1. Field of the Invention
The present invention relates to a display driving device and method thereof, and more particularly, to a display driving device for reducing power consumption and method thereof.
2. Description of the Prior Art
A conventional liquid crystal display displays a large amount of frames within a short time for displaying motion pictures, so that an observer may perceive motions of objects on the displayed motion pictures by taking advantages of persistence of vision. A frame rate indicates an amount of frames displayed unit time, and has a unit as frames per second (FPS) or Hertz (Hz). Conventionally, while the frame rate is higher than 16 frames per second, the observer may perceive that a certain object on the motion pictures is continuously-displayed, instead of discretely-displayed, because of the effect of persistence of vision. A conventional motion picture movie is also rapidly displayed using the same principle. While the frame rate reaches 24 frames per second, objects on displayed motion pictures perceived by naked eyes are displayed smoothly enough; however, for some applications or games, which requires high dynamic visual acuity, a higher frame rate is required since a single frame of the applications or games merely includes visual information at an instant moment.
A frame rate, which may also be referred as a frame data updating rate, of a conventional liquid crystal display is always constant. Power consumption of a driving circuit for driving a display panel within the liquid crystal display in displaying frames is also proportional to the frame rate. In other words, the power consumption is also constant for the driving circuit in displaying the frames.
The claimed invention discloses a display driving method and a display system, for reducing power consumption and improving display quality.
The claimed invention discloses a display driving method. The method comprises respectively segmenting a first frame and a second frame into a plurality of first blocks and a plurality of second blocks according to a resolution; calculating a sum of differences between a pair of first and second blocks; calculating a motion proportion according to all sums of differences between the first frame and the second frame, and according to a plurality of weights for sum of differences; and determining a frame rate and whether a frame is displayed according to the motion proportion. The pair of first and second blocks has a same size. The second frame is displayed right after the first frame is displayed, and each of the plurality of first blocks has a corresponding block within the plurality of second blocks to form a pair.
The claimed invention discloses a display system. The display system comprises a block segmenting module, a sum of difference calculating module, a motion proportion calculating module, and a frame modulation module. The block segmenting module is for respectively receiving a first frame and a second frame, and for respectively segmenting the first and second frames into a plurality of first blocks and a plurality of second blocks according to a resolution. The second frame is displayed right after the first frame is displayed. Each of the plurality of first blocks has a corresponding block within the plurality of second blocks to form a pair. The sum of difference calculating module is for calculating a sum of differences between a pair of first and second blocks. The motion proportion calculating module is for calculating a motion proportion according to all sums of differences between the first frame and the second frame, and according to a plurality of weights for sum of differences. The frame modulation module is for determining a frame rate and whether a frame is displayed according to the motion proportion. The pair of first and second blocks has a same size.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
The present invention discloses a display driving method and a display system thereof for reducing power consumption of the display system without reducing display quality, for example, without introducing flickers. In the present invention, two consecutively-received frames are respectively segmented into a plurality of image blocks having different sizes; a sum of difference between the two consecutive frames is calculated in units of image blocks; a motion proportion between the two consecutive frames is calculated according to calculated sums of difference on both the frames; a frame rate for displaying a related frame and whether the related frame is displayed are determined according to the motion proportion, for preventing displaying frames, which have an over-high frame rate or introduce flickers; and as a result, the aim of reducing power consumption without reducing display quality is achieved.
Please refer to
The display system 100 receives two consecutively-displayed frames Fn−1 and Fn, where the frame Fn−1 is received and displayed earlier than the frame Fn. The buffer 150 is used for buffering the frame Fn−1 until the frame Fn is received by the display system 100. Right after the frame Fn is received by the display system 100, the frame Fn is also buffered by the buffer 150.
The block segmenting module 110 segments the frame Fn−1 into a plurality of first blocks, and segments the frame Fn into a plurality of second blocks, according to a resolution, where each of the plurality of first blocks has a corresponding block within the plurality of second blocks to form a pair. Please refer to
The sum of difference calculating module 120 calculates a sum of difference (SOD) between a pair of first and second blocks segmented by the block segmenting module 110. For example, in
Y=kr*R+kg*G+kb*B (1);
Y indicates the luminance difference. R, G, and B respectively indicate a red pixel value, a green pixel value, and a blue pixel value of the pixel difference. kr, kg, and kb are all constants. The equation (1) indicates a conventional way in transforming pixel values into luminance values so that said equation (1) is not further introduced herein. The pixel difference between the first and second blocks BLK1 and BLK2 may be a first sum of differences between pixels the first and second blocks BLK1 and BLK2, or may be a second sum, which is retrieved by normalizing the first sum; however, calculating the pixel difference between the blocks BLK1 and BLK2 are not restricted by the above examples. Similarly, the luminance difference between the first and second blocks BLK1 and BLK2 may be a third sum of differences in luminance between pixels of the first and second blocks BLK1 and BLK2, or may be a fourth sum, which is retrieved by normalizing the third sum, or may be other forms of luminance difference between the blocks BLK1 and BLK2. Therefore, the calculated sum of differences may be a sum of pixel difference or a sum of luminance difference.
