KR101350641B1 - Autostereoscopic 3-d image display evaluation method and autostereoscopic 3-d image display evaluation apparatus - Google Patents

Abstract

The present invention provides a method for evaluating an autostereoscopic three-dimensional image display and an apparatus for evaluating an autostereoscopic three-dimensional image display. The method comprises the steps of: using a first test image, in which a first image for left eye and a second image for right eye are combined side by side, as an input image for an autostereoscopic three-dimensional image display to provide a first projection image for a diffuser screen arranged on an inclined plane, which is spaced apart in the direction of a first axis perpendicular to the plane of the autostereoscopic three-dimensional image display and rotated at a fixed angle around a second axis perpendicular to the first axis and connecting the left and right eyes of the user; arranging a camera at a position spaced apart from the inclined plane of the diffuser screen; allowing the camera to obtain the first projection image projected to the diffuser screen to generate a first signal image; processing the first signal image at a gray level to generate a first gray image; and converting the first gray image into a first brightness image.

Description

Autostereoscopic 3-D Image Display Evaluation Method and Autostereoscopic 3-D Image Display Evaluation Apparatus}

The present invention relates to an autostereoscopic display, and more particularly, to a method for evaluating spatial luminance distribution of autostereoscopic display.

Various 3-D technologies are known, and recently, 3-D technology using special glasses is widely used in theaters or 3-D televisions. In addition, autostereoscopy technology is developing. The principle of autostereoscopy 3-D display is to control the spatial luminance distribution so that each eye of the user can see different images at the user's location.

Accordingly, the spatial luminance distribution is complex but must be characterized at a spatial interval less than the inter-pupillary distance (IPD).

One technical problem to be solved of the present invention is to provide an autostereoscopic 3-D display evaluation method for measuring the spatial luminance distribution in a simple and short time.

The autostereoscopic 3D image display evaluation method according to an embodiment of the present invention inputs an autostereoscopic 3D image display to a first test image in which a first image for a left eye and a second image for a right eye are combined side by side. Using the image as a predetermined angle about a second axis spaced apart in the first axis direction perpendicular to the plane of the autostereoscopic 3D display and perpendicular to the first axis and connecting the user's left eye and the right eye. Providing a first projection image on a diffuser screen disposed on the rotated inclined plane; Placing the camera at a position spaced apart from the inclined plane of the diffuser screen; Generating a first signal image by the camera acquiring a first projection image projected on the diffuser screen; Generating a first gray image by processing the first signal image at a gray level; And converting the first gray image into a first luminance image.

In one embodiment of the present invention, the autostereoscopy using a second test image combining the second image for the left eye and the first image for the right eye side by side as an input image of an autostereoscopic 3D image display. On an inclined plane spaced in a first axial direction perpendicular to the plane of the stereoscopic three-dimensional display and rotated at a predetermined angle about the second axis perpendicular to the first axis and connecting the user's left and right eyes. Providing a second projection image on the diffuser screen disposed; Generating, by the camera, a second signal image by obtaining a second projection image projected on the diffuser screen; Generating a second gray image by processing the second signal image at a gray level; Converting the second gray image into a second luminance image; Generating a three-dimensional cross-talk image for the left eye by using a ratio between the background image in the first luminance image and the background image in the second luminance image; Generating a three-dimensional cross-talk image of the right eye by using a ratio of a difference between a background image in the second luminance image and a background image in the first luminance image; Identifying a position corresponding to a pupil distance in the 3D cross-talk image for the left eye or the right eye; And converting the three-dimensional cross-talk image obtained in the coordinate system XYZ of the diffuser screen into the coordinate system xyz of the three-dimensional display. As shown in FIG.

In one embodiment of the present invention, the method may further include changing a distance between the three-dimensional display and the diffuser screen.

In one embodiment of the present invention, the three-dimensional display may be a lenticular lens method or a parallax barrier method.

In one embodiment of the present invention, the first image may be a white image, and the second image may be a black image.

In one embodiment of the present invention, the camera may be disposed perpendicular to the inclined plane in which the diffuser screen is disposed in a direction looking at the center of the diffuser screen.

An autostereoscopic 3D image display evaluation apparatus according to an embodiment of the present invention includes a 3D display; The first test image, which combines a first image for the left eye and a second image for the right eye, as an input image of the autostereoscopic 3D image display, is used. A diffuser screen spaced in one axial direction and disposed on an inclined plane that is perpendicular to the first axis and rotated at an angle about a second axis connecting the user's left eye and the right eye; A digital camera disposed at a position spaced apart from the inclined plane to obtain a projected image projected onto the diffuser screen; And a signal processor configured to convert the digital image acquired by the digital camera into a gray image, change the gray image into a luminance image, and extract a three-dimensional cross-talk image using the luminance image.

