KR20150139464A - Display panel, method for compensating pixel luminance of display panel and method for compensating pixel paramiters - Google Patents

Abstract

A method for compensating pixel luminance of a display panel comprises the following steps of: receiving pixel parameters corresponding to sub-pixels of the display panel; receiving an input image; adjusting the input image according to the pixel parameters; and displaying the adjusted input image on the display panel. The pixel parameters comprise: a first pixel parameter of a base luminance level of a base color channel; a first residual determined from performing inter-channel prediction; a second residual determined from performing inter-level prediction; and parameters used in the performing of the inter-level prediction.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of compensating a pixel brightness of a display panel and a display panel, and a method of compensating pixel parameters of a display panel,

The present invention relates to a pixel luminance compensation method and a method for compensating pixel parameters of a display panel, and to a display panel thereof, and more particularly to a hierarchical prediction for pixel parameter compression.

The display resolution of mobile devices has been steadily increasing over the years. In particular, display resolutions for mobile devices have increased to include full high definition (HD) (1920x1080) and will include higher resolution formats such as Ultra HD (3840x2160) in the future. However, the size of the display panels will remain approximately unchanged due to human factor constraints. As a result, the pixel density is increased, which in turn increases the difficulty of producing display panels with a constant quality. In addition, organic light emitting diode (OLED) display panels undergo color variations between the pixels (thus affecting the brightness of the pixels), which is caused by current variations in the pixel drive circuit, which causes visible artifacts Mura effects, for example). Increasing the resolution or number of pixels may further increase the likelihood of artifacts.

The information disclosed in this background section is intended only for the enhancement of the understanding of the background of the described technology and may therefore include information that does not constitute prior art already known to those skilled in the art.

SUMMARY OF THE INVENTION The present invention provides a method of compensating for pixel brightness of a display panel and a display panel therefor.

A method of compensating for pixel brightness in a display panel according to an embodiment of the present invention includes receiving pixel parameters corresponding to sub-pixels of a display panel; Receiving an input image; Adjusting an input image according to pixel parameters; And displaying the adjusted input image on a display panel, the pixel parameters comprising: a first pixel parameter of a base luminance level of the base color channel; A first residue determined from performing inter-channel prediction; A second residue determined from performing inter level prediction; And parameters used in performing inter-level prediction.

The received pixel parameters may be compressed pixel parameters.

The method may further comprise decompressing the compressed pixel parameters prior to the step of adjusting the input image.

Pixel parameters are selected by a processor to select a base color channel from a plurality of color channels; Selecting, by the processor, a base luminance level of the selected base color channel from a plurality of luminance levels; Determine, by the processor, pixel parameters for the selected base color channel and base luminance level; And can be compressed by the processor by predicting a second pixel parameter from a first pixel parameter to produce a first residue, wherein the second pixel parameter corresponds to a color channel different than the base color channel, Corresponds to the same luminance level.

Pixel parameters further include instructions for: predicting, by the processor, a third pixel parameter from the predicted second pixel parameter to produce a second residue; And the third pixel parameter corresponds to the same color channel corresponding to the second pixel parameter, and the luminance level corresponding to the second pixel parameter and the luminance level corresponding to the first pixel parameter, Correspond to different brightness levels.

A method for compressing pixel parameters of a display panel according to an embodiment of the present invention includes: selecting, by a processor, a base color channel from a plurality of color channels; Selecting, by the processor, a base luminance level of a base color channel selected from a plurality of luminance levels; Determining, by the processor, a first pixel parameter for a selected base color channel and a base luminance level; And predicting, by the processor, a second pixel parameter from the first pixel parameter to produce a first residue, wherein the second pixel parameter corresponds to a culler channel different from the base color channel, Corresponding to the same luminance level.

The method includes: predicting, by the processor, a third pixel parameter from the predicted second pixel parameter to produce a second residue; And encoding the first pixel parameter, the first residue and the second residue, wherein the third pixel parameter corresponds to the same color channel corresponding to the second pixel parameter, and the third pixel parameter corresponds to the second pixel parameter And corresponds to a luminance level different from the luminance level.

The step of predicting the second pixel parameter may comprise inter-channel prediction.

And the second remainder may be the difference between the second pixel parameter and the third pixel parameter.

The step of predicting the third pixel parameter may include inter-level prediction.

Inter-level prediction may include performing a linear regression.

The first remainder may be the difference between the first pixel parameter and the second pixel parameter.

The method may further comprise multiplexing the first pixel parameter, the first residue and the second residue.

