JPH04324781A - Movement non-adaptive signal transmitter for television signal - Google Patents

Abstract

PURPOSE:To attain transmission of even a moving picture without crosstalk by using an FIR filter whose time is unchanged so as to apply 3-dimensional band-limit to additional information and a multiplex signal when a transmission line for an NTSC signal is used to send the additional information and the multiplex signal. CONSTITUTION:A Y signal is given to a luminance signal separation filter 2, in which the signal is separated into a horizontal low frequency, medium frequency, high frequency and a vertical high frequency component. The low frequency component is subjected to band limit by a VT filter 3 to prevent loopback distortion by an interlace subsample distortion. The vertical and horizontal high frequency components are subject to VT filters 6, 10 respectively to prevent crosstalk with the luminance signal due to a spread signal component in the case of a moving picture. The horizontal medium component is subjected to band limit by a VT filter 13 to prevent a crosstalk between a multiplex signal and a chroma signal due to a spread of the signal component in the case of the moving picture. I, Q signals are subjected to band limit by horizontal LPFs 18, 20. A VT filter 22 applies band limit to the signals to prevent crosstalk with a luminance signal.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television signal transmission device, and more particularly to a motion-inadaptive signal transmission device for television signals that is capable of multiplexing and transmitting additional information while maintaining compatibility with current television systems. .

0002

2. Description of the Related Art When additional information is multiplexed onto a current NTSC signal, there is an "atrium hole" as a multiplexing area that does not damage the original NTSC signal. FIG. 3 shows a signal spectrum in the time-vertical frequency domain when signals are multiplexed in this domain. In the figure, (a) is a still image, (b)
is the time of video. It can be seen that when a still image is displayed, there is no crosstalk between the luminance signal and the multiplexed signal, and between the luminance signal and the chrominance signal and they can be separated. However, when moving images, each spectrum spreads in the time direction and crosstalks with each other. Therefore, multiplexing using an atrium hall has the limitation that the luminance signal and additional information cannot be separated when moving images. It's a bit of a nuisance, but of course there is crosstalk between color and brightness when recording videos.

Under these restrictions, means for multiplexing additional information using this area can be roughly divided into (1) motion adaptive processing that changes the processing method depending on still images/moving images, and (2) still image/moving image multiplexing means.
There is motion non-adaptive processing that does not change the processing method for videos.

[0004] Motion adaptive processing multiplexes additional information in this area only for still images and not for moving images. Such processing is used, for example, in the ``fully compatible EDTV system'' TV. Academic journal Vol. 39. No. 10
(1985).

As motion non-adaptive processing, for example, "E
coding for Compatibility
and Recoverability in
ACTV System” IEEE TRANS.
on Broadcasting Vol. BC-
33, No. 4 DEC. Shown in 1987,
This allows additional information to be multiplexed in the atrium hall even during moving images by performing frame averaging (time-varying filter technology) processing on luminance signals and chroma signals with a horizontal frequency of 1.5 MHz or more.

[0006] To explain motion adaptive processing,
To prevent crosstalk between luminance and multiplexed signals due to the spread of the signal spectrum when transmitting moving images, the amount of movement in the image to be transmitted is detected by a motion detector, and multiplexed signals are transmitted only when transmitting still images. There is a motion adaptive signal transmission method in which multiplexed signal transmission is stopped during moving image transmission. That is, as shown in FIG. 4, on the encoder side, there is a digitized 525-line non-interlaced luminance (Y) signal input terminal 1, a PI converter 2 for interlacing sub-sampling of this signal, and an input terminal 1. a motion detector 3 that detects the amount of motion of an input image from the luminance signal, a digitized 525-line non-interlaced multiple signal input terminal 4, and a PI converter 5 that interlace subsamples this signal. , a modulator 6 that frequency-shifts this output to a multiple frequency domain, and a signal switch 7 that selects the output signal of the modulator 6 only when no motion is detected in the image based on the control signal output from the motion detector 3. , a digitized 525-line non-interlaced I signal input terminal 8, a PI converter 10 for interlacing subsampling this signal, and a digitized 525-line non-interlaced I signal input terminal 8;
A non-interlace Q signal input terminal 9, a PI converter 11 that interlaces subsamples this signal, and this P
A chroma processing unit 12 that outputs a chroma (C) signal from the output signals of the I converter 10 and the PI converter 11, and an adder 13 that adds the output signals of the PI converter 2, signal switch 7, and chroma processing unit 12. and an encoder output terminal 14.

