JPH06178324A - Method and device for transmitting picture signal - Google Patents

Abstract

PURPOSE:To improve transmission efficiency and picture quality at the time of converting a wide picture signal into a letter box signal and transmitting it by extracting one high band component from the wide picture signal, inserting a reinforcing signal generated by compressing a time base into upper and lower non-picture areas of the letter box signal, and transmitting it. CONSTITUTION:The luminance/chrominance signals of original wide picture signals 2 whose number of horizontal scanning lines is 240/FLD are inputted to VLPF 3 and VHPF 4. VLPF 3 executes additional arithmetic processing on the picture signal of an adjacent horizontal scanning line and reduces the number of the horizontal scanning lines. Then, a main picture signal 5 whose number of the horizontal lines is 180/FLD is generated. In VHPF 4 on the other hand, a subtractive arithmetic processing is executed on the picture signal of the adjacent horizontal scanning line and the number of the horizontal scanning lines is reduced. Then, the vertical high band reinforcing signal 6 whose number of the horizontal scanning lines is 60 is generated. The signal 6 is transmitted to an amplitude adjustment means 7, amplitude is restricted to about a 201IRE unit, an average level is suppressed to about a black level, and it is transmitted to a signal synthesis means 8 with the signal 5. Then, it is rearranged in a vertical direction and a synthesis output signal 9 whose number of the horizontal scanning lines is 240 is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention realizes an image signal transmitting method suitable for use in, for example, a VTR (video tape recorder), a VD (video disc), a camera-integrated VTR, a still video camera, and the like. According to the image signal transmission device to be obtained, in particular, a wide image signal expanded in the horizontal scanning direction as compared with the standard image signal is processed by the same synchronization signal system as the standard image signal, and a position corresponding to the upper and lower sides of the screen is set as a non-image area. And apparatus for transmitting as a letterbox signal.

[0002]

2. Description of the Related Art TV of current standard system such as NTSC system
(Television) The image signal has a screen aspect ratio of 3:
It is defined as 4 and is in operation. On the other hand, in recent TV receivers, the image quality has been improved and the display screen has been significantly enlarged. In such a large screen, the aspect ratio of the standard system is 3:
A horizontal screen that is stretched more horizontally than 4 and has a wide screen such as the aspect ratio of 9:16, which is used in high-definition TV broadcasting, etc., matches the human visual field and is easy to see and natural and realistic. It is known.

By the way, such a wide image signal for a wide screen cannot be generally handled as it is by a transmission device having an existing signal processing system such as the current NTSC system. Therefore, as one of the solutions, a wide image signal is electronically processed to be converted into a letterbox signal having a non-image (usually black) region above and below the display screen.

However, the signal transmitted by this method is
It is convenient in terms of compatibility when projected on a standard TV monitor, but when restored by performing electronic processing again to project on a landscape TV monitor for wide image signals. However, there is a drawback in that information is lost from the original wide image signal and the image quality is significantly deteriorated. Therefore, as a method of compensating for such a defect, when converting a wide image signal into a letterbox signal, by inserting a reinforcement signal extracted from the original wide image signal into the non-image signal region corresponding to the upper and lower parts of the screen of the letterbox signal. It has been proposed to enhance the image quality by transmitting this signal and synthesizing this reinforcing signal with the signal in the effective image (main image) region of the letterbox signal when restoring the wide image signal.

For example, an example of the EDTV2 broadcasting system currently under discussion will be described in the form of a screen as shown in FIG.
As shown in (B), when converting an original image with an aspect ratio of 9:16 to a letterbox signal with an aspect ratio of 3: 4, it is extracted from the original image signal in the upper and lower non-image areas (hatched areas in the figure). In the example of FIG. 15 (A), a signal obtained by compressing the vertical high-frequency component of the luminance signal by 1/3 on the time axis is inserted as the reinforcing signal. Further, in the example of FIG. 7B, the non-image area is divided into two (hatched areas with different slopes in the figure), and the vertical high-frequency component of the luminance signal is compressed to 1/6 in each area. And the horizontal high frequency component of the luminance signal is 1/6
A time-compressed signal is inserted in. The original image signal in this case is a non-interlaced scanning signal with a frequency band of 6 MHz and vertical scanning lines of 525 lines (effective screen = 480 lines) converted to a letterbox signal conforming to the normal NTSC system. There is.

