A seamless display system for a tiled screen

Abstract

The present invention discloses a seamless display system for a splicing screen, which includes splicing display screens arranged in parallel with each other, a lens array, and a rear projection scattering film. The lens array is placed between the splicing display screen and the rear projection scattering film to perform downsampling on the image to be displayed, and the image to be displayed after downsampling is equally divided into a number of square unit images to be displayed with a side length of Ls. The unit images to be displayed form an array of unit images to be displayed. In the array of unit images to be displayed, unit images are intercepted at a pixel interval of △. When intercepting, any unit image and its adjacent unit images around it are separated by △ pixels in both the row and column directions. After mirror flipping the unit images, they are displayed through the splicing screen. The unit images displayed on the splicing screen are centered and aligned with the lenses in the lens array one by one. The lens array magnifies the unit images displayed on the splicing screen by M times and flips and projects them onto the rear projection scattering film to form unit reconstructed images, and the unit reconstructed images are spliced with each other to form a seamless image to be displayed.

Description

Technical Field

[0001] The present invention belongs to the technical field of large-screen splicing display, and particularly relates to a seamless display system for splicing screens. Background Art

[0002] Generally, a display with an area exceeding 1 square meter can be called a large-screen display. Currently, people have a stronger demand for larger-area displays. Especially in exhibition halls, large conferences, and outdoor advertisements, large-screen displays have become standard facilities. Currently, the mainstream large-screen products on the market include projection, LED displays, liquid crystal splicing screens, etc.

[0003] DLP is the current mainstream projection display technology, which has the advantages of seamless splicing, large picture, high image quality, etc. However, the image quality is easily affected by ambient light. When the environment is relatively bright, the ambient light will suppress the screen brightness, resulting in a white or gray projection image. The light source bulb of DLP has high power consumption and high heat dissipation, and the bulb needs to be frequently replaced to maintain a good display effect. In addition, the projector must have a projection space. If there is an obstruction in the space through which the projection light path passes, it will surely affect the viewing.

[0004] The picture display of the LED screen is not fine enough and the cost is high, so it is mostly used for outdoor advertising displays. With the progress of technology, small-pitch LEDs have been developed. The reduction of the pixel pitch has greatly improved the fineness of the LED screen picture and reduced the graininess. Nevertheless, compared with liquid crystal display screens, its graininess is still very obvious, and the price is expensive. In addition, the LED lamp beads are easy to fall off, resulting in damaged pictures. Therefore, the subsequent maintenance is more troublesome, and this is an inevitable defect.

[0005] Liquid crystal splicing screens have quickly obtained nearly 1 / 4 of the large-screen splicing market share in just a few years by virtue of their advantages of high definition, high brightness, high color saturation, flexible splicing methods, environmental protection, long life, and low operation and maintenance costs. However, liquid crystal splicing has a fatal flaw, that is, the physical seam that cannot be eliminated. Despite a lot of efforts, the physical seams of liquid crystal screen splicing are getting smaller and smaller. It is reported that currently it can reach a seam of 0.88, but the visible seam grid still affects the overall sense of the picture. As Figure 1 shown. Summary of the Invention

[0006] To solve the defect of the ineliminable seams in existing liquid crystal splicing, based on the principle of integral imaging seamless splicing large-screen display, the present invention re-encodes and arranges the pixels of the video image to be displayed, displays the re-arranged video through a liquid crystal splicing display screen, then uses a lens array to reconstruct the image displayed on the splicing display screen, and finally a seamless continuous image display can be obtained.

[0007] The technical solution of the present invention is as follows: A seamless display system for a splicing screen, including splicing display screens arranged in parallel with each other, a lens array, and a rear projection scattering film. The lens array is placed between the splicing display screen and the rear projection scattering film to perform downsampling on the image to be displayed, and the image to be displayed after downsampling is equally divided into a plurality of square images to be displayed units with a side length of Ls. The images to be displayed units form an image array of units to be displayed. In the image array of units to be displayed, unit images are intercepted at pixel intervals of △. When intercepting, any unit image and the surrounding adjacent unit images are △ pixels apart in the row and column directions respectively. After mirror flipping the unit images, they are displayed through the splicing screen. The unit images displayed on the splicing screen are centered and aligned with the lenses in the lens array one by one. The lens array magnifies the unit images displayed on the splicing screen by M times and flips and projects them onto the rear projection scattering film to form unit reconstructed images, and the unit reconstructed images are spliced together to form a seamless image to be displayed;

