[li] Patent Number: 4,941,042 [45] Date of Patent: Jul. 10,1990
[54] TELEVISION TRANSMISSION SYSTEM INCLUDING A HYBRID ENCODING CIRCUIT
[75] Inventor: Jean B. O. S. Martens, Eindhoven, Netherlands
[73] Assignee: U. S. Philips Corporation, New York, N.Y.
[21] Appl. No.: 339,550
[22] Filed: Apr. 17,1989
[30] Foreign Application Priority Data
May 3, 1988 [NL] Netherlands 8801155
[51] Int. CI.* H04N 7/133; H04N 7/137
[52] U.S. CI 358/133; 358/135;
358/136
[58] Field of Search 358/133, 135, 136, 138
[56] References Cited
U.S. PATENT DOCUMENTS
4,704,628 11/1987 Chen 358/136
4,825,285 4/1989 Speidel 358/135
4,827,338 5/1989 Gerard ;358/136
4,849,812 7/1989 Borgers 358/133
Primary Examiner—Howard W. Britton
Attorney, Agent, or Firm—Michael E. Marion
[57] ABSTRACT
In a television transmission system each picture is subjected to a number of picture transforms for limiting the bit rate. In each picture transform the picture is partitioned into sub-pictures of a given size. The sub-picture size is different for the different picture transforms. Each sub-picture is converted into a limited number of predetermined coefficients by use of a sub-picture transform. This number is related to the sub-picture size. With the matrix of coefficients thus obtained for each picture an approximation of the original picture is made by use of an inverse transform and this approximation is subjected to one of the said forward transforms. The matrix of coefficients now obtained is subtracted from this matrix of coefficients which is obtained by subjecting the original picture to the same forward transform.
4 Claims, 5 Drawing Sheets