In one embodiment of the present invention, the three-dimensional display may be a lenticular lens method or a parallax barrier method.

In one embodiment of the present invention, it may further include a moving unit for moving the position of the three-dimensional display.

The autostereoscopic 3-D display evaluation method according to an embodiment of the present invention can evaluate the 3-D cross-talk of the 3-D display in a simple and short time with a simple structure.

1A is a diagram illustrating an experimental apparatus for measuring a spatial luminance distribution at a user's position. FIG. 1B is a cross-sectional view taken along the xz plane of FIG. 1A.
2A to 2C are diagrams illustrating a test image according to example embodiments.
3A to 3D are photographs illustrating first to second digital images capturing first to second projection images according to an embodiment of the present invention.
4A is a 3-D cross-talk contour graph represented on a logarithmic scale with base 10 at y0 = 300 mm.
4B is a 3-D cross-talk contour plot on a logarithmic scale with base 10 at y0 = 200 mm.
5 is a diagram illustrating coordinate transformation according to an embodiment of the present invention.
6A and 6B are diagrams illustrating a lenticular lens type 3-D display and a parallax barrier type 3-D display, respectively.

Methods of characterizing various 3-D displays have been reported. One method is to measure luminance at the user's location using the luminance measurement device (LMD). Another method is to interpret the spatial luminance distribution from the angular luminance distribution measured at multiple points in the autostereoscopic 3-D display. The former takes a lot of time and gives reliable results. On the other hand, the latter can be performed in a short time, but a precise measuring device having an angular resolution of 0.03 degrees or less is required. Therefore, there is a need for a method for measuring the spatial luminance distribution in a simple and short time.

According to one embodiment of the invention, a diffuser screen is placed at the user's position and the spatial brightness of the diffuser screen irradiated from the 3-D display is measured via a digital camera. The diffuser screen is tilted to obtain the luminance distribution at different distances relative to the 3-D display.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are being provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. In the drawings, the components have been exaggerated for clarity. Portions denoted by like reference numerals denote like elements throughout the specification.

1A is a diagram illustrating an experimental apparatus for measuring a spatial luminance distribution at a user's position. FIG. 1B is a cross-sectional view taken along the xz plane of FIG. 1A.

1A and 1B, the method for evaluating autostereoscopic 3D image display may include providing a first projection image. The providing of the first projection image may be performed by using a first test image combining a first image for the left eye and a second image for the right eye as an input image of the autostereoscopic 3D display 110. A second axis (x-axis) spaced apart in the direction of the first axis (y-axis) perpendicular to the plane of the glasses stereoscopic three-dimensional display 110 and perpendicular to the first axis and connecting the user's left eye and the right eye The first projection image may be provided to the diffuser screen 120 disposed in the inclined plane rotated at a predetermined angle φ.

The camera 130 is disposed at a position spaced apart from the inclined plane of the diffuser screen 120. The camera 130 obtains a first projection image projected on the diffuser screen 120, generates a first signal image, and provides the first signal image to the signal processor 140. The signal processor 140 receives the first signal image and processes the gray level to generate a first gray image. The signal processor 140 converts the first gray image into a first luminance image. When the camera 130 is a black and white camera, the step of converting the first signal image into the first gray image may be omitted.

The 3D display 110 uses an autostereoscopic 3D display as an input image of an autostereoscopic 3D display using a second test image in which the second image for the left eye and the first image for the right eye are combined side by side. A predetermined angle about a second axis (x-axis) spaced in a direction of a first axis (y-axis) perpendicular to the plane of the three-dimensional display and perpendicular to the first axis and connecting the user's left eye and the right eye A second projection image may be provided to the diffuser screen 120 disposed in the inclined plane rotated by φ.

The camera 130 obtains a second projection image projected on the diffuser screen 120, generates a second signal image, and provides the second signal image to the signal processor 140. The signal processor 140 receives the second signal image to process the gray level to generate a second gray image. When the camera 130 is a black and white camera, the step of converting the second signal image into a second gray image may be omitted. The signal processor 140 may convert the second gray image into a second luminance image.

The signal processor 140 may generate a 3D cross-talk image for the left eye by using a ratio between the background image in the first luminance image and the background image in the second luminance image. The signal processor 140 may generate a 3D cross-talk image of the right eye by using a ratio of the difference between the background image in the second luminance image and the difference between the background image in the first luminance image.