[0008] Ls is determined by the distortion-free object space field of view of the unit lenses in the lens array, and the gap width between the unit images of the splicing screen display screen is S l , and the center distance P between adjacent lenses in the lens array in the row or column direction is ≥ S l +L s , M ≥ P / L s , and M is an integer multiple of P / L s , and the number of lenses is fix represents rounding towards zero, M s ×N s is the number of pixels of the splicing display screen, d s is the pixel interval of the splicing display screen, and the number of pixels of each unit image is L pix ×L pix , L pix =L s / d s , the number of pixels of the unit reconstructed image pixel interval round represents rounding to the nearest integer, N s , N i , N Ls are respectively the number of pixels of the splicing display screen image in the column direction, the number of pixels of the image to be displayed after downsampling, and the number of lenses, M s , M i , M Ls are respectively the number of pixels of the splicing display screen image in the row direction, the number of pixels of the image to be displayed after downsampling, and the number of lenses.

[0009] Further, the downsampling means: adjusting the resolution of the image to be displayed from M s ×N s to M i ×N iThe resolution of the image to be displayed after downsampling is 1 / M times that of the image to be displayed in the original splicing screen, where M is the magnification of the unit lens: S is a non-zero integer, P is the pitch of the lens array, and Ls is the side length of the unit image.

[0010] Furthermore, the unit image is intercepted starting from the first row and first column of the unit image array, and a total of M Ls ×N Ls unit images are intercepted. The unit image EI Ls in the m Ls -th row and n mLsnLs -th column is:

[0011]

[0012] The number of unit images in the unit image array is the same as the number of lenses in the lens array.

[0013] It should be noted that the present invention achieves the goal of eliminating the splicing seam by sacrificing some resolution of the display screen. Even so, the final displayed resolution is still much higher than that of a general LED display. For example, the pixel pitch of a 4K 65-inch LCD screen is 0.372 mm. When it is spliced in a 3×3 manner, the final seamless display pixel pitch is 0.56 mm; while if an 8K 65-inch LCD screen is spliced, the final seamless image pixel pitch is only 0.23 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of a splicing display screen in the prior art;

[0015] Figure 2 is a schematic diagram of the seamless splicing large screen display of the present invention;

[0016] Figure 3 is a schematic diagram of the principle of the seamless splicing display method of the present invention;

[0017] Figure 4 is an example of the pixel re-arrangement coding of the present invention;

[0018] Figure 5 is a schematic diagram after seamless splicing display when the unit image is not reconstructed;

[0019] Figure 6 is a schematic diagram after seamless splicing display when the unit image is reconstructed;

[0020] Figure 7 is to display a continuous image on a scattering screen by using the method of the present invention;

[0021] Figure 8 is a schematic diagram of the unit image array. Detailed implementation mode

[0022] Based on the principle of seamless splicing large screen display of integral imaging, the video image pixels to be displayed are re-encoded and arranged, and the rearranged video is displayed through a liquid crystal splicing screen. Then, a lens array is used to reconstruct the image displayed on the splicing screen, and finally, a seamless continuous image display can be obtained. As Figure 2 。

[0023] The following uses Figure 3 to illustrate the principle of the seamless splicing display method of the present invention. In Figure 3 , a lens array is placed in front of the splicing screen. Each lens in the array is called a "unit lens", and the unit lens can magnify and image the corresponding area on the screen behind it. In the present invention, the area image on the screen corresponding to the unit lens is called a "unit image". For example, unit lenses A and B respectively magnify and image the unit images I A and I B on the splicing display screen into I′ A and I′ B . When I′ A and I′ B are exactly adjacent, the splicing seam between the two images disappears. We call I′ A and I′ B "reconstructed images".

[0024] Obviously, I′ A and I′ B are from two discontinuous unit images on the splicing display screen. In order to make I′ A and I′ B continuous, I A and I B must be re-encoded. Suppose I′ A and I′ B each have 4 pixels, corresponding to the continuous image pixel numbers 1, 2, 3, 4; and 5, 6, 7, 8. Then the corresponding unit images I A and I B element numbers are as Figure 3 shown.

[0025] In Figure 3 , the interval P between adjacent unit lenses is called the pitch, and the gap of the splicing display screen is S l . The pitch P must be greater than S l .

