Method of and arrangement for reducing the number of lines of a picture signal, as well as an arrangement for increasing the number of lines of a picture signal

Claim 3

A method as claimed in Claim 1, characterized by a vertical filtering having a transfer function for odd and even fields including at least factors equal to (3, 1, 0) and (0, 3, 1), or (1, 3, 0) and (0, 1, 3), respectively.

Claim 4

A method as claimed in Claim 2, characterized in that the vertical filtering comprises a factor having a gain for signals having frequencies around half a sampling frequency with which the picture signal is sampled.

Claim 5

An arrangement for obtaining from an input picture signal assembled from input lines and having a first number of lines, an output picture signal which is field-sequentially assembled from output lines and has a lower number of lines than the first number of lines, the arrangement comprising means for obtaining first samples of pairs of neighboring samples on the output lines of even and odd fields by means of weighted averging samples from first and second even and odd input lines,respectively, of the input picture signal, characterized in that said means are further arranged for obtaining second samples of the pairs of neighboring samples on the output lines of odd and even fields by means of weighted averaging of samples from at least the second and third odd and even input lines, respectively, centres of gravity of the weighted averaging for obtaining the first samples on the output lines of odd fields being located at 1/4 of the first odd input lines and at 3/4 of the second odd input lines, centres of gravity of the weighted averaging for obtaining the second samples on the output lines of odd fields being located at 1/4 of the second odd input lines and at 3/4 of the third odd input lines, centres of gravity of the weighted averaging for obtaining the first samples on the output lines of even fields being located at 3/4 of the first input lines and at 1/4 of the second even input lines and centres of gravity of the weighted averaging for obtaining the second samples on the output lines of even fields being located at 3/4 of the second even input lines and at 1/4 of the third even input lines.

Claim 6

An arrangement for obtaining from an input picture signal assembled from input lines and having a first number of lines, an output picture signal which is field-sequentially assembled from output lines and has a lower number of lines than the first number of lines, the arrangement comprising means for obtaining first samples of pairs of neighboring samples on the output lines of even and odd fields by means of weighted averging samples from first and second even and odd input lines,respectively, of the input picture signal, characterized in that said means are further arranged for obtaining second samples of the pairs of neighboring samples on the output lines of odd and even fields by means of weighted averaging of samples from at least the second and third odd and even input lines, respectively, centres of gravity of the weighted averaging for obtaining the first samples on the output lines of odd fields being located at 1/4 of the first odd input lines and at 3/4 of the second odd input lines, centres of gravity of the weighted averaging for obtaining the second samples on the output lines of odd fields being located at 1/4 of the second odd input lines and at 3/4 of the third odd input lines, centres of gravity of the weighted averaging for obtaining the first samples on the output lines of even fields being located at 3/4 of the first input lines and at 1/4 of the second even input lines and centres of gravity of the weighted averaging for obtaining the second samples on the output lines of even fields being located at 3/4 of the second even input lines and at 1/4 of the third even input lines.

Claim 7

An arrangement as claimed in Claim 4, characterized in that said means include a vertical filter circuit having a transfer function for odd and even fields comprising at least factors equal to (3, 1, 0) and (0, 3, 1), or (1, 3, 0) and (0, 1, 3) respectively.

Claim 8

An arrangement as claimed in Claim 5, characterized in that the transfer function of the vertical filter circuit includes a factor having a gain for signals having frequencies around half a sampling frequency with which the picture signal is sampled.

Claim 9

An arrangement for obtaining from an input picture signal which is assembled field-sequentially and has a first number of lines, an output picture signal assembled from output lines and having a higher number of lines than the first number of lines, characterized by a vertical filter circuit for obtaining output lines by means of weighted averaging of consecutive input lines, centres of gravity of the weighted averaging in odd and even fields being located at 3/4 from input lines which are located above and below the output lines, respectively, and at 1/4 of input lines located below and above the output lines, respectively.

Claim 10

An arrangement for obtaining from an input picture signal which is assembled field-sequentially and has a first number of lines, an output picture signal assembled from output lines and having a higher number of lines than the first number of lines, characterized by a vertical filter circuit for obtaining output lines by means of weighted averaging of consecutive input lines, centres of gravity of the weighted averaging in odd and even fields being located at 3/4 from input lines which are located above and below the output lines, respectively, and at 1/4 of input lines located below and above the output lines, respectively.

Claim 11

An arrangement as claimed in Claim 7, characterized in that a transfer function of the vertical filter circuit for odd and even fields includes at least a factor equal to (1, 3) and (3, 1), respectively.