The signal processor 140 may identify a position corresponding to the pupil distance in the 3D cross-talk image for the left eye or the right eye. The signal processor may coordinate-convert the three-dimensional crosstalk image acquired in the coordinate system XYZ of the diffuser screen to the coordinate system xyz of the three-dimensional display.

The signal processor 140 may drive the moving unit 150 on which the 3D display 110 is mounted to change a distance between the 3D display 110 and the diffuser screen 120. The signal processor 120 may receive data from the digital camera, process the data, and control the 3D display 140. The signal processor 140 may be a computer.

The three-dimensional display 110 is disposed in the xz plane, in the xyz rectangular coordinate system. The 3D display may be a lenticular lens method or a parallax barrier method in an autostereoscopic method.

The diffuser screen 120 may be disposed to be spaced apart at a predetermined distance y0 in a direction y perpendicular to a plane on which the 3D display is disposed. The diffuser screen 120 is disposed to rotate at a predetermined angle φ with respect to the x-axis connecting the left and right eyes of the user. The diffuser screen 120 may be 45 degrees with respect to the x-axis. The center of the diffuser screen 120 and the center of the 3D display 110 are separated by a predetermined distance y0, and the center of the diffuser screen 120 and the center of the 3D display 110 are y. May be disposed on the axis.

The plane in which the diffuser screen 120 is disposed may be the XY plane of the new rectangular coordinate system. The digital camera 130 may be disposed on the Z axis of the diffuser screen 120. The width of the diffuser screen 120 may be W, and the height of the diffuser screen 120 may be H. The width may be in the X-axis direction or the x-axis direction, and the height may be in the Y-axis direction.

The center of the diffuser screen 120 and the digital camera 130 may be spaced apart by a predetermined distance d. The direction in which the digital camera is disposed may be in the Z axis direction.

The diffuser screen 120 is illuminated by the three-dimensional display 110, and the spatial brightness on the diffuser screen 120 is measured by the digital camera 130. The horizontal and vertical directions of the 3D display 110 plane are selected as x and z axes, respectively. The distance between the three-dimensional display 110 and the diffuser screen 120 is selected as the y axis. The center of the three-dimensional display 110 is defined as (0,0,0), while the center of the correlator screen 120 is defined as (0, y0,0). Here, y0 is the distance between the center of the tilted diffuser screen 120 and the center of the three-dimensional display 110.

The diffuser screen 120 may rotate by 45 degrees about a rotation axis parallel to the x axis. In the autostereoscopic three-dimensional display 110, it is known that the luminance distribution along the vertical direction z is less varied than the luminance distribution along the x and y axis directions. Therefore, the measurement of the spatial luminance distribution along the x and y axis directions is more important than the spatial luminance along the z axis direction.

As the diffuser screen 120 is tilted, the y position of the diffuser screen 120 is not a fixed value. Thus, luminance at various y positions can be obtained. The luminance on the diffuser screen 120 is measured by the digital camera 130. The digital camera 130 may be located at a distance d perpendicular to the diffuser screen 120 at a distance of 80 cm. The digital camera 130 may be a color or black and white digital camera.

For example, the three-dimensional display may be a three-dimensional mobile communication terminal. The three-dimensional display 110 may have a screen size of 94 × 56 mm wide and may have a resolution of 800 × 480. The 3D display 110 may be a 2-view autostereoscopic display by a switchable parallax barrier. The three-dimensional display 110 may be used as a three-dimensional sample. The luminance of the three-dimensional sample is typically designed to look around the arm length.

The distance y0 between the tilted diffuser screen 120 and the three-dimensional display 110 was chosen to be 300 mm. Also measuring conditions of y0 = 200 mm can also be used. y0 can be changed by moving the three-dimensional sample.

On the other hand, A4-size paper 210 mm high and 297 mm wide can be used as the diffuser screen 120. A square pattern 187 mm high and 275 mm wide may be formed in the diffuser screen 120. The width of the square pattern is slightly larger than four times the pupil distance (IPD), which is typically 60 mm to 65 mm. Accordingly, this width is expected to be wide enough to observe the periodic characteristics of the luminance distribution in the viewing zone.

Typically, three-dimensional performance is characterized by 3-D cross-talk. To measure 3-D cross-talk, test image data is used for the measurement.

2A to 2C are diagrams illustrating a test image according to example embodiments.

