An image processing apparatus that is configured to read color images, the apparatus comprising: a color separating unit configured to separate a color image into a plurality of color components to generate images of respective colors; a pixel specifying unit configured to specify a target pixel in the color image; a periodicity determining unit configured to determine, for each of the images of the respective colors, whether an image region including the target pixel whose pixel value is to be interpolated is a periodic region in which pixel values vary periodically; a first pixel value generating unit configured to generate pixel values of the respective colors of a pixel using a first interpolation method when the periodicity determining unit determines that the image region is a periodic region; a second pixel value generating unit configured to generate pixel values of the respective colors of a pixel using a second interpolation method different from the first interpolation method when the periodicity determining unit determines that the image region is not a periodic region; a control unit configured to determine, based on the determination result obtained by the periodicity determining unit, which one of the first and second pixel value generating units is to be used for generating pixel values of the respective colors of the target pixel; and a pixel value combining unit configured to combine candidate pixel values which are the pixel values of the respective colors of the target pixel and which are generated by the first or second pixel value generating unit determined by the control unit to calculate a combined pixel value for interpolating the target pixel, wherein the pixel value combining unit is configured to determine whether the candidate pixel value is suitable for combination based on the interpolation method that has been used for generating the candidate pixel value and performs the combination using only the candidate pixel value which is determined to be suitable for the combination, wherein a determination criterion is set such that the candidate pixel values generated by the first pixel value generating unit are employed preferentially and wherein the pixel values generated by the first pixel value generating unit are generated by acquiring pixel values of the images of the respective colors at a position corresponding to interpolation target pixels in a template. a color separating unit configured to separate a color image into a plurality of color components to generate images of respective colors; a pixel specifying unit configured to specify a target pixel in the color image; a periodicity determining unit configured to determine, for each of the images of the respective colors, whether an image region including the target pixel whose pixel value is to be interpolated is a periodic region in which pixel values vary periodically; a first pixel value generating unit configured to generate pixel values of the respective colors of a pixel using a first interpolation method when the periodicity determining unit determines that the image region is a periodic region; a second pixel value generating unit configured to generate pixel values of the respective colors of a pixel using a second interpolation method different from the first interpolation method when the periodicity determining unit determines that the image region is not a periodic region; a control unit configured to determine, based on the determination result obtained by the periodicity determining unit, which one of the first and second pixel value generating units is to be used for generating pixel values of the respective colors of the target pixel; and a pixel value combining unit configured to combine candidate pixel values which are the pixel values of the respective colors of the target pixel and which are generated by the first or second pixel value generating unit determined by the control unit to calculate a combined pixel value for interpolating the target pixel, wherein the pixel value combining unit is configured to determine whether the candidate pixel value is suitable for combination based on the interpolation method that has been used for generating the candidate pixel value and performs the combination using only the candidate pixel value which is determined to be suitable for the combination, wherein a determination criterion is set such that the candidate pixel values generated by the first pixel value generating unit are employed preferentially and wherein the pixel values generated by the first pixel value generating unit are generated by acquiring pixel values of the images of the respective colors at a position corresponding to interpolation target pixels in a template.