A transparent display apparatus, comprising: a transparent display panel including a plurality of pixels configured to display an image and a plurality of see-through portions disposed adjacent to the plurality of pixels; at least one optical sensor configured to measure characteristics of light incident into a back surface of the transparent display panel; a light control unit (1430, 1450) configured to control an amount of light that passes through the plurality of see-through portions, the light being incident into the back surface of the transparent display panel; and a controller configured to: compare the measured characteristics of the incident light with the characteristics of an image to be displayed by the plurality of pixels; adjust a transmittance of the light control unit (1430, 1450) and the image of the transparent display panel based on the compared characteristics of the measured incident light, wherein the characteristics of the measured incident light are colors of external light incident into the back surface of the transparent display panel; perform an image processing of the image to be displayed by the plurality of pixels with: decreasing brightness of the plurality of pixels whose color corresponds to a color of the measured incident light when at least a value of the color of the measured incident light is equal to or higher than a first predetermined threshold value; and comparing the color values of the measured incident light with a second predetermined threshold value and not emitting light by the plurality of pixels whose color corresponds to a color of the measured incident light when it is determined by the comparing step that the color value of the measured incident light is higher than a color value of the image of said plurality of pixels. a transparent display panel including a plurality of pixels configured to display an image and a plurality of see-through portions disposed adjacent to the plurality of pixels; at least one optical sensor configured to measure characteristics of light incident into a back surface of the transparent display panel; a light control unit (1430, 1450) configured to control an amount of light that passes through the plurality of see-through portions, the light being incident into the back surface of the transparent display panel; and a controller configured to: compare the measured characteristics of the incident light with the characteristics of an image to be displayed by the plurality of pixels; adjust a transmittance of the light control unit (1430, 1450) and the image of the transparent display panel based on the compared characteristics of the measured incident light, wherein the characteristics of the measured incident light are colors of external light incident into the back surface of the transparent display panel; perform an image processing of the image to be displayed by the plurality of pixels with: decreasing brightness of the plurality of pixels whose color corresponds to a color of the measured incident light when at least a value of the color of the measured incident light is equal to or higher than a first predetermined threshold value; and comparing the color values of the measured incident light with a second predetermined threshold value and not emitting light by the plurality of pixels whose color corresponds to a color of the measured incident light when it is determined by the comparing step that the color value of the measured incident light is higher than a color value of the image of said plurality of pixels. compare the measured characteristics of the incident light with the characteristics of an image to be displayed by the plurality of pixels; adjust a transmittance of the light control unit (1430, 1450) and the image of the transparent display panel based on the compared characteristics of the measured incident light, wherein the characteristics of the measured incident light are colors of external light incident into the back surface of the transparent display panel; perform an image processing of the image to be displayed by the plurality of pixels with: decreasing brightness of the plurality of pixels whose color corresponds to a color of the measured incident light when at least a value of the color of the measured incident light is equal to or higher than a first predetermined threshold value; and comparing the color values of the measured incident light with a second predetermined threshold value and not emitting light by the plurality of pixels whose color corresponds to a color of the measured incident light when it is determined by the comparing step that the color value of the measured incident light is higher than a color value of the image of said plurality of pixels. decreasing brightness of the plurality of pixels whose color corresponds to a color of the measured incident light when at least a value of the color of the measured incident light is equal to or higher than a first predetermined threshold value; and comparing the color values of the measured incident light with a second predetermined threshold value and not emitting light by the plurality of pixels whose color corresponds to a color of the measured incident light when it is determined by the comparing step that the color value of the measured incident light is higher than a color value of the image of said plurality of pixels.