So far, we have discussed purely spatial filtering methods for image and video frame deinterlacing. The spatial approach however does not take into account the temporal continuity of video frames that led to the idea of interlacing to begin with. A different approach that takes into account the differences and similarities between consecutive frames so that missing lines are filled, is called inter-frame filtering. Methods based on this approach rely on blending rows from consecutive frames to construct the deinterlaced version of a frame. In this section, we will discuss two alternative inter-frame methods.
The first inter-frame method used for deinterlacing is field merging. This method is pretty simple and relies on substitution of the missing odd rows of a frame with the odd rows of the next one and consequent substitution of the even rows of the next frame with the even rows of its previous one.
This...