1. A method for building a recovery model, the recovery model being used to reduce a zipper of image data, said method comprising: producing a plurality of outputted signals from image sensors according to a plurality of brightness, wherein the brightness are not all the same; measuring a plurality of differences according to the outputted signals and a plurality of estimated signals corresponding to the brightness, wherein the plurality of estimated signals vary in magnitude in relation to the brightness intensity; establishing an interference model according to the differences, wherein the interference model is a mathematical model that describes an effect of distortion on a real signal caused by a mixing of outputs from a first image sensor and a second image sensor; producing the recovery model according to the interference model, such that the recovery model is a mathematical inverse of the interference model; and applying the recovery model to the a distorted signal to generate a recovered signal, wherein the recovered signal has reduced zipper of the image data.