As another example, for example, Japanese Patent Laid-Open No. 2-156785
There is a conventional technique described in the publication, and in this example, a technique of inserting a horizontal high frequency component of a color signal extracted from an original image signal by time axis compression is introduced as a reinforcement signal.

[0007]

However, the above-mentioned ED
In the TV2 broadcasting system, the original image signal is limited to the non-interlaced signal, and the reinforcement signal is limited to only the luminance signal component, so that the application is limited, and the reconstructed wide image has insufficient color reproducibility. Is. In addition,
In the device described in Japanese Patent Laid-Open No. 2-156785, since only the color signal is used as the reinforcement signal, the luminance signal of the restored wide image lacks the luminance information with respect to the original image, and the deterioration of the resolution is considerable. There was a problem of being conspicuous.

[0008]

Therefore, in order to solve the above-mentioned problems, the present invention is directed to converting a wide image signal having an aspect ratio different from the standard to a letterbox signal having a standard aspect ratio and transmitting the same. In addition, at least one high frequency component of the luminance signal vertical high frequency component, the luminance signal horizontal high frequency component, and the color signal horizontal high frequency component is extracted from the wide image signal, and further time axis compression is performed to generate a reinforcement signal. The reinforcing signal is selectively inserted in the upper and lower non-image areas of the letterbox signal and transmitted, and the receiving side synthesizes the reinforcing signal with the video signal of the main image area of the letterbox signal as necessary. The present invention provides a method for transmitting an image signal, which performs the signal processing of 1.

Further, at least one high-pass filter for extracting any of the high-frequency component of the luminance signal vertical high-frequency component, the luminance signal horizontal high-frequency component, and the color signal horizontal high-frequency component from the wide image signal, At least one time axis compressor that individually compresses the output high frequency components on the time axis to generate a reinforcement signal, and rearrangement within a screen that outputs the reinforcement signal by inserting it into the upper and lower non-image areas of the letterbox signal. An image signal transmission device is provided with a means and a synthesizing means for synthesizing the above reinforcement signal with a video signal of a main image area of a letterbox signal on the receiving side via a predetermined transmission path as required. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the method and apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a block system diagram for explaining a signal processing operation of a first embodiment of the present invention. Here, as shown in the figure, the original wide image signal has a signal frequency band of 6 MHz and a horizontal scanning line number on an effective screen. 240 lines / FLD (field; 480 lines / frame) and a screen aspect ratio of 9:16. When this is converted into a letterbox signal having the same horizontal scanning line number and a screen aspect ratio of 3: 4, the aspect ratio of the original wide image signal and the letterbox signal is 3: 4.
(← 12: 16) Therefore, the main image area of the letterbox signal is 180 horizontal lines / FLD in the area corresponding to the screen center.
This is equivalent to a total of 60 lines at the top and bottom of the screen with no image area.
Must be FLD.

Therefore, the luminance signal and the chrominance signal of the original wide image signal 2 having 240 horizontal scanning lines / FLD are respectively the low-pass filter (VLPF) 3 for vertical scanning signal and the high-pass filter for vertical scanning signal. The image signal of the adjacent horizontal scanning line is sent to the (VHPF) 4, and the number of horizontal scanning lines is reduced by subjecting the image signal of the adjacent horizontal scanning line to the additive arithmetic processing, and the main image signal 5 of 180 horizontal scanning lines / FLD is generated. On the other hand, in the VLPF 4, the number of horizontal scanning lines is reduced by subjecting the image signals of the adjacent horizontal scanning lines to subtractive calculation processing, and the vertical high frequency reinforcing signal 6 of 60 horizontal scanning lines / FLD is added.
To generate.

