US 6,134,373 A · System for recording and reproducing a wide bandwidth video signal via a narrow bandwidth medium

Abstract

An encoder separates luminance and chrominance signal components of a composite video signal. The frame-to-frame changes in the luminance signal are detected, and a motion signal is derived therefrom. The higher frequency portion of the luminance signal is adaptively de-emphasized in amplitude and folded into the spectrum of the lower frequency portion of the luminance signal, to generate a folded-spectrum luminance signal for modulating the frequency of a luma carrier. In a combined signal, suitable for magnetic recording in accordance with a modified VHS standard, the chrominance signal is translated in frequency to generate a color-under signal in a frequency band below that occupied by the FM luma carrier. The de-emphasized higher frequency portion of the luminance signal, as folded into its lower frequency portion, and encoding of the motion signal onto vacant portions of the frequency band below that occupied by the FM luma carrier in such a magnetic recording facilitate its being compatibly reproduced by conventional VHS reproduction devices. In a wideband reproduction device a decoder demodulates the folded-spectrum luminance signal from the FM luma carrier, unfolds the lumininance signal, and reemphasizes the high frequencies of the unfolded luminance signal. The color-under signal is translated in frequency to regenerate chrominance signal combined with the unfolded luminance signal with its high frequencies re-emphasized to their original amplitude, regenerating a composite signal descriptive of a full bandwidth image. The motion signal is utilized in the encoder for motion-adaptively pre-filtering the input luminance and is recovered in the decoder for motion-adaptively post-filtering the unfolded luminance.

Claims128

Dependent claims

A video signal processing system for transmitting a wide bandwidth video signal via a limited bandwidth medium, comprising:

encoder means connectable to a limited bandwidth video medium, for receiving an input video signal including at least a wide bandwidth luminance signal having low frequency and high frequency luminance components and for producing therefrom a limited bandwidth luminance signal having a low frequency luminance band with a bandwidth limited to a limited bandwidth and a high frequency luminance band component de-emphasized in amplitude from said input video signal and folded into a bandwidth of said low frequency luminance band component, wherein the amount of de-emphasis of said high frequency luminance band component varies in dependence on an amplitude thereof in the input video signal.

A video signal processing system for transmitting a wide bandwidth video signal via a limited bandwidth medium, comprising:

encoder means connectable to a limited bandwidth video medium, for receiving an input video signal including at least an input wide bandwidth luminance signal and for producing therefrom a limited bandwidth video signal including a limited bandwidth luminance signal having a high frequency luminance component of said input wide bandwidth luminance signal de-emphasized in amplitude from said input video signal and folded into a bandwidth of a low frequency luminance component limited to said limited bandwidth, wherein the amount of de-emphasis of said high frequency luminance component varies in dependence on the amplitude thereof in the input video signal, and for also generating a motion signal representative of a degree of image motion in said input video signal;
and
means for transmitting said motion signal together with said limited bandwidth video signal.

A video signal processing system for transmitting a wide bandwidth video signal via a limited bandwidth medium, comprising:

encoder means having an input terminal connectable to a source of composite video signals and an output terminal connectable to a limited bandwidth video medium,
for receiving at said input terminal an input composite video signal including a wide bandwidth baseband luminance signal component having low frequency and high luminance frequencies together with a chrominance signal component, and for producing therefrom a limited bandwidth luminance signal having a high frequency luminance component de-emphasized in amplitude from said input video signal and folded into a bandwidth of a low frequency luminance component which is limited to a limited bandwidth, wherein the amount of de-emphasis of said high frequency luminance component varies in dependence on an amplitude thereof in the input video signal;
for deriving from said input video signal a motion signal representative of a degree of image motion in said input video signal;
for spatially filtering said baseband luminance signal to produce a spatially filtered luminance signal;
for temporally filtering said baseband luminance signal to produce a temporally filtered luminance signal;
for varying, in response to said motion signal, a proportion of said spatially filtered luminance signal and a proportion of said temporally filtered luminance signal in said limited bandwidth luminance signal;
for combining said motion signal with said chrominance signal to produce a composite chrominance-plus-motion signal;
and
for providing said limited bandwidth luminance signal and said chrominance-plus-motion signal at said output terminal.

6 more elements

A video signal processing system for converting an input wide bandwidth composite video signal including a wide bandwidth baseband luminance signal component and a chrominance component into a limited bandwidth video signal, comprising:

chrominance/luminance separation means for separating said input wide bandwidth composite video signal into its said wide bandwidth baseband luminance signal and chrominance signal components;
motion signal generation means for deriving from said wide bandwidth baseband luminance signal a motion signal representative of a degree of image motion in said input wide bandwidth composite video signal;
spatial filter means for spatially filtering the wide bandwidth baseband luminance signal to produce a spatially filtered baseband luminance signal;
temporal filter means for temporally filtering the wide bandwidth baseband luminance signal to produce a temporally filtered baseband luminance signal;
motion-adaptive means for varying, in response to said motion signal, respective proportions of said spatially filtered baseband luminance signal and said temporally filtered baseband luminance signal which are output as a spatio-temporally filtered baseband luminance signal;
band filtering means for receiving said spatio-temporally filtered baseband luminance signal and producing therefrom a low frequency luminance band component having a bandwidth limited to said limited bandwidth and a high frequency luminance band component;
de-emphasis means for adaptively de-emphasizing said high frequency luminance band component in dependence upon an amplitude thereof;
folding means for folding said high frequency luminance band component into the bandwidth of said low frequency luminance band component to provide a folded limited bandwidth luminance signal;
and
chrominance/motion combining means for combining said chrominance signal component and said motion signal into a composite chrominance-plus-motion signal.