On the decoder side, as shown in FIG.
A decoder input terminal 15 that inputs the encoder output, a horizontal HPF 16 that separates signal components with a horizontal frequency of 2.1 MHz or more from the input digital signal, and a horizontal HPF 16 that separates signal components with a horizontal frequency of 2.1 MHz or more from the input signal of the encoder. A subtracter 17 outputs a signal component with a horizontal frequency of 2.1 MHz or more, a motion detection unit 18 detects motion from the input signal, and a horizontal signal component with a horizontal frequency of 2.1 MHz or more output from the horizontal HPF 16 frequency 2
．． Luminance (Y) signal of 1MHz or more, multiplex signal and chroma (
C) A multiplex signal separator 19 that separates signals; a luminance signal with a horizontal frequency of 2.1 MHz or more output from the multiplex signal separator 19 and a horizontal frequency 2.1 output from the subtracter 17;
Adder 20 that adds and outputs luminance signal components of MHz or less
The IP converter 21 performs scanning line interpolation on this output signal and converts it into a 525-line non-interlaced signal, the luminance (Y) signal output terminal 22, and the multiplexed signal output from the multiplexed signal separation unit 19. a signal switch 24 that selects the output signal of the demodulator 23 and outputs a multiplexed signal only when no motion is detected by the control signal from the motion detector 18; an IP converter 25 that performs scanning line interpolation and converts the signal into a 525-line non-interlaced signal, and a multiplex signal output terminal 2.
6 and the chroma (C) output from the multiplex signal separation unit 19
A chroma demodulation processor 27 demodulates the signal and outputs an I signal and a Q signal, and performs scanning line interpolation on the I and Q signals output from the chroma demodulation processor 27, converting them into 525-line non-interlaced signals and outputting them. It has an IP converter 28 and an IP converter 29, an I signal output terminal 30, and a Q signal output terminal 31.

[0008]

In this conventional motion adaptive method, an image motion detection circuit is required on both the encoder side and the decoder side, which increases the circuit scale and increases the cost. In addition, when trying to improve image resolution by transmitting high-definition components of images as multiplexed signals, the high-definition components are transmitted when transmitting still images, whereas the high-definition components are transmitted when transmitting moving images. Therefore, the difference in resolution between still images and moving images becomes significant. In addition, if the image is moving at a speed close to the motion/stillness determination threshold, the motion/stillness determination in the motion detection section changes due to subtle changes in speed, etc., and the resolution of the reproduced image on the decoder side accordingly changes. Due to the unstable change, there is a problem in that the unstable change in resolution appears as a kind of noise in the reproduced image.

[0009] Furthermore, in the conventional motion non-adaptive method, 1.5
Since the same signal is repeatedly transmitted for two fields using a luminance signal of MHz or more, there is a problem in that the temporal resolution decreases and jerkiness becomes noticeable in moving images.

0010

[Means for Solving the Problems] The present invention multiplexes additional information in the atrium even during moving images by means different from frame averaging. In other words, as a means of transmitting additional information regardless of whether it is a moving image or a still image while maintaining compatibility with current signals using the NTSC signal transmission path,
By band-limiting the additional information and the multiplexed region three-dimensionally (time, vertically, and horizontally) using a time-invariant FIR filter, the additional information can be multiplexed, transmitted, and separated at any time.