In the above arithmetic processing, when the horizontal scanning line rank of the original wide image signal 2 is n, the horizontal scanning line rank of the main image signal 5 is m, and the horizontal scanning line rank of the vertical high frequency reinforcing signal 6 is j, In order to generate the signal on each scanning line, for example, the calculation shown in the following equation may be repeated 60 times with n = 1, 5, 9, ..., 237,
FIG. 2 is a schematic diagram showing this calculation.

[0013]

[Equation 1] The signal frequency band of the outputs of VLPF3 and VHPF4 remains 6 MHz, which is the same as that of the original wide image signal 2.

Next, the vertical high frequency reinforcing signal 6 is supplied to the amplitude adjusting means 7 so that the amplitude is adjusted to 20 IRE (Institute for Ra) so as not to be noticed when it is displayed on a standard TV monitor.
(dioEngineers) unit, and the average brightness level is suppressed to be near the black level, and then sent to the signal combining (in-screen rearrangement) means 8 together with the main image signal 5, where the amplitude is adjusted in order from the position corresponding to the upper part of the screen. The number of horizontal scanning lines in the vertical high-frequency augmentation signal 6 that has been adjusted is 30, then the number of horizontal scanning lines of the main image signal 5 is 180, and the number of remaining horizontal scanning lines of the vertical high-frequency enhancement signal 6 whose amplitude has been adjusted is 30. By rearranging the signals in the vertical direction like a book, a combined output of 240 horizontal scanning lines can be obtained. It should be noted that, at the time of signal synthesis (screen rearrangement), the amplitude-adjusted vertical high-frequency reinforcement signal 6
Are arranged evenly on the upper and lower parts of the screen, but they may be arranged unevenly on the upper and lower parts.

The composite output signal 9 thus obtained
In this state, the current standard TV monitor and V
It can be transmitted by TR, etc., and when projected on a standard TV monitor, there is no image (black) at the top and bottom of the screen.
Therefore, the main image signal with 180 effective horizontal scanning lines can be displayed in the other substantially central portion.

Here, as an example, a case where the composite output signal 9 is recorded on a magnetic tape in a home standard VTR format of the current standard system and reproduced and displayed on a TV monitor for wide screen is used as an example. -If description is made assuming that a VHS (registered trademark) type VTR is used, the process of recording on a magnetic tape and reproducing at any time is performed by the conventional S-VHS type V
TR can be performed without any substantial modification, and the main image signal and the reinforcement signal are obtained from the obtained reproduction signal by the reverse process of the signal processing operation shown in FIG. By performing the signal processing for generating the original wide image signal from, it is possible to obtain a wide image signal of high image quality with little information loss.

In this case, the frequency band of the signal used in the S-VHS system VTR is limited to 5 MHz,
Since it does not reach the frequency band (6 MHz) of the original wide image signal,
Although the horizontal resolution is slightly degraded, the vertical resolution can be as high as that of the original wide image. If the color signal exists only in the main image signal, the burst signal is inserted over all the effective scan lines in order to stabilize the operation of the color signal processing process.

By the way, in the first embodiment described above,
The horizontal signal frequency band is limited by the performance of the VTR and the like, and there is a drawback that the information contained in the original wide image signal cannot be sufficiently transmitted without omission.

As is well known, the ITEJ Technical Report
According to Vol.14 No.8 p.25 to 30, etc., regarding the transmission of image signals, "Of the high frequency signals in the vertical direction, the most important signals on the screen are
A low frequency component in the horizontal direction and a high frequency component in the horizontal direction contributes little to image quality. " Therefore, in the second embodiment of the present invention, the reinforcement signal is 1 /
2) The time axis is compressed to 30 horizontal scanning lines, and the information of the horizontal high-frequency component (for example, 5 to 6 MHz) extracted from the main image signal is inserted into the gap corresponding to this and it is transmitted. Is.

