1. An electronic document generation system for generating an electronic document based on a scanned image, comprising: a first layer generation unit configured to generate a character image layer that represents a character image in the scanned image by a predetermined number of bits; an edge image generation unit configured to generate an edge image of the character image; a second layer generation unit configured to generate an antialiasing layer that includes a binarized image generated based on the edge image and that is to be superimposed in a semi-transparent state on the character image layer; a file generation unit configured to generate the electronic document that includes the character image layer and the antialiasing layer; and a base color determination unit configured to determine a base color of the character image, wherein the second layer generation unit sets the same color as the base color for the antialiasing layer.