The present invention generally relates to a signal processing, and more particularly to a de-jaggy processing system and method adaptable to an organic light-emitting diode (OLED) display.
An organic light-emitting diode (OLED) is a light-emitting diode (LED) in which an emissive electroluminescent layer made of organic compound, disposed between two electrodes, can emit light in response to an electric current. OLEDs may be used to make digital displays in devices such as televisions, computer monitors, and portable systems (e.g., smartphones).
As OLEDs emit light, an OLED display can work without a backlight module. Therefore, the OLED display can display deep black levels and can be made thinner and lighter than a liquid crystal display (LCD). In low ambient light conditions (such as a dark room), the OLED display can achieve a higher contrast ratio than the LCD.
An OLED display is composed of plural pixels, each of which includes a red sub-pixel, a green sub-pixel and a blue sub-pixel that are specifically arranged. However, the OLED display suffers jaggy patterns at curved bezel or a space around the OLED display. Further, the OLED display suffers aliasing (or distortion) artifacts along straight lines (e.g., verticals or horizontals) or diagonals of the OLED display.
A need has thus arisen to propose a novel scheme to remove or reduce jaggy patterns (i.e., de-jaggy) at curved bezel of the OLED display, and/or to remove or reduce aliasing artifacts of the OLED display.
In view of the foregoing, it is an object of the embodiment of the present invention to provide a de-jaggy processing system and method adaptable to an organic light-emitting diode (OLED) display to remove or reduce jaggy patterns at curved bezel or aliasing artifacts of the OLED display.
According to one embodiment, a de-jaggy processing method includes the following steps: dividing a display area of a display into a plurality of sub-areas; providing a first table composed of gray-level weights associated with corresponding luminances of each primary color for each said sub-area; providing a second table composed of distance-gain weights each correspondingly associated with a distance between a sub-pixel and a reference point; and obtaining a corrected luminance of a sub-pixel of a pixel by multiplying an original luminance of the sub-pixel by a corresponding gray-level weight and a corresponding distance-gain weight.
According to another embodiment, a de-jaggy processing method includes the following steps: providing a table composed of edge-gain weights for each primary color; determining adjacent sub-pixels for a current sub-pixel of a display; and obtaining a corrected luminance of the current sub-pixel by subtracting or adding weighted luminances of the adjacent sub-pixels from or to an original luminance of the current sub-pixel. The weighted luminance is obtained by multiplying a luminance of the adjacent sub-pixel by a corresponding edge-gain weight.
In step 301, a display area of the OLED display is divided into a plurality of sub-areas.
In step 302, for each sub-area 311, a first table (e.g., lookup table or LUT) composed of gray-level weights for each primary color (red, green or blue) is provided by a gray-level weight device (
Next, in step 303, a second table (e.g., lookup table or LUT) composed of distance-gain weights is provided by a distance-gain weight device 22 (
In step 304, a corrected luminance of a primary color at each pixel may be obtained (by a pixel correcting device 23 in
R′(x,y)=R(x,y)*GL-weight(R(x,y))*DistanceGain(R(x,y))
G′(x,y)=G(x,y)*GL-weight(G(x,y))*DistanceGain(G(x,y))
B′(x,y)=B(x,y)*GL-weight(B(x,y))*DistanceGain(B(x,y))
where R′/G′/B′ represents the corrected luminance, R/G/B represents the original luminance, GL-weight represents the gray-level weight (of the first table), and DistanceGain represents the distance-gain weight (of the second table).