The second embodiment will be described below with reference to FIGS. 3 to 6. FIG. 3 is a block diagram of the apparatus of the second embodiment for generating a letterbox signal with a reinforcement signal from an original wide image signal, and FIG. 4 is an explanatory diagram of the signal processing operation thereof. In FIGS. The same components as those of the first embodiment shown in FIG. Further, the illustration of the amplitude adjusting means 7 is also omitted for convenience.

As shown in FIGS. 3 and 4, the original wide image signal 2 coming from the input terminal In ₁ is VLPF 3 and VH.
The main image signal 5 and the vertical high range reinforcement signal 6 are supplied to the PF 4.
Are generated according to the same principle as in the first embodiment. Next, the main image signal 5 is sent to the signal synthesizing means 82 and also supplied to the horizontal high-pass filter (HHPF) 10, where the high-frequency component (for example, 5 to 6 MHz) 11 of the horizontal image signal is extracted and It is sent to the frequency converter 12 of the stage, where, for example, 1-2 MHz
As described above, the low-frequency converted signal 13 that is low-frequency converted into a frequency band that can be sufficiently transmitted by the standard VTR is obtained.

This signal 13 is sent to a vertical scanning signal low-pass filter (VLPF2) 14 where signals in a plurality of scanning lines are added and averaged so that, for example, the number of horizontal scanning lines is 1. It becomes / 3 and becomes 60 low-pass converted horizontal high frequency signals 15, which are further sent to the time axis compressor 16 to compress the time axis and convert two horizontal scanning lines into one. As a result, a horizontal high-frequency reinforcement signal 17 having 30 horizontal scanning lines is obtained. On the other hand, the vertical high frequency reinforcement signal 6 is supplied to the second time axis compressor 18, where the time axis is compressed to 1/2, and two horizontal scanning lines are converted into one to obtain a compression reinforcement signal 19.
To get

The main image signal 5, obtained as described above,
The horizontal high-frequency reinforcing signal 17 and the compression reinforcing signal 19 are sent to the signal synthesizing means 8, where, for example, half of the horizontal scanning lines of the horizontal high-frequency reinforcing signal 17 are sequentially arranged from the position corresponding to the upper part of the screen.
By rearranging each signal in the vertical direction in the order of half the number of horizontal scanning lines of the compression reinforcement signal 19, the main image signal 5, the remaining half of the compression reinforcement signal 19, and the remaining half of the horizontal high frequency reinforcement signal 17, It is possible to obtain a combined output signal 20 having 240 scanning lines / field. This composite output signal 2
When 0 is received on the monitor TV or transmitted (recorded and reproduced) via the VTR, compared with the first embodiment,
Although the frequency band after the restoration of the compression reinforcement signal 19 is halved to about 2.5 MHz, there is no problem in practical use as described above by citing the reference, and the luminance signal of the luminance signal due to the transmission characteristic of the standard VTR or other device is used. There is an advantage that loss of information of high frequency components can be prevented.

Here, the HHPF 10 and the frequency converter 12
Will be described in more detail with reference to FIG. Figure 5
(A) is a frequency vs. signal distribution diagram of the main image signal 5, and shows that the main image signal 5 is a signal having a component of frequency 0 (DC) to 6 MHz. Next, FIG. 5B shows the HHPF.
FIG. 3 is a frequency-to-signal distribution diagram of the high-frequency component 11 of the main image signal 5 extracted by 10, showing that it is distributed at frequencies of 5 to 6 MHz. Further, FIG. 5 (C) shows the low-frequency converted horizontal high-frequency signal 1 output from the frequency converter 12.
5 is a frequency vs. signal distribution chart of FIG. 5, and if the carrier frequency of the frequency converter 12 is 7 MHz, for example, the low-frequency converted signal 13
Indicates that the frequency component is 1 to 2 MHz. With regard to this low frequency conversion, when digital signal processing is performed, the same result as the above low frequency conversion can be obtained even with 1/2 down sampling.

Next, the operation of the VLPF2 14 will be described in more detail. When the scanning line order of the main image signal is m and the scanning line order after conversion is k, for example, the conversion shown by the following equation is performed as m = It may be repeated 60 times as 1,5,9, ..., 237.