A display panel according to an embodiment of the present invention includes a memory including compressed parameters for sub-pixels of a display panel; A decoder configured to decompress the compressed parameters; And a processor configured to apply the decompressed parameters to the input image signal, wherein each parameter of the parameters corresponds to a respective sub-pixel of the sub-pixels, Select a color channel; Selecting a base luminance level of a base color channel selected from a plurality of luminance levels; Determine a first pixel parameter for a selected base color channel and a base luminance level; Predicting a second pixel parameter from a first pixel parameter to produce a first residue, the second pixel parameter corresponding to a different color channel from the base color channel and corresponding to a luminance level equal to the base luminance level; Predict a third pixel parameter from the predicted second pixel parameter to generate a second residue, and wherein the third pixel parameter corresponds to the same color channel corresponding to the second pixel parameter, and the luminance corresponding to the second pixel parameter Corresponding to a luminance level that is different from the level; And by compressing the first pixel parameter, the first residue and the second residue.

The prediction of the second pixel parameter may include inter-channel prediction.

Prediction of the third pixel parameter may include inter-level prediction.

Inter-level prediction may include performing a linear regression.

The first remainder may be the difference between the first pixel parameter and the second pixel parameter.

The second remainder may be the difference between the second pixel parameter and the third pixel parameter.

The display panel may further comprise multiplexing the first pixel parameter, the first residue and the second residue.

According to an embodiment of the present invention, a method of compensating for pixel luminance of a display panel and a display panel therefor are provided.

Figure 1 is an exemplary schematic and block diagram of a display device.
Fig. 2 shows an enlarged view of a display panel of the display device shown in Fig.
Figure 3 is a drawing of an exemplary color sub-pixel layout with a 4: 2: 2 color sampling scheme.
Figure 4 is a block diagram of the display panel of Figure 1, showing the information flow of pixel parameters from the calibration step during manufacturing.
Figure 5 shows an example of parameters for the red, green and blue sub-pixels, each having three brightness levels.
6 shows a block diagram corresponding to the parameters for the green, red and blue sub-pixels, each including sub-pixel parameters for three brightness levels.
Figures 7A and 7B illustrate exemplary results for predicting pixel parameters for two different luminance levels from a base level.
Figure 8 is a flow chart illustrating an encoding process that utilizes a hierarchical prediction method to compress pixel parameters.
9 is a flow chart for encoding pixel parameters.

Hereinafter, exemplary embodiments will be described in more detail with reference to the accompanying drawings, wherein like reference numerals refer to like elements throughout the drawings. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Thus, for some of the embodiments of the present invention, processes, elements, and techniques that are not essential to those skilled in the art for a thorough understanding of aspects and features of the present invention are not described. Unless otherwise stated, like reference numerals in the drawings and throughout the remainder of the description denote like elements, and so their description will not be repeated. In the drawings, the relative sizes of the elements, layers and regions may be exaggerated for clarity.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or portions, Sections, layers, and / or portions should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, without departing from the spirit and scope of the present invention, a first element, component, region, layer or section described below may be referred to as a second element, component, region, layer or section.

Spatially relative terms, such as "lower "," lower ", "lower "," lower ", & May be used to describe the relationship of one element or feature to another element (s) or feature (s). It will be appreciated that spatially relative terms are intended to include different orientations of the device being used or operated, in addition to the orientation shown in the figures. For example, when a device in the figures is inverted, elements described as "under" or "under" or "under" other elements or features will be oriented "above" other elements or features. Thus, the exemplary terms "below" and "lower" may include both orientation above and below. The device may be oriented differently (e.g., rotated 90 degrees or other orientations) and the spatially relative descriptors used herein should be interpreted accordingly.

When an element or layer is referred to as being "on," "connected to", or "coupled to" another element or layer, the element or layer may be directly on, connected to, , Coupled thereto, or that there may be one or more intervening elements or layers. However, when an element or layer is referred to as being "directly over" another element or layer, "directly connected thereto" or "directly coupled thereto," there are no intervening elements or layers. Also, where an element or layer is referred to as being "between" two elements or layers, the element or layer may be the only element or layer between two elements or layers, or one or more intervening elements or layers ≪ / RTI > may also be present.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended as a limitation of the invention. As used herein, singular forms are intended to include plural forms unless the context clearly dictates otherwise. The terms " comprises "and / or" comprising " as used herein specify the presence of stated features, integers, steps, operations, elements, and / It will be understood that they do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one" modify the entire list of elements if preceded by a list of elements, but do not modify individual elements of the list. In addition, the use of "can" when describing embodiments of the present invention refers to "one or more embodiments of the present invention ".