Specifically, the motion non-adaptive signal transmission method of the present invention is based on the input 525 line signal transmission method on the encoder side.
A means for separating a non-interlaced Y signal into a horizontal low-frequency component and a horizontal mid-range component, and a means for band-limiting the horizontal low-frequency component in the vertical-temporal frequency domain to prevent aliasing distortion during interlaced subsampling. , a means for interlace subsampling this band-limited signal and converting it into a 525-line interlace signal, and a means for subsampling the band-limited signal into a 525-line interlace signal, and a means for vertically subsampling the horizontal midrange component to prevent crosstalk with the chroma signal or multiplex signal during video transmission. A means for band-limiting in the time-frequency domain to prevent signal leakage to the multiple frequency domain, a means for interlacing sub-sampling of this band-limited signal and converting it into a 525-line interlace signal, and video transmission for the multiplex signal. Sometimes, in order to prevent crosstalk with horizontal midrange signals, band limiting is performed in the vertical-time frequency domain to prevent signal leakage outside the signal multiplexing frequency domain, and this band-limited signal is interlace sub-sampled 525. means for converting the converted signal into a line interlaced signal; means for frequency shifting the converted signal into a multi-frequency domain; Means for band-limiting in the vertical-time frequency domain to prevent signals from leaking out of the multiple frequency domain; means for interlacing sub-sampling the band-limited signal and converting it into a 525-line interlaced signal; means for frequency shifting the converted signal to a multiple frequency domain (multiple domain of chroma signals) and outputting a chroma signal; a horizontal low frequency signal converted to a 525 line interlaced signal, a horizontal mid frequency signal and a multiplex signal; It has means for adding and outputting chroma signals.

On the decoder side, there is a means for separating horizontal low frequency components, horizontal mid frequency components, multiplexed signals and chroma signals of luminance from the input signal of the decoder, and scanning line interpolation for the separated horizontal low frequency components. means for converting into a 525-line non-interlace signal; means for performing scanning line interpolation on the separated horizontal mid-range component and converting it into a 525-line non-interlace signal; means for adding and outputting a low frequency signal and a horizontal midrange signal;
means for demodulating the separated multiplexed signal; means for performing scanning line interpolation on this signal and converting it into a 525-line non-interlaced signal; and means for demodulating the separated chroma signal and outputting an I signal and a Q signal; A means for performing scanning line interpolation on the demodulated I signal and converting it into a 525 line non-interlaced signal, and a means for performing scanning line interpolation on the demodulated Q signal and converting it into a 525 line non-interlaced signal.
and means for converting the signal into a non-interlaced signal.

[0013]

Embodiment In an embodiment of the present invention, a configuration as shown in FIG. 6 is considered as an image communication system to which the invention is applied. In other words, the transmitting side encodes the output of the 525 TV non-interlaced signal source to make it a signal compatible with NTSC, and converts it to NTSC.
It is transmitted through the C transmission path. On the receiving side, it can also be received and displayed using an NTSC receiver. Furthermore, if decoding processing corresponding to the receiving side is performed, 525 TV non-interlaced signals can be reproduced.

[0014] In order to transmit a non-interlaced signal, a band twice as large as that of NTSC is normally required, but in the present invention, a signal whose band is limited subjectively so that the signal source is not damaged as much as possible is considered. . This signal is shown in FIG. (a) is a band-limited luminance signal, and (b) is a band-limited color signal. Therefore, the vertical high frequency range (V-HI) and horizontal high frequency range (H-HI), which are difference components from the NTSC signal, are considered as the additional information to be multiplexed. The atrium hall and diagonal high range shown in FIG. 8 are used as the areas where signals are multiplexed.

In the present invention, in order to prevent the luminance signal and chrominance signal/multiplex signal from crosstalking each other when the signal spectrum spreads during a moving image, a time-invariant three-dimensional IR filter shown in FIG. Q), multiplex signal (V-H
I, H-HI).

Embodiments of the present invention will be described in detail below with reference to the drawings. 1 and 2 are block diagrams of an encoder section and a decoder section according to an embodiment of the present invention. This example:
The inputs Y, I, and Q are 525-line non-interlaced signals, and the horizontal high frequency component and vertical high frequency component of the luminance signal are transmitted as a multiplexed signal.