[0026] Figure 4 gives an example of pixel rearrangement and encoding. The first dashed box from left to right represents the splicing display screen and the schematic diagram of the corresponding original image pixel distribution. Suppose there are 56 pixels in the illustrated area, and pixels 26, 27, 28, and 29 are missing at the splicing seam.

[0027] The display result after pixel rearrangement based on integral photography technology is shown within the first large dashed box on the right side. A continuous image display is obtained on the scattering surface. It can be seen that the finally displayed image is the result of reconstructing the image within the second dashed box from left to right, which is obtained after downsampling the original image. The downsampled image is segmented into unit images, and then the pixels are flipped and arranged according to the requirements of mirror imaging, and are displayed in the area of the corresponding unit lens on the tiled display screen. See Figure 4 the small dashed box within the first large dashed box on the right side.

[0028] From Figure 4 it can be seen that the missing pixels at the original gap S l are filled by the magnification of the lens. Let the size of the unit image that each lens can image be L s , and the pitch of the lens be P. When L s is magnified to P, the corresponding pixels of L s can be seamlessly displayed on the scattering surface, and the pitch P of the lens array satisfies P ≥ S l + L s . At this time, the magnification M0 of the lens is:

[0029] M0 = P / L s (1)

[0030] The size L s of the unit image is determined by the optical characteristics of the unit lens and the pitch P. First, L s cannot be greater than the pitch P, that is:

[0031] L s ≤ P (2)

[0032] Then, L s is determined by experimentally testing the object space field of view size when the actual unit lens has no distortion during imaging. Can Ls not be greater than the object space field of view?

[0033] Since the size of the area displayed on the scattering screen is the same as the size of the area displayed in the first dashed box from left to right, and the image displayed on the scattering screen is the display result after magnification by M, this means that in order for the image displayed on the scattering screen to be the same as the image displayed in the first dashed box from left to right, the image displayed in the first dashed box from left to right must be reduced by M times. For digital images, so-called reduction is downsampling. In this example, the image displayed in the second dashed box from left to right is the result of downsampling the pixels in the first dashed box from left to right when M = 2.

[0034] Figure 3 Or Figure 4This is the case where the images formed by adjacent lenses are just joined. In fact, as long as the lens magnification is greater than that in Equation (1), a seamless reconstructed image can be obtained. However, if the pixels of the unit images are still arranged as above, two problems will occur:

[0035] 1. The pixels of the reconstructed image overlap with each other. For example, pixels 4 and 5, pixels 8 and 9, pixels 12 and 13. This kind of pixel overlap will cause serious blurring of the reconstructed image.

[0036] 2. The pixel overlap is uneven. For example, pixels 2 and 3, pixels 6 and 7, pixels 14 and 15 have no overlapping pixels. The overlapping areas will be brighter, and the non - overlapping areas will be darker. This results in uneven brightness of the reconstructed image. Since the unit lenses are in a periodic array, finally, a grid of bright and dark areas will appear in the reconstructed image.

[0037] The solution to this problem is to first ensure the uniform brightness of the reconstructed image. To achieve this, it is only necessary that the magnification of the unit lens is an integer multiple of M0 in Equation (1). Figure 6 This is the schematic diagram of the reconstruction of unit images when the magnification of the unit lens is 2 times that of M0.

[0038] At this time, all the pixels in the reconstructed areas corresponding to the two middle unit lenses B and C overlap pairwise. Since there are still unit lenses not shown outside lenses A and D, in fact, the corresponding reconstructed areas of them should also overlap pairwise. This solves the problem of uneven brightness of the reconstructed image. It can be proved that if the magnification of the unit lens is S times that of M0 in Equation (1), then each point of the reconstructed image has S overlapping pixels.

[0039] However, at this time, the overlapping pixels will cause blurring of the reconstructed image. The solution to the problem is to resample the original image and re - encode the unit images. In Figure 6 the pixel overlapping area should originally display 12 pixels. Due to the overlap, 3 and 5, 4 and 6, 7 and 9,... are combined into one pixel. Now let 3 and 5 display the same pixel 4, 4 and 6 display pixel 6, 7 and 9 display pixel 8,..., as Figure 6 shown. At the same time, according to the requirements of the reconstructed image, re - order the unit images, as Figure 7 shown.