Figure 1 illustrates a schematic and block diagram of a display device 100 including a plurality of pixels 160 in a timing controller 110, a scan driver 120, a data driver 130, do. Each of the plurality of pixels 160 is connected to each of the scan lines SL1 to SLn (where n is a positive integer) and the data lines DL1 to SLn in the crossing regions of the scan lines SL1 to SLn and the data lines DL1 to DLj To DLj (where j is a positive integer). Each of the pixels 160 is connected to the data driver 130 via a respective line of data lines DL1 through DLj when a scan signal is received from the scan driver 120 through a respective line of scan lines SL1 through SLn. Lt; / RTI >

The timing controller 110 receives the image signal IMAGE, the synchronization signal SYNC and the clock signal CLK from an external source (e.g., a source external to the timing controller). The timing controller 110 generates image data DATA, a data driver control signal DCS, and a scan driver control signal SCS. The synchronization signal SYNC may include a vertical synchronization signal Vsync and a horizontal synchronization signal Hsync.

The timing controller 110 is coupled to the data driver 130 and the scan driver 120. The timing controller 110 transmits the image data DATA and the data driver control signal DCS to the data driver 130 and transmits the scan driver control signal SCS to the scan driver 120. [

FIG. 2 shows an enlarged view of a plurality of pixels 160 of the display panel 140. FIG. Each of the plurality of pixels 160 includes a plurality of sub-pixels 200 having an R1G1B2G2R3G3B4G4 layout, as shown in more detail in Fig. 3, where R is a red sub- Represents a pixel, G represents a green pixel, and B represents a blue pixel. This arrangement will be understood by those skilled in the art to have 4: 2: 2 color sampling (i.e., each pixel corresponds to two sets of eight color sub-pixels). Although a 4: 2: 2 color sampling layout is described herein as an example, the description is not intended to be limiting. Thus, the pixels may have other arrangements known to those skilled in the art, such as, for example, 4: 4: 4.

The luminance change of the pixels, which can be caused by a change in the driving current of the pixel driving circuit in the OLED display panel, is unique to each display panel. Thus, according to embodiments of the present invention, when a display panel is manufactured, the sub-pixels are measured and the compensation parameters specific to each particular sub-pixel are adjusted so that the luminance levels of the sub- You can decide. In this way, the display panels are calibrated during manufacture, so that the changes can be compensated during operation. The change can be modeled with per-pixel or sub-pixel compensation parameters, and digital compensation logic can be introduced as a post-manufacturing solution to keep the color variation below the perceptible threshold. The per-pixel compensation parameters (or later "parameters") are typically stored in memory for use by the digital compensation logic. The digital compensation logic compensates the pixels of the display panel at various luminance levels. Each pixel may have a number of parameters corresponding to a color change at different brightness levels. For example, in the case of UHD-4K (3840x2160 resolution), a panel with 4: 2: 2 color sampling representing, for example, each sub-pixel parameter with 8 bits, The parameter information for a single luminance level can be derived. Thus, storing parameters with 8 bits for three luminance levels (e.g., high, medium, low luminance levels) will result in parameter information of 384 Mb. Storing 384 Mb of parameter data at the display level increases the demand for storage memory, resulting in too high a cost to mount on the display panel. In many cases, the memory size of some display panels may be only a few megabits. Thus, reducing the memory size requirements of the display panels can reduce manufacturing costs.

One way to reduce the memory requirements for storing the parameters is to reduce the number of parameters stored in the memory, for example, by storing only one parameter for a plurality of pixels or sub-pixels . However, simply reducing the number of parameters (e. G., By grouping a plurality of pixels or sub-pixels together) may reduce the effectiveness of any compensation logic using the parameters, and consequently, If the size is large, the image quality may deteriorate.

Figure 4 shows a display panel 140 and block diagram in accordance with an embodiment illustrating a method of compensating for color variations in pixels while reducing memory requirements.

4, the parameters for some of the sub-pixels are generated by the parameter generator 430 and the parameter remainders (hereinafter "remainder") are generated by the parameters generated by the pixel parameter compressor 420 , Which together form parameters for all of the sub-pixels of the display panel. The generated parameters and the predicted remainder are compressed and encoded by the pixel parameter compressor 420 and the compressed parameters are provided to the memory 410 for storage. The parameter generator 430 and the compressor 420 are utilized during manufacture and, therefore, may be separate from and external to the display panel 140. For example, the parameter generator 430 and the compressor 420 may be external hardware or software modules coupled with the display device 140 during fabrication for calibration.

The display panel 140 includes a memory 410 for storing parameters and a pixel parameter decompressor 480 for decoding and decompressing the encoded and compressed parameters retrieved from the memory 410. The display panel 140 also includes a pixel processor 470 for processing the input image 450. That is, the decoded and decompressed parameters provided from decompressor 480 are applied to the input image in pixel processor 470 to compensate for color variations by sub-pixels. The compensated image, which is the adjusted input image, is displayed by the sub-pixel on the display panel 140 as the output image 460. Thus, compression of the parameters and the remainder provides a lightweight calculation that allows decoding of the compressed parameters at the same rate as the sub-pixels are rendered on the display, while maintaining a relatively high reliability of the parameters.