[0026]

[Equation 2] This conversion algorithm is shown in FIG. 6, and the number of horizontal scanning lines can be compressed to 1/3. In this conversion, it is empirically known that the high frequency signal components in the vertical direction have high vertical correlation, so that the loss of information due to the conversion can be almost ignored.

In the second embodiment described above, the horizontal high frequency reinforcing signal 17 and the compression reinforcing signal 19 for scanning line recovery are inserted in the non-image area of the letterbox signal by the same number of scanning lines and transmitted. However, the ratio may be changed depending on the application, for example, only the horizontal high-frequency reinforcing signal 17 is used.

By the way, as a transmission line, for example, S-VHS is used.
When the VTR of the method is used, the frequency band of the color signal is defined as 350 kHz according to the standard, but this value is a considerably narrow band as the image transmission path in the present invention. In the second embodiment, deterioration due to the transmission of this color signal is expected. Therefore, as a third embodiment of the present invention, an example in which a transmission path having a narrow color signal frequency band is considered will be described with reference to FIGS. FIG. 7 is an arrangement example of color difference signals, and FIG. 8 is a block diagram showing the configuration of the third embodiment. In FIG. 8, the same elements as those of the first and second embodiments shown in FIGS. Are denoted by the same reference numerals and detailed description thereof will be omitted.

In FIG. 8, the input signals supplied from the input terminals In _{2 and} In ₃ are the primary color signal and the primary color signal, respectively.
21c and the original luminance signal 21y.
It is assumed that the primary color signal 21c has been converted into the form of the color difference signal "RY / BY" (or the well-known I / Q signal form is possible), which is the first color signal vertical low-pass filter. (CV
LPF) 22. In the CVLPF22, the horizontal scanning lines are 240 lines / FLD to 180 lines /
The main image color signal 23 is generated by being reduced to FLD. The main image color signal 23 is sent to the signal synthesizing means 24 and is also supplied to a color signal horizontal high-pass filter (CHHPF) 25. Here, for example, a color signal exceeding 350 kHz which cannot be transmitted by the S-VHS system VTR. The high frequency component 26 is extracted, and the second color signal vertical low pass filter (CVLPF2
) 27.

In the CVLPF2 27, the CVLPF1 2
By the same method as in 2, the color signal high frequency conversion signal 28 having 60 horizontal scanning lines / FLD is generated, and further the time axis compressor 29 compresses the time axis to 1/2. That is, the processing for reducing the signals for two horizontal scanning lines to one is performed, and the color signal compression reinforcement signal 30 of 30 horizontal scanning lines / FLD is obtained,
Further, it is sent to the signal synthesizing means 24. FIG. 7 shows an arrangement example of color difference signals in one horizontal scanning line at this time.

On the other hand, the original luminance signal 21y has the same structure and algorithm as those of the first and second embodiments already described, and the main image (luminance) signal 5 and the vertical high frequency reinforcing signal 6 are added to the time axis compressor 18. Compressed reinforcement signal 1 whose time axis has been compressed to 1/2
9 is generated, and both signals 5 and 19 are combined with the signal combining means 24.
Sent to. And here, for example, as shown in FIG.
Half of the color signal compression reinforcement signal 30, half of the compression reinforcement signal 19, the composite signal of the main image signal 5 and the main image color signal 23, the remaining half of the compression reinforcement signal 19, and the color signal compression reinforcement in order from the position corresponding to the upper part of the screen. The other half of the signal 30,
The signals are combined and the signals are rearranged, and the signals are output to the transmission path (for example, S-VHS VTR).

Since the color signal compression reinforcement signal 30 thus inserted is transmitted by occupying 30 horizontal scanning lines / FLD, the S-VHS system having a frequency band of 5 MHz is used as a transmission line. Even in VTR, 0 per color difference signal (DC)
Although transmission in the frequency band of up to 1.25MHz is possible, the low-frequency component close to direct current is reflected on the letterbox signal on a conventional standard TV monitor even if the amplitude is limited. In the lower non-image area, as shown in FIG. 9, two strips each having a certain width (area) and different in lightness are formed so that they are conspicuous. For example, in the time axis compressor 29 of FIG. It is advantageous in terms of compatibility with the conventional system to remove the frequency component of about 350 kHz from the direct current and transmit it by connecting an HPF (high-pass filter) afterwards.

