Image adjustment device and image adjustment method suitable for light-emitting diode display

An image adjustment device suitable for a light-emitting diode display, comprising:

• a grayscale conversion circuit, configured to generate a grayscale value of a target pixel by weighted averaging a plurality of input sub-pixel data of the target pixel;
• a grayscale difference value calculation circuit, configured to:
• calculate an average of grayscale values of all pixels comprising the target pixel in a first window to generate a foreground value of the target pixel;
• calculate an average of grayscale values of all pixels comprising the target pixel in a second window to generate a background value of the target pixel, wherein a scope of the second window is larger than a scope of the first window and covers the scope of the first window;
• and
• according to the foreground value of the target pixel and the background value of the target pixel, obtain a just-noticeable difference value in a look-up table recording a plurality of just-noticeable difference values as a grayscale difference value, wherein the grayscale difference value indicates a grayscale threshold value at which a change in the grayscale value of the target pixel becomes noticeable;
• an output grayscale calculation circuit, configured to generate an adjusted grayscale value of the target pixel according to the grayscale difference value;
• and
• a sub-pixel data adjustment circuit, configured to generate a plurality of output sub-pixel data according to the plurality of input sub-pixel data of the target pixel and the adjusted grayscale value.