To obtain an image without causing any moire due to interference fringes in an image processing method by which image processing is performed by applying multiplex resolution conversion to the image containing a grid image.

In a resolution demultiplexing processing means 32, an image signal S inputted from an image input means 31 and expressing an image containing the grid image is decomposed into the images of multiple resolutions by the method such as Laplacian pyramid. In this case, a filter for applying filtering processing to an original image is constituted of a filter having characteristics for removing the grid image. The emphasis degree of a desired frequency band in the decomposed image is decided based on the signal value of image in lower frequency band and at an emphasizing processing means 22, emphasizing processing is executed to the image. The emphasizing processed image and the other image are restored at a restoring processing means 34 and a processed image signal S' is obtained. The processed image signal S' is reproduced as a visible image in an image output means 35.