Image display device, image display method, and image display program

Abstract

The present application aims at improving the display quality of a display device in which a plurality of display panels are stacked. According to the present application, there is provided a display device for displaying an image, comprising a light source, a plurality of display panels stacked, a wide-area smoothing unit, a narrow-area smoothing unit, and a mixing unit, the plurality of display panels comprising a first panel and a second panel disposed between the light source and the first panel, the wide-area smoothing unit performing smoothing processing on luminance information values of a target region including a target pixel and surrounding pixels thereof and outputting a wide-area smoothed value, the narrow-area smoothing unit performing smoothing processing on luminance information values of a target region including the target pixel and surrounding pixels thereof and smaller than the target region of the wide-area smoothing unit and outputting a narrow-area smoothed value, the mixing unit mixing the wide-area smoothed value and the narrow-area smoothed value at a predetermined mixing ratio and outputting a mixed value, the second panel displaying an image generated using the mixed value, and the luminance information values being generated using luminances of the pixels.

Description

Technical Field

[0001] This invention relates to an image display device, an image display method, and an image display program. Background Technology

[0002] To improve the display quality of image display devices, a technique is known in which multiple display panels are stacked and arranged to display images on each display panel. In the display device disclosed in Patent Document 1, a first display panel disposed on the front side of the display device displays a color image, and a second display panel disposed on the back side of the first display panel displays a black and white image. This method can display the low grayscale areas of the displayed image with high quality and can improve the contrast of the display device.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent document 1: Japanese Patent No. 6746464 Summary of the Invention

[0006] (The problem that the invention aims to solve)

[0007] Because the pixels on the front display panel and the corresponding pixels on the rear display panel are separated from each other along the thickness direction of the display panels, visual differences may occur due to the degree of pixel overlap caused by the observer's line of sight. When the observer's line of sight is tilted towards the display screen, the deviation in the degree of pixel overlap may cause bright spots to appear to disappear or ghosting to be seen. To suppress this degradation in display quality, in the display device of Patent Document 1, the brightness changes are smoothed by performing smoothing processing on the black and white image data used for the second display panel.

[0008] However, while smoothing can suppress the decline in display quality caused by parallax, it can sometimes easily cause interference patterns or halos depending on the input image.

[0009] The present invention was made in view of the above circumstances, and its object is to improve the display quality of a display device composed of multiple display panels stacked together.

[0010] (Technical solution used to solve the problem)

[0011] This invention provides a display device for displaying images, comprising a light source, a plurality of display panels arranged in layers, a wide-area smoothing unit, a narrow-area smoothing unit, and a mixing unit. The plurality of display panels include a first panel and a second panel disposed between the light source and the first panel. The wide-area smoothing unit smooths the luminance information values ​​of a target region including a target pixel in an input image and surrounding pixels of the target pixel, and outputs a wide-area smoothed value. The narrow-area smoothing unit smooths the luminance information values ​​of a target region including the target pixel and surrounding pixels of the target pixel, and smaller than the target region of the wide-area smoothing unit, and outputs a narrow-area smoothed value. The mixing unit mixes the wide-area smoothed value and the narrow-area smoothed value according to a predetermined mixing ratio and outputs a mixed value. The second panel displays an image generated using the mixed value, wherein the luminance information value is generated using the luminance of the pixels.

[0012] (Invention Effects)

[0013] In the display device of this invention, the luminance information values ​​of target areas of different sizes are smoothed, and a mixed value obtained by mixing the smoothed values ​​is used to generate an image displayed on a second panel. Smoothing can suppress the degradation of display quality caused by parallax, and by mixing the smoothed values ​​of target areas in relative wide and narrow domain relationships, the occurrence of interference patterns or halos caused by the drawbacks of smoothing can be suppressed.

[0014] Next, various embodiments of the present invention will be illustrated. The embodiments shown below can be combined with each other.

[0015] Preferably, the mixing unit includes a mixing ratio determination unit and a mixing processing unit. The mixing ratio determination unit calculates the luminance level using the luminance of the target pixel or the luminance of a nearby region containing the target pixel and its neighboring pixels, and determines the mixing ratio based on the luminance level. The mixing processing unit outputs the mixing value using the mixing ratio.

[0016] Preferably, the mixing ratio determining unit determines the mixing ratio such that the mixing ratio of the wide-area smoothing value is monotonically non-decreasing relative to the luminance level.

[0017] Preferably, the wide-area smoothing unit includes a first pre-processing unit and a first smoothing processing unit. The first pre-processing unit uses at least one of the luminance of each pixel in the target region that includes at least the wide-area smoothing unit and a representative value of the luminance of each pixel to generate the luminance information value for the wide-area smoothing unit. The first smoothing processing unit performs smoothing processing on the luminance information value and outputs the wide-area smoothing value.

[0018] Preferably, the first preprocessing unit further uses the grayscale values ​​of the color components of each pixel to generate the luminance information value of the target region of the wide-area smoothing unit.

[0019] Preferably, the narrow-area smoothing unit includes a second pre-processing unit and a second smoothing processing unit. The second pre-processing unit uses at least one of the luminance of each pixel in the target region that includes at least the narrow-area smoothing unit and a representative value of the luminance of each pixel to generate the luminance information value for the narrow-area smoothing unit. The second smoothing processing unit performs smoothing processing on the luminance information value and outputs the narrow-area smoothing value.

[0020] Preferably, the second preprocessing unit further uses the grayscale values ​​of the color components of each pixel in the target region that includes at least the narrow smoothing portion to generate the luminance information value of the target region of the narrow smoothing portion.

[0021] Preferably, the smoothing process is a process using an averaging filter.

[0022] Another aspect of the present invention provides a method for displaying an image on a display device, comprising a wide-area smoothing step, a narrow-area smoothing step, a blending step, and a display step. The display device includes a light source and a plurality of display panels arranged in a multilayer configuration. The plurality of display panels include a first panel and a second panel disposed between the light source and the first panel. In the wide-area smoothing step, luminance information values ​​of a target region including a target pixel in an input image and surrounding pixels of the target pixel are smoothed, and a wide-area smoothed value is output. In the narrow-area smoothing step, luminance information values ​​of a target region including the target pixel and surrounding pixels of the target pixel, and which is smaller than the target region of the wide-area smoothing step, are smoothed, and a narrow-area smoothed value is output. In the blending step, a blended value obtained by blending the wide-area smoothed value and the narrow-area smoothed value according to a predetermined blending ratio is output. In the display step, an image generated using the blended value is displayed on the second panel, wherein the luminance information value is generated using the luminance of the pixels.

[0023] Another aspect of the present invention provides a program for executing a method of displaying an image on a computer or a processor disposed in a display device, wherein the method includes a wide-area smoothing step, a narrow-area smoothing step, a mixing step, and a display step, the display device having a light source and a plurality of display panels configured in a multilayered manner, the plurality of display panels having a first panel and a second panel disposed between the light source and the first panel, in the wide-area smoothing step, smoothing the luminance information values ​​of a target region including a target pixel in an input image and surrounding pixels of the target pixel and outputting a wide-area smoothed value, in the narrow-area smoothing step, smoothing the luminance information values ​​of a target region including the target pixel and surrounding pixels of the target pixel and being smaller than the target region of the wide-area smoothing step and outputting a narrow-area smoothed value, in the mixing step, outputting a mixed value obtained by mixing the wide-area smoothed value and the narrow-area smoothed value according to a predetermined mixing ratio, and in the display step, displaying an image generated using the mixed value on the second panel, wherein the luminance information value is generated using the luminance of the pixels. Attached Figure Description

[0024] Figure 1 This is a block diagram illustrating the functional structure of the display device 1 according to an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram showing the positional relationship between the display section 2 of the display device 1 and the viewer's viewpoint e0.

[0026] Figure 3 This is a block diagram showing the functional structure of the image processing unit 3 of the display device 1.

