TWI492012B - Backlight calibration method and apparatus - Google Patents

Description

Backlight brightness adjustment method and device

The present invention relates to backlight brightness adjustment techniques.

In order to save the power consumption of the display panel and take into account the contrast of the screen, the screen brightness is usually adjusted by the Content Adaptive Brightness Control (CABC). The main practice of this technology is to calculate an adjustment parameter according to the displayed screen content, and the backlight module can adjust the percentage of the backlight on according to the adjustment parameter, as shown in FIG. 1 .

In general, the dynamic backlight control technology counts the brightness of the screen and determines the aforementioned adjustment parameters by "average brightness" or "maximum brightness". Figure 2 is a statistical graph of the brightness of the screen in an example to illustrate the adjustment of the backlight brightness according to the "average brightness value" of the screen. In this example, the brightness of the picture pixels is between 1 and 25. However, since the screen itself is located in a dark area (with a luminance of 12 or less), the luminance average value 11 of the entire screen is lower than the median of 13. If the average value of the brightness is used as the basis for adjusting the backlight, the overall picture is easily adjusted too dark, so that the brightest part 202 of the picture appears to be insufficiently contrasted. Fig. 3 is a statistical graph of the brightness of the screen in another example, for explaining the case where the brightness of the backlight is adjusted according to the "maximum brightness" of the screen. In this example, the brightness of the picture pixels is also between 1 and 25. Although there are very few pixels in the bright area in the picture, since the maximum brightness of the picture is 25 pixels, the brightness of the backlight is easily adjusted too high and is lost. The original intention of saving backlight energy.

The invention provides a backlight brightness adjustment method. The method includes: detecting, from an image, a plurality of bright area objects whose brightness value exceeds a predetermined brightness and whose area exceeds a predetermined area; and calculating one of all bright area objects by using the area of the bright area objects as a weight An area-weighted average brightness; and adjusting the backlight brightness of the image based at least on the area-weighted average brightness.

The invention further provides a backlight brightness adjusting device. The device includes: a detecting unit, configured to detect, from an image, a plurality of bright area objects having a brightness value exceeding a predetermined brightness and an area exceeding a predetermined area; and a calculating unit for using the bright areas The area of the object is a weight, and an area-weighted average brightness of one of the bright area objects is calculated; and an adjusting unit is configured to adjust a backlight to display the backlight brightness of the image according to the area-weighted average brightness.

The following is a description of the preferred embodiment of the invention. The examples are intended to illustrate the principles of the invention, but are not intended to limit the invention. The scope of the invention is defined by the appended claims.

In order to make up for the deficiencies of the conventional dynamic backlight control technology, the present invention further provides a backlight brightness adjustment method and apparatus based on the "area" of a picture object. Various embodiments of the backlight brightness adjustment method of the present invention will be described below with reference to the accompanying drawings.

Backlight brightness adjustment method

4 is a flow chart of a backlight brightness adjustment method according to an embodiment of the invention. The backlight brightness adjustment method 400 of the present invention includes: detecting, in step S402, a plurality of bright area objects whose brightness value exceeds a predetermined brightness and whose area exceeds a predetermined area; and in step S404, The area of the bright area object is weighted, and an area-weighted average brightness of all the bright area objects is calculated; and in step S406, the backlight brightness of the image is adjusted according to at least the area weighted average brightness.

FIG. 5A is a schematic diagram of a bright area object in step S402 of the present invention. For example, the backlight brightness adjustment method of the present invention first defines a preset brightness, for example, the brightness value 13 of FIG. 1 is a preset brightness; and further defines a preset area, for example, 1% of the total image area. . Step 402 of the present invention detects a bright area object whose brightness value exceeds the preset brightness and whose area exceeds the preset area in image 500, such as bright area object 502 in FIG. It should be noted that the preset brightness and the preset area in this embodiment are only for convenience of description, and the present invention is not limited to this value.

