1. An image processing device comprising: a frequency component resolution section that resolves an image obtained from an image sensor having a light-shielded pixel area and a non-light-shielded pixel area into a low frequency component, a vertical direction high frequency component, a horizontal direction high frequency component, and a diagonal direction high frequency component by performing a wavelet transform on the image; a noise amount calculation section that calculates a noise amount for the vertical direction high frequency component and the horizontal direction high frequency component in the light-shielded pixel area; a noise suppression section that suppresses a noise component for the vertical direction high frequency component and the horizontal direction high frequency component in the non-light-shielded pixel area according to the noise amount calculated by the noise amount calculation section; and a frequency component synthesis section that synthesizes the vertical direction high frequency component and the horizontal direction high frequency component in the non-light-shielded pixel area of which the noise component is suppressed by the noise suppression section, and the low frequency component and the diagonal direction high frequency component in the non-light-shielded pixel area of which a noise component is not suppressed by the noise suppression section to thereby form an image.