To interpolate a frame between the current frame and a first delayed frame preceding the current frame, an image processing device generates test interpolation data for the first delayed frame from data in point-symmetric positions in the current frame and in a second delayed frame preceding the first delayed frame. Motion vectors pointing from the first delayed frame to the current frame are found by evaluating different test interpolation data against the actual data of the first delayed frame. These motion vectors are converted to pairs of motion vectors pointing from the first delayed frame and the current frame to the interpolated frame, and these pairs of motion vectors are used to generate accurate data for the interpolated frame from the data of the first delayed frame and the current frame.