Figure 5B is a schematic diagram of a bright area object of another embodiment of the screen of Figure 5A. In some embodiments, in order to make the picture with complex brightness easy to calculate, as shown in FIG. 5B, the entire picture is first subdivided into a plurality of blocks (where each block has the same number of pixels), and then the area is The number of pixels in the block whose brightness exceeds the aforementioned "preset brightness" is regarded as the "bright area" of the block, and when the "bright area" is larger than the aforementioned "preset area", the entire block is regarded as A bright area object. Thus, the picture of Figure 5A will appear in the embodiment of Figure 5B with two bright area objects 522 and 524 (although it should be noted that the areas are not the same). When the brightness of the picture changes complexly, the shape of the object is trivial. In this way, the "bright object" can be reasonably defined in this way.

In some embodiments, the step S402 of the present invention detects a plurality of bright-area objects having different brightnesses and different areas, such as the bright-area object 602 and the bright-area object 604 in the image 600 of FIG. The brightness of the bright object 602 is B1, and the area is A1; and the brightness of the bright object 604 is B2, and the area is A2. Thereafter, the present invention will proceed to step S404 to calculate the area-weighted average brightness of one of all bright-area objects by weighting the area of the bright-area objects. In an embodiment, step S404 calculates the area weighted average brightness Bavg according to the following formula: Bavg = (B1 x A1 + B2 x A2) / (A1 + A2). In this embodiment, two bright-area objects 602 and 604 are taken as an example. In a practical example with two or more bright-area objects, the calculation method of the area-weighted brightness can also be deduced.

Finally, in step S406, the present invention adjusts the backlight brightness of the image based on at least the area weighted average brightness. In general, since human visual senses tend to pay attention to objects having a large area in the screen, the present invention can obtain a relatively ideal effect by adjusting the brightness of the backlight based on the area of the object.

The present invention is not limited to simply adjusting the backlight brightness of an image based on the area-weighted average brightness. In other words, in some embodiments, while adjusting the backlight brightness of the image according to the area weighted average brightness as described above, the present invention can still adjust the backlight of the image according to the Content Adaptive Brightness Control (CABC). Brightness (where dynamic backlight control technology adjusts the backlight brightness of the image based on the overall brightness average of the image, the maximum brightness, or a linear or Nonlinear combination). Specifically, in some embodiments, the degree of brightness of the image backlight is adjusted according to the area-weighted average brightness (ie, the proportion of the final adjustment parameter, such as 0.6), and the degree of brightness of the image backlight is adjusted according to the dynamic backlight control technique. (meaning that the proportion of the final adjustment parameters, such as 0.4) is a specific ratio (ie 3:2).

Backlight brightness adjustment device

In addition to the foregoing backlight brightness adjustment method, the present invention further provides a backlight brightness adjustment device. Figure 7 is a schematic diagram of a backlight brightness adjusting device according to an embodiment of the present invention. In one embodiment, the backlight brightness adjustment device 700 can be independently operated or integrated into an image processor (not shown) for adjusting the backlight brightness of a backlight 750. The backlight brightness adjusting device 700 of the present invention comprises a detecting unit 710, a calculating unit 720 and an adjusting unit 730, wherein each component can respectively perform the respective steps of the foregoing backlight brightness adjusting method 400 of the present invention. Specifically, the detecting unit 710 can detect, from an image, a plurality of bright area objects whose brightness value exceeds a predetermined brightness and whose area exceeds a predetermined area. The calculating unit 720 can calculate the area-weighted average brightness of one of all bright area objects by using the area of the bright area objects as a weight. The adjusting unit 730 can adjust the backlight brightness of the image displayed by the backlight 750 according to the area weighted average brightness.

