1. An image processing apparatus, comprising: a false contour detection circuit, configured to detect an image input signal, wherein the false contour detection circuit comprises a plurality of detection modules and a determination module, the detection modules respectively detect different features of the image input signal and correspondingly output a plurality of feature coefficients, and the determination module is coupled to the detection modules to determine a false contour coefficient by using the feature coefficients; and a false contour reduction circuit, coupled to the determination module of the false contour detection circuit to receive the false contour coefficient, and configured to perform false contour reduction on the image input signal according to the false contour coefficient, so as to correspondingly output an image output signal, wherein the detection modules comprise: a low-frequency area detection unit, coupled to the determination module, and configured to detect whether a current pixel belongs to a low-frequency area and correspondingly output a third feature coefficient among the feature coefficients to the determination module.