1. An image processing device comprising: a depth acquisition unit for acquiring a depth of a subject in correlation with a pixel in a captured image of the subject; and a smoothing processing unit for designating a pixel in a region outside a predetermined region in the image as a target pixel, and for performing a smoothing process of the target pixel to simulate panning of the subject, wherein the amount of smoothing of the target pixel is according to the depth corresponding to the target pixel for a pixel value of the target pixel in a predetermined direction.