[0027] Figure 4 This is a block diagram representing the functional structure of the first main processing unit 5.

[0028] Figure 5 middle, Figure 5 A is a block diagram representing the functional structure of the second main processing unit 8. Figure 5 B is a flowchart representing the processing in the second main processing unit 8.

[0029] Figure 6 This is a schematic diagram representing the pixel array I of the input image.

[0030] Figure 7 This is a schematic diagram of a two-dimensional array representing luminance V.

[0031] Figure 8 middle, Figure 8 A represents the luminance information value V' used in the wide-area smoothing section 82. l A schematic diagram of a two-dimensional array. Figure 8B represents the target region A in the wide-area smoothing part 82. l＿m，n luminance information value V' l A summary diagram.

[0032] Figure 9 middle, Figure 9 A represents the luminance information value V' used in the narrow smoothing section 85. s A schematic diagram of a two-dimensional array. Figure 9 B represents the target region A in the narrow smoothing section 85. s＿m，n luminance information value V' s A summary diagram.

[0033] Figure 10 This is a block diagram representing the functional structure of the mixing section 88.

[0034] Figure 11 This indicates the surrounding area A used in the mixing ratio determination unit 88a. n＿m，n A summary diagram of the luminance V.

[0035] Figure 12 It represents the brightness level V g With wide-area smoothing value V' mean－l The mixing ratio f l A diagram illustrating an example of a relationship.

[0036] Figure 13 middle, Figure 13 A is a block diagram representing the functional structure of the first preprocessing unit 83. Figure 13 B is a block diagram representing the functional structure of the second preprocessing unit 86.

[0037] Figure 14 middle, Figure 14 A is a schematic diagram showing a two-dimensional array of luminance V used in the absolute luminance calculation unit 83a and the relative luminance calculation unit 83b of the first preprocessing unit 83. Figure 14 B is a schematic diagram showing a two-dimensional array of luminance V used in the absolute luminance calculation unit 86a and the relative luminance calculation unit 86b of the second preprocessing unit 86.

[0038] Figure 15 It represents the average luminance V in LUT83b2 of the relative luminance calculation unit 83b. mean－l With corresponding value f v－l A diagram illustrating an example of a relationship.

[0039] Figure 16 This represents the average grayscale value (RGB) in the LUT83c2 of the adjustment coefficient calculation unit 83c. mean－l With adjustment factor f a－l A diagram illustrating an example of a relationship. Detailed Implementation

[0040] Next, embodiments of the present invention will be described with reference to the accompanying drawings. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature independently constitutes the present invention.

[0041] It should be noted that the term "section" in this specification can refer to a combination of hardware resources operated by a circuit in a broad sense and software information processing specifically achievable by these hardware resources. In this embodiment, various types of information are processed, which can be represented as a set of binary bits consisting of 0s or 1s, and are indicated by the high or low signal values, and can be obtained through communication or computation using a circuit in a broad sense. Furthermore, the term "circuit in a broad sense" refers to a circuit implemented at least by a suitable combination of circuits, circuitry, processors, and memory. That is, it can include application-specific integrated circuits (ASICs), programmable logic devices (e.g., simple programmable logic devices (SPLDs), complex programmable logic devices (CPLDs), and field-programmable gate arrays (FPGAs)).

[0042] 1. Overall Structure

[0043] like Figure 1 As shown, the display device 1 according to this embodiment includes a display unit 2 and an image processing unit 3. The display unit 2 and the image processing unit 3 are connected by a signal line so that they can communicate with each other. Figure 2 As shown, the display unit 2 includes a light source 23 disposed on the rear side of the display unit 2 and a plurality of display panels stacked together. The display unit 2 according to this embodiment includes two liquid crystal panels: a first panel 21 disposed on the front side of the display unit 2 as a plurality of display panels, and a second panel 22 disposed between the light source 23 and the first panel 21. When viewed from the viewpoint e0 of an observer located in front of the display unit 2, the second panel 22 is positioned further away than the first panel 21. It should be noted that in the following description, the entire assembly of the plurality of display panels (the first panel 21 and the second panel 22 in this embodiment) is sometimes referred to as a stacked display panel.

[0044] The image processing unit 3 performs prescribed image processing on the input image, and then outputs the first image data DAT1 and the second image data DAT2 to the display unit 2. Based on control signals or data transmitted from the image processing unit 3 via signal lines, the first panel 21 displays the first image based on the first image data DAT1, and the second panel 22 displays the second image based on the second image data DAT2. In this embodiment, the first panel 21 is a color liquid crystal panel displaying the first image (color image), and the second panel 22 is a monochrome liquid crystal panel displaying the second image (monochrome image).

[0045] The first image is displayed on the laminated display panel by displaying the first image on the first panel 21 and the second image on the second panel 22 respectively, and by controlling the transmittance of the light L emitted from the light source 23. For example... Figure 2 As shown, pixel p1 of the first panel 21 and pixel p2 of the second panel 22 are separated by a distance d in the thickness direction of the display panel. Therefore, when the observer's line of sight is facing the front of the pixel ( Figure 2 In the case of viewing line e1, a high-quality image can be seen, while when the observer's line of sight is tilted towards the pixel ( Figure 2 In cases where the line of sight is e2 or e3, the overlap between pixel p1 and pixel p2 can cause a deviation, resulting in the disappearance of bright spots or the appearance of ghosting. To suppress this adverse effect of using the second panel 22, smoothing processing is performed when generating the second image data DAT2 using the image processing unit 3.

[0046] 2. Image Processing Unit 3

[0047] Next, the structural elements of the image processing unit 3 will be described in detail. For example... Figure 1 and Figure 3 As shown, the image processing unit 3 according to this embodiment includes a linear transformation unit 31, a first image generation unit 4, and a second image generation unit 7. The linear transformation unit 31 performs predetermined processing on the input image data and outputs it to the first image generation unit 4 and the second image generation unit 7. The first image generation unit 4 and the second image generation unit 7 generate first image data DAT1 and second image data DAT2, respectively.

[0048] 2.1. Linear Transformation Unit 31

[0049] The linear transformation unit 31 receives the input signal RGBγ as input image data, where each of the R, G, and B components is represented by 10 bits for grayscale. The "input signal RGBγ" refers to the input image's grayscale value after gamma correction for gamma characteristics. The linear transformation unit 31 generates a transformed linear signal RGB, which exhibits a linear characteristic of increasing brightness with increasing grayscale value for each component of the input signal RGBγ. In this embodiment, three LUTs (Lookup Tables) set for each component are used for transformation to obtain the linear signal RGB.

[0050] 2.2. Second Image Generation Unit 7

[0051] The second image generation unit 7 includes a second main processing unit 8 and a second nonlinear transformation unit 9. The second main processing unit 8 receives a linear signal RGB from the linear transformation unit 31, performs a predetermined process including smoothing, and generates a second processed signal D. The processing performed by the second main processing unit 8 will be described in detail later. The second nonlinear transformation unit 9 receives the second processed signal D from the second main processing unit 8 and uses a LUT (Local Unified Transformer) based on the display characteristics of the second panel 22 to transform the second processed signal D into a nonlinear signal, a second image signal Dγ. The second image signal Dγ is output to the display unit 2 as second image data DAT2, and a second image is displayed on the second panel 22 based on the second image signal Dγ.

[0052] 2.3. First Image Generation Unit 4

[0053] The first image generation unit 4 includes a first main processing unit 5 and a first nonlinear transformation unit 6. For example... Figure 4 As shown, the first main processing unit 5 includes a coefficient calculation unit 51 and an arithmetic unit 52. The coefficient calculation unit 51 receives a second processing signal D from the second main processing unit 8 of the second image generation unit 7 and outputs a coefficient F associated with the second processing signal D using a LUT. The arithmetic unit 52 receives a linear signal RGB from the linear transformation unit 31 and a coefficient F from the coefficient calculation unit 51, multiplies the linear signal RGB by the coefficient F to generate a first processing signal RGB'. In this embodiment, light emitted from the light source 23 is transmitted through the second display panel with a transmittance based on the second image data DAT2, and further through the first display panel with a transmittance based on the first image data DAT1, ultimately achieving the desired transmittance corresponding to the input image data in the multilayer display panel. The coefficient F is stored in the LUT used by the coefficient calculation unit 51. This coefficient F is an output data coefficient associated with the second processing signal D, which is the input data, based on the relationship between the transmittance of the first and second display panels.

