1. An interactive display system, comprising: an image provider, providing a display image; and a ranging apparatus, comprising: an image sensor; an imaging lens, configured to image an object on the image sensor to produce an image of the object having a plurality of image parameters onto the image sensor, wherein the image parameters change differently with change of an object distance of the object, and the image sensor converts the image of the object into a signal, wherein the imaging lens has at least one non-axisymmetric lens, the non-axisymmetric lens has at least one non-axisymmetric curved surface, and a profile of the at least one non-axisymmetric curved surface in two different directions is not the same; and a processor, configured to determine whether the object is within a predetermined object distance range according to the signal and different changes of the image parameters with the change of the object distance; wherein the processor determines the change of the object distance according to different change of image parameters in different directions, wherein the image parameters comprise a plurality of image blur metrics in different directions, a modulation transfer function, a concentration of energy distribution of point spread function, or a combination thereof, wherein the image blur metrics in different directions are caused to change differently with change of the object distance; wherein a ratio of axial chromatic aberration of the imaging lens to a focal length of the imaging lens falls within a range of 0.0010 to 0.0100 or a range of −0.0010 to −0.0100, when the axial chromatic aberration being measured is of a 640 nm red light and a 550 nm green light corresponding to the image parameters, and wherein when the processor determines that the object is within the predetermined object distance range, the processor determines that the object touches the display image.