Abstract: A method for determining which of similar video fields may be excised to enhance video signal compression evaluates parameters of four successive fields denoted 0, 1, 2, and 3. Accumulated differences d(0, 2) and d(1,3) of corresponding pixels in successive frames are generated. In addition a determination is made whether fields 1 and 2 exhibit interlace characteristics. If they do not exhibit interlaced characteristics, a comparison is made of d(0, 2) and d(1, 3). If d(0, 2) is less than d(1, 3) by a predetermined amount, field 2 is excised from the signal stream and a code is generated to condition a receiver to display two of the remaining four fields in a three field interval. Subsequently the latter two fields of the set of 0, 1, 2 and 3 fields, and the next two occurring fields are similarly analyzed.

Abstract: A method for determining which of pairs of successive video fields have interlace scan characteristics includes generating accumulated differences FD of pixels in successive lines of respective fields of successive pairs of fields and generating accumulated differences FR of pixels in successive lines of interlaced said pairs of fields. The accumulated differences FD and FR are compared and pairs of said fields are classified as interlaced if the ratio of accumulated differences FR/FD is greater than a predetermined threshold value.