[0054] The first nonlinear transformation unit 6 receives the first processed signal RGB' from the first main processing unit 5, and uses a LUT created for each color component based on the display characteristics of the first panel 21 to convert the first processed signal RGB' into a nonlinear signal, the first image signal RGB'γ. The first image signal RGB'γ is output to the display unit 2 as the first image data DAT1, and the first image based on the first image signal RGB'γ is displayed on the first panel 21.

[0055] In the image processing unit 3 according to this embodiment, before processing by the first main processing unit 5 and the second main processing unit 8, a linear transformation unit 31 converts the signal into a linear signal. Furthermore, the first processing signal RGB' and the second processing signal D generated by the first main processing unit 5 and the second main processing unit 8 respectively are converted into non-linear signals by the first non-linear transformation unit 6 and the second non-linear transformation unit 9 and output to the display unit 2. In this structure, the first main processing unit 5 and the second main processing unit 8 process linear signals that correspond to grayscale values ​​visible through the multilayer display panel. Therefore, the first main processing unit 5 can more accurately process the colors displayed when multiple display panels are combined, thus obtaining more suitable results in smoothing and other processes in the second main processing unit 8.

[0056] 3. Second Main Processing Unit 8

[0057] Next, the processing performed by the second main processing unit 8 will be described in detail. For example... Figure 5 As shown in Figure A, the second main processing unit 8 includes a brightness conversion unit 81, a wide-area smoothing unit 82, a narrow-area smoothing unit 85, and a mixing unit 88. Figure 5 B is a flowchart representing the processing in the second main processing unit 8.

[0058] 3.1. Luminosity Transformation Unit 81

[0059] The luminance conversion unit 81 receives the linear signal RGB and outputs the luminance V based on the grayscale value of each pixel in the input image. Figure 5 Step S1 in B). In this embodiment, the luminance conversion unit 81 outputs the largest gray value among the gray values ​​of various color components of each pixel as the luminance V. Figure 6 This refers to the pixel array I of the input image involved in this embodiment, where pixel array I has M×N pixels. Figure 6 Using the top-left pixel as a reference, the pixel in the m-th row and n-th column is represented as i. m，n When the pixel i in the input image is in the linear RGB signal... m，n The grayscale values ​​are normalized to a range of 0 to 1, and the resulting values ​​are (R0). m，n G m，n B m，nWhen ), R will be as expressed in formula (1). m，n G m，n B m，n The maximum value in is taken as pixel i m，n luminance v m，n .

[0060] v m，n =max{R m，n G m，n B m，n} (1)

[0061] (0≤R m，n G m，n B m，n ≤1)

[0062] The luminance conversion unit 81 outputs luminance V, which is as follows: Figure 7 Each pixel i shown m，n luminance v m，n A two-dimensional array. It should be noted that the method for calculating luminance V is not limited to the above example. For example, the luminance V can also be output by weighting the gray values ​​of the various color components of each pixel.

[0063] 3.2. Wide-area smoothing section 82 and narrow-area smoothing section 85

[0064] Wide-area smoothing section 82 and narrow-area smoothing section 85 provide information related to luminance V (i.e., luminance information value V'). l ,V' s Perform smoothing processing and output the wide-area smoothing value V' respectively. mean－l and narrow smoothing value V' mean－s Using luminance V, generate luminance information value V'. l V' s Here, the wide-area smoothing unit 82 targets the target region A, which includes the target pixel in the input image and the surrounding pixels of that target pixel. l luminance information value V' l Smoothing processing is performed; in contrast, the narrow-area smoothing unit 85 smooths the target region A, which includes the target pixel and the surrounding pixels, compared to the wide-area smoothing unit 82. l Small target area A s luminance information value V' s Perform smoothing processing.

[0065] like Figure 5 As shown in Figure A, the wide-area smoothing unit 82 includes a first pre-processing unit 83 and a first smoothing processing unit 84. The first pre-processing unit 83 performs a predetermined pre-processing on the luminance V (…). Figure 5 Step S2 in B), and output the luminance information value V' l，The luminance information value V' l Is it like this? Figure 8 Each pixel i shown in A m，n luminance information value v' l＿m，n A two-dimensional array. It should be noted that the details of the processing performed by the first preprocessing unit 83 will be described later.

[0066] When the pixel i in the m-th row and n-th column is... m，n As the target pixel and target pixel i m，n Corresponding target area A l Represented as A l＿m，n At that time, target area A l＿m，n Set to target pixel i m，n Approximately centered and containing the target pixel i m，n The total number of pixels, including those surrounding it, is k. l ×k l A region consisting of 1 pixel. k l For example, it is 99 to 999, preferably 149 to 599. In this embodiment, it is set to k. l =301. k l Specifically, these could be 99, 199, 299, 399, 499, 599, 699, 799, 899, or 999, or any range between any two values ​​listed here. The first smoothing processing unit 84... Figure 8 The target area A is indicated by a thick line in B. l＿m，n luminance information value V' l Perform smoothing processing (wide-area smoothing step, i.e.) Figure 5 Step S3 in B). Therefore, the target pixel i can be obtained. m，n The relevant wide-area smoothing value v' mean－l＿m， n .

[0067] For the purpose of suppressing interference patterns, the smoothing process performed by the first smoothing processing unit 84 is on the target area A with a relatively large contrast. l＿m，n Smoothing processing was performed on target region A. l＿m，n Size k l ×k l Not limited to the examples in this embodiment, the size of the display panel and the expected range of the observer's viewpoint relative to the multilayer display panel can be considered and determined to be large enough that the interfering pattern will not be perceived even when the line of sight is tilted relative to the multilayer display panel. It should be noted that the target area A in this embodiment... l＿m，n Although it consists of the same number of pixels (k) in both the row and column directions l It consists of (a, b) units, but the target area A can also be considered. l＿m，nIt is configured to consist of different numbers of pixels in the row and column directions.

[0068] The first smoothing processing unit 84 of this embodiment smooths the target area A determined by this method. l＿m，n luminance information value V' l Applicable filter size is k l ×k l An averaging filter is used for smoothing. Therefore, the wide-area smoothed value v' mean－l＿m，n Target area A l＿m，n The sum of the luminance information values ​​V' of the pixels within the range divided by k l ×k l The value after that.

[0069] like Figure 5 As shown in Figure A, the narrow-domain smoothing unit 85 includes a second pre-processing unit 86 and a second smoothing processing unit 87. The second pre-processing unit 86 performs a predetermined pre-processing on the luminance V output from the luminance conversion unit 81. Figure 5 Step S4 in B), and output the luminance information value V' s The luminance information value V' s Is it like this? Figure 9 Each pixel i shown in A m，n luminance information value v' s＿m，n A two-dimensional array. It should be noted that the details of the processing performed by the second preprocessing unit 86 will be described later.

[0070] When using A s＿m，n Represents target pixel i m，n Corresponding target area A s At that time, target area A s＿m，n Set to target pixel i m，n Approximately centered and consisting of the target pixel i m，n The total k of the surrounding pixels s ×k s The region comprised of k pixels. s For example, it is 5 to 61, preferably 11 to 39, and in this embodiment it is set to k. s =15. k s Specifically, these could be 5, 13, 21, 29, 37, 45, 53, or 61, or any two values ​​listed here within a range. The second smoothing processing unit 87... Figure 9 The target area A is indicated by a thick line in B. s＿m，n luminance information value V' s Perform smoothing processing (narrow smoothing steps, Figure 5 Step S5 in B). Thus, the target pixel i can be obtained. m，nThe relevant narrow-range smoothing value v'mean － s ＿ m ， n.