The pixel processor 470 is a central processing unit that executes program instructions stored in a non-volatile medium (e.g., memory) to perform various methods and operations in accordance with embodiments of the present invention, Or a processor such as a central processing unit (CPU).

The memory 410 may be any suitable type of memory device such as, for example, a drive array, a flash memory, or a random access memory (RAM), for storing instructions used by the display device 100 to cause the processor 470 to execute additional instructions stored in the memory. Such as a random access memory (RAM), for storing instructions to be executed by the processor 470.

The processor 470 may execute instructions of the software routine based on the information stored in the memory 410. [ Those skilled in the art will also appreciate that the process may be performed in hardware, via firmware (e.g., via an ASIC), or in any combination of software, firmware, and / or hardware. In addition, the order of the steps of the process is not fixed, but may be changed in any desired order as recognized by those skilled in the art. It is also to be understood that the functionality of the various computing modules may be combined or integrated into a single computing device, or that the functionality of a particular computing module may be distributed across one or more other computing devices, without departing from the scope of example embodiments of the present invention A person skilled in the art should recognize.

5 shows an example of parameters for red, green and blue sub-pixels each having three luminance levels on a 1080x1920 panel, where L1, L2 and L3 correspond to low, medium and high luminance levels, respectively do. The parameters can be normalized to a range of [0, 255]. Although only three luminance levels are shown in this example, other embodiments may include more than three luminance levels of parameters generated for the display panel.

In accordance with an embodiment of the present invention, the parameters may be used to generate color (e.g., red, green, and blue) of sub-pixels to produce color at a given brightness level (e.g., ). ≪ / RTI > Each generated sub-pixel parameter can be represented by 8 bits if quantized into a range of [0, 255]. Thus, each of the sub-pixels can be compensated by applying a parameter to the input image signal for the corresponding sub-pixel.

In some embodiments, instead of generating parameters for each of the sub-pixels, hierarchical prediction may be utilized to compress multi-channel and multi-luminance-level parameters. That is, the parameters for some of the sub-pixels may be hierarchically predicted as the remainder from known parameters of other sub-pixels (e.g., adjacent sub-pixels). For example, parameters corresponding to different color sub-pixels are correlated due to their spatial adjacencies (e.g., the spatial adjacencies of blue L2 with red L2 and L2 with green L2). Thus, according to the embodiment, inter-channel prediction can be performed between parameters of adjacent color sub-pixels, and inter-level prediction can be performed between parameters of the same color having different luminance levels. That is, the remainder can be determined by performing inter-channel prediction and / or inter-level prediction.

6 shows a block diagram corresponding to the parameters for the green sub-pixel 601, the red sub-pixel 602 and the blue sub-pixel 603. Each corresponding parameter box 601, 602, 603 contains sub-pixel parameters for three luminance levels L1, L2, L3 for each color. According to an embodiment, the base channel (or base color channel) is initially selected as the start point (or start parameter). In the example shown in Fig. 6, a green sub-pixel 601 is selected as the base channel. In particular, the intermediate brightness level L2 parameter for the green sub-pixel 601 is selected as the base level (or base brightness level) and the base channel, respectively. Although any color can be selected as the base channel, a green color can be selected as the base channel since the green color has a full pixel resolution and the green channel generally has the least amount of noise to be. The term "channel" as used herein refers to the color of the sub-pixel to which the parameter corresponds among all sub-pixel parameters.

When the base channel is selected (e.g., green L2), parameters of other channels (e.g., green L2 and / or blue L2) for the same brightness level (e.g., L2) Inter-channel prediction is performed. That is, to predict the intermediate luminance level L2 parameter for the red and blue sub-pixels, the parameters from the intermediate luminance level L2 of the green sub-pixel are utilized. Then, to obtain the remainders of L2 red / blue, the difference between the L2 green parameter and the L2 red / blue parameters is calculated. That is, the L2 red / blue remainder form the difference between the L2 green parameter and the L2 red / blue parameter. As a result, instead of storing both the base channel parameters and the parameters of the other channels, the memory space can be preserved by storing the base channel parameters and the rest of the other channels.

According to an embodiment, interchannel prediction may be performed by calculating the difference between the red sub-pixel parameter and the encoded-decoded version of the green sub-pixel parameter. For example,

(i,j) (1) d _R (i, j) = R (i, j) -

(i, j) (1)

(i,j)는, 동일한 픽셀 (i,j)에 대응하는 녹색 서브-픽셀 파라미터의 인코딩-다음-디코딩된 버전을 나타낸다. 이 예에 따르면, R(i,j) 및 G(i,j)는 [0, 255]의 범위를 갖고, 따라서 나머지 d _R (i,j)는 [-255, 255]의 범위를 갖는다., Where R (i, j) represents the red sub-pixel parameter, where (i, j) represents the pixel location,

(i, j) represents the encoding-next-decoded version of the green sub-pixel parameter corresponding to the same pixel (i, j). According to this example, R (i, j) and G (i, j) have a range of [0, 255], so the remaining d _R (i, j) has a range of [-255, 255].

