1. An imaging apparatus comprising: a solid-state imaging device including: a plurality of pixels which are arranged and formed in a two-dimensional array in a semiconductor substrate; a plurality of color filters of a first color which are arranged and stacked in accordance with a predetermined rule on a first pixel group that includes one of odd rows and even rows of the pixels; and a plurality of color filters of a second color which are arranged and stacked in accordance with a predetermined rule on a second pixel group that includes the other one of the odd rows and the even rows, the color filters of the second color being different in spectral sensitivity from the plurality of color filters of the first color; and an image process section which obtains a level difference between captured image signals of the pixels of the first pixel group and captured image signals of the pixels of the second pixel group, the level difference being due to a spectral sensitivity difference between the plurality of color filters including the first color and the plurality of color filters including the second color, and which combines a first captured image that is obtained from the first pixel group by correcting the level difference, with a second captured image that is obtained from the second pixel group, wherein the image process section obtains the level difference from a first mean value which is a mean value of the captured image signals of a predetermined number of pixels that are in a periphery of a pixel that is a correction subject, and that belong to the first pixel group, and a second mean value which is a mean value of the captured image signals of a predetermined number of pixels that are in a periphery of the pixel that is the correction subject, and that belong to the second pixel group, and corrects the level difference, and the image process section determines whether an image of an edge portion indicating a contour portion of an object is contained in the first and second captured images or not, and obtains the first mean value and the second mean value while excluding the edge portion.