Display apparatus and operating method thereof

1. A display apparatus comprising:

a controller; and

a display,

wherein the controller is configured to:

acquire input image data,

generate a first tone mapping curve based on a luminance distribution histogram of the acquired input image data,

generate first image data from the acquired input image data using the generated first tone mapping curve,

generate a Red, Green, Blue (RGB) distribution histogram, a detail region histogram, and a high-luminance region histogram based on pixel information of the generated first image data,

generate a second tone mapping curve using the generated RGB distribution histogram, the generated detail region histogram, and the generated high-luminance region histogram, and

cause the display to display output image data using the generated second tone mapping curve, wherein the output image data is generated from the generated first image data, wherein the RGB distribution histogram is generated based on a luminance value of each pixel in an entire region of the generated first image data,

wherein the detail region histogram is generated based on luminance values of pixels each having a detail degree greater than or equal to a predetermined detail reference value in the generated first image data, and

wherein the high-luminance region histogram is generated based on luminance values of pixels greater than or equal to a predetermined luminance reference value in the generated first image data.

2. The display apparatus of claim 1 , wherein the luminance distribution histogram is generated based on a luminance value of each pixel in an entire region of the acquired input image data, and wherein the first tone mapping curve is generated for equalizing the luminance distribution histogram.

3. The display apparatus of claim 1 , wherein the detail degree corresponds to a change in luminance value between adjacent pixels within a certain distance.

4. The display apparatus of claim 1 , wherein the controller is further configured to:

convert each of the generated RGB distribution histogram, the generated detail region histogram, and the generated high-luminance region histogram into corresponding log scale histograms, and

generate a weighted log-scale histogram by weighting the converted log-scale RGB distribution histogram, the converted log-scale detail region histogram, and the converted log-scale high-luminance region histogram based on a predetermined weight, wherein the second tone mapping curve is generated for equalizing the generated weighted log-scale histogram.

5. The display apparatus of claim 4 , wherein the controller is further configured to modify the second tone mapping curve based on a predetermined boundary line.

6. The display apparatus of claim 5 , wherein the predetermined boundary line corresponds to a straight line separated from a linear mapping straight line by a predetermined distance, and

wherein the controller is further configured to modify the second tone mapping curve to not exceed the predetermined boundary line.

7. The display apparatus of claim 6 , wherein the predetermined boundary line comprises a first boundary line located above the linear mapping straight line and a second boundary line located below the linear mapping straight line, and

wherein the controller is further configured to modify the second tone mapping curve to not deviate from a region between the first boundary line and the second boundary line.

8. The display apparatus of claim 1 , wherein the output image data is generated from the generated first image data using at least one of a central processing unit (CPU) or a graphic processing unit (GPU).

9. A tone mapping method of a display apparatus comprising:

generating a first tone mapping curve based on a luminance distribution histogram of input image data;

generating first image data from the input image data using the generated first tone mapping curve;

generating a Red, Green, Blue (RGB) distribution histogram, a detail region histogram and a high-luminance region histogram based on pixel information of the generated first image data;

generating a second tone mapping curve using the generated RGB distribution histogram, the generated detail region histogram, and the generated high-luminance region histogram; and

display output image data using the generated second tone mapping curve, wherein the output image data is generated from the generated first image data, wherein the RGB distribution histogram is generated based on a luminance value of each pixel in an entire region of the generated first image data,

wherein the detail region histogram is generated based on luminance values of pixels each having a detail degree greater than or equal to a predetermined detail reference value in the generated first image data, and

wherein the high-luminance region histogram is generated based on luminance values of pixels greater than or equal to a predetermined luminance reference value in the generated first image data.

10. The tone mapping method of claim 9 , wherein the luminance distribution histogram is generated based on a luminance value of each pixel in an entire region of the input image data, and wherein the first tone mapping curve is generated for equalizing the luminance distribution histogram.

11. The tone mapping method of claim 9 , wherein the detail degree corresponds to a change in luminance value between adjacent pixels within a certain distance.

12. The tone mapping method of claim 9 , further comprising:

converting each of the generated RGB distribution histogram, the generated detail region histogram, and the generated high-luminance region histogram into corresponding log scale histograms, and

generating a weighted log-scale histogram by weighting the converted log-scale RGB distribution histogram, the converted log-scale detail region histogram, and the converted log-scale high-luminance region histogram based on a predetermined weight, wherein the second tone mapping curve is generated for equalizing the generated weighted log-scale histogram.

13. The mapping method of claim 12 , further comprising modifying the second tone mapping curve based on a predetermined boundary line.

14. A recording medium having recorded thereon a tone mapping method, the tone mapping method comprising:

generating a first tone mapping curve based on a luminance distribution histogram of input image data;

generating first image data from the input image data using the generated first tone mapping curve;

generating a Red, Green, Blue (RGB) distribution histogram, a detail region histogram and a high-luminance region histogram based on pixel information of the generated first image data;

generating a second tone mapping curve using the generated RGB distribution histogram, the generated detail region histogram, and the generated high-luminance region histogram; and

display output image data using the generated second tone mapping curve, wherein the output image data is generated from the generated first image data, wherein the RGB distribution histogram is generated based on a luminance value of each pixel in an entire region of the generated first image data,

wherein the detail region histogram is generated based on luminance values of pixels each having a detail degree greater than or equal to a predetermined detail reference value in the generated first image data, and

wherein the high-luminance region histogram is generated based on luminance values of pixels greater than or equal to a predetermined luminance reference value in the generated first image data.

15. The recording medium of claim 14 , wherein the luminance distribution histogram is generated based on a luminance value of each pixel in an entire region of the input image data, and wherein the first tone mapping curve is generated for equalizing the luminance distribution histogram.

16. The recording medium of claim 14 , wherein the detail degree corresponds to a change in luminance value between adjacent pixels within a certain distance.

17. The recording medium of claim 14 , wherein the output image data is generated from the generated first image data using at least one of a central processing unit (CPU) or a graphic processing unit (GPU).