In the embodiment, the corrected luminance obtained from step 304 may be further subjected to digital gamma correction (DGC) by a digital gamma correction device 24 (
In step 61, luminance differences (or edge levels) between a current sub-pixel and neighboring sub-pixels are determined by an edge level device 25 (
EdU_R=(R(x,y)−R(x,y−1))
EdL_R=(R(x,y)−R(x−1,y))
EdR_R=(R(x,y)−R(x+1,y))
EdUL_R=(R(x,y)−R(x−1,y−1))
EdUR_R=(R(x,y)−R(x+1,y−1))
EdD_R=(R(x,y)−R(x,y+1))
EdDL_R=(R(x,y)−R(x−1,y+1))
EdDR_R=(R(x,y)−R(x+1,y+1))
Similarly, the luminance differences (or edge levels or Ed) of different directions for color green may be expressed as follows:
EdU_G=(G(x,y)−G(x,y−1))
EdL_G=(G(x,y)−G(x−1,y))
EdR_G=(G(x,y)−G(x+1,y))
EdUL_G=(G(x,y)−G(x−1,y−1))
EdUR_G=(G(x,y)−G(x+1,y−1))
EdD_G=(G(x,y)−G(x,y+1))
EdDL_G=(G(x,y)−G(x−1,y+1))
EdDR_G=(G(x,y)−G(x+1,y+1))
The luminance differences (or edge levels or Ed) of different directions for color blue may be expressed as follows:
EdU_B=(B(x,y)−B(x,y−1))
EdL_B=(B(x,y)−B(x−1,y))
EdR_B=(B(x,y)−B(x+1,y))
EdUL_B=(B(x,y)−B(x−1,y−1))
EdUR_B=(B(x,y)−B(x+1,y−1))
EdD_B=(B(x,y)−B(x,y+1))
EdDL_B=(B(x,y)−B(x−1,y+1))
EdDR_B=(B(x,y)−B(x+1,y+1))
In the embodiment, the luminance differences as determined above may be used to determine whether aliasing artifacts exist along straight lines (e.g., verticals or horizontals) or diagonals of the OLED display.
Next, in step 62, a (third) table (e.g., lookup table or LUT) composed of edge-gain weights for each primary color (red, green or blue) is provided. The edge-gain weights are associated with corresponding luminance differences of the primary color.
In step 63, nearest adjacent sub-pixels for each primary color may be determined.
In step 64, a corrected luminance of a current sub-pixel may be obtained (by the sub-pixel correcting device 26 in
R′(C)=R(C)±R(U)*Ed(EdU_R)/256±R(UL)*Ed(EdUL_R)/256±R(L)*Ed(EdL_R)/256±R(DL)*Ed(EdDL_R)/256±R(D)*Ed(EdD_R)/256
G′(C)=G(C)±G(U)*Ed(EdU_G)/256±G(UL)*Ed(EdUL_G)/256±G(L)*Ed(EdL_G)/256±G(DL)*Ed(EdDL_G)/256±G(D)*Ed(EdD_G)/256
B′(C)=B(C)±B(U)*Ed(EdU_B)/256±B(UR)*Ed(EdUR_B)/256±B(R)*Ed(EdR_R)/256±B(DR)*Ed(EdDR_B)/256±B(D)*Ed(EdD_B)/256
where R′/G′/B′ represents the corrected luminance, R/G/B represents the original luminance, Ed represents the edge-gain weight, addition is adopted when the current sub-pixel is less than the adjacent sub-pixels, otherwise subtraction is adopted.
In the embodiment, the corrected luminance obtained from step 64 may be further subjected to digital gamma correction (DGC) by the digital gamma correction device 24 (
According to steps 61-64 as described above, aliasing artifacts along straight lines (e.g., verticals or horizontals) of the OLED display, particularly a gray image, may be substantially removed or reduced.
If the sub-pixel correcting device 26 (
R′(C)=R(C)±R(U)*Ed(EdU_R)/256±R(L)*Ed(EdL_R)/256±R(D)*Ed(EdD_R)/256±R(R)*Ed(EdR_R)/256
G′(C)=G(C)±G(U)*Ed(EdU_G)/256±G(L)*Ed(EdL_G)/256±G(D)*Ed(EdD_G)/256±G(R)*Ed(EdR_G)/256
B′(C)=B(C)±B(U)*Ed(EdU_B)/256±B(L)*Ed(EdL_B)/256±B(D)*Ed(EdD_B)/256±B(R)*Ed(EdR_B)/256
where R′/G′/B′ represents the corrected luminance, R/G/B represents the original luminance, Ed represents the edge-gain weight, addition is adopted when the current sub-pixel is less than the adjacent sub-pixels, otherwise subtraction is adopted.
Accordingly, aliasing artifacts along diagonals of the OLED display, particularly a color image, may be substantially removed or reduced.
Although specific embodiments have been illustrated and described, it will be appreciated by those skilled in the art that various modifications may be made without departing from the scope of the present invention, which is intended to be limited solely by the appended claims.
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