A signal processing apparatus and a signal processing method are disclosed. The signal processing apparatus includes a correction block and a division correction block. The correction block receives grayscale data comprising achromatic color grayscale data or chromatic color grayscale data to create corrected grayscale data. The division correction block receives the corrected grayscale data to create first division grayscale data and second division grayscale data having a grayscale value less than or equal to a grayscale value of the first division grayscale data. The correction block includes a first correction block and a second correction block. The first correction block receives the grayscale data and includes a one-dimensional lookup table to create corrected create achromatic color grayscale data. The second correction block includes a three-dimensional lookup table and an interpolator.