Concretely speaking, a sum of difference calculated by the sum of difference calculating module 120 may be indicated as follows:
M and N respectively indicate a length and a width of a block matrix on a single frame, for example, while a frame includes 120*192 blocks, M should be 120, and N should be 192. (m,n) indicates both coordinates of a first reference pixel on the first block BLK1 and a second reference pixel on the second block BLK2; for example, the first reference pixel may be a pixel at the northwest corner of the block BLK1 (11,1901), and the second reference pixel may be a pixel at the northwest corner of the block BLK2 (11,1901), i.e., the pixel at the coordinate (11,1901) on both the frames Fn−1 and Fn, where m should be 11, and n should be 1901. FA_SOD(m,n) indicates the sum of differences, and as mentioned above, FA_SOD(m,n) may be a sum of pixel differences or a sum of luminance difference. FA_P(m,n) indicates a representative difference of the first block BLK1, which may be a representative pixel difference or a representative luminance difference of the first block BLK1. Similarly, FB_P(m,n) indicates a representative difference of the second block BLK2, which may be a representative pixel difference or a representative luminance difference of the second block BLK2. After the sum of difference calculating module 120 processes all blocks on the frames Fn−1 and Fn, there will be a sum of differences for each block on either one of the frames Fn−1 and Fn, i.e., FA_SOD(m,n).
In an embodiment of the present invention, the sum of difference calculating module 120 further fetches a plurality of most significant bits (MSB) on each sum of differences to normalize each the sum of differences, so as to generate a plurality of normalized sums of difference. For example, under an assumption that a pixel value ranges from 1 to 255, the sum of difference calculating module 120 fetches two most significant bits from the pixel values 36, 95, 172, and 232, which are indicated as “00100100”, “01011111”, “10101100”, and “11101000” in respective binary forms, to generate binary normalized sums of difference “00”, “01”, “10”, and “11”; it indicates the fact that the pixel values are normalized to be normalized sums of difference 0, 1, 2, 3 so that the pixels values can be classified, and as a result, the motion proportion calculating module 130 may process according to the normalized sums of difference.
The motion proportion calculating module 130 calculates a motion proportion MP according to all sums of difference between the frames Fn−1 and Fn, and according to a plurality of weights of sum of difference. The motion proportion MP provides a more concrete indication on a degree of difference between the frames Fn−1 and Fn in pixel values or in luminance. That is, a higher motion proportion MP indicates a larger difference between the frames Fn−1 and Fn. In an embodiment of the present invention, the motion proportion calculating module 130 multiplies each of the normalized sums of difference between the frames Fn−1 and Fn with one of the plurality of weights for sum of differences according to different values of the sums of pixel difference, for generating a total weighted sum of pixel difference, where the normalized sums of difference between the frames Fn−1 and Fn are generated by the sum of difference calculating module 120. At last, the motion proportion calculating module 130 fetches a plurality of most significant bits from the total weighted sum of difference to generate the required motion proportion MP. By following the example mentioned above and related to normalization of the sum of difference calculating module 120, the motion proportion calculating module 130 may multiply an amount of blocks having a normalized sum of difference equal to 0 with both the normalized sum of difference 0 and a weight 0, may multiply a number of blocks having a normalized sum of difference equal to 1 with both the normalized sum of difference 1 and a weight 1, may multiply a number of blocks having a normalized sum of difference equal to 2 with both the normalized sum of difference 2 and a weight 4, and may multiply a number of blocks having a normalized sum of difference equal to 3 with both the normalized sum of difference 3 and a weight 8, to generate four weighted sums of difference. Then the motion proportion calculating module 130 sums the four weighted sum of difference to generate a total weighted sum of difference. At last, the motion proportion calculating module 130 fetches two most significant bits from the total weighted sum of difference to generate the motion proportion MP, which may be “00”, “01”, “10”, “11” in binary form or be 0, 1, 2, 3 in decimal form. Taking a more concrete example, assume that the sum of difference calculating module 120 calculates a result, which indicates that there are 12*192 blocks having a normalized sum of difference 0, 36*192 blocks having a normalized sum of difference 1, 64*192 blocks having a normalized sum of difference 2, and 8*192 blocks having a normalized sum of difference 3 in the 120*192 blocks on a single frame, the total weighted sum of difference should be 0*(12*192)*1+1*(36*192)*2+2*(64*192)*4+3*(8*192)*8=148992; since two most significant bits of the total weighted sum of difference 148992 are “10”, the motion proportion calculating module 130 will determine the motion proportion MP to be “10” in binary form or 3 in decimal form.
The frame modulation module 140 determines a frame rate FR for displaying the frame Fn or whether the frame Fn is displayed according to the motion proportion MP calculated by the motion proportion calculating module 130. The frame modulation module 140 establishes a lookup table 145, which serves as a basis in determining the frame rate FR and whether the frame FR is displayed. Please refer to
As can be observed from
Besides, in the lookup table 145 shown in
Please refer to
The lookup table 145 shown in
Besides determining the frame rate FR and whether the frame Fn is displayed by using the display system 100 shown in
Please refer to
Step 702: Respectively segment a first frame and a second frame into a plurality of first blocks and a plurality of second blocks according to a resolution;
Step 704: Calculate a sum of differences between a pair of first and second blocks;
Step 706: Calculating a motion proportion according to all sums of differences between the first frame and the second frame, and according to a plurality of weights for sum of differences; and
Step 708: Determine a frame rate and whether a frame is displayed according to the motion proportion.
The steps form a summary about the above descriptions from
The present invention discloses a method of reducing power consumption without reducing displaying quality of a display system and the display system thereof. In the present invention, a sum of difference between two consecutively-displayed frames is calculated according to practical frame differences, which may include pixel differences or luminance differences. A motion proportion is generated by weighting sums of difference of various blocks in both the frames according to different values of the sums of difference, for concretely indicating the difference between the consecutive frames. At last, by setting a lookup table, different values of the motion proportion may be corresponding to different values of frame rates and different displaying states under different requirements, so that the aim of reducing power consumption without reducing the displaying quality is fulfilled.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.
Number | Date | Country | Kind |
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098129356 | Sep 2009 | TW | national |