Further, in the present embodiment, the compression reinforcement signal 19 and the color signal compression reinforcement signal 30 occupy 30 horizontal scanning lines / FLD each, but this ratio is not limited to half and half, and the ratio may be varied depending on the application. , 0 to 100% may be used. Further, the color signal compression reinforcement signal 30 is not limited to the arrangement mode of the color difference signals shown in FIG. 7, and may be line sequential as one type of color difference signal for one horizontal scanning line, for example.

In the above three embodiments, the processing in a single field has been described, and it is premised that the processing is repeated for each field. However, the correlation between image signals is high between two adjacent fields. Since it is empirically known, the luminance signal horizontal high-frequency component and the color signal horizontal high-frequency component having a low vertical resolution are often similar signals in succession.

Therefore, in the fourth embodiment of the present invention, attention is paid to this point, for example, in an odd field (or Ch. 1 in the case of VTR), in the non-image area of the letterbox signal, the main image signal described in detail in the second embodiment. The horizontal high-frequency reinforcement signal 17 and the compression reinforcement signal 19 obtained from the original wide image and compressed on the time axis are inserted to generate a composite output signal. In the even field (VTR, Ch.2), the third embodiment is used. A signal that inserts the color signal compression reinforcement signal 30 and the compression reinforcement signal 19 into the non-image area of the letterbox signal described in detail to generate a composite output signal and sequentially repeats this in a predetermined transmission sequence is generated. I am trying to transmit. Then, the receiving side (reproduction signal processing system side in the case of VTR) performs a process of interpolating between the fields with these transmitted signals to enable high-quality image signal transmission.

In the fourth embodiment, when the image is a moving image, correct interpolation may not be performed between fields. Therefore, as a countermeasure against this, the receiving side (VTR
If it is a moving image, the synthesis of each reinforcement signal into the main image signal is stopped, or the transmitting side (recording system side if VTR). By passing an inter-field comb filter to each reinforcement signal in advance (so-called precom filtering), each reinforcement signal is synthesized and output only in a portion (still image portion) where the image does not move on the screen.

Further, the actual image to be transmitted includes all the reinforcement signals described so far in consideration of the contents of the image itself, the intended use at the receiving side, and the transmission efficiency. In some cases, or in some cases it may not be necessary to transmit some or all of the reinforcement signals. Therefore, as a fifth embodiment of the present invention, the first
Through the three types of reinforcement signals described in the third embodiment, that is, the vertical high-frequency reinforcement signal 6, the horizontal high-frequency reinforcement signal 17, and the color signal compression reinforcement signal 30 (in each case, presence or absence of time axis compression is arbitrary). From among, the optimum reinforcement signal according to the target image,
An example in which each field is arbitrarily selected and transmitted will be described.

In this case, in order to reproduce a correct image on the receiving side, it is necessary for the transmitting side to simultaneously transmit the information indicating the type of the reinforcement signal inserted for each field. Therefore, in the fifth embodiment, an index code (ID code) for identifying the type of the reinforcement signal or the combination thereof is attached, and this is transmitted for each field. This ID code may be inserted in the signal transmission path (signal processing path) of either the luminance signal or the color signal. As an example, when a letterbox signal conforming to the current NTSC system is transmitted, a method of inserting it into the vertical blanking of the luminance signal will be described.
For example, in the 15th horizontal scan line in the odd field and in the 277th horizontal scan line in the even field, the ID
Insert the code.