[0071] The second smoothing processing unit 87 performs smoothing processing on the target area A. s＿m，n The target area A is set to be smoothed by the first smoothing processing unit 84. l＿m，n Small. In this embodiment, target area A sm，n Set to satisfy k s <k l The relationship, and the target area A of the second smoothing processing unit 87 sm，n The target area A of the first smoothing processing unit 84 l＿m，n As part of the method. To suppress the disappearance of bright spots caused by the overlap deviation between pixels of the first panel 21 and the second panel 22 due to the observer's gaze tilting towards the multilayer display panel, the smoothing process performed by the second smoothing processing unit 87 is applied to the relatively small target area A. s＿m，n Proceedings. Target area A s＿m，n The distance between pixels of the first panel 21 and the second panel 22 in the thickness direction of the display panel, or the viewing angle of the observer relative to the multilayer display panel, can be considered to determine the minimum size k that satisfies the following condition. This condition ensures that the disappearance of bright spots is not perceived even when the viewer's gaze is tilted towards the multilayer display panel. s ×k s The method. When the target area A of the second smoothing processing unit 87. s＿m，n The size relative to the target area A of the first smoothing processing unit 84 l＿m，n When the size is 1 / a times the horizontal and vertical dimensions, 'a' can be, for example, 5 ≤ a ≤ 50, preferably 10 ≤ a ≤ 40, and in this embodiment, 'a' is approximately 20. Specifically, 'a' can be, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50, or it can be within the range of any two values ​​exemplified here. It should be noted that although the target area A in this embodiment... s＿m，n It consists of the same number of pixels (k) in both the row and column directions. s It consists of (a, b) units, but the target area A can also be considered. s＿m，n It is set to be composed of different numbers of pixels in the row and column directions.

[0072] The second smoothing processing unit 87 processes the target area A determined in this way. s＿m，n luminance information value V' s Smoothing is performed using a filter with size k. s ×k sThe average filter is used for smoothing. Therefore, the narrow-domain smoothed value v' mean－s＿m，n Target area A s＿m，n The sum of the luminance information values ​​V' of the pixels within the range divided by k s ×k s The value obtained afterwards.

[0073] In this embodiment, the first smoothing processing unit 84 and the second smoothing processing unit 87 use an averaging filter for smoothing. Compared to a low-pass filter (LPF) that assigns weights based on distance, the grayscale gradient in the smoothed image is constant after averaging. This reduces interference patterns generated when the relative positions of the first panel 21 and the second panel 22 are offset. In other words, by using an averaging filter, which is an LPF with a widened attenuation range both spatially and frequency-wise, interference can be reduced over a wide range.

[0074] 3.3. Mixing section 88

[0075] The mixing unit 88 receives the wide-area smoothing value V' from the wide-area smoothing unit 82. mean－l , and the narrow smoothing value V' from the narrow smoothing part 85 mean－s They are mixed with a specified mixing ratio, and the mixed value is output as the second processing signal D. Figure 10 As shown, the mixing unit 88 includes a mixing ratio determination unit 88a and a mixing processing unit 88b.

[0076] The blending ratio determination unit 88a receives luminance V from the luminance conversion unit 81 and uses either the luminance V including the target pixel, or the target pixel and the neighborhood region A of the target pixel and its neighboring pixels. n Calculate the luminance level V using luminance V. g The mixing ratio determination unit 88a is based on the luminance level V. g Determine the mixing ratio f l f s Mixing ratio f l f s Used to smooth the wide-area value V' mean－l and narrow smoothing value V' mean－s When, the smoothing values ​​shown in formula (2) are weighted.

[0077] D = f l ×V' mean－l +f s ×V' mean－s (2)

[0078] (0≤f l f s ≤1, and f s=1-f l )

[0079] When compared with target pixel i m，n The corresponding nearby area A n Represented as A n＿m，n At that time, the vicinity area A of this embodiment n＿m，n Set as i m，n Approximately centered and consisting of the target pixel i m，n The total k of its neighboring pixels n ×k n A region consisting of 100 pixels. In this embodiment, k is set to 100. n =9. The mixing ratio determination unit 88a of this embodiment is for... Figure 11 The nearby area A, indicated by the thick line in the middle. n＿m，n The luminance V was processed using LPF88a1 based on a Gaussian distribution to calculate the value relative to the target pixel i. m，n The relevant luminance level v g＿m，n Because LPF88a1 affects the surrounding area A n＿m，n The luminance V was weighted, and this weighting was based on the target pixel i. m，n The distance was measured, so a reflection of the surrounding area A can be obtained. n＿m，n The distribution of luminance V in the luminance level v g＿m，n It should be noted that the weighting of LPF88a1 is not limited to the structure of this embodiment based on the Gaussian distribution, and other weighting methods can also be used.

[0080] If nearby area A n＿m，n If the size is too large, then the target pixel i m，n The distribution of luminance V in the vicinity cannot be represented by the luminance level v. g＿m，n This is reflected appropriately, resulting in a decrease in the processing performance of the mixing section 88. Therefore, the surrounding area A... n＿m，n The size is preferably set to the target region A in the wide-area smoothing section 82. l＿m，n The size is less than that, and more preferably it is set to the target region A in the narrow smoothing section 85. s＿m，n The size is less than that. In this embodiment, the nearby area A is... n＿m，n The size is set to be larger than the target region A in the narrow smooth section 85. s＿m，n The size is small (relative to k) s =15, which is k n =9). It should be noted that, although the nearby area A in this embodiment... n＿m，n It consists of the same number of pixels (k) in both the row and column directions. n It consists of (a) units, but it can also include the nearby area A. n＿m，n It is configured to consist of different numbers of pixels in the row and column directions.

[0081] It should be noted that the luminance level v g＿m，n The calculation method is not limited to the example of this embodiment; the target pixel i can also be calculated. m，n luminance v m，n Directly used as the luminance level v g＿m，n .

[0082] The blending ratio determination unit 88a uses LUT88a2 to determine the blending ratio with the target pixel i. m，n luminance level v g＿m，n The corresponding mixing ratio f l＿m，n LUT88a2 stores wide-area smoothing values ​​V' as output data, which are associated with the luminance level Vg, which is the input data. mean－l The mixing ratio f l It stores the mixing ratio f. l The LUT88a2 is based on the display performance of the first panel 21 in the low grayscale region, or on the perceived ease of interference patterns based on the actual size of the display panel. Here, the wide-area smoothing value V' mean－l The mixing ratio f l Preferably relative to the luminance level V g It exhibits a monotonically non-decreasing trend. In other words, the narrow-domain smoothing value V' mean－s The mixing ratio f s Preferably relative to the luminance level V g It is monotonically non-increasing. Furthermore, it is more preferable to increase the mixing ratio f. l f s The determination is: luminance level V g Wide-area smoothing value V' in relatively high regions mean－l The mixing ratio f l Narrow smoothing value V' mean－s The mixing ratio f s Large, luminance level V g Narrow smoothing value V' in a relatively low region mean－s The mixing ratio f s Compared to the wide-area smoothing value V' mean－l The mixing ratio f l Large. This can suppress the occurrence of interfering patterns when displaying images, and also suppress the degradation of display quality in low grayscale areas.

[0083] Figure 12 This represents the luminance level V in LUT88a2. g With wide-area smoothing value V' mean－l The mixing ratio f l A diagram illustrating an example of the relationship. At the luminance level V g Low region, mixing ratio f l Monotonically increasing at luminance level Vg From medium to high regions, the mixing ratio f l Roughly constant. It should be noted that the luminance level V... g With mixing ratio f l The relationship is not limited to this example; for example, it could also be a monotonically non-decreasing relationship in the shape of an S-curve or a monotonically non-decreasing relationship in the shape of a step function.

