In an image deblurring method, an image processor determines an absolute difference between a pixel value of each pixel in a current image frame and a pixel value of a corresponding pixel in a reference image frame to obtain a total absolute difference corresponding to the current image frame by summing up the absolute differences corresponding respectively the pixels of the current image frame. When the total absolute difference is smaller than a predetermined first threshold value and not smaller than a predetermined third threshold value, the image processor generates an interpolated image frame based on the current and reference image frames using one of unidirectional motion estimation and bidirectional motion estimation.