2A to 2C, the first image and the second image may be used as test image data. The first image may be a white image (W), and the second image may be a black image (B). WB, BW and BB represent test image data of two eyes. Here, the first character is data for the left eye, and the second character is data for the right eye.

The left and right images are arranged side by side and combined into one image file. The side-by-side image file may be in the format of J-PG (jpg) and have an image size of 1600 × 480 pixels. This image file is used for three-dimensional samples. The first test image may be a WB image, the second test image may be a BW image, and the third test image may be a BB image. The first test image may provide a first projection image to the diffuser screen 120 by the three-dimensional display 110. The second test image may provide a second projection image to the diffuser screen 120 by the three-dimensional display 110. The third test image may provide a third projection image of the background.

According to a modified embodiment of the present invention, the first image may be a red image, a blue image, or a green image, and the second image may be a black image.

The first projection image is obtained by the digital camera. The digital camera 130 captures the first projection image to generate a first digital image. The first digital image may be changed into a first gray image of gray scale by the signal processor 140. The signal processor 140 may convert the first gray image into a first luminance image. The data of the first gray image may be converted into luminance data through the following relational expression.

Here, γ may be 2.2. Here, γ may vary depending on the type of digital camera.

In addition, the second test image may provide a second projection image to the diffuser screen 120 by the three-dimensional display 110. The second projection image is captured by the digital camera 130. The digital camera 130 captures the second projection image to generate a second digital image. The second digital image may be changed into a second gray image of gray scale by the signal processor 140. The signal processor 140 may convert the second gray image into a second luminance image.

In addition, the third test image BB may provide a third projection image or a background image to the diffuser screen 120 by the three-dimensional display 110. The third projection image is captured by the digital camera 130. The digital camera 130 captures the third projection image to generate a third digital image. The third digital image may be changed into a third gray image of gray scale by the signal processor. The signal processor may convert the third gray image into a third luminance image.

3-D cross-tog can be defined as follows.

Here, Lum (BW), Lum (WB), and Lum (BB) represent the luminance when the test image data BW.WB and BB are used, respectively.

The 3-D cross-talk of the right eye is equal to the inversion of 3-D cross-talk of the left eye. Thus, only the cross-talk of the left eye is considered.

In order to measure 3-D cross-talk, the diffuser screen 120 and the three-dimensional display 130 are aligned.

The test image data of FIGS. 2A-2C are used for the three-dimensional display 110 respectively. Under the respective test image data and the conditions of y0 = 200 mm and y0 = 300 mm, the digital camera 130 captures the first to third projection images of the diffuser screen 120 to display the first to third images. Digital images can be obtained. This measurement is performed in a dark room, where the brightness at the location of the diffuser screen 120 can be less than 1 lx (lux).

Subsequently, the 3D cross-talk image for the left eye is obtained by using Equation 1 as a difference between the first luminance image Lum (BW) and the background image Lum (BB) and the second luminance image Lum ( WB)) can be extracted using the ratio of the background image Lum (BB).

In addition, the 3D cross-talk image of the right eye includes a difference between the background image Lum (BB) in the second luminance image Lum (WB) and a background image Lum in the first luminance image Lum (BW). (BB)) can be extracted using the ratio of the differences.

3A to 3D are photographs illustrating first to second digital images capturing first to second projection images according to an embodiment of the present invention.

Referring to FIG. 3A, the first test image has a WB structure and y0 = 300 mm. Referring to FIG. 3B, the second test image has a BW structure and y0 = 300 mm. Referring to FIG. 3C, the first test image has a WB structure and y0 = 200 mm. Referring to FIG. 3C, the second test image has a BW structure and y0 = 200 mm.

4A is a 3-D cross-talk contour graph represented on a logarithmic scale with base 10 at y0 = 300 mm.

4B is a 3-D cross-talk contour plot on a logarithmic scale with base 10 at y0 = 200 mm.

Referring to FIG. 4A, the pupil gap IPD is typically 65 mm. Thus, the 3-D cross-talk appears periodically along the X axis. The 3-D cross-talk is 1 and the position coinciding with the user's pupil gap (IPD) is the point at Y = -49 mm. When the diffuser screen 120 is tilted 45 degrees, in the xyz coordinate system y = y0 (300 mm) -34.6 mm = 264.5 mm and z = -34.6 mm. Thus, the user can feel the optimal 3-D image at (x, 264.5 mm, -34.6 mm).

The 3D cross-talk image obtained in the coordinate system XYZ of the diffuser screen 120 may be coordinate converted into a coordinate system xyz of the 3D display. The xyz coordinates and the XYZ coordinates may be expressed by the following relation when the diffuser screen is inclined at a predetermined angle φ.