[0084] Using the mixing ratio f obtained in this way l＿m，n The mixing processing unit 88b calculates the relationship between pixel i and pixel i using formula (2). m，n The relevant mixed value d m，n (mixing steps, Figure 5 Step S6 in B). Furthermore, the wide-area smoothing section 82, the narrow-area smoothing section 85, and the blending section 88 change the target pixel i. m，n And repeat the above process simultaneously. Figure 5 Step S7 in B). The blend value d of all pixels. m，n The two-dimensional array is output as the second processed signal D.

[0085] When only the target region A with a relatively large contrast, which is the wide-area smoothing part 82, is used. l The wide-area smoothed value V' obtained after smoothing processing mean－l When generating the second image data DAT2, interference patterns are not easily perceived in the image displayed on the multilayer display panel. On the other hand, it is possible that blurry and bright areas (so-called white halos) can easily extend over a wide range from high grayscale areas to low grayscale areas in the image, resulting in a deterioration in the display quality of low grayscale areas. When only the A with a minimum size is used by the narrow-area smoothing section 85... s The narrow smooth value V' obtained by smoothing is mean－s When generating the second image data DAT2, although the occurrence of white halos can be suppressed to a narrow range, interference patterns in the displayed image are easily perceived.

[0086] In this invention, the wide-area smoothing value V' is used. mean－l and narrow smoothing value V' mean－s Mixing can be achieved by using a wide-area smooth value V' mean－l While effectively suppressing interference patterns, it can also suppress interference caused by using a wide-area smoothing value V'. mean－l The white halo effect, which can be a drawback, can cause a decrease in display quality in low grayscale areas.

[0087] Furthermore, in this invention, the smoothing processes performed on luminance information values ​​by the wide-area smoothing unit 82 and the narrow-area smoothing unit 85 can be performed independently and in parallel. When serial processing is used (i.e., the result of smoothing by one smoothing unit is further smoothed by another smoothing unit), the smoothing process may become excessive and the contrast may decrease, thereby impairing the effect of the smoothing process performed by the other smoothing unit. By performing smoothing processes independently on target areas of different sizes and then mixing the results, the above situation can be avoided.

[0088] Furthermore, interference patterns are easily perceived in areas with gray levels above the middle, but difficult to perceive in low gray levels. This is achieved by smoothing the wide-area smoothing value V' as described above. mean－l The mixing ratio f l Set relative to the luminance level V g It exhibits a monotonically non-decreasing pattern at the luminance level V. g A higher value in the region increases the wide-area smoothness value V' in the mixture. mean－l The ratio can be adjusted to improve the suppression of interference patterns, and the brightness level V can also be adjusted. g Lower regions increase narrow-area smoothing value V' in the blend. mean－s The ratio is used to improve the suppression of display quality degradation in low grayscale areas.

[0089] 3.4. First pre-processing unit 83 and second pre-processing unit 86

[0090] <Overall Structure of the First Pre-processing Unit 83>

[0091] like Figure 13 As shown in Figure A, the first preprocessing unit 83 of the wide-area smoothing unit 82 includes an absolute luminance calculation unit 83a, a relative luminance calculation unit 83b, an adjustment coefficient calculation unit 83c, and an adjustment value calculation unit 83d. The absolute luminance calculation unit 83a receives luminance V from the luminance transformation unit 81 and outputs a region of interest B containing the target pixel. l The maximum luminance V in max－l .

[0092] The relative luminance calculation unit 83b receives luminance V data from the luminance transformation unit 81 and performs calculations on the region of interest B containing the target pixel. l The luminance V is calculated using an averaging filter 83b1. mean－l Furthermore, the relative luminance calculation unit 83b uses LUT83b2 to determine the luminance average value V. mean－l The corresponding value f v－l .

[0093] The adjustment factor calculation unit 83c uses the grayscale values ​​of various color components of the pixel to determine the adjustment factor f. a-l. In this embodiment, the adjustment coefficient calculation unit 83c calculates the region of interest B containing the target pixel. l The linear RGB signal in the image is processed using an 83c1 averaging filter to calculate the grayscale average RGB value. mean－l Then, LUT83c2 is used to determine the grayscale average RGB value. mean－l The corresponding adjustment factor f a－l .

[0094] The adjustment value calculation unit 83d receives the maximum luminance V from the absolute luminance calculation unit 83a. max－l And the corresponding value f from the relative luminance calculation unit 83b v－l And based on formulas (3) and (4), the lower limit value V of luminance is set. limit－l .

[0095] V max－l <f v－l V limit－l =f v－l (3)

[0096] V max－l ≥f v－l V limit－l V max－l (4)

[0097] In addition, the adjustment value calculation unit 83d receives the adjustment coefficient f from the adjustment coefficient calculation unit 83c. a－l And based on formula (5), the luminance information value V' used in the wide-area smoothing section 82 is calculated. l .

[0098] V l =1-f a－l ×(1-V limit－l (5)

[0099] It should be noted that the first preprocessing unit 83 is not limited to the above structure, and may also be a structure that has only one or both of the absolute luminance calculation unit 83a, the relative luminance calculation unit 83b and the adjustment coefficient calculation unit 83c.

[0100] <Overall Structure of the Second Pre-processing Unit 86>

[0101] like Figure 13 As shown in B, the second preprocessing unit 86 of the narrow-area smoothing unit 85 includes an absolute luminance calculation unit 86a, a relative luminance calculation unit 86b, an adjustment coefficient calculation unit 86c, and an adjustment value calculation unit 86d. The processing performed by these components includes the region of interest B of the target pixel. s Except for the size, the processing is the same as that performed on the constituent elements of the first preprocessing unit 83. The absolute luminance calculation unit 86a outputs the area of ​​interest B.s The maximum luminance V in max－s The relative luminance calculation unit 86b calculates the luminance for region B of interest. s The luminance V is applied to an averaging filter 86b1 and the average luminance V is calculated. mean－s Using LUT86b2 to determine the value relative to the average luminance V mean－s The corresponding value f v－s The adjustment coefficient calculation unit 86c adjusts the region of interest B. s The linear RGB signal in the image is calculated using an 86c1 averaging filter to calculate the grayscale average RGB value. mean－s Using LUT86c2 to determine the grayscale average RGB mean－s The corresponding adjustment factor f a－s .

[0102] The adjustment value calculation unit 86d sets the lower limit value V of luminance based on formulas (6) and (7). limit－s .

[0103] V max－s <f v－s V limit－s =f v－s (6)

[0104] V max－s ≥f v－s V limit－s =V max－s (7)

[0105] The adjustment value calculation unit 83d calculates the luminance information value V' for the narrow-area smoothing unit 85 based on formula (8). s .

[0106] V s =1-f a－s ×(1-V limit－s (8)

[0107] It should be noted that the second preprocessing unit 86 is not limited to the above structure, and may also have only one or both of the absolute luminance calculation unit 86a, the relative luminance calculation unit 86b, and the adjustment coefficient calculation unit 86c.

[0108] <Absolute luminance calculation section 83a, 86a>

[0109] The processing of each target pixel in the absolute luminance calculation units 83a and 86a and the effect of this processing are further explained in detail. The first preprocessing unit 83 is compared with the target pixel i... m，n The corresponding area of ​​interest is represented as B. l＿m，n Pay attention to area B l＿m，n Set to target pixel i m，nApproximately centered and consisting of the target pixel i m，n The total j of the pixels and their surrounding pixels l ×j l A region consisting of pixels. In this embodiment, it is set to j. l =305. The absolute luminance calculation unit 83a of the first preprocessing unit 83 calculates... Figure 14 The area of ​​interest is indicated by a thick line in section A. l＿m，n The maximum value of the luminance V is used as the reference for the target pixel i. m，n The relevant maximum luminance v max－l＿ m，n .

