Television – Monitoring – testing – or measuring – Test signal generator
Reexamination Certificate
2000-08-01
2003-04-29
Miller, John (Department: 2614)
Television
Monitoring, testing, or measuring
Test signal generator
C348S181000, C348S180000, C348S445000
Reexamination Certificate
active
06556238
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a color-bar signal generation unit compatible with a plurality of television signal formats. More particularly, this invention is concerned with a color-bar signal generation unit for generating a color-bar signal that enables broadcasting conforming to both the high-definition television (HD) format and the standard-definition television (SD) format including the National Television System Committee-recommended (NTSC) format. Using the color-bar signal produced by the novel color-bar generation unit in accordance with the present invention, both a 16:9 aspect ratio picture produced in the HD format and a 4:3 aspect ratio picture resulting from conversion of the HD picture into the SD format can be broadcast according to the same procedure as that adopted when a conventional color-bar signal is used.
2. Description of the Related Art
Digital broadcasting falls into HD broadcasting and SD broadcasting which deliver pictures of different sizes or aspect ratios of 16:9 and 4:3, respectively. Moreover, ongoing broadcasting conforming to the NTSC format may be used. It is therefore becoming a matter of common practice that programs are produced in the HD form, which offers high image quality and which permits the aspect ratio of 16:9, are converted into the SD (including the NTSC) format, and are then broadcast. A color-bar signal is an important signal providing a reference for optimizing pictures. Even when a video signal format is converted into one conforming to the SD format, the color-bar signal should preferably not be replaced with another in order to preserve the original picture.
Preferably, one color-bar signal enables both HD broadcasting and SD broadcasting (including broadcasting conforming to the NTSC format). Using the color-bar signal, both the 16:9 aspect ratio HD picture and the 4:3 aspect ratio picture resulting from conversion of the HD picture into the SD format can be broadcast according to the same procedure as that adopted when a conventional color-bar signal is used.
At present, a 100%-full-color-bar signal is employed in HD broadcasting, and a 100%- or 75%-full-color-bar signal or an SMPTE color-bar signal (a color-bar signal recommended by the Society of Motion Picture and Television Engineers (SMPTE)) is employed in SD broadcasting.
According to the present invention, what is referred to as a 100%-full-color-bar signal (or simply, a color-bar signal) is a color-bar signal that contains red, green and blue color signals whose levels corresponds to 100% of their designed level. Moreover, this color-bar signal represents a color-bar test pattern composed of color bars that include red, green, and blue bars, and combinations thereof and that are arranged over a whole screen in descending order of the level of a relevant luminance signal from the left side of the screen. What is referred to as a 75%-full-color-bar signal is a color-bar signal containing red, green, and blue color signals whose levels correspond to 75% of their designed level. This color-bar signal also represents a color-bar test pattern composed of color bars that include red, green, and blue bars, and combinations thereof and that are arranged over a whole screen in descending order of the level of a relevant luminance signal from the left side of the screen. These color-bar signals are structured in conformity with the different video signal formats. The color-bar signal structured in conformity with the HD format (16:9) is not intended to be used even after the video signal format is converted into one conforming to the SD format (4:3) (this conversion shall be referred to as down-conversion). The SMPTE color-bar signal contains a chroma control signal for use in controlling saturation on a monitor. Nevertheless, the SMPTE color-bar signal is employed in NTSC broadcasting.
The chroma control signal for use in controlling saturation on an SMPTE monitor cannot be used to control saturation on an HD monitor that handles a luminance signal and chrominance signals as signal components.
Along with down-conversion of the video signal format representing a program, a color-bar signal conforming to the HD format (16:9) must be down-converted into one conforming to the SD format (4:3), representing a color-bar test pattern displayed on a full screen. At this time, signal components representing portions of the color-bar test pattern that appear on both sides of the screen are cut off. The resultant signal cannot therefore be used as a color-bar signal. The color-bar signal must therefore be replaced with another. However, the replacement impairs the original video signal. For this reason, there is an increasing demand for a color-bar signal usable in common for the HD and SD formats.
For NTSC (SD) broadcasting, the SMPTE color-bar signal (75%-full-color-bar signal) is usually adopted. The HD 100%-full-color-bar signal resulting from down-conversion may be taken for the 75%-full-color-bar signal differs from the HD 100%-full-color-bar signal solely in terms of the signal level. Moreover, when the level of the color-bar signal is adjusted incorrectly and broadcast, a broadcasting error occurs.
A vector scope is used to manage colors of a picture produced in the NTSC form. In particular, a color of a face (flesh color) reflects the condition of health. Viewers are conscious of the face color. Therefore, a video signal is magnified with the amplitude of a color burst used as a reference in order to monitor the face color (FIG.
9
C). However, an HD video signal containing a luminance signal and chrominance signals as components does not have a component corresponding to the color burst contained in the NTSC video signal.
Signals whose levels correspond to ±2% of the designed level are adopted as luminance control signals used to control luminance on a monitor and are contained in an HD color-bar signal. Signals whose levels correspond to ±4% thereof are adopted as the luminance control signals contained in an SD color-bar signal. However, a down-converter does not output signal components of negative levels (numeral
63
in
FIG. 6
or numeral
71
in FIG.
7
). Therefore, the signal whose level corresponds to −4% thereof cannot be adopted as one of the luminance control signals contained in the SD color-bar signal (numerals
111
and
112
in FIG.
11
).
The SMPTE color-bar signal employed in NTSC broadcasting cannot be used to control saturation on an HD monitor that handles a luminance signal and chrominance signals as signal components (FIG.
10
A).
SUMMARY OF THE INVENTION
An object of the present invention is to provide a color-bar signal generation unit compatible with a plurality of television signal formats.
In detail, an object of the present invention is to provide a color-bar signal generation unit for generating a color-bar signal enabling both HD broadcasting and SD broadcasting (including NTSC broadcasting). Using the color-bar signal produced by the novel color-bar signal generation unit in accordance with the present invention, both a 16:9 aspect ratio HD picture of and a 4:3 aspect ratio picture resulting from conversion of the HD picture into the SD format can be broadcast according to the same procedure adopted when a conventional color-bar signal is used.
The first point to which the present inventors have directed their attention in efforts to accomplish the foregoing object will be described below. In general, the problems underlying the related art are presumably solved by producing a color-bar signal composed of an HD color-bar signal and an SD color-bar signal. The HD color-bar signal is assign to a 16:9 aspect ratio color-bar test pattern for HD broadcasting, while the SD color-bar signal is assigned to a 4:3 aspect ratio color-bar test pattern for SD broadcasting. However, the waveform of the color-bar signal displayed on a waveform monitor becomes more complex than that of a conventional one. A conventional method of observing the waveform using the waveform monitor
Abe Satoru
Abe Yoshiyuki
Kasuga Yasushi
Kenmotsu Tadashi
Yoshida Kihei
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