_R 로 표기되는 나머지의 디코딩된 버전은, 디코딩된 녹색 서브-픽셀 파라미터

와 함께 이용되어, 예측된 베이스 레벨 적색 파라미터를 재구성할 것이고, 예측된 베이스 레벨 적색 파라미터는,Performing inter-channel prediction will derive the remainder d _R for the red sub-pixel parameter, which will be encoded later. In some embodiments, when reconstructing the predicted red parameter,

The remaining decoded version, denoted by _R , is the decoded green sub-pixel parameter

To reconstruct the predicted base-level red parameter, and the predicted base-level red parameter is used to reconstruct the predicted base-

(i,j) =

_R (i,j) +

(i,j) (2)

(i, j) =

_R (i, j) +

(i, j) (2)

As shown in FIG.

,

및

는 3개의 채널들 각각에 대한 레벨간 예측에 대한 베이스들로서 이용될 것이고, 이는 추후에 더 상세히 설명될 것이다. 따라서, 채널간 예측은, 베이스 채널(예를 들어, 녹색)의 베이스 레벨(예를 들어, L2)과 동일한 레벨(예를 들어, L2)의 다른 채널들(예를 들어, 적색 및 청색)의 베이스 레벨 사이에 수행되어, 나머지들을 결정할 수 있다.The same process can be repeated to predict the base level parameters of another channel (e.g., a blue channel), and the notations are still applied by replacing "R" with "B". The reconstructed parameters

,

And

Will be used as the bases for inter-level prediction for each of the three channels, which will be described in more detail later. Thus, the inter-channel prediction may be performed on other channels (e.g., red and blue) of the same level (e.g., L2) as the base level (e.g., L2) Is performed between the base levels to determine the rest.

According to another embodiment, inter-level prediction may be performed between different levels of the same color channel as the base level of each color channel. That is, the remainders of green L1 and L3 can be determined from the green L2 (i.e., the base channel and base level), the red L1 and L3 can be determined from the red L2 and the blue L1 and L3 can be determined from the blue L2 Lt; / RTI > It will be appreciated by those skilled in the art that in the exemplary embodiment of FIG. 5 only two levels are predicted in each channel, but more levels can be predicted by the following substantially similar steps.

로서 표기되고, 이것은, 앞서 설명된 바와 같은 채널간 예측, 및 X_k(k≠0)로서의 넌-베이스 레벨 파라미터에 의해 생성된다.For purposes of describing inter-level prediction herein, a color channel is denoted X, where X = R, G, or B. The reconstructed base level parameter X

, Which is generated by the inter-channel prediction as described above and the non-base level parameter as X _k (k? 0).

부터 X_k까지의 레벨간 예측은 블록 기반으로 그리고 파라미터 모델을 통해 수행된다. 즉, 데이터의 로컬 선형성을 가정하면, 인접한 파라미터들의 영역에 대해 동일한 예측 파라미터들 (α, β)가 이용된다. 몇몇 실시예들에서, 파라미터 모델은 선형 회귀 모델일 수 있다. 예를 들어, 선형 회귀 모델은, 2개의 예측 파라미터들 (α, β)로 B의 선형 변환된 버전을 결정함으로써, 벡터 V(여기서 V는

의 재구성된 픽셀 파라미터들의 블록임)로부터 벡터 U(여기서 U는 X_k의 픽셀 파라미터들의 블록임)를 예측한다.Unlike the inter-channel prediction in which prediction is performed by calculating the difference per pixel,

Inter-level prediction from X to _k is performed on a block-by-block basis and through a parameter model. That is, assuming the local linearity of the data, the same prediction parameters (?,?) Are used for the region of adjacent parameters. In some embodiments, the parameter model may be a linear regression model. For example, a linear regression model, the two predicted by determining the parameters (α, β) by the linear transformed version of the B, vector V (where V is

(Where U is a block of pixel parameters of X _k ) from the reconstructed block of pixel parameters of the vector u .

= αV+ β (3)

= ? V +? (3)

사이의 제곱 평균 에러가 최소화되도록 결정될 수 있다.Parameters (α, β) and U is

May be determined such that the root mean square error between the < / RTI >

(4)

(4)

For each block of pixel parameters of X _k , the linear regression-based prediction derives a pair of prediction parameters (?,?) And the remainder for each pixel parameter of the block. The prediction parameters are encoded with the rest to reconstruct the block in the decoder.

