Display apparatus including image processor, and image processing method

An image processing method comprising the steps of:

• converting a first color space of image signals to a second color space having first brightness data, first chrominance data, and second chrominance data;
• increasing a value of a low brightness portion of the first brightness data, which is lower than a reference brightness, to generate second brightness data;
• adjusting the second brightness data with respect to the first chrominance data and the second chrominance data such that an image signal converted depending on the second brightness data lie within the first color space to generate third brightness data;
• calculating a blend coefficient depending on an illuminance value of an external environment;
• synthesizing the first brightness data with the third brightness data depending on the blend coefficient to generate fourth brightness data;
• and
• converting the fourth brightness data, the first chrominance data, and the second chrominance data to output image signals that lie within the first color space.

A display apparatus comprising:

• a display panel having a plurality of pixels;
• a gate driver to apply a plurality of gate signals to the plurality of pixels;
• a data driver to apply a plurality of data voltages corresponding to image signals to the pixels;
• and
• a timing controller including an image processor to convert a data format of the image signals, to apply the image signals to the data driver as the image data, and to increase a value of low brightness data of the image signals depending on an illuminance value of an external environment to generate output image signals from the image signals, the image processor comprising:
• a color converter to convert a first color space of the image signals to a second color space having first brightness data, first chrominance data, and second chrominance data;
• a brightness converter to increase a value of a low brightness portion of the first brightness data, which is lower than a reference brightness, to generate second brightness data;
• a color variation limit unit to adjust the second brightness data with respect to the first chrominance data and the second chrominance data such that image data converted depending on the second brightness data lie within the first color space to generate third brightness data;
• a blend coefficient calculator to calculate a blend coefficient depending on an illuminance value of an external environment;
• a synthesizer to synthesize the first brightness data with the third brightness data depending on the blend coefficient to generate fourth brightness data;
• and
• a signal output unit to convert the fourth brightness data, the first chrominance data, and the second chrominance data to the output image signals that lie within the first color space.