An image processing apparatus is provided. The image processing apparatus comprises a converting module, a sampling module, a processing module, a storage module, an output module and a display module. The converting module is used for converting an input image to image data. The sampling module is coupled to the converting module for sampling the image data and generating sampling data. The processing module is coupled to the sampling module for processing the sampling data according a preset process and generating processing data. The storage module is coupled to the processing module for storing the processing data. The output module is coupled to the storage module for retrieving the processing data stored in the storage module and generating an image signal. The display module is coupled to the output module for displaying the image signal.