The effect of the inter-level prediction is shown in Figs. 7A and 7B, where the results for predicting the L1 and L3 parameters, respectively, from L2 (e.g., base level) of the red channel parameters are shown. The plots shown at 701 and 703 in Figures 7A and 7B respectively show the root mean square errors between the original L1 / L3 data and the L2 data, while the plots indicated at 702 and 704 show predicted L1 / L3 data and L2 data Lt; RTI ID = 0.0 > a < / RTI > Each prediction unit included as shown in the exemplary embodiment shows two lines of pixel parameters, and the x-axes represent line indices corresponding to different prediction units. From the plots, it can be seen that the mean square error of the predicted L1 / L3 data is significantly reduced compared to the root mean square errors of the original L1 / L3. This indicates that the compressed information after the inter-level prediction is much smaller than the information of the original data, confirming the effect of prediction.

Figure 8 is a flow chart illustrating the encoding process of the hierarchical prediction of parameters. As previously described, the base channel and base level are first determined, and in the illustrated example, the base channel and base level are the intermediate brightness level L2 of the green sub-pixel. Thus, the parameters for the green L2 are generated by the parameter generator 430 and encoded at block 800. The encoded L2 green parameter is provided to a bitstream multiplexer 809, which is multiplexed with other parameters and the rest. The encoded L2 green parameter may also be decoded at block 801 to utilize the decoded L2 green parameter to predict inter-channel prediction of the L2 red and L2 blue parameters. The difference between the L2 green parameter and the L2 red parameter in block 804 and the difference between the L2 green parameter and the L2 blue parameter are computed in block 804 to produce the remainder between L2 green and L2 red and the remainder between L2 green and L2 blue do. L2 red and L2 blue remainders are encoded in block 805 and provided to the bitstream multiplexer in block 809. [ The encoded L2 red and L2 blue remainders are decoded at block 806 and utilized to level-predict and generate L1 / L3 red / blue parameters at block 807. [ The differences between the predicted inter-level predicted L1 / L3 red / blue parameters and the L2 red / blue parameters are the difference between predicted interleaved L1 / L3 red / blue parameters and the remainder between L2 red / ≪ / RTI > The L1 / L3 red / blue remainders are encoded in block 808 and provided to bitstream multiplexer 809. [

Returning to block 801, the decoded L2 green parameter is also utilized to level-predict the L1 green and L3 green parameters at block 802. [ The difference between the interlevel predicted L1 and L3 green parameters and the L2 green parameter is calculated to produce the remainder between the predicted L1 and L3 green parameters and the L2 green parameter. The remainder are encoded in block 803 and provided to bitstream multiplexer 809. Thus, the encoding of the multi-channel, multi-level parameters may include four sets of parameters and residual data: parameter information for the base level of the base channel, remainder of each interchannel prediction, (E.g., the linear regression parameters determined by Equation 4) utilized by the inter-level prediction by the bitstream multiplexer 809. The bitstream multiplexer 809 may be any of those described above.

In some embodiments, the remainder of each interchannel / inter-level prediction and the encoded parameters (e.g., blocks 800, 803, 805, 808) are multiplexed by bitstream multiplexer 809 , The multiplexed output is encoded by grouping the parameters and the remainder into blocks and performing transform-based encoding by applying a Haar or Hadamard transform preceding the entropy coding.

Interchannel and interlevel prediction are performed in a hierarchical manner in the steps provided in the exemplary embodiment of FIG. 8, but each of the interchannel and interlevel predictions are independent of one another, individually and in any order or in parallel . For example, inter-level prediction may be performed between multiple levels of each color channel, while parameters of each color channel may be separately encoded. It will be appreciated by those skilled in the art that other variations are possible, and that each change can have varying degrees of compression efficiency.

According to another embodiment, when the compressed parameters and the remainder are retrieved from the memory 410, the multiplexed parameters and the remainder are the four individual sets of parameters and residual data, i.e. the parameters for the base level of the base channel Multiplexed to obtain the information, the remainder of each interchannel prediction, the remainders of each inter-level prediction, and the parameters utilized in the inter-level prediction. The remainder may be decoded with the parameters to reconstruct the predicted parameters for each of the channels and levels. According to an embodiment, the remainder may be decoded with parameters to reconstruct the predicted parameters. The parameters for each of the channels and levels are decoded by decoding the remaining data, reconstructing the corresponding predicted parameters, and adding the remaining data and reconstructed parameters together to form corresponding decoded parameters.