[0040] Figure 7 It can be understood in this way: If it is desired to display a continuous image 2, 4, 6, 8, 10,... on the scattering screen, it is necessary to display the corresponding pixels on the tiled display screen as required by the dashed blue box. The image displayed on the tiled display screen is the mirror image of the unit image within the yellow box, and the unit view within the yellow box is obtained by resampling the original image (the left - most first box) and then re - ordering and encoding (the left - most second box).

[0041] The key technology of the present invention is how to perform descending order and re - sorting encoding on the original image. Suppose the magnification of the unit lens is S times that of Equation (1), then the total magnification of the lens is:

[0042]

[0043] Considering that digital images generally represent resolution in terms of the number of pixels, the above formula can be written in a form related to pixels. Suppose the pixel pitch of the tiled display screen is d s , then the number of pixels P corresponding to the lens pitch P pix and the number of pixels L corresponding to the unit image L s are respectively: pix respectively:

[0044]

[0045]

[0046] The total magnification of the lens can be written as:

[0047]

[0048] The reconstructed image is the image magnified by the lens array, so the pixel pitch of the reconstructed image is:

[0049]

[0050] Due to the existence of the splicing gap, it is necessary to magnify through the lens to supplement the pixels in the tiled screen. Magnification means a reduction in the final display resolution. The larger the magnification factor, the lower the resolution. There is no waste of resolution here, but a sacrifice that has to be made to fill the splicing seam.

[0051] The diffuser screen is the same size as the tiled display screen. Suppose the horizontal dimension of the diffuser screen is Lx and the vertical dimension is Ly, then the number of pixels of the reconstructed image is:

[0052]

[0053] For a lens array with a pitch of P, suppose the number of unit lenses in the horizontal direction is N Ls , and in the vertical direction is M Ls , then the total number of unit lenses is:

[0054]

[0055] The number of unit images is the same as the number of unit lenses.

[0056] Steps for fabricating unit images:

[0057] 1) Resample (downsample) the image (video) to be displayed to obtain the resampled (video) image Irs . Make its number of pixels equal to the size given by equation (8).

[0058] 2) From image I rs The number of unit images determined by formula (9) is intercepted. The number of pixels of each unit image is determined by formula (5), that is,

[0059]

[0060] Taking the horizontal direction as an example, from image I rs The image array captured by the first unit view is:

[0061] EI1=I rs [(1:L pix ),(1:L pix )] (11)

[0062] Formula (11) indicates that the unit image EI1 is image I rs 1 to L pix Rows and 1 to L pix The coordinate area in pixels between columns.

[0063] Then move Δ pixels to the right to intercept the second unit image EI2. The EI2 unit image array is:

[0064] EI2=I rs [(1:L pix ),(1+Δ:L pix +Δ)] (12)

[0065] Then move Δ pixels to the right to capture the third unit image EI3. The EI3 unit image array is:

[0066] EI2=I rs [(1:L pix ),(1+2Δ:L pix +2Δ)] (13)

[0067] By analogy, N Ls The cell image array is:

[0068]

[0069] Nth Ls The unit image is the last image captured in the horizontal direction, and its corresponding I rs Column number L pix +(N Ls -1)Δ should be equal to N in equation (8) i ,Right now:

[0070] L pix+(N Ls -1)Δ) = N i (15)

[0071] From this, it is solved that: Substitute the relevant variables in equations (3) to (9) into equation (16), and finally obtain:

[0072]

[0073] In the formula: L pix is the number of pixels of the unit image,

[0074] P is the pitch of the lens array,

[0075] L x is the display size of the scattering screen in the horizontal direction,

[0076] S is an integer multiple of M0 = P / L s and take the integer value,

[0077] The interception of the unit image in the vertical direction is the same as that in the horizontal direction. Thus, the unit image in the m Ls -th row and n Ls -th column can be uniformly expressed as:

[0078]

[0079] 3) Perform a mirror transformation on the intercepted unit image, that is, flip the unit image up and down and left and right.

[0080] 4) Arrange the mirrored unit images according to the pitch P to form a rearranged video image. Figure 8 is a schematic diagram of the unit image array.