First, the encoder section will be explained with reference to FIG. The Y, I, and Q signals of the 525-line non-interlaced signal are input to Y signal input terminal 1 and I signal input terminal 17, respectively.
, and the Q signal input terminal 19. The Y signal input to the Y signal input terminal 1 is separated by a luminance signal separation filter 2 into horizontal low frequency components (horizontal frequency 0 to 2.1 MHz), horizontal mid frequency components (horizontal frequency 2.1 to 4.2 MHz), and horizontal high frequency components. It is separated into a frequency component (horizontal frequency 4.2 to 6 MHz) and a vertical high frequency component. In order to prevent aliasing distortion due to interlaced sub-sampling, the horizontal low-frequency component is band-limited in advance by a VT filter 3, and then scan line thinned out by an interlaced sub-sampling section 4 and converted into a 525-line interlaced signal. This converted signal is input to the horizontal LPF 5, and only signal components with a horizontal frequency of 2 MHz or less are output.

The vertical high frequency component output from the luminance signal separation filter 2 is passed through a VT filter 6 to prevent crosstalk with the luminance signal due to the spread of signal components during moving images.
After band limiting is performed in the interlaced subsample section 7
The scanning line is thinned out and converted into a 525-line interlaced signal. Further, the horizontal frequency of this converted signal is shifted by 2.2 MHz in a horizontal frequency shift section 8, and components with a horizontal frequency of 2.2 MHz or more are outputted in a horizontal HPF section 9 having a Nyquist characteristic.

The horizontal high-frequency component output from the luminance signal separation filter 2 is passed through the VT filter 1 to prevent crosstalk with the luminance signal due to the spread of signal components during moving images.
After band limiting with 0, the interlaced subsample section 11
The scanning line is thinned out and converted into a 525 line interlaced signal, and the modulator 12 shifts the frequency to a frequency domain conjugate with the chroma signal. The horizontal midrange component output from the luminance signal separation filter 2 is band-limited by a VT filter 13 to prevent crosstalk with multiplexed signals and chroma signals due to spread of signal components during moving images, and then passed to an interlaced sub-sampling section 14. Perform scanning line thinning with 52
Convert to 5-line interlaced signal. The signals output from the modulator 12 and the interlaced sub-sampling section 14 are added by an adder 15, and the horizontal frequency 2 is converted by the horizontal HPF 16.
Only components above MHz are output.

The I signal input to the I signal input terminal 17 is band-limited by the horizontal LPF 18 to a horizontal frequency of 1.5 MHz or less. The Q signal input to the Q signal input terminal 19 is band-limited by the horizontal LPF 20 to a horizontal frequency of 0.5 MHz or less. In the array conversion unit 21, the horizontal LPF 18 and the horizontal L
The output data of the PF 20 is regularly arranged and output. VT
The filter 22 band-limits this signal to prevent crosstalk with the luminance signal during moving images, and the interlace sub-sampling section 23 performs scanning line thinning.
Convert to line interlaced signal. This converted signal is converted into a chroma signal by the NTSC modulator 24 and output. Horizontal LPF5 and Nyquist horizontal HPF9 and horizontal LP
The output signals of F16 and the NTSC modulator 24 are added by an adder 25 and output to an encoder output terminal 26.

