1. An image processing apparatus comprising: an image processing section configured to include a defect detection unit and a defect correction unit, wherein the defect detection unit calculates, based on one of a plurality of resolution modes, a gradient direction with respect to a target pixel found within a pixel section, wherein the pixel section is configured to include a plurality of pixel groups, each of the pixel groups including at least two pixels, and wherein the image processing section including the defect detection unit and the defect correction unit is implemented via at least one processor.