JP2928561B2 - Method and apparatus for forming television signal - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for forming a television signal, and more particularly, to a method for transmitting a television signal having a larger number of scanning lines than a conventional method. The present invention relates to a method and apparatus for forming a television signal suitable for applying a signal source.

[Conventional technology]

In the current television system (NTSC system), an image is transmitted by dividing one frame into two fields by interlaced scanning. In conventional TV receivers,
Since the display is performed with interlaced scanning, the roughness of the reproduced image and the flicker interference (flicker) due to the scanning line structure every other line have caused deterioration of the image quality.

To reduce this image quality degradation, a high-definition television system (EDT) that is completely compatible with the current television system
V) Alternatively, in a system (IDTV) for increasing the definition of a current television signal by signal processing on the receiving side, display is performed by performing interlaced-sequential scanning conversion on the receiving side. At this time, movement is detected on the receiving side, and scanning line interpolation processing is performed using processing parameters corresponding to the movement (for example, see
-130685).

However, since the transmitted information is an interlaced signal, there is a restriction, and there is a motion that cannot be detected in principle. For example, an image that moves exactly at a frame period (1/30 second) cannot be distinguished from a still image, so that interpolation processing is performed in the still image mode even though the image is a moving image, resulting in a large deterioration in image quality. In addition, in a portion determined to be a moving image, a scanning line that is not transmitted is created by interpolating from upper and lower scanning lines in the same field, so that an image having a high vertical frequency (such as fine horizontal stripes) cannot be reproduced.

In order to compensate for the above drawbacks, a normal scanning signal (hereinafter abbreviated as a main signal) is created by performing a sequential-interlaced scan conversion using a progressive scanning camera on the transmitting side, and a scanning line interpolation process on the receiving side is performed. Transmission of a signal for assisting (hereinafter, abbreviated as an auxiliary signal) has been considered. For example, in the Advanced Compatible TV (ACTV) proposed by the United States DSRC (David Sarnoff Research Center), a difference signal between a scan line that is not transmitted due to interlace scanning and a scan line at the same position before and after one feed. (Field difference signal) is transmitted as an auxiliary signal.

FIG. 3 shows a method of reproducing a non-transmitted scanning line from a transmitted scanning line (hereinafter, abbreviated as a sequential signal system) (IEEE Transactions on Consumer Electronics, Vol. 3).
4, No. 1, February 1988). 4A shows the positional relationship of the scanning lines photographed by the sequential scanning camera, FIG. 4B shows the positional relationship of the main signal, and FIG. 4C shows the positional relationship of the scanning lines of the auxiliary signal. (D) shows the positional relationship between the reproduced scanning lines. In FIG. 6A, scanning lines A and B are scanning lines of a field before and after the scanning line X that is not transmitted at the same position. In the above ACTV example, as shown in FIG.
B) / 2) is transmitted. On the other hand, on the receiving side, the transmitted scanning lines A and B and the auxiliary signal Y are transmitted as shown in FIG.
The scanning line X (= Y + (A + B) / 2) that is not transmitted from is reproduced.

FIG. 4 and FIG. 5 show only simplified portions of the luminance signal processing portion in the above-mentioned conventional configuration on the transmission side and the reception side, and show them in a simplified manner. In FIG. 4, a progressive scanning camera
The scanning speed of the signal from 23 is halved by using the demultiplexer 3 in the encoder 101 to form a pair of interlaced signals. For one of the interlaced signals A and B, an average of one frame (= (A + B) / 2) is created using a one-frame delay circuit 4, an adder 5, and a multiplier 6, and the other is used using a subtractor 7. Auxiliary signal Y (= X− (A + B) / 2) is created by subtracting from interlaced signal X. The interlace signals A and B are subjected to delay adjustment by the one-field delay circuit 8 to become a main signal, and then input to the multiplexing circuit 9 together with the auxiliary signal Y. The multiplexing circuit 9 multiplexes the main signal and the auxiliary signal by a multiplexing method described later, and outputs the multiplexed signal as a transmission signal.

In FIG. 5, first, the main signals A and B and the auxiliary signal Y are separated from the transmission signal using the separation answer 24. For the main signal, one frame average (= (A + B) / 2) using one frame delay circuit 25, adder 26 and multiplier 27
Is added to the auxiliary signal Y using an adder 28 to create an interpolation scanning line X (= Y + (A + B) / 2). The main signals A and B are subjected to delay adjustment by a one-field delay circuit 29, and then, together with an interpolation scanning line X, a multiplexer 30.
To enter. The multiplexer 30 doubles the scanning speed, converts the scanning speed into a progressive scanning signal, and inputs the signal to the progressive scanning monitor 31.