[0081] The seamless display system for the splicing screen described above includes splicing display screens arranged in parallel with each other, a lens array, and a rear projection scattering film. The lens array is placed between the splicing display screen and the rear projection scattering film. Adjust the resolution of the image to be displayed to M i ×N i , divide the image to be displayed into several square unit images to be displayed with a side length of L s . The unit images to be displayed form an array of unit images to be displayed. In the array of unit images to be displayed, intercept unit images at pixel intervals of △. When intercepting, any unit image and its adjacent unit images around it are △ pixels apart in both the row and column directions. After mirror-flipping the unit images, display them through the splicing screen. The unit images displayed on the splicing screen are centered and aligned with the lenses in the lens array one by one. The lens array magnifies the unit images displayed on the splicing screen by M times and flips and projects them onto the rear projection scattering film to form unit reconstructed images. The unit reconstructed images are spliced with each other to form a seamless image to be displayed;

[0082] Ls is determined by the distortion-free object field of view of the middle unit lens of the lens array, and the gap width between the unit images of the tiled display screen is S l , the center distance P between adjacent lenses in the lens array in the row or column direction is ≥ S l +L s , M ≥ P / L s , and M is an integer multiple of P / L s , and the number of lenses is fix represents rounding down to zero, M s ×N s is the number of pixels of the tiled display screen, d s is the pixel pitch of the tiled display screen, and the number of pixels of the downsampled image is the number of pixels of each unit image is L pix ×L pix , L pix = L s / d s , and the movement interval of the intercepted unit image round represents rounding to the nearest integer, N s , N i , N Ls are respectively the number of pixels of the tiled display screen image in the column direction, the number of pixels of the downsampled image to be displayed, and the number of lenses, M s , M i , M Ls are respectively the number of pixels of the tiled display screen image in the row direction, the number of pixels of the downsampled image to be displayed, and the number of lenses.

[0083] The unit image is intercepted starting from the pixel in the first row and first column of the unit image array to be displayed, and a total of M Ls ×N Ls unit images are intercepted. The unit image EI Ls in the m Ls th row and n mLsnLs th column intercepted is:

[0084]

[0085] The number of unit images in the unit image array is the same as the number of lenses in the lens array.

Claims

1. A seamless display system for a tiled screen, characterized in that, It includes a tiled display screen, a lens array, and a rear projection diffuser film that are arranged parallel to each other. The lens array is placed between the tiled display screen and the rear projection diffuser film to downsample the image to be displayed, and the downsampled image to be displayed is equally divided into a number of square image units to be displayed with a side length of L s The image units to be displayed form an image unit array to be displayed. In the image unit array to be displayed, unit images are intercepted at pixel intervals of △. When intercepting, any unit image and its adjacent unit images around it are separated by △ pixels in the row and column directions respectively. After mirror flipping the unit images, they are displayed through the tiled screen. The unit images displayed on the tiled screen are centered and aligned with the lenses in the lens array one by one. The lens array magnifies the unit images displayed on the tiled screen by M times and flips and projects them onto the rear projection diffuser film to form unit reconstructed images. The unit reconstructed images are spliced together to form a seamless image to be displayed; Ls is not greater than the distortion-free object space field of view of the unit lenses in the lens array, and the gap width between the display screen units of the tiled screen is S l The center distance P between adjacent lenses in the lens array in the row or column direction is ≥ S l +L s M ≥ P / L s and M is an integer multiple of P / L s , and the number of lenses is fix represents rounding towards zero, M s ×N s is the number of pixels of the tiled display screen, d s is the pixel interval of the tiled display screen, and the number of pixels of each unit image is L pix ×L pix , L pix = L s / d s , the number of pixels of the unit reconstructed image pixel interval round represents rounding to the nearest integer, N s 、N i 、N Ls are respectively the number of pixels of the tiled display screen image in the column direction, the number of pixels of the image to be displayed after downsampling, and the number of lenses, M s 、M i 、M Ls are respectively the number of pixels of the tiled display screen image in the row direction, the number of pixels of the image to be displayed after downsampling, and the number of lenses.

2. The seamless display system for a tiled screen according to claim 1, wherein The resolution of the image to be displayed after downsampling is 1 / M times that of the image to be displayed in the original splicing screen, where M is the magnification of the unit lens: S takes a non-zero integer, P is the pitch of the lens array, and Ls is the side length of the unit image.

3. The seamless display system for the splicing screen according to claim 2, wherein, The unit image is intercepted starting from the pixel at the first row and the first column in the unit image array, and a total of M Ls ×N Ls unit images are intercepted. The unit image EI Ls at the m Ls -th row and n mLsnLs -th column intercepted is as follows: The number of unit images in the unit image array is the same as the number of lenses in the lens array.

Images