To accurately extract a text described in a document without being influenced by the background design of the document.SOLUTION: The recognition device includes a color removal unit, a uniformizing unit, and a correction unit. When a luminance value of a pixel in an acquired image data is equal to or greater than a first threshold value and a chroma value of the pixel is equal to or greater than a second threshold value, the color removal unit sets the chroma value of the pixel to a first chroma value equal to or less than the second threshold value. When the luminance value of the pixel is equal to or greater than a third threshold value, the uniformizing unit replaces the pixel with a background pixel. When an absolute value of a difference between the luminance of a pixel among pixels in the image data, which is located between the background pixel and an information transmission pixel, and the luminance of the information transmission pixel is equal to or greater than a fourth threshold value, the correction unit replaces the pixel located between the background pixel and the information transmission pixel with the background pixel.SELECTED DRAWING: Figure 1
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