FIG. 6 shows a method of multiplexing the main signal and the auxiliary signal. the above
In the example of the ACTV, as shown in FIG. 1A, the sequential scanning auxiliary signal is modulated by using a carrier that is orthogonal to the video carrier for modulating the main signal (having a phase difference of 90 degrees).
It is multiplexed on a channel and transmitted. As shown in FIG. 2B, there is a method in which a part of the screen is masked in black, and an auxiliary signal is multiplexed and transmitted in this mask portion so as to be inconspicuous. Further, there is a method of transmitting the auxiliary signal using a channel different from the main signal.

Further, as another example of the sequential signal transmission method, for a scanning line X not to be transmitted, scanning lines above and below it in the same field are respectively scanning lines C and D, and an auxiliary signal Y is (X− (C + D) / The same effect can be obtained by transmitting 2).

[Problems to be solved by the invention]

The above-described sequential signal transmission method has a remarkable effect of improving the image quality especially in moving images. However, in the transition period of the system introduction, the progressive scanning camera is difficult to obtain, expensive, and not economical. For this reason, it is considered that there is a gradual transition from interlaced scanning cameras to progressive scanning cameras. In this case, two systems, a double-speed progressive scanning signal system and a conventional interlace signal system, are mixed in a broadcasting station, and handling becomes complicated. Furthermore, when an interlaced scanning camera is used as in the past, an auxiliary signal cannot be created because the scanning line X not to be transmitted does not exist, and an area for transmitting the auxiliary signal (RF quadrature modulation area or blackness of the screen). Area, etc.) cannot be used effectively. Further, when another auxiliary signal is transmitted using this area, there is a problem that mode information for identifying the auxiliary signal must be added and the receiver must be changed separately.

Therefore, although the object of the present invention is slightly lower in performance than the case of using a progressive scanning camera, even when the above-mentioned sequential signal transmission system is introduced, the receiver for the sequential signal transmission system is not modified at all. Another object of the present invention is to provide a television signal forming method which can use a conventional interlaced scanning camera without requiring new mode information.

[Means for solving the problem]

The object is to convert an interlaced signal into a progressive scanning signal using an interlaced scanning camera and an interlaced to progressive scanning conversion circuit, and convert the progressive scanning signal into a transmission signal in exactly the same way as when using a progressive scanning camera. This is achieved by converting and transmitting.

[Action]

The operation of the present invention will be described again with reference to FIG.
In FIG. 9A, only the scanning lines (A, B, C, D, etc.) indicated by white circles are output from the interlaced scanning camera.
The interlaced signal is generated by interpolating a scanning line (such as X) indicated by a black circle using an interlaced-to-sequential scan conversion circuit. Hereinafter, the case where a progressive scan camera is used as the progressive scan signal will be described. Treat the same. That is, an auxiliary signal is created and transmitted from the interpolated scanning line on the transmission side.

When the transmitting side interpolates the scanning line X from the scanning lines A, B, C, and D, a method of switching the interpolation method according to the movement can be considered. For example, in the case of a still image, the interpolation is performed from the preceding and succeeding fields (X = (A + B) / 2), and in the case of the moving image, the interpolation is performed from the upper and lower lines (X = (C + D) / 2). Using the motion amount k detected by the motion detection circuit, these are switched adaptively and continuously, and the following scanning line signal X is output.

X = (1−k) · (A + B) / 2 + K · (C + D) / 2 (1) (However, for a still image: k = 0, for a moving image: k = 1, 0 ≦ k ≦
1) In this case, the auxiliary signal Y shown in FIG. 3C can be expressed as follows.

Y = X− (A + B) / 2 = k · (C + DA−B) / 2 (2) In the receiver for the sequential signal transmission system, as shown in FIG. The scanning line X is reproduced by taking the sum of the value ((A + B) / 2) and the auxiliary signal Y.

X = (A + B) / 2 + Y = (A + B) / 2 + k · (C + D−A−B) / 2 = (1−k) · (A + B) / 2 + k · (C + D) / 2 (3) This is the same as the result of the motion adaptive scanning line interpolation performed on the transmission side. That is, despite the fact that the receiver of the sequential signal transmission system is not changed at all and is in the fixed mode (inter-field interpolation + auxiliary signal), the receiver automatically performs the optimal interpolation according to the motion of the image. Therefore, the image quality is improved as compared with the case where only the simple inter-field interpolation is performed.

