Display device for adjusting color temperature of image and display method for the same

1. A display device comprising:

a display;

a sensor module configured to sense a color temperature of light incident to the sensor module from an outside of the display device; and

a processor electrically connected to the display and the sensor module,

wherein the processor is configured to:

operate in one of a first mode and a second mode depending on a user input;

in the first mode, output a moving picture to the display;

in the second mode,

when a user is detected, compare a color temperature of a still image to the color temperature sensed by using the sensor module, adjust the color temperature of the still image based on the comparison of the color temperature of the still image to the color temperature sensed by using the sensor module, and output the still image having the adjusted color temperature to the display; and

when the user is not detected, turn off the display,

wherein the processor is further configured to:

identify a background object behind a rear surface of the display device, and

adjust a color temperature of the still image based on a color temperature of the background object.

2. The display device of claim 1 , further comprising:

a communication module configured to communicate with an external electronic device,

wherein the sensor module includes a motion sensor configured to sense movement of the user, and

wherein the processor is configured to:

output the still image to the display by adjusting a backlight of the display to have a first brightness, when the movement of the user is sensed by using the motion sensor;

determine whether a signal received from the external electronic device has a strength equal to or greater than a threshold strength when the movement of the user is not sensed;

output the still image to the display by adjusting the backlight of the display to have a second brightness less than the first brightness when it is determined the signal received from the external electronic device has the strength equal to or greater than the threshold strength; and

turn off the display when it is determined the signal received from the external electronic device has a strength less than the threshold strength.

3. The display device of claim 1 , wherein the processor is configured to:

update the moving picture output to the display at a first frame rate in the first mode; and

update the still image output to the display at a second frame rate in the second mode, and

wherein the second frame rate is lower than the first frame rate.

4. The display device of claim 1 , wherein the processor is configured to:

adjust color temperatures of whole pixels of the still image by using a specified change ratio.

5. The display device of claim 4 , wherein the processor is configured to:

adjust color temperatures of some pixels among the whole pixels by using a first change ratio; and

adjust color temperatures of other pixels among the whole pixels by using a second change ratio.

6. The display device of claim 1 , wherein the processor is configured to:

adjust a brightness of the still image to correspond to a brightness of the background.

7. The display device of claim 1 , wherein the processor is configured to:

reduce one or both of a contrast and a sharpness of the still image.

8. The display device of claim 1 , wherein the sensor module is configured to:

sense illuminance of the light; and

adjust a brightness of the still image to correspond to the illuminance of the light.

9. The display device of claim 8 , wherein the processor is configured to:

decrease a brightness of a first area of the still image, the first area having less than a first brightness, when the illuminance of the light is less than a first threshold value; and

increase a brightness of a second area of the still image, the second area having at least a second brightness, when the illuminance of the light is equal to or greater than the first threshold value.

10. The display device of claim 8 , wherein the processor is configured to:

increase sharpness of a first area of the still image, the first area having less than a first brightness, when the illuminance of the light is less than a first threshold value; and

decrease sharpness of a second area of the still image, the second area having at least a second brightness, when the illuminance of the light is equal to or greater than the first threshold value.

11. The display device of claim 1 , wherein the sensor module senses a direction of the light, and

wherein the processor is configured to:

apply a shadow effect to an area of the still image, the area of the image corresponding to an edge of the display, in accordance with the direction of the light.

12. The display device of claim 11 , wherein the light is applied to a plurality of photo-sensors and the sensor module includes a color sensor configured to output information on variation in a quantity of the light over time, and

wherein the processor is configured to:

determine the direction of the light by using the information on the variation in the quantity of the light over time.

13. A display method by a display device, the display method comprising:

determining that a mode related to the display device has been switched to a second mode from either a first mode of outputting a moving picture or from a device off state, depending on a user input; and

in the second mode,

when a user is not detected, turning off a display; and

when the user is detected, sensing a color temperature of light incident from an outside of the display device, comparing a color temperature of a still image to the color temperature of the light, adjusting the color temperature of the still image based on the comparison of the color temperature of the still image to the color temperature of the light, and outputting the still image having the adjusted color temperature to the display,

wherein the method further comprises:

identifying a background object behind a rear surface of the display device, and

adjusting a color temperature of the still image based on a color temperature of the background object.

14. The display method of claim 13 , wherein the adjusting of the color temperature of the still image includes:

adjusting color temperatures of whole pixels of the still image by using a specified change ratio.

15. The display method of claim 14 , wherein the adjusting of the color temperature of the still image further includes:

adjusting color temperatures of some pixels among the whole pixels by using a first change ratio; and

adjusting color temperatures of other pixels among the whole pixels by using a second change ratio.

16. The display method of claim 13 , further comprising:

sensing illuminance of the light; and

adjusting a brightness of the still image to correspond to the illuminance of the light.

17. The display method of claim 13 , further comprising:

sensing illuminance of the light;

decreasing a brightness of a first area of the still image, the first area having less than a first brightness, when the illuminance of the light is less than a first threshold value; and

increasing a brightness of a second area of the still image, the second area having less than a second brightness, when the illuminance of the light is equal to or more than the first threshold value.

18. The display method of claim 13 , further comprising:

sensing illuminance of the light;

increasing sharpness of a first area of the still image, the first area having less than a first brightness, when the illuminance of the light is less than a first threshold value; and

decreasing sharpness of a second area of the still image, the second area having at least a second brightness, when the illuminance of the light is equal to or greater than the first threshold value.

19. The display method of claim 13 , further comprising:

sensing a direction of the light incident from the outside; and

applying a shadow effect to an area of the still image, the area corresponding to an edge of the display, in accordance with the direction of the light.