Patent ID: 7916967

Claim:
An image processing apparatus that reduces distortion in an input image, said apparatus comprising: a masking signal generating unit operable to generate a masking signal for reducing the distortion; and a masking signal adding unit operable to add the masking signal to the input image, wherein said masking signal generating unit includes: a level difference processing unit operable to smooth a level difference between pixel values of pixels in the input image; a difference calculating unit operable to calculate a difference between the input image and an image which has been processed by said level difference processing unit; and a random number setting unit operable to set an amplitude, to create a random number having the set amplitude, and to generate, as the masking signal, a signal based on the created random number, the amplitude decreasing, as the difference approaches a predetermined value; wherein said masking signal generating unit further includes a gradation conversion unit operable to output a converted difference by converting gradation of the difference, such that an absolute value of the converted difference is equal to or less than a first threshold value, and said random number setting unit is operable to set an amplitude, and to create a random number having the set amplitude, the amplitude decreasing, as the converted difference approaches a predetermined value.