5 is a diagram illustrating coordinate transformation according to an embodiment of the present invention.

Referring to FIG. 5, the angle of inclination φ of the diffuser screen may be 45 degrees.

Subsequently, the distance between the 3D display 110 and the diffuser screen 120 may be changed and the above procedure may be repeated to obtain a 3D cross-talk image.

In conclusion, when the diffuser screen 120 is tilted, a projection image is acquired, image processed, and 3-D cross-torque is obtained, the result of cross-talk about the y axis can be obtained in one measurement. have. Accordingly, it is possible to save time for obtaining the autostereoscopic 3-D cross-talk.

6A and 6B are diagrams illustrating a lenticular lens type 3D display and a parallax barrier type 3D display, respectively.

Referring to FIG. 6A, the three-dimensional display 110 may include a grid-structured Ferrax barrier 112 on its surface.

Referring to FIG. 6B, the 3D display 110 may include a lenticular lens 113 having a micro lens structure on a surface thereof.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, And all of the various forms of embodiments that can be practiced without departing from the technical spirit.

110: three-dimensional display
120: diffuser screen
130: digital camera
140: signal processing unit
150:

Claims (9)

The first test image, which combines a first image for the left eye and a second image for the right eye, is used as an input image of the autostereoscopic 3D image display, and is used as the input image of the autostereoscopic 3D display. Providing a first projection image to a diffuser screen spaced in one axial direction and disposed in an inclined plane that is perpendicular to the first axis and rotated at an angle about a second axis connecting the user's left and right eyes Making;
Placing the camera at a position spaced apart from the inclined plane of the diffuser screen;
Generating a first signal image by the camera acquiring a first projection image projected on the diffuser screen;
Generating a first gray image by processing the first signal image at a gray level; And
And converting the first gray image into a first luminance image. The method according to claim 1,
A second test image combining the second image for the left eye and the first image for the right eye side by side is used as an input image of the autostereoscopic 3D image display to be perpendicular to the plane of the autostereoscopic 3D display. A second to the diffuser screen disposed in an inclined plane spaced in a first axial direction and rotated at a predetermined angle about the second axis perpendicular to the first axis and connecting the user's left and right eyes; Providing a projected image;
Generating, by the camera, a second signal image by obtaining a second projection image projected on the diffuser screen;
Generating a second gray image by processing the second signal image at a gray level;
Converting the second gray image into a second luminance image;
Generating a 3D crosstalk image for the left eye by using a ratio of a difference between a background image in the first luminance image and a difference between a background image in the second luminance image;
Generating a 3D cross-talk image for the right eye using a ratio of a difference between a background image in the second luminance image and a difference between a background image in the first luminance image;
Identifying a position corresponding to a pupil distance in the 3D cross-talk image for the left eye or the right eye; And
Coordinate conversion of the three-dimensional cross-talk image obtained in the coordinate system XYZ of the diffuser screen to the coordinate system xyz of the three-dimensional display; The autostereoscopic 3D image display evaluation method further comprising at least one of the. The method according to claim 1,
And changing the distance between the three-dimensional display and the diffuser screen. The method according to claim 1,
The three-dimensional display is a lenticular lens (lenticular lens) method or a parallax barrier (parallax barrier) method, characterized in that the autostereoscopic 3D image display evaluation method. The method according to claim 1,
And the first image is a white image, and the second image is a black image. The method according to claim 1,
And the camera is disposed perpendicular to the inclined plane in which the light diffuser screen is disposed in a direction looking at the center of the light diffuser screen. Three-dimensional display;
The first test image, which combines a first image for the left eye and a second image for the right eye, as an input image of the autostereoscopic 3D image display, is used. A diffuser screen spaced in one axial direction and disposed on an inclined plane that is perpendicular to the first axis and rotated at a predetermined angle about a second axis connecting the user's left eye and the right eye;
A digital camera disposed at a position spaced apart from the inclined plane to obtain a projected image projected onto the diffuser screen; And
And a signal processor for converting the digital image acquired by the digital camera into a gray image, changing the gray image into a luminance image, and extracting a three-dimensional crosstalk image using the luminance image. 3D visual display evaluation device. The method of claim 7, wherein
The three-dimensional display is a lenticular lens (lenticular lens) method or a parallax barrier (parallax barrier), characterized in that the autostereoscopic 3D image display evaluation apparatus. The method of claim 7, wherein
An autostereoscopic 3D image display evaluation apparatus further comprising a moving unit for moving the position of the 3D display.

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