Next, the decoder section will be explained with reference to FIG. The output signal of the encoder is input to the decoder input terminal 27. The horizontal LPF 28 separates signal components having a horizontal frequency of 2 MHz or less from this input signal, and the IP converter 29 performs scanning line interpolation to convert it into a 525-line non-interlaced signal. In addition, the signal input to the decoder input terminal 27 has a horizontal frequency of 2.2 MH by the horizontal HPF 30.
The signals of z or more are separated, and the horizontal frequency shift section 32 converts them into 2
．． The horizontal frequency is shifted by 2 MHz, and the horizontal LPF 33 extracts the signal component which has been frequency shifted to a lower frequency range.The IP converter 34 performs scanning line interpolation and converts it into a 525 line non-interlaced signal. Further, the signal input to the decoder input terminal 27 has a horizontal frequency of 2.1 M through the horizontal HPF 35.
Signals above Hz are separated. This separated signal is
The signal is input to a horizontal LPF 36 having a Nyquist characteristic, and components with a horizontal frequency of 4.2 MHz or less are separated. From this signal, the VT filter 37 removes the chroma signal and signal components in its conjugate frequency domain, so the VT filter 37 removes the mid-range component of the luminance signal (horizontal frequency 2.1 to 4.2M).
Hz) is output. The mid-range component of this luminance signal undergoes scanning line interpolation in the IP converter 38 and is converted into a 525-line non-interlaced signal.

Furthermore, from the output signal of the horizontal LPF 36, VT
A filter 39 separates signal components in the frequency domain that are conjugate with the chroma signal. This separated signal is sent to the demodulator 4
After being demodulated at 0 (frequency shifted to a horizontal frequency range of 4.2 to 6 MHz), the IP converter 41 performs scanning line interpolation and converts it into a 525-line interlaced signal. IP converter 29, IP converter 34, and IP converter 38
and the signals output from the IP converter 41 are added by the adder 42 and output to the Y signal output terminal 43. Horizontal HPF
A VT filter 44 separates the chroma signal from the signal output from the NTSC demodulator 45, and the NTSC demodulator 45 demodulates the signal into an I signal and a Q signal. The demodulated I signal is band-limited to a horizontal frequency of 1.5 MHz by the LPF 45, subjected to scanning line interpolation by the IP converter 47, and converted into a 525-line non-interlaced signal, which is output to the I signal output terminal 48. NTSC
The Q signal demodulated by the demodulator 45 is band-limited to a horizontal frequency of 0.5 MHz by the LPF 49, subjected to scanning line interpolation by the IP converter 50, converted into a 525-line non-interlaced signal, and output to the Q signal output terminal 51. be done.

[0023]

[Effects of the Invention] As explained above, according to the present invention,
In order to prevent horizontal frequency components of luminance signals of 2.1 MHz or higher, chroma signals, and multiplex signals from causing mutual crosstalk, each band is limited by a VT filter, and there is no crosstalk even when transmitting moving images. Signal transmission is possible. Therefore, there is no need to distinguish between moving images and still images, and a circuit necessary for motion adaptive processing such as a motion detection circuit is not required. Therefore, the circuit scale can be reduced and costs can be reduced. Further, when attempting to improve the resolution of an image by transmitting high-definition components of the image as a multiplexed signal, in this method, the resolution of the transmitted image changes continuously in accordance with the moving speed of the image. Therefore, unlike the motion adaptive processing method, there is no interference with image quality for images having motion near the threshold for motion/still determination. In other words, when the image moves at a speed close to the motion/stillness determination threshold, the motion/stillness determination in the motion detection section changes due to subtle changes in speed, etc., and accordingly, the transmission of the high-definition signal component is turned on. /OFF, and the resolution of the reproduced image on the decoder side changes unstablely. This appears as a kind of noise in the reproduced image, but since no adaptive processing is performed in this method, such a phenomenon does not occur.

Furthermore, since only the luminance signal above 2 MHz is limited by the filter in the vertical and temporal directions, jerkiness disturbance in moving images does not occur.

In this method, since the chroma signal is also band-limited to suppress crosstalk with the luminance signal, image quality disturbances such as cross color and cross luminance can also be reduced.

[Brief explanation of drawings]

FIG. 1 shows a block diagram of an encoding unit according to an embodiment of the present invention.

FIG. 2 shows a block diagram of a decoding section according to an embodiment of the present invention.

FIG. 3 is a spectrum diagram in the time-vertical frequency domain when additional information is multiplexed to an NTSC signal in an atrium, where (a) shows the case of a still image and (b) shows the case of a moving image.

