IMAGE DISPLAY APPARATUS, METHOD OF DRIVING IMAGE DISPLAY APPARATUS, GRAYSCALE CONVERSION PROGRAM, AND GRAYSCALE CONVERSION APPARATUS

An image display apparatus includes: a grayscale conversion device configured to perform grayscale conversion processing on input data to output data; and a display device configured to operate in accordance with the output data to display an image by pixels arranged in a two-dimensional matrix state, wherein the grayscale conversion device is configured to perform first error diffusion processing for converting N0-grayscale input data into N1-grayscale data (2<N1<N0), to perform second error diffusion processing for converting data having a predetermined grayscale or less into lower grayscale data having N2 grayscales (1<N2<N1), to perform third error diffusion processing for converting data having the predetermined grayscale or more into higher grayscale data having N3 grayscales (1<N3<N1), and to combine the lower grayscale data and the higher grayscale data to generate N4-grayscale output data (1<N4<N1).