1. An image processing device comprising: an image acquisition unit configured to acquire a mosaic image including pixels of a plurality of colors; a storage unit configured to store a color mix ratio caused from peripheral pixels adjacent to an object pixel for mixed color correction in the mosaic image, the storage unit storing the color mix ratio corresponding to a combination of a first parameter indicating azimuth directions of the peripheral pixels and a second parameter indicating colors of the peripheral pixels; and a mixed color correction unit configured to eliminate, from a color signal of each of pixels in the mosaic image acquired by the image acquisition unit, mixed color components that are caused from the peripheral pixels, and are included in the color signal, wherein the mixed color correction unit includes a parameter acquisition unit configured to acquire the first parameter and the second parameter of each of the peripheral pixels corresponding to any object pixel based on a position of the object pixel in the mosaic image, and reads out the corresponding color mix ratio from the storage unit based on the acquired first parameter and the acquired second parameter, and wherein when the mixed color correction is applied to any object pixel, the mixed color correction unit acquires a color signal of the object pixel and color signals of peripheral pixels of the object pixel, reads out the corresponding color mix ratio from the storage unit based on azimuth directions and colors of the peripheral pixels, and eliminates mixed color components included in the object pixel based on the color signal of the object pixel for the mixed color correction and the color signals of the peripheral pixels adjacent to the object pixel, and the read-out color mix ratio of each of the peripheral pixels, wherein the mosaic image is outputted from an imaging element having an element structure in which an amplifier is shared for each predetermined pixel group, when a third parameter is positional information showing the position of the object pixel for the mixed color correction in the pixel group sharing the amplifier, the storage unit stores a color mix ratio corresponding to a combination of the first parameter, the second parameter, and the third parameter, the parameter acquisition unit acquires the first parameter, the second parameter, and the third parameter for each of the peripheral pixels based on the position of any object pixel in the mosaic image, and the mixed color correction unit reads out the corresponding color mix ratio from the storage unit for each of the peripheral pixels based on the acquired first parameter, the acquired second parameter, and the acquired third parameter.