Therefore, the above object can be achieved by temporarily converting the interlaced signal into a scanning signal, generating an auxiliary signal from the interpolated scanning line on the transmission side, and transmitting the auxiliary signal.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a configuration diagram of an embodiment of the present invention. In FIG. 1, a signal from an interlace camera 1 is temporarily converted into a sequential scanning signal by an interlace-to-sequential scanning conversion circuit 2 described later. From this signal, a transmission signal is created by the same encoder as the encoder 101 shown in FIG. That is, the scanning speed is halved by using the demultiplexer 3 to form a pair of interlaced signals, and one of the interlaced signals A and B is converted into one frame by using the one-frame delay circuit 4, the adder 5, and the multiplier 6. An average (= (A + B) / 2) is created and subtracted from the other interlaced signal X using a subtractor 7 to obtain an auxiliary signal Y (=
X- (A + B) / 2). The interlace signals A and B are subjected to delay adjustment by the one-field delay circuit 8 to become a main signal, and then input to the multiplexing circuit 9 together with the auxiliary signal Y. The multiplexing circuit 9 multiplexes the main signal and the auxiliary signal to form a transmission signal and outputs it.

FIG. 2 shows a detailed circuit configuration example of the interlace-sequential scan conversion circuit 2. First, a main signal and an interpolation scanning line signal are created from the input interlace signal. The procedure for creating an interpolation scanning line signal is as follows. Using the one-field delay circuits 10 and 12 and the one-line delay circuit 11, the scanning lines A, B, C and D as shown in FIG. The interpolators 14 and 16 create inter-line interpolation values ((C + D) / 2) and inter-field interpolation values ((A + B) / 2) in the same field. Further, the motion detection circuit 20 outputs a motion amount k from the input signal.
Here, k = 0 for a complete still image, k = 1 for a complete moving image, and (0 <k <
1). Using the multipliers 17 and 18 and the adder 19, the interpolation scanning line signal ((1−k) · (A + B) / 2 +
k · (C + D) / 2). Further, the input interlace signal is subjected to delay adjustment using a one-field delay circuit 21 to become a main signal, and a multiplexer together with an interpolation scanning line signal.
Enter 22. The multiplexer 22 doubles the scanning speed, converts the scanning speed into a sequential scanning signal, and outputs the signal. The motion detection circuit 20 can be easily realized by detecting a one-frame difference or a two-frame difference between images. In addition, since the transmitting side can detect the motion from the red, green, and blue signals of the component, or the luminance signal and the color signal of the component, the receiving side can detect the motion more accurately than detecting the motion from the composite signal. Further, the interlace-sequential scan conversion circuit 2 is generally used for an IDTV or an EDTV receiver, and can be easily obtained and realized.

FIG. 7 shows another embodiment of the present invention in which the configurations shown in FIG. 1 and FIG. 2 are simplified together. From the signal from the interlaced camera 1, one-field delay circuits 32, 3
After the scanning lines A, B, C, and D as shown in FIG. 3B are created by using the four- and one-line delay circuits 33, the adders 35 and
The interpolated value between lines ((C + D) / 2) and interpolated value between fields ((A +
B) / 2), that is, (C + DAB) / 2 is created. Further, the motion detection circuit 39 outputs a motion amount k from the input signal. Here, for a complete still image, k = 0
It is assumed that k = 1 for a complete moving image and (0 <k <1) for an intermediate movement. An auxiliary signal Y (= k · (C + DA−B) / 2) is set using the multiplier 40. Further, the input interlace signal is subjected to delay adjustment using a one-field delay circuit 41 to become a main signal, and
And multiplexed with the auxiliary signal to obtain a transmission signal.

FIG. 8 shows the transition period of the introduction of the sequential signal transmission system.
1 shows an example of a conventional system configuration in a broadcasting station. The signal from the newly introduced progressive scanning camera 23 is subjected to signal processing by a processing circuit 42 dedicated to the progressive scanning signal. The signal from the conventional interlace camera 1 is processed by a processing circuit 43 dedicated to the interlace scanning signal. The signal processing here refers to video effects such as image enlargement / reduction and chroma keying, processing such as multiplexing of high-quality and high-definition information and vertical compression for wide aspect ratio, and conversion of the number of scanning lines. Including. The signals from the processing circuits 42 and 43 are selected by the switch 44 and converted by the encoder 101 into transmission signals. Therefore, conventionally, two sets of expensive processing circuits are required for progressive scanning and interlaced scanning, and two systems of signals run in a broadcasting station.
Handling was complicated.

FIG. 9 shows an example of a system configuration when the present invention is incorporated in a camera. A signal from a signal source 100 in which an interlace-sequential scan conversion circuit 2 is built in a conventional interlace scan camera 1 is in a progressive scan form. Therefore, it is possible to directly switch with the signal from the progressive scanning camera 23 by using the switch 44, and when performing signal processing, only the processing circuit 42 having a common interlace of the sequential signal is sufficient, and the Can be unified into one signal format.

Many variations of the present invention are possible, as described below.

(1) In the above description, for simplicity, the interpolation method between scanning lines has been described as an average interpolation from neighboring scanning lines.
Further, the interpolation characteristics may be improved by increasing the number of taps. Although the interpolation performance is slightly reduced, the circuit scale may be reduced by using only the preceding value interpolation.

