The X-ray imaging system of this invention includes: a detecting member which detects a salt and pepper noise region in the reconstructed image based on at least one characteristic value of the moire stripe image not including the object and/or the moire stripe image including the object； a masked-image generating member which generates a masked image for identifying the detected salt and pepper noise region； and an image processing member which masks or trims at least one of the reconstructed image and the moire stripe images with the generated masked image.
