1. An image processing device comprising: a processor; and a memory which stores a plurality of instructions, which when executed by the processor, cause the processor to execute, acquiring an image that includes a marker that includes a plurality of first color regions and a plurality of second color regions, of which a color is different from a color of the first color regions, the plurality of first color regions being opposed to each other and the plurality of second color regions being opposed to each other; extracting the first color regions or the second color regions from the image; reducing the first color regions or the second color regions until a first degree of similarity between a shape of the first color regions or the second color regions, the first color regions or the second color regions being extracted, and a predetermined elliptical shape satisfies a predetermined first threshold value; calculating a second degree of similarity between the first color regions or the second color regions, the first color regions or the second color regions satisfying the first threshold value, and a predetermined butterfly shape; and recognizing the first color regions or the second color regions of which the second degree of similarity does not satisfy a predetermined second threshold value, as the first color regions or the second color regions that constitute the marker, wherein an intersecting point between a first line segment that couples predetermined positions of the plurality of first color regions that do not satisfy the second threshold value and are opposed to each other and a second line segment that couples predetermined positions of the plurality of second color regions that do not satisfy the second threshold value and are opposed to each other, is recognized as a feature point of the marker, in the recognizing.