FIG. 4 shows a block diagram of a conventional encoding unit using motion adaptive processing.

FIG. 5 shows a block diagram of a conventional decoding unit using motion adaptive processing.

FIG. 6 shows an EDTV signal transmission/reception system to which the present invention is applied.

FIG. 7 is a diagram showing band limitations when a non-interlaced signal is transmitted via an NTSC TV signal transmission path, where (a) shows a band-limited luminance signal, and (b) shows a band-limited luminance signal. color signal.

FIG. 8 is a diagram showing a multiplexing area when multiplexing signals.

FIG. 9 is a diagram showing the characteristics of a time-invariant three-dimensional FIR filter used when performing signal multiplexing according to the present invention.

[Explanation of symbols]

1 Y signal input terminal 2 Luminance signal separation filter section 3 VT filter section 4 Interlace sub-sample section 5 Horizontal LPF 6 VT filter section 7 Interlace sub-sample section 8 Horizontal frequency shift section 9 Horizontal HPF section 10 VT filter section 11 Interlace Sub sample section 12
Modulator 13 VT filter section 14 Interlace sub-sampling section 15
Adder 16 Horizontal HPF section 17 I signal input terminal 18 Horizontal LPF section 19 Q signal input terminal 20 Horizontal LPF section 21 Array conversion section 22 VT filter section 23 Interlace sub-sampling section 24
NTSC modulator 25 Adder 26 Encoder output terminal 27 Decoder input terminal 28 Horizontal LPF section 29 IP converter 30 Horizontal HPF section 31 VT filter section 32 Horizontal frequency shift section 33 Horizontal LPF section 34 IP converter 35 Horizontal HPF section 36 Horizontal LPF Section 37 VT filter section 38 IP converter 39 VT filter section 40 Demodulator 41 IP converter 42 Adder 43 Y signal output terminal 44 VT filter section 45 NTSC demodulator 46 Horizontal LPF section 47 Horizontal LPF section 48 I signal output terminal 49 Horizontal LPF section 50 IP converter 51 Q signal output terminal

Claims (2)

[Claims] [Claim 1] A device that uses an NTSC signal transmission path and transmits additional information regardless of whether it is a moving image or a still image while maintaining compatibility with current signals, and which makes the additional information and multiplexed area invariant over time. 1. A non-motion adaptive signal transmission device for television signals, characterized in that it is possible to multiplex, transmit, and separate additional information by three-dimensionally (temporally, vertically, horizontally) band limiting using an FIR filter. 2. The input 525-line non-interlaced luminance signal is divided into horizontal low frequency components (for example, horizontal frequency 0 to 2.1 MHz) and horizontal mid frequency components (for example, horizontal frequency 2.1 to 4.2 MHz). ), means for band-limiting using a VT filter in the vertical-temporal frequency domain to prevent aliasing distortion when converting the horizontal low-frequency component of luminance into a 525-line interlaced signal, and Means for converting the signal into a 525-line interlace signal by interlace subsampling, and band-limiting the horizontal mid-range component of the luminance using a VT filter in the vertical-temporal frequency domain to prevent leakage of the luminance signal to the multiplexed signal and chroma signal. a means for band-limiting a 525-line non-interlaced multiplexed signal using a VT filter in the vertical time frequency domain to prevent the multiplexed signal from leaking into the luminance signal; and a means for interlacing the band-limited signal. means for converting into a 525-line interlaced signal by subsampling, and 525-line non-interlaced I and Q signals;
means for band-limiting the signal in the vertical-temporal frequency domain with a VT filter to prevent leakage of the chroma signal into the luminance signal; a means for outputting the chroma signal from the band-limited I signal and Q signal; Means for converting a chroma signal into a 525-line interlaced signal using interlace subsampling, and adding and outputting the horizontal low-frequency component, horizontal high-frequency component, multiplex signal, and chroma signal converted into the 525-line non-interlaced signal. 1. A motion non-adaptive signal transmission device for a television signal, characterized in that it has means for transmitting motion-inadaptive television signals.