7 more elements

A video signal processing system, comprising:

unfolding means for unfolding a limited bandwidth folded video luminance signal containing a low frequency luminance band component having a bandwidth limited to a limited bandwidth and a high frequency luminance band component folded into a spectrum of said low frequency luminance band component to provide therefrom an unfolded baseband luminance signal having a bandwidth greater than said limited bandwidth and containing said low frequency luminance band component of said folded video luminance signal and said high frequency luminance band component unfolded from said folded video luminance signal;
spatial filter means for spatially filtering the unfolded baseband luminance signal to produce a spatially filtered baseband luminance signal;
temporal filter means for temporally filtering the unfolded baseband luminance signal to produce a temporally filtered baseband luminance signal;
chrominance/motion separation means for separating a composite chrominance-plus-motion signal containing a video chrominance signal component combined with a motion signal component representative of a degree of motion in a video image to provide therefrom a separated chrominance signal and a separated motion signal;
motion-adaptive means for varying, in response to said motion signal, respective proportions of said spatially filtered baseband luminance signal and said temporally filtered baseband luminance signal which are output as a spatio-temporally filtered baseband luminance signal;
band filtering means for receiving said spatio-temporally filtered baseband luminance signal and producing therefrom a spatio-temporally filtered low frequency luminance band component having a bandwidth limited to said limited bandwidth and a spatio-temporally filtered high frequency luminance band component;
emphasis means for adaptively emphasizing said spatio-temporally filtered high frequency luminance band component in amplitude in dependence upon a magnitude thereof to provide an emphasized spatio-temporally filtered high frequency luminance band component;
and
combining means for contiguously combining said emphasized spatio-temporally filtered high frequency luminance band component with said spatio-temporally filtered low frequency luminance band component to provide a wide bandwidth luminance signal.

6 more elements

A video signal processing system, comprising:

encoder means for encoding an input video signal including at least an input wide bandwidth luminance signal having low and high luminance frequencies to produce therefrom a limited bandwidth video signal containing at least an encoded limited bandwidth luminance signal having a low frequency luminance band component with a bandwidth limited to a limited bandwidth together with a high frequency luminance band component de-emphasized in magnitude from a magnitude thereof in said input wide bandwidth luminance signal and folded into a bandwidth of said low frequency luminance band component and with the amount of de-emphasis of said high frequency luminance band component varying in dependence upon the magnitude thereof in said input wide bandwidth luminance signal;
and
decoder means for decoding said limited bandwidth video signal to produce therefrom an output video signal including at least a decoded wide bandwidth luminance signal having a bandwidth greater than said limited bandwidth and containing said low frequency luminance band component along with said high frequency luminance band component unfolded from said limited bandwidth signal, and for re-emphasizing said unfolded high frequency luminance band component in magnitude by an amount corresponding to said amount of de-emphasis thereof by said encoder means for thereby restoring said high frequency luminance band component to said magnitude thereof in said input wide bandwidth luminance signal.

A method for processing a wide bandwidth video luminance signal into a limited bandwidth video luminance signal, comprising the steps of:

receiving a wide bandwidth video luminance signal and producing therefrom a low frequency luminance component having a bandwidth limited to a limited bandwidth and a high frequency luminance component having a bandwidth not exceeding said limited bandwidth;
reducing said high frequency luminance component in amplitude by an amount which varies in dependence upon an amplitude thereof, for de-emphasizing high frequency luminance component;
shifting said high frequency luminance component to a frequency spectrum of said low frequency luminance component for providing a folded high frequency luminance component;
and
adding said folded high frequency luminance component to said low frequency luminance component for producing a folded video luminance signal having a bandwidth limited to said limited bandwidth.

2 more elements

A method for converting a full bandwidth video luminance signal into a limited bandwidth video luminance signal retaining therein luminance information of the full bandwidth luminance signal within a limited bandwidth, and for reconverting the limited bandwidth video luminance signal into a wide bandwidth baseband luminance signal corresponding to the full bandwidth video luminance signal, comprising the steps of:

receiving said full bandwidth video luminance signal and producing therefrom a low frequency luminance component having a bandwidth limited to a limited bandwidth and a high frequency luminance component having a bandwidth not exceeding said limited bandwidth;
reducing said high frequency luminance component in amplitude by an amount dependent upon the amplitude of said high frequency luminance component;
shifting said high frequency luminance component to a frequency spectrum of said low frequency luminance component for producing a folded high frequency luminance component;
and
adding said folded high frequency luminance component to said low frequency luminance component for producing a limited bandwidth video luminance signal;
unfolding said limited bandwidth video luminance signal for providing an unfolded baseband luminance signal having said low frequency luminance component of said limited bandwidth video luminance signal and said folded high frequency luminance component of said limited bandwidth video luminance signal in unfolded form;
and
increasing said unfolded high frequency luminance component in amplitude by an amount which varies in dependence upon the amplitude thereof, for providing a wide bandwidth baseband video luminance signal having said low frequency luminance component and said unfolded high frequency luminance component, said unfolded high frequency luminance component being thereby emphasized in amplitude.

5 more elements

Dependencies are inferred from the claim text.

System for recording and reproducing a wide bandwidth video signal via a narrow bandwidth medium

Life of this patent

System for recording and reproducing a wide bandwidth video signal via a narrow bandwidth medium

Life of this patent

Abstract

Claims128