1. A de-interlacing method of converting an interlaced format into a progressive format comprising: performing low pass filtering on respective predetermined pixels of a current frame and a previous frame; comparing a threshold value to a difference value between the respective filtered pixels in a current field to be subjected to de-interlacing in one of the current and previous frames and corresponding respective filtered pixels in preceding and succeeding fields to the current field and in the current and previous frames; determining motion index values of the respective pixels in the current and previous frames based upon the comparing; determining a motion mode of a pixel subject to the de-interlacing in the current field based upon the determined motion index values of temporally and spatially adjacent pixels to the current field pixel, in the preceding and succeeding fields to the current field and in the current and previous frames; and selectively performing spatial interpolation and temporal interpolation on the current field pixel according to the determined pixel motion mode.