CN111510723B

CN111510723B - Time sequence controller

Info

Publication number: CN111510723B
Application number: CN201910092326.4A
Authority: CN
Inventors: 陈秋妤
Original assignee: Himax Technologies Ltd
Current assignee: Himax Technologies Ltd
Priority date: 2019-01-30
Filing date: 2019-01-30
Publication date: 2022-02-22
Anticipated expiration: 2039-01-30
Also published as: CN111510723A

Abstract

A timing controller is suitable for a display, the display includes a panel; a scan driver, controlled by the timing controller, uses a plurality of scan lines to sequentially activate pixels in a corresponding row of the control panel; a data driver is controlled by the timing control The device receives the image signal, and then transmits it to the pixels of the corresponding row of the panel respectively through a plurality of data lines. The timing controller includes an encoder that uses downsampling for data compression of the image signal. The downsampling method mainly includes determining the dense area of the gray-scale distribution of the image signal; determining the weighted sum, the maximum value and the minimum value of the two data to be compressed; located in a dense area. If it is located in a dense area, set it as the downsampled value, otherwise determine the weighted sum, the maximum value and the minimum value, which is closest to the dense area, and set it as the downsampled value.

Description

Time sequence controller

Technical Field

The present invention relates to image compression, and more particularly, to a histogram-based downsampling method.

Background

In the field of signal processing (signal processing), data compression (data compression) is a technique for encoding (encoding) information using fewer bits. Image compression (image compression) is an image processing technique that applies a data compression method to digital images. Down sampling (down sampling) is a common approach for image compression, which is used to reduce the sampling rate of the signal. However, down-sampling tends to cause aliasing (aliasing) distortion in the high frequency components of the signal.

Therefore, it is necessary to ensure that important data information can be retained without causing data distortion while performing image compression using downsampling.

Disclosure of Invention

In view of the foregoing, it is therefore an object of the present invention to provide an image compression system and method that effectively ensure that the down-sampled signal can hold important data information without data distortion.

The time schedule controller suitable for the display according to the embodiment of the invention comprises a panel; the scanning driver is controlled by the time schedule controller and sequentially starts the pixels of the corresponding rows of the control panel by a plurality of scanning lines; the data driver is controlled by the time schedule controller and receives the image signals, and then respectively transmits the image signals to the pixels of the corresponding columns of the panel by a plurality of data lines. The timing controller includes an encoder for performing data compression of an image signal using a down-sampling method. The method comprises establishing gray scale distribution of image signal; determining a dense area of gray scale distribution; determining the weighted sum, the maximum value and the minimum value of two data to be compressed; determining whether the weighted sum, the maximum value or the minimum value is positioned in a dense area according to a preset priority order; and if the weighted sum, the maximum value or the minimum value is judged to be in the dense area, setting the weighted sum, the maximum value or the minimum value as a reduced sampling value, otherwise, determining the closest dense area among the weighted sum, the maximum value and the minimum value, and setting the closest dense area as the reduced sampling value.

Drawings

FIG. 1 is a block diagram of a display according to an embodiment of the present invention.

Fig. 2 shows a simplified example of down-sampling.

FIG. 3A is a flow chart of a down-sampling method according to an embodiment of the invention.

Fig. 3B shows a detailed flowchart of step 24 of fig. 3A.

Fig. 4 illustrates a histogram.

FIG. 5 shows a truth table listing the mechanism for determining the downsampled value of the present embodiment.

[ description of reference ]

100 display

11 Panel

12 scan driver

121 scan line

13 data driver

131 data line

14 time sequence controller

141 encoder

200 down-sampling method

21 establishing a gray scale distribution

22 determining dense zones

23 determine weighted sum, maximum value, minimum value

24 decide whether to locate in a dense area

241 determine if the weighted sum is located in a dense area

242 determines whether the maximum is located in the dense region

243 determine whether the minimum value is located in the dense region

25 obtaining reduced sample values

26 is set to the lower sample value

Detailed Description

FIG. 1 is a block diagram of a display 100 according to an embodiment of the invention. In the present embodiment, the display 100 (e.g., a liquid crystal display) may include a panel 11, a scan driver 12, a data driver 13, and a timing controller (T-con) 14. The panel 11 includes a plurality of pixels (not shown) arranged in a matrix. The scan driver 12 is controlled by the timing controller 14 to sequentially activate the pixels of the corresponding row of the control panel 11 via a plurality of scan lines 121. The data driver 13 is controlled by the timing controller 14 and receives the image signals, and then respectively transmits the image signals to the pixels of the corresponding columns (or channels) of the panel 11 via the data lines 131. The timing controller 14 includes an encoder 141 that performs data compression of the image signal using a down sampling (down sampling) method.

FIG. 2 shows a simplified example of down-sampling, in which

data

1, 2 … 8 represent the original data, and data 1 ', 2', 3 ', 4' are obtained after the down-sampling operation, which is the first down-sampled data. If the first down-sampled data is further down-sampled, the data 1 ', 2' can be obtained as the second down-sampled data. In other words, the two original data are down-sampled to generate a down-sampled (or compressed) data.