Figure 9 shows a flow chart for compressing parameters for a plurality of luminance levels by performing a Hadamard or Haar transformation. According to an embodiment, the parameters or remainder for all sub-pixels of the display panel are determined for three different brightness levels (e.g., L1, L2, L3). The sub-pixels may be grouped into blocks or superblocks according to the color and luminance levels of the sub-pixels at block 910. [ In this exemplary embodiment, each super block may have a size of 768 parameters or remainders of three blocks, each of which has 256 parameters or remainders. After grouping the parameters or remainder into blocks or superblocks, a mathematical transformation, such as a Hadamard or Haar transformation, is applied to each of the 768 parameters at block 920 to determine a predefined scan order Thereby generating a sequence of 768 integer coefficients that follow. The following integer conversions can be applied:

T ₂ = H ₁ - H ₂ ,

t = H ₂ + [T ₂ 1]

T ₁ = H ₃ - t,

T ₃ = t + [T ₁ »1],

Where H represents different luminance levels for each color sub-pixel (e.g., R, G, B) and T represents actual values used for compression. By marking D (T _n ) with the corresponding decoded values, the following can be calculated:

t = D (T ₃ ) - [D (T ₁ ) 1].

H ₃ = t + D (T ₁ ),

H ₂ = t - [D (T ₂ ) 1]

H ₁ = H ₂ + D (T ₂ )

For some block sizes / arrays, the scan order may be, for example, an incremental scan order, while for other block sizes / arrays the scan order may be a zigzag scan order. The coefficients are then scanned from the highest bit plane to the lower bit planes and at block 930 the joint bits planes are encoded as zeros for each non-zero coefficient and as a series of codes, (E. G., A bit stream). ≪ / RTI > In some embodiments, the encoding of zeros may be in fixed-length form if the overhead is relatively small as compared to encoding the remainder, as understood by those skilled in the art, or may be based on a variable length code (VLC) table . The scan and encoding continues until the target data size (e.g., 512x3 bits for 4-to-1 compression) is reached. That is, each of the 768 parameters is scanned according to a predefined scan order to apply Hadamard or Haar transforms to produce 768 integer coefficients. To code the coefficients into a sequence of bits by encoding 930, a code pre-generated code table (e.g., look-up table) is used. The Hadamard or Haar transformation method is described by way of example and is not intended to be limiting. Further disclosures of block-based transform and entropy coding can be found in related U.S. Patent Application No. 14 / 658,039, filed March 13, 2015, the contents of which are incorporated herein by reference in their entirety Are incorporated herein by reference.

The display device and / or any other related devices or components in accordance with the embodiments of the invention described herein may be implemented in any suitable hardware, firmware (e.g., application specific integrated circuit), software, Can be implemented utilizing appropriate combination of hardware. For example, the various components of the display device may be formed on one integrated circuit (IC) chip or on separate IC chips. In addition, various components of the display device may be embodied on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or formed on the same substrate as the display device. Additionally, the various components of the display device may be implemented as a process running on one or more processors of one or more computing devices that execute computer program instructions and interact with other system components to perform the various functions described herein It can be a thread. The computer program instructions are stored in a memory that can be implemented in a computing device using a standard memory device, such as, for example, random access memory (RAM). The computer program instructions may also be stored on other non-volatile computer readable media, such as, for example, CD-ROMs, flash drives, and the like. It is also to be understood that the functionality of the various computing devices may be combined or integrated into a single computing device, or that the functionality of a particular computing device may be distributed across one or more other computing devices, without departing from the scope of example embodiments of the present invention Those skilled in the art will recognize.

Although the present invention has been described with reference to exemplary embodiments, those skilled in the art will appreciate that various changes and modifications to the described embodiments can be made without departing from the spirit and scope of the present invention. In addition, those skilled in the art will appreciate that the present invention as described herein provides solutions for other tasks and adaptations to other applications. For example, embodiments of the present invention may be used to store and retrieve device-specific pixel-by-pixel parameters to improve image quality, such as, but not limited to, display panels, cameras and printers But may be applied to any image devices.

It will be understood by those of ordinary skill in the art that the present invention may be practiced without departing from the spirit and scope of the present invention by the claims of the present specification and all such uses of the present invention and exemplary embodiments of the present invention selected herein for purposes of this disclosure It is the applicant's intention to cover such variations and modifications that may occur. Accordingly, the illustrative embodiments of the invention should, however, be considered in all respects as illustrative and not restrictive, the spirit and scope of the invention being indicated by the appended claims and their equivalents.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning of the terms in the relevant field and / or the context of the present specification, and unless explicitly so defined herein, Or should not be interpreted in an overly formalized manner.

