Television – Format conversion
Reexamination Certificate
2000-02-23
2001-07-17
Eisenzopf, Reinhard J. (Department: 2614)
Television
Format conversion
C348S450000, C348S428100
Reexamination Certificate
active
06262771
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method of converting a picture signal, an apparatus for converting a picture signal, and an apparatus for recording and reproducing a picture signal. In addition, this invention relates to a method of encoding a picture signal, a method of decoding a picture signal, an apparatus for encoding a picture signal, and an apparatus for decoding a picture signal.
2. Description of the Related Art
Some digital VTR's (video tape recorders) handle digital component video signals (digital Y, Cr, and Cb signals) which are derived from analog component video signals (analog Y, Cr, and Cb signals) through an analog-to-digital conversion process. Here, the Y signals mean luminance signals. In addition, the Cr signals mean R-Y signals (first color difference signals) while the Cb signals mean B-Y signals (second color difference signals). Specifically, during the analog-to-digital conversion process, the analog Y, Cr, and Cb signals are sampled at given sampling frequencies respectively, and then the samples of the analog Y, Cr, and Cb signals are digitized.
There are the DV standards (the DVC standards) for home-use digital VTR's. Here, “DV” is short for digital video, and “DVC” is short for a digital video cassette. According to the DV standards, the ratio among the sampling frequencies for the respective analog Y, Cr, and Cb signals is “4:1:1”.
Digital picture signals for DVD's (digital versatile discs) and CS digital broadcasting conform to the MPEG2 (Moving Picture Experts Group 2) standards. According to the MPEG2 standards, the ratio among the sampling frequencies for respective analog Y, Cr, and Cb signals is “4:2:0 (4:0:2)”. In an example of the 4:2:0 signal format, horizontal scanning lines related to a sampling frequency ratio of “4:2:0” alternate with horizontal scanning lines related to a sampling frequency ratio of “4:2:0”. Such a signal format is denoted by “4:2:0” for convenience.
Any simple methods and apparatuses for converting 4:1:1 picture signals into 4:2:0 picture signals are unknown. In addition, any simple methods and apparatuses for converting 4:2:0 picture signals into 4:1:1 picture signals are unknown. Japanese published unexamined patent application 8-46519 discloses a specification conversion circuit which operates to convert a 4:2:2 picture signal into a 4:2:0 picture signal.
SUMMARY OF THE INVENTION
It is a first object of this invention to provide a method of converting a 4:1:1 picture signal into a 4:2:0 picture signal.
It is a second object of this invention to provide a method of converting a 4:2:0 picture signal into a 4:1:1 picture signal.
It is a third object of this invention to provide an apparatus for converting a 4:1:1 picture signal into a 4:2:0 picture signal.
It is a fourth object of this invention to provide an apparatus for converting a 4:2:0 picture signal into a 4:1:1 picture signal.
It is a fifth object of this invention to provide a picture-signal recording and reproducing apparatus in which conversion between a 4:1:1 picture signal and a 4:2:0 picture signal is implemented.
It is a sixth object of this invention to provide a method of encoding or decoding a 4:1:1 picture signal into a 4:2:0 picture signal.
It is a seventh object of this invention to provide a method of encoding or decoding a 4:2:0 picture signal into a 4:1:1 picture signal.
It is an eighth object of this invention to provide an apparatus for encoding or decoding a 4:1:1 picture signal into a 4:2:0 picture signal.
It is a ninth object of this invention to provide an apparatus for encoding or decoding a 4:2:0 picture signal into a 4:1:1 picture signal.
A first aspect of this invention provides a method of converting a picture signal including a luminance signal and a color signal, wherein a first predetermined number of sample points of the luminance signal are located on every actual scanning line, and a second predetermined number of sample points of the color signal are located on every actual scanning line, and wherein the second predetermined number is equal to the first predetermined number multiplied by “1
”, where “n” denotes a predetermined integer equal to or greater than 2. The method comprises the steps of setting virtual scanning lines which correspond to respective pairs each having two successive actual scanning lines; and moving sample points of the color signal from each pair of two successive actual scanning lines to a corresponding virtual scanning line while rearranging the sample points on the corresponding virtual scanning line to convert the picture signal; wherein a total number of sample points of the color signal per virtual scanning line is equal to the first predetermined number multiplied by “2
”, and a portion of the color signal whose sample points are located on a virtual scanning line corresponds to a portion of the luminance signal which relates to the corresponding pair of two successive actual scanning lines.
A second aspect of this invention is based on the first aspect thereof, and provides a method wherein the moving and rearranging step comprises making nearest before-conversion sample points into neighboring after-conversion sample points on a virtual scanning line.
A third aspect of this invention provides a method of converting a picture signal including a luminance signal and a color signal, wherein virtual scanning lines are set for respective pairs each having two successive actual scanning lines, wherein a first predetermined number of sample points of the luminance signal are located on every actual scanning line, and a second predetermined number of sample points of the color signal are located on every virtual scanning line, wherein the second predetermined number is equal to the first predetermined number multiplied by “2
”, where “n” denotes a predetermined integer equal to or greater than 2. The method comprises the steps of separating sample points of the color signal on every virtual scanning line into first and second groups assigned to respective two successive actual scanning lines in a corresponding pair respectively; and moving the sample points in the first group to first one of the two successive actual scanning lines while moving the sample points in the second group to second one of the two successive actual scanning lines to convert the picture signal; wherein a total number of the sample points of the color signal per actual scanning line is equal to the first predetermined number multiplied by “1
”, and a portion of the color signal whose sample points are located on an actual scanning line corresponds to a portion of the luminance signal which relates to the same actual scanning line.
A fourth aspect of this invention provides an apparatus for converting a picture signal including a luminance signal and a color signal, wherein a first predetermined number of sample points of the luminance signal are located on every actual scanning line, and a second predetermined number of sample points of the color signal are located on every actual scanning line, and wherein the second predetermined number is equal to the first predetermined number multiplied by “1
”, where “n” denotes a predetermined integer equal to or greater than 2. The apparatus comprises means for setting virtual scanning lines which correspond to respective pairs each having two successive actual scanning lines; and means for moving sample points of the color signal from each pair of two successive actual scanning lines to a corresponding virtual scanning line while rearranging the sample points on the corresponding virtual scanning line to convert the picture signal; wherein a total number of sample points of the color signal per virtual scanning line is equal to the first predetermined number multiplied by “2
”, and a portion of the color signal whose sample points are located on a virtual scanning line corresponds to a portion of the luminance signal which relates to the corresponding pair of two successive actual scanning lines.
A fifth aspect
Higurashi Seiji
Sugahara Takayuki
Eisenzopf Reinhard J.
Victor Company of Japan Ltd.
Woo Louis
Yenke Brian P.
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