Fig. 3A shows a flowchart of a down-sampling method 200 according to an embodiment of the invention, which can be applied to the display 100 (for example, but not limited to, the encoder 141 of the timing controller 14) shown in fig. 1. In one embodiment, the downsampling method 200 is performed on each block of the image in sequence. According to one feature of this embodiment, in step 21, a gray scale distribution, such as a histogram (histogram), of the image signal is established, as illustrated in fig. 4. First, divide the gray level into plural sections, and assign a color index (color index) accordingly. For example, the gray levels 0-9 are the first interval, and the corresponding color index is 0; the gray levels 10-19 are the second interval, the corresponding color index is 1, and so on. Then, the number of the video signals in each interval is counted.

In step 22, the dense region of gray scale distribution, i.e. the main distribution region of the image signal, is determined. In this embodiment, when determining whether a certain interval belongs to a dense area, the sum of the interval and the number of left and right adjacent intervals is compared with a preset threshold, if the sum is greater than the threshold, the interval is determined to belong to the dense area, and a corresponding check value is assigned as (logic) 1; otherwise, it is determined that the interval does not belong to a dense area, and it assigns a corresponding check value of (logical) 0. This step can be expressed mathematically as follows:

check value (i) ═ critical value [ (number (i-1) + number (i +1)) > threshold ]

Wherein i represents the ith interval.

In step 23, the weighted sum (weighted sum), the maximum value and the minimum value of the two data to be compressed are determined. The weighted sum is a weighted sum of a maximum value and a minimum value, and can be expressed as follows:

weighted sum w1 max + w2 min

Wherein w1, w2 are weights, and w1+ w2 is 1.

In step 24, it is determined whether the weighted sum, the maximum value or the minimum value is located in the dense area according to a predetermined priority (priority) order. In the present embodiment, the priority order is a weighted sum, a maximum value, and a minimum value in this order, but the present invention is not limited to this. If it is determined to be located in a dense region, it is set to a down sampled (down sampled) value (step 25). For example, if the weighted sum (of the largest priority) does not belong to a dense area, then a determination is made as to whether the largest value (of the next largest priority) is located in a dense area. If so, setting the maximum value as the reduced sample value; otherwise, it is next determined whether the minimum value is located in the dense region. Fig. 3B shows a detailed flowchart of step 24 of fig. 3A. Wherein step 241 determines whether the weighted sum is located in the dense region, step 242 determines whether the maximum value is located in the dense region, and step 243 determines whether the minimum value is located in the dense region.

If the weighted sum, the maximum value and the minimum value are all determined not to be in the dense area in sequence in step 24, the flow proceeds to step 26, where the closest dense area among the weighted sum, the maximum value and the minimum value is determined and set as the reduced sampling value. FIG. 5 shows a truth table listing the mechanism for determining downsampled values for this embodiment, where x represents the don't care state. For the first column case, it is determined that the weighted sum (of the greatest priority) is located in the dense region, thus setting the weighted sum to a reduced sample value; for the second, three column case, it is determined that the maximum (of the next highest priority) is located in the dense region, thus setting the maximum to the lower sample value; for the fourth case, it is determined that the minimum (of minimum priority) is in the dense region, thus setting the minimum to a reduced sample value; for the case of the fifth column, the weighted sum, the maximum value and the minimum value are all determined not to be located in the dense region in sequence, and therefore the closest one of the weighted sum, the maximum value and the minimum value to the dense region is set as the reduced sampling value.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention; it is intended that all such equivalent changes and modifications be included within the spirit of the disclosure, which is encompassed by the following claims.

Claims

1. A timing controller, suitable for a display, the display comprising a panel; a scan driver, controlled by the timing controller, through a plurality of scan lines to sequentially activate and control the pixels of the corresponding columns of the panel; data The driver is controlled by the timing controller and receives the image signal, and then transmits it to the pixels of the corresponding row of the panel through a plurality of data lines. The timing controller includes:

an encoder for data compression of the image signal using a downsampling method, the downsampling method comprising:

establishing a grayscale distribution of the image signal, including dividing into a plurality of intervals according to the size of the grayscale and counting the number of the image signal in each interval;

Determining the dense area of the gray-scale distribution includes comparing the sum of an interval and the number of left and right adjacent intervals with a preset critical value, and if the sum is greater than the critical value, determining the interval It belongs to a dense area, otherwise it is determined that the interval does not belong to a dense area;

determining the weighted sum, the maximum value and the minimum value of the gray levels of two image signals in the data of the image signal to be compressed;

determining whether the weighted sum, the maximum value or the minimum value is located in a dense area according to a predetermined priority order; and

If the weighted sum, the maximum value or the minimum value is determined to be located in a dense area, it is set as the downsampled value, otherwise it is determined that the weighted sum, the maximum value and the minimum value are the closest among the three In dense areas, set it to the downsampled value.

2 . The timing controller of claim 1 , wherein the grayscale distribution comprises a histogram. 3 .

3. sequence controller according to claim 1, is characterized in that, also comprises:

Color indicators are assigned to the intervals accordingly.

4. The timing controller according to claim 1, wherein the weighted sum is expressed as follows:

Weighted sum=w1·maximum+w2·minimum

where w1 and w2 are weights, and w1+w2=1.

5 . The timing controller according to claim 1 , wherein the priority order is the weighted sum, the maximum value, and the minimum value in sequence. 6 .