1. An image processing apparatus, comprising: at least one processor connected to a memory, wherein the at least one processor is configured to: extract and translate a plurality of first high-frequency components of an input image to generate a first image; extract a plurality of second high-frequency components of the input image to generate a second image; generate a plurality of detail gains respectively associated with a plurality of input pixels in the input image according to a conversion table and pixel values of the input pixels, wherein the detail gain of a first input pixel of the input pixels is corresponding to a pixel value sum of pixel values of the first input pixel and a plurality of neighboring pixels separate from the first input pixel by at least one pixel; and calculate a weighted superposition of the first image and the second image and to generate a high-frequency component of an output image according to the detail gains and the weighted superposition.