1. A method for enhancing image data, comprising: analyzing image data, and determining a first region which is part of an image of the image data; and enhancing the image data based on values of first and second parameters, the value of the first parameter being determined based on pixel values of the image data which corresponds to the first region, the value of the second parameter being determined based on pixel values of the image data corresponding to a second region which is part of the image and which differs from the first region, wherein the enhancing the image data includes preparing a first target value representing an ideal value for the first parameter, and a second target value representing an ideal value for the second parameter, calculating a weight for the weighted average based on a difference between the value of the first parameter and the value of the second parameter, and enhancing the image data based on the weighted average of a difference between the first target value and the value of the first parameter, and a difference between the second target value and the value of the second parameter, the difference between the first target value and the value of the first parameter and the difference between the second target value and the value of the second parameter being obtained by a subtraction operation.