An image processing method includes photographing an object by a camera via a filter, separating image data, which is obtained by photographing by the camera, into a red component, a green component and a blue component, determining a relationship of correspondency between pixels in the red component, the green component and the blue component, with reference to departure of pixel values in the red component, the green component and the blue component from a linear color model in a three-dimensional color space, and finding a depth of each of the pixels in the image data in accordance with positional displacement amounts of the corresponding pixels of the red component, the green component and the blue component. The image processing method further includes processing the image data in accordance with the depth.