Claims (20)

Receiving pixel parameters corresponding to sub-pixels of the display panel;
Receiving an input image;
Adjusting the input image according to the pixel parameters; And
And displaying the adjusted input image on the display panel,
The pixel parameters comprising: a first pixel parameter of a base luminance level of a base color channel; A first residue determined from performing inter-channel prediction; A second residue determined from performing inter level prediction; And < RTI ID = 0.0 > a < / RTI >
A method for compensating for pixel brightness in a display panel. The method according to claim 1,
Wherein the received pixel parameters are compressed pixel parameters,
A method for compensating for pixel brightness in a display panel. 3. The method of claim 2,
Further comprising decompressing the compressed pixel parameters prior to adjusting the input image.
A method for compensating for pixel brightness in a display panel. 3. The method of claim 2,
Wherein the pixel parameters comprise:
Selecting, by the processor, the base color channel from a plurality of color channels;
Selecting, by the processor, a base luminance level of the selected base color channel from a plurality of luminance levels;
Determine, by the processor, pixel parameters for the selected base color channel and the base luminance level; And
By the processor, to predict the second pixel parameter from the first pixel parameter to produce the first residue
Compressed,
Wherein the second pixel parameter corresponds to a color channel different from the base color channel and corresponds to a luminance level equal to the base luminance level,
A method for compensating for pixel brightness in a display panel. 5. The method of claim 4,
The pixel parameters may further include,
Predicting, by the processor, a third pixel parameter from the predicted second pixel parameter to produce the second residue; And
By encoding the first pixel parameter, the first residue and the second residue
Compressed,
Wherein the third pixel parameter corresponds to the same color channel corresponding to the second pixel parameter and corresponds to a luminance level different from the luminance level corresponding to the second pixel parameter,
A method for compensating for pixel brightness in a display panel. Selecting, by the processor, a base color channel from a plurality of color channels;
Selecting, by the processor, a base luminance level of the selected base color channel from a plurality of luminance levels;
Determining, by the processor, a first pixel parameter for the selected base color channel and the base luminance level; And
Predicting, by the processor, a second pixel parameter from the first pixel parameter to produce a first residue,
Wherein the second pixel parameter corresponds to a color channel different from the base color channel and corresponds to a luminance level equal to the base luminance level,
A method for compensating pixel parameters. The method according to claim 6,
Predicting, by the processor, a third pixel parameter from the predicted second pixel parameter to produce a second residue; And
Further comprising encoding the first pixel parameter, the first residue and the second residue,
Wherein the third pixel parameter corresponds to the same color channel corresponding to the second pixel parameter and corresponds to a luminance level different from the luminance level corresponding to the second pixel parameter,
A method for compensating pixel parameters. 8. The method of claim 7,
Wherein the step of predicting the second pixel parameter comprises an interchannel prediction,
A method for compensating pixel parameters. 8. The method of claim 7,
Wherein the second residue is a difference between the second pixel parameter and the third pixel parameter,
A method for compensating pixel parameters. 8. The method of claim 7,
Wherein the step of predicting the third pixel parameter comprises an inter-
A method for compensating pixel parameters. 11. The method of claim 10,
Wherein the inter-level prediction comprises performing a linear regression,
A method for compensating pixel parameters. The method according to claim 6,
Wherein the first residue is a difference between the first pixel parameter and the second pixel parameter,
A method for compensating pixel parameters. The method according to claim 6,
Further comprising multiplexing the first pixel parameter, the first residue, and the second residue.
A method for compensating pixel parameters. A memory containing compressed parameters for the sub-pixels of the display panel;
A decoder configured to decompress the compressed parameters; And
A processor configured to apply the decompressed parameters to an input image signal,
Each parameter of the parameters corresponding to a respective sub-pixel of the sub-pixels,
The parameters include,
Selecting a base color channel from a plurality of color channels;
Selecting a base luminance level of the selected base color channel from a plurality of luminance levels;
Determine a first pixel parameter for the selected base color channel and the base luminance level;
Predicting a second pixel parameter from the first pixel parameter to produce a first residue, the second pixel parameter corresponding to a different color channel from the base color channel and corresponding to a luminance level equal to the base luminance level -;
Predicting a third pixel parameter from the predicted second pixel parameter to generate a second residue, the third pixel parameter corresponding to the same color channel corresponding to the second pixel parameter, and the second pixel parameter Corresponding to a brightness level different from the brightness level corresponding to the brightness level; And
By encoding the first pixel parameter, the first residue and the second residue
Compressed,
Display panel. 15. The method of claim 14,
Wherein predicting the second pixel parameter comprises interchannel prediction,
Display panel. 15. The method of claim 14,
Wherein predicting the third pixel parameter comprises inter-level prediction,
Display panel. 17. The method of claim 16,
Wherein the inter-level prediction comprises performing a linear regression,
Display panel. 15. The method of claim 14,
Wherein the first residue is a difference between the first pixel parameter and the second pixel parameter,
Display panel. 15. The method of claim 14,
Wherein the second residue is a difference between the second pixel parameter and the third pixel parameter,
Display panel. 15. The method of claim 14,
Further comprising multiplexing the first pixel parameter, the first residue, and the second residue.
Display panel.

Images