 to 10, but the conditions to be satisfied are different as follows.

(Condition 5)

(Condition 6)

Therefore, the vertical viewing angle of the stereoscopic image to be reproduced is enlarged. The enlarged vertical viewing angle is represented by Equation 12 above.

Meanwhile, when the bent lens array is used as in the first and second embodiments, when all the basic images are simultaneously displayed on the image display unit 10, not only the desired stereoscopic image but also the flip image can be simultaneously observed as shown in FIG. 5. Can be done.

Therefore, in the third embodiment of the present invention, such a flip image is removed using a partition wall.

Next, a stereoscopic display system according to a third embodiment of the present invention will be described.

7 is a structural diagram of a stereoscopic display system according to a third embodiment of the present invention. The stereoscopic display system according to the third embodiment of the present invention includes an image display unit 10, an image processing unit 20, and a lens array 30 that perform the same functions as those of the first embodiment. Alternatively, the partition wall 40 is positioned between the lens array 30 and the image display portion 10.

In detail, the flip image is a stereoscopic image formed by forming the base image through the adjacent lens, not through the corresponding base lens, and may be viewed as shown in FIG. 5. In the third embodiment of the present invention, a barrier rib is added to eliminate such an unwanted flip image. The partition walls 40 are respectively installed as shown in FIG. 7 along a line segment connecting a boundary between both ends of each elementary lens of the lens array 30 and the elementary image area corresponding thereto.

When applied to a lens array that is bent in the horizontal direction, the bulkhead must be equal in length to the length of the lens array and must be equal to the distance of the line segments connecting the ends of each elementary lens to the boundary of the corresponding elementary image area. The further the distance from, the longer the length of the transverse. On the other hand, when applied to the lens array bent in the vertical direction, the partition wall is vertically equal to the distance of the line connecting the edge of the respective basic lens and the boundary of the corresponding basic image area, the horizontal must have the same size as the horizontal of the lens array. Therefore, the length of the vertical increases as the distance from the center.

In the third embodiment, as shown in the first and second embodiments, a base image is generated and displayed on the image display unit 10, and both ends of each base lens of the lens array 30 and corresponding base image regions are provided. By the partition wall 40 formed along the line connecting the boundary of the image, the base image is formed only through the corresponding base lens, thereby ensuring a wide viewing angle as in the first and second embodiments. Gagged.

Therefore, the lens array is bent to have a constant curvature to increase the number of the base image and the area in which the base images having the information about the stereoscopic image are displayed, and the partition wall is used to display the flip image, i.e., the neighboring lens. By eliminating the image that is not used, it is possible to display a stereoscopic image with a considerably increased viewing angle than the conventional IP method.

Although the 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 above, according to the embodiment of the present invention described above. Since the basic images, which are not displayed in the basic image production method by the conventional IP, are displayed on each basic lens by the bent structure of the lens array, the viewing angle is increased.

In addition, according to an exemplary embodiment of the present invention, a partition wall positioned between the lens array having the curved structure and the image display unit effectively removes the flip image to significantly widen the viewing angle.

FIG. 1A illustrates a basic concept of general integrated photography (IP).

1B is a diagram illustrating a basic concept of computer-generated integrated photography (CGIP).

2 is a diagram illustrating the concept of a real IP and a virtual IP.

3 is a structural diagram of a stereoscopic display system according to a first embodiment of the present invention.

4 is a view showing the viewing angle limitation when displaying a stereoscopic image by the IP method using a conventional flat lens array.

FIG. 5 is a diagram illustrating an increase in viewing angle when displaying a stereoscopic image by an IP method using a bent lens array according to the first exemplary embodiment of the present invention.

FIG. 6 is a block diagram illustrating a rectangular coordinate system used when calculating the position of each elementary lens and the elementary image in the present invention.

7 is a diagram illustrating a structure of a stereoscopic display system using a partition wall to remove a flip image according to a third embodiment of the present invention.

Claims (8)

An image processor which generates a plurality of basic images for reproducing a 3D image; An image display unit which displays a basic image generated by the image processor; And A lens array comprising a plurality of elementary lenses arranged in a matrix, and forming an elementary image displayed on the image display unit to reproduce a corresponding 3D image. Including, And the lens array has a predetermined curvature so that the center of the lens array is bent in the first direction or the second direction. The method of claim 1, And a boundary of a base image area in which each base image is displayed on an image display unit is a point where a straight line connecting both ends of each base lens meets the image display unit at the center of the radius of curvature of the lens array. The method of claim 1, The lens array has a predetermined curvature so that the center of the lens array is bent in the first direction, The image display unit displays only a basic image corresponding to some basic lenses among the basic lenses arranged in the second direction in the second direction, and the number of the basic lenses arranged in the first direction in the first direction. Stereoscopic display system for displaying the same number of base images. The method of claim 1, When the coordinate of the point P which is an object point of 3D image information is (x, y, z) and the distance from the lens array to where the image of the point P is formed is z, A basic image (Elemental_image_x [i] [j], Elemental_image_y [i] [j]) with respect to the point P is calculated according to the following equation. In case of fact If it is a virtual image (lens_x [i] [j], lens_y [i] [j], lens_z [i] [j]): the center coordinates of the elementary lens located in the i-th from the left and the j-th from the top of the lens of the lens array , f: focal length of the elementary lens) The method of claim 4, wherein The image processor sets a base image of the point P when the following two conditions are satisfied among the elementary images (Elemental_image_x [i] [j] and Elemental_image_y [i] [j]) of the point P. Stereoscopic display system. (L_x: size of x direction of the base lens, L_y: size of y direction of the base lens) The method of claim 1, The gap mismatch generated in the stereoscopic display system , Where If the maximum acceptable G [n] is satisfied, the maximum integer value 3D display system in which the viewing angle (Ω) satisfies the following equation. g: Distance between the center of each elementary lens and the image display portion G [n]: The difference between the respective g values of the center base lens and the nth lens away from the center base lens when n, which is the order of the center base lens, is zero. The method of claim 1, A plurality of partition walls are positioned between the lens array and the image display unit, And the barrier ribs are positioned along line segments connecting the edges of the respective basic lenses of the lens array and the corresponding basic image region. The method of claim 7, wherein When the lens array is a lens array having a curvature bent in a horizontal direction, the partition wall has a length equal to the length of the lens array vertically, and a line segment connecting the two edges of each basic lens horizontally with a corresponding basic image region. Has the same size as the distance of, When the lens array is a lens array having a curvature that is bent in a vertical direction, the partition wall is vertically equal to a distance of a line segment connecting both ends of each elementary lens and a corresponding elementary image area, and horizontally the lens array horizontally. Stereoscopic display system having the same size as.