Television – Format conversion – Line doublers type
Reexamination Certificate
2000-05-23
2002-04-23
Lee, Michael (Department: 2714)
Television
Format conversion
Line doublers type
C348S458000
Reexamination Certificate
active
06377307
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a line interpolation apparatus, and relates in particular to a line interpolation apparatus that converts an interlaced video scan signal, such as an NTSC television signal or a PAL television signal, into a progressive video scan signal.
The present invention also relates to a video signal conversion device for performing a video signal conversion to obtain a video signal that has a higher resolution.
2. Description of the Related Art
For conventional use, plasma display devices (PDPs), liquid crystal display devices (LCDs) and electroluminescence display devices (ELs), which can reproduce images at high resolutions, have become popular.
In the process for converting an interlaced video scan signal into a progressive video scan signal, since every other scan signal is an intermittent signal obtained by interlaced scanning performed in the field of an interlaced video scan signal, the intermittent portion should be interpolated by using an interpolated scan signal.
For this interpolated scan signal, a well known, so-called average value interpolation method is used. According to this method, for a static image an inter-field process is performed, and, for example, parallel to the time axis, the average value of pixel signals in adjacent fields along corresponding scan lines is inserted as an interpolated scan signal. For a moving image, an intra-field process is performed, and, for example, the average value of pixel signals along scan lines that are vertically adjacent in the same field is inserted as an interpolated signal.
More specifically, as shown in
FIG. 15
, when interpolated gray level scan signals y
12
to y
56
(designated by &Circlesolid;s) are to be generated based on real scan signals (designated by ∘s) for individual gray level pixels X
1
to X
6
, first, an upper interpolation element (designated by a &Dgr;) and a lower interpolation element (designated by a □) are generated that have gray levels of 1/2 of those of the individual real scan signals. Then, adjacent upper interpolation elements are individually paired with lower interpolation elements and are added together, and interpolated gray level scan signals y
12
to y
56
are generated and inserted between the real scan signals.
For example, to generate an interpolated scan signal y
23
that is to be inserted between real scan signals X
2
and X
3
, a lower interpolation element X
2
/2, which is designated by a □ and which is calculated using the real scan signal X
3
, and an upper interpolation element X
3
/2, which is designated by a &Dgr; and which is calculated using a real scan signal X
3
, are added together, i.e., the calculation (X
2
/2)+(X
3
/2) is performed.
However, when the conventional average value interpolated method is used, it is difficult to reproduce a peak value that is lost during a process performed to convert a sampled video signal into a digital signal, so that image sharpness is deteriorated and a degraded image quality is obtained.
SUMMARY OF THE INVENTION
To resolve the above shortcoming, it is an objective of the invention to provide a progressive scan conversion apparatus for a video signal that can reproduce the peak value of a video signal that is lost during digital sampling, and that can effectively obtain a preferable converted image.
It is also an objective of the invention to provide a video signal conversion device that can reproduce the peak value of a video signal that is lost during digital sampling, and that can effectively provide a preferable converted image.
To achieve the above objects, according to an aspect of the invention, there is provided a line interpolation apparatus for converting a video signal for interlaced scanning into a video signal for progressive scanning, which comprises:
lower interpolated element generation means for employing an upper real scan signal, along a real scan line that is above and adjacent to an interpolated scan line, and real scan signals, along a plurality of sequential real scan lines that are vertical relative to the upper real scan line, to generate a lower interpolation element for the upper real scan signal;
upper interpolation element generation means for employing a lower real scan signal, along a lower real scan line that is below and adjacent to the interpolated scan line, and real scan signals, along a plurality of sequential real scan lines that are vertical to the lower real scan line, to generate an upper interpolation element for the lower real scan signal;
inclination detection means for detecting inclination information for an image based on two or more real scan signals, including the upper and the lower real scan signals;
limitation means for adjusting the levels of the upper interpolation element and the lower interpolation element in accordance with the inclination information detected by the inclination detection means, and for generating a first interpolation element and a second interpolation element whose levels are adjusted; and
addition means for adding the first and the second interpolation elements to generate an interpolated scan signal that is to be inserted into the interpolated scan lines that are adjacent to the upper and the lower real scan lines.
In the thus arranged line interpolated apparatus, the lower interpolation element means employs the upper real scan signal (a real scan signal along a real scan line above and adjacent to the interpolated scan line) and real scan signals that are located along a plurality of sequential real scan lines, which are vertical relative to the upper real scan line, to generate the lower interpolation element of the upper real scan signal. And the upper interpolation element means employs the lower real scan signal (a real scan signal along a real scan line below and adjacent to the interpolated scan line) and real scan signals that are located along a plurality of sequential real scan lines, which are vertical relative to the upper real scan line, to generate the upper interpolation element of the lower real scan signal.
The inclination detection means detects inclination information for an image based on two or more real scan signals, including the upper real scan signal and the lower real scan signal. Then, in accordance with the inclination information (the detected information), the limitation means adjusts the levels of the lower and upper interpolation elements to generate the first and the second interpolation elements.
The addition means adds together the first and the second interpolation elements to generate an interpolated scan signal, which it inserts into the interpolated scan line.
According to another aspect of the invention, there is provided a video signal conversion device, which comprises:
first interpolation element generation means for employing pixel data for a first pixel, which is vertically (or horizontally) adjacent to one side of an interpolation pixel, and pixel data for a plurality of pixels, which are vertically (or horizontally) contiguous with the first pixel, to generate an interpolation element for the first pixel positioned beside the interpolation pixel;
second interpolation element generation means for employing pixel data for a second pixel, which is vertically (or horizontally) adjacent to the other side of the interpolation pixel, and pixel data for a plurality of pixels, which are vertically (or horizontally) contiguous with the second pixel, to generate an interpolation element for the second pixel positioned beside the interpolation pixel;
addition means for adding together the first interpolation element and the second interpolation element to generate interpolation pixel data for the interpolation pixel; and
compensation means for generating a compensation value based on the pixel data for the first or Lhe second pixel and the pixel data for the plurality of pixels that are vertically (or horizontally) contiguous with the relevant pixel, and for mixing the compensation value with the pixel data for t
Lee Michael
Pioneer Corporation
Sughrue & Mion, PLLC
LandOfFree
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