As with the previous embodiments, the present invention is not limited to simply adjusting the backlight brightness of an image based on the area-weighted average brightness. In other words, in some embodiments, while adjusting the backlight brightness of the image according to the area weighted average brightness as described above, the present invention can still adjust the backlight brightness of the image according to the dynamic backlight control technology (wherein the dynamic backlight control technology) Adjust the backlight of the image to be bright The degree of practice is based on the overall brightness average of the image, the maximum brightness, or a combination of linear or non-linear combinations of the two. Specifically, in some embodiments, the degree of brightness of the image backlight is adjusted according to the area-weighted average brightness (ie, the proportion of the final adjustment parameter, such as 0.6), and the degree of brightness of the image backlight is adjusted according to the dynamic backlight control technique. (meaning that the proportion of the final adjustment parameters, such as 0.4) is a specific ratio (ie 3:2). The features and functions of the backlight brightness adjusting device of the present invention are consistent with the foregoing backlight brightness adjusting method of the present invention. To save space, details thereof will not be described again.

The present invention has been described above with reference to the preferred embodiments thereof, and is not intended to limit the scope of the present invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

202‧‧‧The brightest part of the picture

400‧‧‧Backlight brightness adjustment method

S402~S406‧‧‧Steps

700‧‧‧Backlight brightness adjustment device

710‧‧‧Detection unit

720‧‧‧Computation unit

730‧‧‧Adjustment unit

750‧‧‧Backlight

Figure 1 is a plot of the adjustment parameters versus the percentage of backlight turn-on.

Figure 2 is a statistical graph of the brightness of the screen in an example to illustrate the adjustment of the backlight brightness according to the "average brightness value" of the screen.

Figure 3 is a statistical graph of the brightness of the screen in an example to illustrate the adjustment of the brightness of the backlight according to the "maximum brightness" of the picture.

4 is a flow chart of a backlight brightness adjustment method according to an embodiment of the invention.

5A and 6 are schematic views of the bright area object in step S402 of the present invention.

Figure 5B is a schematic diagram of a bright area object of another embodiment of the screen of Figure 5A.

Figure 7 is a schematic diagram of a backlight brightness adjusting device according to an embodiment of the present invention.

400‧‧‧Backlight brightness adjustment method

S402~S406‧‧‧Steps

Claims (8)

A backlight brightness adjustment method includes: detecting, from an image, a plurality of bright-area objects whose luminance value exceeds a predetermined brightness and whose area exceeds a predetermined area; and calculating all the bright lights by using the area of the bright-area objects as weights An area-weighted average brightness of the area object; and adjusting the backlight brightness of the image based on at least the area weighted average brightness. The backlight brightness adjustment method of claim 1, further comprising: adjusting the backlight brightness of the image according to the Content Adaptive Brightness Control (CABC). The backlight brightness adjustment method of claim 2, wherein the dynamic backlight control technology comprises: adjusting a backlight brightness of the image according to an average value of the overall brightness of the image; or adjusting the brightness according to a maximum value of the overall brightness of the image. The backlight brightness of the image; or a combination of the above. The backlight brightness adjustment method according to claim 2, wherein the degree of backlight brightness of the image is adjusted according to the area weighted average brightness, and the degree of backlight brightness of the image is adjusted according to dynamic backlight control technology. proportion. A backlight brightness adjusting device includes: a detecting unit, configured to detect, from an image, a plurality of bright area objects whose brightness value exceeds a predetermined brightness and whose area exceeds a predetermined area; a calculating unit for calculating an area-weighted average brightness of all the bright area objects by using the area of the bright area objects as a weight; and an adjusting unit for weighting the average brightness according to the area at least Adjusting a backlight displays the backlight brightness of the image. The backlight brightness adjusting device according to claim 5, wherein the backlight brightness adjusting device is further configured to adjust the backlight brightness of the image according to the Content Adaptive Brightness Control (CABC). The backlight brightness adjusting device of claim 6, wherein the dynamic backlight control technology comprises: adjusting a backlight brightness of the image according to an average value of the overall brightness of the image; or adjusting the brightness according to a maximum brightness of the image. The backlight brightness of the image; or a combination of the above. The backlight brightness adjusting device according to claim 6, wherein the degree of backlight brightness of the image is adjusted according to the area weighted average brightness, and the degree of backlight brightness of the image is adjusted according to dynamic backlight control technology. proportion.