1. An image display device, comprising; a display unit that displays an image; a scene change detection unit that detects a change observed in a scene of the image and calculates at least one parameter based on the change observed, the at least one parameter including: a first parameter determined by a difference of: a square of a frequency value of a first frame, and a product of a frequency value of a frame subsequent to the first frame and the frequency value of the first frame, and a second parameter determined by a difference of: a square of a frequency value of a second frame, and a product of a frequency value of a frame preceding the second frame and the frequency value of the second frame; a scene change determination unit that determines a scene change level of the image based on a comparison between the at least one parameter calculated by the scene change detection unit and more than one threshold value, the more than one threshold value including; a first threshold value, and a second threshold value, the first threshold being greater than the second threshold, the scene change level determined to be zero in a case where both the first parameter and the second parameter are less than the second threshold, the scene change level determined to be large with respect to a boundary level in a case where both the first parameter and the second parameter are greater than the first threshold, and the scene change level determined to be small with respect to the boundary level in all other cases; and a brightness enhancement unit that subjects an image signal of the image to a brightness enhancement process in which, based on a determination result of the scene change determination unit, a brightness enhancement amount is set to 0 in a case where the scene change level is large, set to a first value in a case where the scene change level is zero, and set to a second value which is smaller than the first value in a case where the scene change level is small.