[0110] The second preprocessing unit 86 is connected to the target pixel i m，n The corresponding area of ​​interest is represented as B. s＿m，n Pay attention to area B s＿m，n Set to target pixel i m，n Approximately centered and consisting of the target pixel i m，n The total j of the pixels surrounding it s ×j s A region consisting of pixels. In this embodiment, it is set to j. s =19. The absolute luminance calculation unit 86a of the second preprocessing unit 86 calculates... Figure 14 The area of ​​interest is indicated by a thick line in B. s＿m，n The maximum value of the luminance V is used as the reference for the target pixel i. m，n The relevant maximum luminance v max－s＿m，n .

[0111] If the luminance V output from the luminance transformation unit 81 is used directly for smoothing, the wide-area smoothing value v' mean－l＿m，n and narrow smoothing value v' mean－s＿m，n Sometimes the luminance becomes higher than before smoothing. m，n Small. In this situation, the weakening of peak luminance in the displayed image, or the appearance of blurred and dark areas (so-called black halos) from low grayscale areas to high grayscale areas in the image, can be perceived, which may cause a problem of degraded display quality in high grayscale areas. In this embodiment, the maximum luminance value v calculated by the absolute luminance calculation units 83a and 86a is... max－l＿m，n v max－s＿m，n This serves as a lower limit for luminance to prevent luminance reduction caused by this smoothing process. It is achieved by using a value based on the maximum luminance v. max－l＿m，n v max－s＿m，n Set target pixel i m，n The relevant lower limit value of luminance v limit－l＿m，n and v limit－s＿m，n To calculate the luminance information value v'l＿m，n v' s＿m，n Make the wide-area smooth value v' mean－l＿m and narrow smoothing value v' mean－s＿m，n luminance v before smoothing m，n The above values ​​can suppress the weakening of peak brightness and black halos.

[0112] It should be noted that the absolute luminance calculation units 83a and 86a are not limited to the above configuration. For example, they can also be configured to calculate the maximum luminance value v. max－l＿m，n and v max－s＿m，n Perform other calculations and output the composition of the values, or output the region of interest B. l＿m，n B s＿m，n The composition of other representative values ​​of luminance V in the figure.

[0113] <Relative luminance calculation unit 83b, 86b>

[0114] The processing for each target pixel in the relative brightness calculation units 83b and 86b is further explained in detail, along with the effect of this processing. The relative brightness calculation unit 83b of the first preprocessing unit 83... Figure 14 Area of ​​interest in A, B l＿m，n The luminance V is suitable for a filter size of j. l ×j l The averaging filter 83b1 is used to calculate the average pixel i. m，n The corresponding average luminance v mean－l＿m，n Therefore, the average luminance v mean－l＿m，n It is the area of ​​interest B. l＿m，n The sum of the luminance V of the pixels within the range divided by j l ×j l The value obtained later. The average luminance V, which is used as input data, is stored in the LUT83b2 used by the relative luminance calculation unit 83b. mean－l The associated value f, which is the corresponding output data. v－l Using LUT83b2, the average luminance v can be obtained. mean－l＿m，n Determine the target pixel i m，n The relevant corresponding value f v－l＿m，n .

[0115] The relative luminance calculation unit 86b of the second preprocessing unit 86 calculates... Figure 14 B's area of ​​interest s＿m，n The luminance V is suitable for a filter size of j. s ×j s The averaging filter 86b1 calculates the ratio with the target pixel i. m，n The corresponding average luminance v mean－s＿m，n Therefore, the average luminance v mean－s＿m，n It is the area of ​​interest B.s＿m，n The sum of the luminance V of the pixels within the range divided by j s ×j s The value obtained later. The LUT86b2 used in the relative luminance calculation unit 86b stores the average luminance V, which is the input data. mean－s The associated value f, which is the corresponding output data. s－l Using LUT86b2, from the luminance average v mean－s＿m，n Determine the target pixel i m，n The relevant corresponding value f s－l＿m，n .

[0116] By using the second panel 22, in other words, by reducing the grayscale value of the second panel 22, the display quality in low grayscale areas can be improved in particular. On the other hand, when the target pixel is surrounded by a relatively high-brightness area, it is difficult to perceive changes in the performance of the relatively low grayscale target pixel due to the light diffusing from that area, thus reducing the usefulness of the second panel 22. In this embodiment, the corresponding value f determined by the relative brightness calculation units 83b and 86b is... v－l＿m，n、 f s－l＿m，n It can serve as a lower limit value, which is for the region of interest B. l＿m，n B s＿m，n The improvement in display capability of the target pixels within the second panel 22 can be expected as a perceptible lower limit of brightness. This is achieved by using a method based on the corresponding value f. v－l＿m，n f s－l＿m，n Set target pixel i m，n The relevant lower limit value of luminance v limit－l＿m，n v limit－s＿m，n Calculate the luminance information value v' l＿m，n v' s＿m，n In addition to improving performance at low-brightness pixels, it can also minimize the use of the second panel 22.

[0117] In the LUTs 83b2 and 86b2 used in the relative luminance calculation units 83b and 86b, the corresponding value f v－l f v－s Relative to the average luminance V mean－l V mean－s Each is monotonically non-decreasing. In this way, the average luminance V... mean－l V mean－s In areas with lower brightness, using the second panel 22 can improve display quality, while also improving the average brightness V. mean－l V mean－s In areas with higher elevations, the use of panel 22 can be minimized.

[0118] Figure 15It represents the average luminance V in LUT83b2 of the relative luminance calculation unit 83b. mean－l With corresponding value f v－l A graph illustrating an example of the relationship between the average luminance V and the luminance. mean－l The increase of f corresponds to the value v－l As the linear increase occurs, the average luminance V mean－l The value on the higher side remains constant at the corresponding value f. v－l =1. It should be noted that the average luminance V... mean－l With corresponding value f v－l The relationship is not limited to this example; for instance, it could also be a monotonically non-decreasing curve-like relationship. Furthermore, the average luminance V in the LUT86b2 of the relative luminance calculation unit 86b... mean－s With corresponding value f v The relationship between -s and the average luminance V in the LUT83b2 of the relative luminance calculation unit 83b can be compared with that of the LUT83b2. mean－l With corresponding value f v－l The relationships can be the same or different.

[0119] It should be noted that the relative luminance calculation units 83b and 86b are not limited to the above configuration. For example, the average luminance value v mean－l＿m，n v mean－s＿m，n It could also be the value after further processing, or it could be the region of interest B. l＿m，n B s＿m，n Other representative values ​​of luminance in the image (such as the median value, the most frequent value, and the value after weighting using a Gaussian filter) are used to determine the corresponding value f. v－l＿m，n f s－l＿m，n In this way.

[0120] <Adjustment coefficient calculation section 83c, 86c>

[0121] Further details are provided regarding the processing performed on each target pixel in the adjustment coefficient calculation units 83c and 86c, and the effect of this processing. The adjustment coefficient calculation unit 83c of the first preprocessing unit 83 processes the region of interest B... l＿m，n The linear signal RGB is suitable for a filter size of j. l ×j l The averaging filter 83c1 is used to calculate the ratio of the average pixel i to the target pixel i. m，n Corresponding grayscale average RGB mean－l＿m，n In this embodiment, for each region of interest B l＿m，n The average grayscale value of the color component of each pixel is calculated, and an averaging filter 83c1 is applied to this average value to calculate the grayscale average RGB value. mean－l＿m，n The adjustment factor f is stored in the LUT83c2 used by the adjustment factor calculation unit 83c. a－l The adjustment factor fa－l It is the average grayscale value of the input data (RGB). mean－l The associated output data. Using this LUT83c2, it is possible to extract the grayscale average RGB data. mean－l＿m，n Determine the target pixel i m，n The relevant adjustment factor f a－l＿m，n .