(2) Another example of the sequential signal transmission method, that is, scanning lines X not shown in FIG. 3 and scanning lines C and D above and below it in the same field, respectively,
When (X- (C + D) / 2) is transmitted as the auxiliary signal Y, the same effect can be obtained by replacing the above-described scanning lines A and C with B and D.

(3) Although only the luminance signal has been described in a simplified manner, it is obvious that the present invention can be applied to a general color television signal (component signal), and the composite may be performed on the signal after the present invention is applied. . Further, the present invention may be applied to a signal source (VTR, video disc, etc.) other than a camera.

(4) The present invention is not limited to the transmission of television signals,
It can also be applied to recording on a VTR or video disc.

(5) Not only the progressive scanning signal (525 lines, 1: 1) is used in a common signal format, but also a signal for HDTV (1125
Book, 2: 1) and interlaced double-speed signals (1050, 2: 1).

〔The invention's effect〕

By applying the present invention, even when a new sequential signal transmission system is introduced, no changes are made to the receiver,
In the transition period, the conventional interlaced camera can be used as it is, which is economically advantageous, and the broadcasting station is also limited to only one system of signals (sequential scanning signals, signals encoded in the same format, etc.). Since the handling becomes convenient, the effect is extremely large when implemented.

[Brief description of the drawings]

FIG. 1 and FIG. 2 are configuration diagrams of an embodiment of the present invention, and FIG.
FIG. 6 and FIG. 6 are explanatory diagrams of the operation of the conventional example, FIG. 4 and FIG. 5 are configuration examples of a conventional transmitting side and a receiver of a sequential signal transmission system, and FIG. 7 is a configuration of another embodiment of the present invention. FIG. 8, FIG. 8 is a conventional system configuration diagram, and FIG. 9 is a system configuration diagram to which the present invention is applied. DESCRIPTION OF SYMBOLS 1 ... interlace scanning camera, 2 ... interlace-sequential scan conversion circuit, 3 ... demultiplexer, 4,8,10,11,12,2
1,25,29,32,33,34,41… Delay circuit, 5,13,15,19,26,28,3
5,36… Adder, 6,14,16,17,18,27,38,40… Multiplier, 7,37
… Subtractor, 9… Multiplexing circuit, 20,39… Motion detecting circuit, 22,30
... Multiplexer, 23 ... progressive scan camera, 24 ... separation circuit, 31 ... progressive scan monitor, 42, 43 ... processing circuit, 44 ... switcher, 100 ... signal source, 101 ... encoder.

Claims (5)

(57) [Claims] A main signal and an auxiliary signal are created by performing scan conversion from a signal having a second number of scanning lines while maintaining compatibility with a television system having a first number of scanning lines. In a method of forming a television signal in a television system in which the auxiliary signal is multiplexed and transmitted, first scan conversion is performed from a signal having a first number of scanning lines to a signal having a second number of scanning lines. Forming a main signal and an auxiliary signal by performing a second scan conversion from a signal having a second number of scanning lines, and multiplexing the main signal and the auxiliary signal. Method. 2. A first scanning conversion means for receiving an interlaced scanning signal as input and performing a scan conversion of the interlaced scanning signal to obtain a sequential scanning signal, and a main signal in the interlaced scanning form by performing scanning conversion of the progressive scanning signal. Second scan conversion means for obtaining, and auxiliary signal generation means for obtaining, based on the progressive scanning signal, an auxiliary signal for assisting reproduction of a signal of a scanning line not included in the main signal on a receiving side; An apparatus for forming a television signal, comprising: multiplexing means for multiplexing a main signal and the auxiliary signal. 3. The interpolated scanning line generating means for generating an interpolated scanning line, wherein the interpolated scanning line means obtains an inter-line interpolation value based on an interlaced scanning signal. Means for obtaining an inter-frame interpolation value, means for obtaining a motion amount, and mixing the inter-line interpolation value and the inter-frame interpolation value at a mixing ratio corresponding to the motion amount and outputting the result as a signal of a complementary scanning line. 3. The television signal forming apparatus according to claim 2, comprising a mixing means. 4. An auxiliary signal generating means for obtaining an inter-line interpolation value or an inter-frame interpolation value based on the main signal, and a difference signal or inter-frame inter-line interpolation value and a signal of the interpolation scanning line. 4. The television signal forming apparatus according to claim 3, further comprising means for outputting a difference signal between an interpolation value and a signal of the interpolation scanning line as an auxiliary signal. 5. An interpolated scanning signal, a means for obtaining an inter-line interpolation value, a means for obtaining an inter-frame interpolation value, a means for obtaining a motion amount based on the interlaced scanning signal, A subtractor for obtaining a difference signal between the signal and the inter-frame interpolation value; a multiplier for multiplying the difference signal by a motion amount; and a multiplexing unit for the interlaced scanning signal and an output signal from the multiplier. An apparatus for forming a television signal.