1. An image processing apparatus that converts interlace image data into progressive image data, the image processing apparatus comprising: a detecting unit configured to detect an amount of a pixel motion between a plurality of field images included in the interlace image data; a determination unit configured to determine a pixel region having a large motion by comparing the amount of each pixel motion detected by the detecting unit to a predetermined threshold value; a conversion unit configured to convert the interlace image data into the progressive image data; and an image processing unit configured to combine a predetermined pattern with the pixel region that is included in the progressive image converted by the conversion unit and determined by the determination unit to have the large motion.