[0122] The adjustment coefficient calculation unit 86c of the second preprocessing unit 86 calculates the adjustment coefficient for the region of interest B. s＿m，n The linear signal RGB is suitable for a filter size of j. s ×j s An averaging filter 86c1 is used to calculate the ratio of the average pixel i to the target pixel i. m，n Corresponding grayscale average RGB mean－s＿m，n In this embodiment, for each region of interest B s＿m，n The average grayscale value of the color components of each pixel is calculated, and an averaging filter 86c1 is applied to this average value to calculate the RGB average grayscale value. mean－s＿m，n The adjustment factor f is stored in the LUT86c2 used by the adjustment factor calculation unit 86c. a－s The adjustment factor f a－s It is the average grayscale value of the input data (RGB). mean－s The associated output data. Using this LUT86c2, from the grayscale average RGB... mean－s＿m，n Determine the target pixel i m，n The relevant adjustment factor f a－s＿m，n .

[0123] The improved display capability achieved using the second panel 22 varies based on the grayscale values ​​of various color components of the pixels. In this embodiment, the adjustment coefficient f determined by the adjustment coefficient calculation units 83c and 86c is... a－l＿m，n f a－s＿m，n It is for area B of interest. l＿m，n B s＿m，n target pixel i within m，n The coefficients reflecting the necessary degree of grayscale values ​​based on color components in the second panel 22 are used to function. Therefore, the adjustment coefficient f is used simultaneously. a－l＿m，n f a－s＿m，n Calculate the luminance information value v' l＿m，n v' s＿m，n This allows users to enjoy improved display quality in low grayscale areas while minimizing the use of the second panel 22.

[0124] Here, in the LUTs 83c2 and 86c2 used in the adjustment coefficient calculation units 83c and 86c, the adjustment coefficient f is preferred. a－l f a－sRelative to the average grayscale value of RGB mean－l RGB mean－s Each is monotonically non-increasing. Through this configuration, the average grayscale value of RGB... mean－l RGB mean－s In areas with lower grayscale values, using the second panel 22 can improve display quality, while also improving the average RGB grayscale value. mean－l RGB mean－s For areas with higher elevations, minimize the use of panel 22.

[0125] Figure 16 This represents the average grayscale value (RGB) in the LUT83c2 of the adjustment coefficient calculation unit 83c. mean－l and adjustment factor f a－l A graph illustrating an example of the relationship. The horizontal axis represents the average RGB value of grayscale within the range of 0 to 1. mean－l The value after normalization. (This is related to the average grayscale value in RGB). mean－l The increase of the adjustment coefficient f a－l It decreases linearly, and in the grayscale average RGB mean－l On the side with the higher value, adjust the coefficient to keep it constant at f. a－l =0. It should be noted that the average grayscale value is RGB. mean－l With adjustment factor f a－l The relationship is not limited to this; it can also be a monotonically non-increasing relationship in a curved manner. Furthermore, the grayscale average RGB value in the LUT86c2 of the adjustment coefficient calculation unit 86c... mean－s With adjustment factor f a－s The relationship can be compared with the grayscale average RGB value in the LUT83c2 of the adjustment coefficient calculation unit 83c. mean－l With adjustment factor f a－l The relationships can be the same or different.

[0126] It should be noted that the adjustment coefficient calculation units 83c and 86c are not limited to the above structure. For example, the differences in the observer's sensitivity to each color component or the optical characteristics of the display panel can be considered, and the signal values ​​of the linear RGB signals corresponding to each color component can be weighted, and then the averaging filters 83c1 and 86c1 can be applied to the weighted signal values. Alternatively, it can be configured to use the region of interest B. l＿m，n B s＿m，n Other representative values ​​of the grayscale values ​​(such as the median, most frequent value, and values ​​weighted using a Gaussian filter) are used to determine the adjustment coefficient f. a－l＿m，n f a－s＿m，n In this way.

[0127] <Area of ​​Concern>

[0128] The target pixel i in the absolute luminance calculation unit 83a, relative luminance calculation unit 83b and adjustment coefficient calculation unit 83c of the first preprocessing unit 83 m，n Corresponding area of ​​interest B l＿m，n Preferred target area A in the first smoothing processing unit 84 l＿m，n Same, or set to be larger than target area A l＿m，n A larger area. Similarly, the target pixel i in the absolute luminance calculation unit 83a, relative luminance calculation unit 83b, and adjustment coefficient calculation unit 83c of the second preprocessing unit 86. m，n Corresponding area of ​​interest B s＿m，n Preferably, it is the target area A in the second smoothing processing unit 87. s＿m，n Same, or set to be larger than target area A s＿m，n A larger area.

[0129] By focusing on region B l＿m，n、 B s＿m，n Set to match the target area A in each smoothing processing unit 84, 87 l＿m，n A s＿m，n Similarly, when viewing the target pixel i from the front... m，n At this time, the aforementioned effects involved in the absolute luminance calculation units 83a and 86a, the relative luminance calculation units 83b and 86b, and the adjustment coefficient calculation units 83c and 86c can be obtained. Furthermore, by adjusting the region of interest B... l＿m，n、 B s＿m，n Expanded to the target area A in each smoothing processing unit 84, 87 lm，n A sm，n In a large way, when viewing the target pixel i from an oblique direction m，n At the same time, the aforementioned effects involved in the absolute luminance calculation units 83a and 86a, the relative luminance calculation units 83b and 86b, and the adjustment coefficient calculation units 83c and 86c can also be obtained. It should be noted that, relative to the target area A in each smoothing processing unit 84 and 87... l＿m，n A s＿m，n Area of ​​Concern B l＿m，n B s＿m，n If the expansion is too large, adverse effects such as white halo may easily occur. Therefore, considering the likelihood of adverse effects occurring depending on the actual display panel conditions, it is preferable to target area A in each smoothing processing section 84, 87. l＿m，n A s＿m，n Slightly expand the focus area B l＿m，n B s＿m，n When relative to each target region A in each smoothing processing unit 84, 87 l＿m，n A s＿m，n Expand the area of ​​interest B in both the row and column directions. l＿m，nB s＿m，n When h is a pixel, for example, 1≤h≤15, preferably 1≤h≤10. In this embodiment, h=4. h can be, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or it can be any two values ​​listed here.

[0130] It should be noted that in this embodiment, in the absolute luminance calculation unit 83a, relative luminance calculation unit 83b, and adjustment coefficient calculation unit 83c of the first preprocessing unit 83, the luminance is related to the target pixel i. m，n Corresponding attention area B l＿m，n Similarly, in the absolute luminance calculation unit 86a, relative luminance calculation unit 86b, and adjustment coefficient calculation unit 86c of the second preprocessing unit 86, the luminance is calculated in relation to the target pixel i. m，n Corresponding attention area B s＿m，n Same. Focus on region B. l＿m，n B s＿m，n The setting method is not limited to this. For example, the areas of interest in the absolute luminance calculation unit 83a, relative luminance calculation unit 83b and adjustment coefficient calculation unit 83c of the first preprocessing unit 83, and the areas of interest in the absolute luminance calculation unit 86a, relative luminance calculation unit 86b and adjustment coefficient calculation unit 86c of the second preprocessing unit 86 can be set in different ways.

[0131] 4. Other implementation methods

[0132] This invention provides a program for executing a method of displaying an image on a display device by a processor located in a computer or display device. The method includes a wide-area smoothing step, a narrow-area smoothing step, a mixing step, and a display step. The display device includes a light source and a plurality of display panels arranged in a multilayer configuration. The plurality of display panels include a first panel and a second panel disposed between the light source and the first panel. In the wide-area smoothing step, luminance information values ​​of a target region including a target pixel in an input image and surrounding pixels of the target pixel are smoothed, and a wide-area smoothed value is output. In the narrow-area smoothing step, luminance information values ​​of a target region including the target pixel and surrounding pixels of the target pixel, which is smaller than the target region in the wide-area smoothing step, are smoothed, and a narrow-area smoothed value is output. In the mixing step, a mixed value is output after mixing the wide-area smoothed value and the narrow-area smoothed value according to a predetermined mixing ratio. In the display step, an image generated using the mixed value is displayed on the second panel. The luminance information value is generated using the luminance of the pixels. This program can be stored in built-in memory or in a computer-readable non-temporary recording medium. Alternatively, the above functionality can be achieved by reading programs stored in external memory through cloud computing.

