1. A method for refining quality of an input image, the method comprising: obtaining information regarding at least one of brightness and colors of a plurality of pixels constituting the input image; determining a weight with respect to at least one pixel of the input image based on the obtained information, the weight indicating a probability value that the at least one pixel is included in one of a texture region and a flat region; and performing at least one low pass filtering and contrast enhancement (CE) with respect to the at least one pixel based on the determined weight, wherein the determining the weight based on the obtained information comprises: determining respective weights for the plurality of pixels constituting the input image based on the obtained information; classifying the respective weights into at least one group based on information regarding the colors of the plurality of pixels; and performing average processing on weights included in the at least one group.