1. A non-transitory computer-readable medium storing a program causing a computer to execute an image processing method applied to an image sensing device, the image processing method comprising: (a) comparing a frame delta between a reference frame and a first frame with a predetermined threshold value to generate a first comparing result; (b) comparing a frame rate of the image sensing device with a minimum frame rate and/or a maximum frame rate, to generate a second comparing result; and (c) adjusting one of the frame rate and an offset for a correlation window of the image sensing device, according to the first comparing result and the second comparing result.