Image displaying methods and display devices

An image displaying method, comprising:

• obtaining three-color sub-pixel data of each of pixels of a current image, wherein the three-color sub-pixel data comprises a first red grayscale value (R1), a first green grayscale value (G1), and a first blue grayscale value (B1);
• obtaining a white grayscale coefficient according to the first red grayscale value (R1), the first green grayscale value (G1), and the first blue grayscale value (B1);
• obtaining a first white grayscale value (W1) in accordance with the white grayscale coefficient and a minimum value selecting from the first red grayscale value (R1), the first green grayscale value (G1), and the first blue grayscale value (B1);
• obtaining a second red grayscale value (R2), a second green grayscale value (G2), a second blue grayscale value (B2), and a second white grayscale value (W2) by performing a color gamut mapping toward the first red grayscale value (R1), the first green grayscale value (G1), the first blue grayscale value (B1), and the first white grayscale value (W1) in accordance with a predetermined rule;
• and
• obtaining updated three-color sub-pixel data corresponding to each of the pixels by performing a sub-pixel rendering process toward the second red grayscale value (R2), the second green grayscale value (G2), the second blue grayscale value (B2), and the second white grayscale value (W2), and outputting the updated three-colors sub-pixel data to a display panel, the updated three-color sub-pixel data comprises any three of the third red grayscale value (R3), the third green grayscale value (G3), the third blue grayscale value (B3), and the third white grayscale value (W3).

An image display device, comprising:

• a first grayscale value obtaining unit configured for receiving three-color sub-pixel data of each of the pixels of a current image, the three-color sub-pixel data comprises the first red grayscale value (R1), the first green grayscale value (G1), and the first blue grayscale value (B1), a white grayscale coefficient is obtained in accordance with the first red grayscale value (R1), the first green grayscale value (G1), and the first blue grayscale value (B1), a first white grayscale value (W1) is obtained in accordance with the white grayscale coefficient and the minimum value selected from the first red grayscale value (R1), the first green grayscale value (G1), and the first blue grayscale value (B1);
• a color gamut unit connects to the first grayscale value obtaining unit, and obtains a second red grayscale value (R2), a second green grayscale value (G2), a second blue grayscale value (B2), and a second white grayscale value (W2) by performing a color gamut mapping toward the first red grayscale value (R1), the first green grayscale value (G1), the first blue grayscale value (B1), and the first white grayscale value (W1) in accordance with a predetermined rule;
• a sub-pixel rendering unit connects to the color gamut unit, and obtains updated three-color sub-pixel data corresponding to each of the pixels by performing a sub-pixel rendering process toward the second red grayscale value (R2), the second green grayscale value (G2), the second blue grayscale value (B2), and the second white grayscale value (W2), and the updated three-color sub-pixel data are outputted to the display panel, the updated three-color sub-pixel data comprises any three of the third red grayscale value (R3), the third green grayscale value (G3), the third blue grayscale value (B3), and the third white grayscale value (W3).