Method for reducing brightness of images, a data-processing apparatus, and a display apparatus
The present application discloses a method for reducing brightness of images at least partially. The method includes determining a grayscale mapping table corresponding to a previous frame of image and adjusting grayscale value of each pixel of a current frame of image based on the grayscale mapping table to enhance a contrast ratio to determine an after-adjust grayscale value of each pixel of the current frame of image. Furthermore, the method includes determining one or more coefficients of grayscale reduction based on the after-adjust grayscale value of each pixel of the current frame of image. Moreover, the method includes reducing grayscale value of each pixel of a next frame of image based on the one or more coefficients of grayscale reduction and after-adjust grayscale values of corresponding pixels of the next frame of image.
1. A data-processing apparatus for reducing brightness of images at least partially displayed in a display apparatus, the data-processing apparatus comprising:
a first processor configured to determine a grayscale mapping table corresponding to the previous frame of image;
a first adjuster coupled to the first processor and configured to adjust grayscale value of each pixel of a current frame of image based on the grayscale mapping table corresponding to the previous frame of image to enhance a contrast ratio;
a second processor coupled to the first adjuster and configured to determine an after-adjust grayscale value of each pixel of the current frame of image;
a third processor coupled to the second processor and configured to determine one or more coefficients of grayscale reduction based on the after-adjust grayscale value of each pixel of the current frame of image; and
a second adjuster coupled to the third processor and configured to reduce grayscale value of each pixel of a next frame of image based on the one or more coefficients of grayscale reduction and after-adjust grayscale values of corresponding pixels of the next frame of image.
2. The data-processing apparatus of claim 1 , wherein the first processor is configured to receive pixel data of a previous frame of image to deduce a grayscale histogram of the previous frame of image.
3. The data-processing apparatus of claim 1 , wherein the second processor is configured to output a grayscale distribution of the current frame of image based on which an average grayscale value, a maximum grayscale value, and a minimum grayscale value are determined.
4. The data-processing apparatus of claim 3 , wherein the third processor is configured to determine that the grayscale distribution of the current frame of image meets a first criterion based on which a coefficient of grayscale reduction is determined to be a single preset coefficient of grayscale reduction value for all pixels of the next frame of image corresponding to the average grayscale value, or to determine that the grayscale distribution meets a second criterion based on which the one or more coefficients of grayscale reduction are determined to be respective multiple preset coefficient of grayscale reduction values for each pixel in corresponding different grayscale ranges of the next frame of image.
5. The data-processing apparatus of claim 4 , wherein the third processor is configured to determine that the first criterion is met when the average grayscale value is smaller than a first threshold value, or when the average grayscale value is equal to or greater than the first threshold value and a ratio of a difference between the maximum grayscale value and the minimum grayscale value over the maximum grayscale value is equal to or smaller than the second threshold value; or to determine that the second criterion is met when the average grayscale value is equal to or greater than the first threshold value and a ratio of a difference between the maximum grayscale value and the minimum grayscale value over the maximum grayscale value is greater than the second threshold value.
6. The data-processing apparatus of claim 5 , wherein the third processor is configured to store a first group of preset coefficient of grayscale reduction values corresponding to different ranges of the average grayscale value, wherein a higher range of the average grayscale value corresponds to a smaller preset coefficient of grayscale reduction value in the first group associated with the first criterion, and store a second group of preset coefficient of grayscale reduction values corresponding to different grayscale ranges of pixels of the current frame of image, wherein a higher grayscale range corresponds to a smaller preset coefficient of grayscale reduction value in the second group associated with the second criterion.
7. The data-processing apparatus of claim 1 , wherein the first processor is configured to determine a grayscale histogram of the previous frame of image, to perform equalization to the grayscale histogram to obtain an equalized grayscale histogram and a dynamic range extension parameter, and to determine the grayscale mapping table based on the equalized grayscale histogram and the dynamic range extension parameter.
8. A display apparatus comprising a data-processing apparatus of claim 1 for reducing brightness of images at least partially displayed thereof.