Page "Line doubler" Paragraph 2

The most basic and literal way to double lines is to repeat each scanline, though the results of this are generally very crude.

Most line doublers use digital interpolation to recreate the missing lines in an interlaced signal, and the resulting quality depends on the technique used.

Generally a line doubler will only interpolate within a single field, rather than merging information from adjacent fields, to preserve the smoothness of motion, resulting in a frame rate equal to the field rate ( i. e. a 60i signal would be converted to 60p.

) Some line doublers are capable of using the former technique in moving areas and the latter in static areas ( to avoid bob effect ), which improves overall sharpness.

It is worth noting that even if a line doubler employs the merging method it cannot be considered a inverse telecine device if a 60p frame rate but the original 24p is obtained.

From this aspect of view some hyped progressive scan technologies ( including Pioneer's PureCinema Progressive Scan ) bearing a inverse telecine insignia are thus overstated.