FIG. 10 shows a specific example of the form of such an ID code (a signal waveform corresponding to the ID code in any of the above scanning lines). FIG. 10 (A) shows the one to which this horizontal scanning line belongs.
The signal waveform of the ID code indicating that the reinforcing signal included in the field is, for example, only the vertical high frequency reinforcing signal 6, FIG.
(B) is also a vertical high range reinforcement signal 6 and a horizontal high range reinforcement signal 1
7 is a combination of the vertical high frequency reinforcing signal 6 and the color signal compression reinforcing signal 30, and shows an example of the signal waveform of the ID code. It should be noted that the line (horizontal scanning line portion) used here usually has no signal, so that
It goes without saying that no malfunction occurs in the monitor device or VTR.

By the way, each of the reinforcing signals described above is limited to a small amplitude so as to be inconspicuous when displayed on a standard TV monitor device. Therefore, in order to obtain a reinforcement signal for displaying on a wide screen from such a signal, the signal is amplified so as to return to the original amplitude on the receiving side (reproduction signal processing system in the case of VTR), so that SN is higher than the signal on the main screen. The disadvantage that the ratio deteriorates occurs. Therefore, as a sixth embodiment of the present invention, high-frequency emphasis (pre-emphasis) is applied only to the reinforcement signal on the transmitting side (recording signal processing system for VTR), and complementary high-frequency attenuation (de-emphasis) is applied to the receiving side. In the blanking period (including the synchronizing signal period) where there is no image signal, the high frequency emphasis on the transmitting side is stopped.

FIG. 11 is a block diagram of the configuration, and FIG.
(A) and (B) show frequency characteristic examples of the high-frequency emphasis circuit 33 and the high-frequency attenuation circuit (not shown), respectively. As shown concretely in FIG. 11, the synthesized output signal 32 obtained by the circuit configuration similar to each of the above-described embodiments outputs the sync separation circuit 3 from the input terminal In _4.
4, supplied to the high-frequency emphasis circuit 33 and the contact B of the switch Sw1. The sync separation circuit 34 extracts the horizontal blanking period data 36 in the combined output signal 32, and also extracts the vertical position data (vertical period data) 37 in which the reinforcing signal is inserted. 37 is supplied to the gate circuit 38, and the gate circuit 38 generates a gate signal for connecting the switch Sw1 to the contact A side only during the reinforcement signal existing period excluding the horizontal blanking period.

On the other hand, in the high frequency emphasizing circuit 33, the synthesized output signal 32 is subjected to gain enhancement of high frequency components as shown in FIG. 12 (A) to generate a high frequency emphasizing signal 40. Output to contact A of switch Sw1. Therefore, the high-frequency emphasis signal 40 is output from the terminal C of the switch Sw1 only during the period when the reinforcement signal is present. And the receiving side (VTR
Then, in the reproduction system side), the SN ratio of the reinforcing signal is improved by performing high frequency attenuation with the complementary frequency characteristic as shown in FIG.

That is, when the high-frequency emphasis reinforcement signal 41 obtained as described above is transmitted through a transmission line such as a VTR recording / reproducing signal processing circuit (including a magnetic tape), a recording signal processing circuit is used. In the (recording system), the high-frequency emphasis reinforcement signal 41 is recorded on the magnetic tape, and in the reproducing system,
The high-frequency emphasis circuit 33 of the circuit configuration shown in FIG.
By constructing a restoration circuit in which the high-frequency attenuation circuit having the frequency characteristic shown in (B) is replaced and transmitting the above signal to the restoration circuit, it is possible to restore a reinforcement signal having a good SN ratio. Such emphasis processing is substantially the same as a well-known emphasis circuit.

By the way, when a transmission system such as a VTR is used in the present invention, a signal may slightly change on the time axis due to the influence of jitter or the like in the process of recording and reproducing. Therefore, a time base collector (TBC) is used to correct such variations, and a seventh embodiment of the present invention having an advantageous function when inserting such a TBC will be described. As is well known, in the current VTR for general household use, normally, a color signal is converted into a low frequency band and recorded, and a signal processing for restoring the color signal is performed at the time of reproduction. For example, a VHS (registered trademark) system is used. In the VTR, the color signal frequency band during recording is defined as 629 kHz ± 500 kHz.

