1. An image processing apparatus comprising: an input unit for inputting original image data of an image composed of a plurality of pixels, each having a color data; a non-transitory storage unit for storing a first condition, wherein the first condition is met if a pixel is in a prescribed absolute position in the original image data and a second condition, wherein the second condition is met if a pixel is in a prescribed position relative to a target pixel in the original image data; a selector for selecting a target pixel included in the image data irrespective of the first condition and also selecting at least one related pixel which satisfies the stored first condition and the stored second condition relative to the selected target pixel, such that the target pixel and the at least one related pixel are selected based on different conditions; a binarization unit for binarizing the target pixel based upon a color data of the target pixel and that of the at least one related pixel to the target pixel in the image to generate a binarized value; and a determination unit for determining whether or not the image has a specified pattern, based upon binarized values obtained by said binarization unit.