[0133] In the above embodiment, the linear transformation unit 31 is configured to receive an input signal RGBγ, which uses 10 bits to represent grayscale for each of the R, G, and B components, as input image data. However, the form of the input image data is not limited to this. In one example, the input image data may also be an input signal that uses 8 bits to represent grayscale for each of the R, G, and B components.

[0134] In the above implementation, although the target pixel i m，n Corresponding target area A l＿m，n A s＿m，n Nearby Area A n＿m，n and Area B of Concern l＿m，n B s＿m，n The region is defined as a quadrilateral, but the shape of each region is not limited to this. Preferably, the target pixel i... m，n Set it to approximately the center, and then set each region to have a line-symmetric shape in each of the row and column directions. For example, each region can be set to a target pixel i m，n It is roughly elliptical or oblong in shape with the center at approximately.

[0135] While various embodiments of the present invention have been described above, these descriptions are merely examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are all included within the scope and spirit of the present invention, and are included within the scope of the invention described in the patent claims and their equivalents.

[0136] (Symbol Explanation)

[0137] 1: Display device; 2: Display unit; 3: Image processing unit; 4: First image generation unit; 5: First main processing unit; 6: First nonlinear transformation unit; 7: Second image generation unit; 8: Second main processing unit; 9: Second nonlinear transformation unit; 21: First panel; 22: Second panel; 23: Light source; 31: Linear transformation unit; 51: Coefficient calculation unit; 52: Calculation unit; 81: Luminance transformation unit; 82: Wide-area smoothing unit; 83: First preprocessing unit; 83a: Absolute luminance calculation unit; 83b: Relative luminance calculation unit; 83b1: Averaging filter; 83c 83c1: Adjustment coefficient calculation unit; 83d: Averaging filter; 84: First smoothing processing unit; 85: Narrow-area smoothing unit; 86: Second pre-processing unit; 86a: Absolute luminance calculation unit; 86b: Relative luminance calculation unit; 86b1: Averaging filter; 86c: Adjustment coefficient calculation unit; 86c1: Averaging filter; 86d: Adjustment value calculation unit; 87: Second smoothing processing unit; 88: Blending unit; 88a: Blending ratio determination unit; 88a1: LPF; 88b: Blending processing unit; p1: Pixel; p2: Pixel.

Claims

1. A display device for displaying images, It features multiple display panels with light sources and multi-layered configurations, a wide-area smoothing section, a narrow-area smoothing section, and a hybrid section. The plurality of display panels include a first panel and a second panel disposed between the light source and the first panel. The wide-area smoothing unit smooths the luminance information values ​​of the target region, which includes the target pixel in the input image and the surrounding pixels of the target pixel, and outputs a wide-area smoothed value. The narrow-area smoothing unit smooths the luminance information values ​​of the target region, which includes the target pixel and the surrounding pixels and is smaller than the target region of the wide-area smoothing unit, and outputs a narrow-area smoothing value. The mixing unit mixes the wide-area smoothing value and the narrow-area smoothing value according to a predetermined mixing ratio and outputs the mixed value. The mixing unit includes a mixing ratio determining unit and a mixing processing unit. The blending ratio determination unit calculates the luminance level using the luminance of the target pixel, or the luminance of a neighborhood containing the target pixel and its neighboring pixels, and determines the blending ratio based on the luminance level. The mixing processing unit outputs the mixing value using the mixing ratio. The second panel displays the image generated using the blended values. The luminance information value is generated using the luminance of the pixels.

2. The display device according to claim 1, wherein, The mixing ratio determination unit determines the mixing ratio such that the mixing ratio of the wide-area smoothing value is monotonically non-decreasing relative to the luminance level.

3. The display device according to claim 1 or 2, wherein, The wide-area smoothing unit includes a first pre-processing unit and a first smoothing processing unit. The first preprocessing unit generates the luminance information value for the wide-area smoothing unit using at least one of the luminance of each pixel selected from the target region including at least the wide-area smoothing unit, and a representative value of the luminance of each pixel. The first smoothing processing unit performs smoothing processing on the luminance information value and outputs the wide-area smoothing value.

4. The display device according to claim 3, wherein, The first preprocessing unit further uses the grayscale values ​​of the color components of each pixel to generate the luminance information value of the target region of the wide-area smoothing unit.

5. The display device according to claim 1 or 2, wherein, The narrow-domain smoothing unit includes a second pre-processing unit and a second smoothing processing unit. The second preprocessing unit uses at least one of the luminance of each pixel selected from the target region including at least the narrow smoothing section, and a representative value of the luminance of each pixel, to generate the luminance information value for the narrow smoothing section. The second smoothing processing unit performs smoothing processing on the luminance information value and outputs the narrow smooth value.

6. The display device according to claim 5, wherein, The second preprocessing unit further uses the grayscale values ​​of the color components of each pixel in the target region that includes at least the narrow smoothing unit to generate the luminance information value of the target region of the narrow smoothing unit.

7. The display device according to claim 1 or 2, wherein, The smoothing process is performed using an averaging filter.

8. A display method for displaying an image on a display device, It features wide-area smoothing steps, narrow-area smoothing steps, blending steps, and display steps. The display device has a light source and multiple display panels arranged in a multilayer configuration. The plurality of display panels include a first panel and a second panel disposed between the light source and the first panel. In the wide-area smoothing step, the luminance information values ​​of the target region, which includes the target pixel in the input image and the surrounding pixels of the target pixel, are smoothed, and a wide-area smoothed value is output. In the narrow-area smoothing step, the luminance information values ​​of the target region, which includes the target pixel and its surrounding pixels and is smaller than the target region in the wide-area smoothing step, are smoothed, and a narrow-area smoothed value is output. In the mixing step, the output is a mixed value obtained by mixing the wide-area smoothing value and the narrow-area smoothing value according to a specified mixing ratio. The mixing step includes a mixing ratio determination step and a mixing processing step. In the blending ratio determination step, the luminance level is calculated using the luminance of the target pixel, or the luminance of a neighborhood containing the target pixel and its neighboring pixels, and the blending ratio is determined based on the luminance level. In the mixing process step, the mixing value is output using the mixing ratio. In the display step, the image generated using the blending values ​​is displayed on the second panel. The luminance information value is generated using the luminance of the pixels.

9. A computer-readable recording medium storing a program for executing, on a computer or a processor disposed in a display device, a method for displaying an image on the display device, wherein, The method includes a wide-area smoothing step, a narrow-area smoothing step, a blending step, and a display step. The display device has a light source and multiple display panels arranged in a multilayer configuration. The plurality of display panels include a first panel and a second panel disposed between the light source and the first panel. In the wide-area smoothing step, the luminance information values ​​of the target region, which includes the target pixel in the input image and the surrounding pixels of the target pixel, are smoothed, and a wide-area smoothed value is output. In the narrow-area smoothing step, the luminance information values ​​of the target region, which includes the target pixel and its surrounding pixels and is smaller than the target region in the wide-area smoothing step, are smoothed, and a narrow-area smoothed value is output. In the mixing step, the output is a mixed value obtained by mixing the wide-area smoothing value and the narrow-area smoothing value according to a specified mixing ratio. The mixing step includes a mixing ratio determination step and a mixing processing step. In the blending ratio determination step, the luminance level is calculated using the luminance of the target pixel, or the luminance of a neighborhood containing the target pixel and its neighboring pixels, and the blending ratio is determined based on the luminance level. In the mixing process step, the mixing value is output using the mixing ratio. In the display step, an image generated using the mixed values ​​is displayed on the second panel. The luminance information value is generated using the luminance of the pixels.

Images