On the other hand, the reinforcing signal in the present invention uses the luminance signal processing process in all the signal processing processes in the VTR when the VTR is used as the transmission path, as described above. Therefore, in any of the methods of the above embodiments, there is no signal in the low-frequency converted color signal frequency band. Therefore, a predetermined amount of a sine wave signal having a constant frequency within the color signal frequency band is inserted in the area of the reinforcement signal, and this signal is frequency division multiplexed and recorded on the magnetic tape as a TBC pilot signal at the time of reproduction. Then, at the time of reproduction, this pilot signal is demodulated, a PLL (Phase Locked Loop) is constructed based on this, and a TBC write clock signal is generated.

A concrete circuit configuration example for generating such a TBC pilot signal waveform is shown in FIG. 13, and a signal waveform diagram (timing chart) for explaining the operation is shown in FIG. 14, respectively. (A) to (D) in FIG.
13A and 13B respectively show signal waveforms at the same symbols in FIG. 13, and FIG. 14A shows the signal waveforms in the upper and lower non-image areas and FIG. 14B shows the signal waveforms in the main image area. The current method VTR
Although only the main image signal is present as the color signal transmitted through the low-pass conversion color signal processing process, all effective scanning line segments are inserted as in the conventional color burst signal for color reproduction.

In FIG. 13, from the input terminal In ₅ , as shown in FIG. 14A, only the color burst signal in the upper and lower non-image areas, and the color signal including the color signal of the image together with the color burst signal in the main image area. (A) has a switch Sw2
Is supplied to the contact A and the burst synchronous wave generator 46. The burst sync wave generator 46 also utilizes a burst gate pulse (BGP), which will be described later, to generate a burst sync wave (a) synchronized with the color burst signal shown in FIG. And is supplied to the contact B of the switch Sw2. The frequency of this color burst sync wave (b) is the same as the current NTS letterbox signal.
If it is a C type signal, it will be 3.58 MHz.

Next, from the input terminal In ₆ , FIG.
The luminance signal (d) as shown in (1) is supplied to the sync separation circuit 47, where the synchronization signal included in the brightness signal is separated and then supplied to the gate generation circuit 48. In the gate generation circuit 48, a burst gate pulse (BGP) that determines the viewpoint and end point of the color burst synchronization wave (a), and a control signal (CTL) that switches the switch Sw2 so as to connect to the contact A side only in the main image signal area. Are generated and supplied to the burst synchronous wave generator 46 and the switch Sw2, respectively, as shown in the figure.

With this configuration, from the terminal C of the switch Sw2, as shown in FIG. 14C, a continuous color burst signal is generated in each horizontal synchronizing period in the upper and lower non-image areas, and in the main image area. An output signal (c) which is the incoming color signal is output from the input terminal In ₅ .
Such an output signal (c) is sent to, for example, an S-VHS system VTR.
When it is supplied to the transmission device 49, such as a color burst signal 3.58MHz is 629k in the color signal processing process built in the device.
As is well known, it is possible to obtain a pilot signal of low frequency (629kHz) that is not easily affected by jitter during the upper and lower image-free signal periods, which is recorded after being converted to low frequency in Hz and recorded during playback. Obtaining the write clock for the time base collector (TBC) based on
As described above.

As is clear from the above description, in the present invention, the time-axis-compressed signal is mainly used as the reinforcement signal, so that it differs from the main screen. That is, 1 / n (n>
1) The fluctuation amount Δ added at the time of compression is expanded as n × Δ when being restored to the original image signal on the reproducing side. On the other hand, in the conventional TBC using the horizontal sync signal,
Since sampling is performed every 15.75 kHz, it is not possible to expect a sufficient removal effect for jitter of several kHz. In this respect, according to the present invention, since sampling is performed at every 629 kHz, there is an effect of removing high frequency jitter components. Alternatively, a pilot signal having a frequency other than 629 kHz may be used and superimposed on the color signal region.
When viewed on the monitor TV of the current system, the pilot signal looks like a single color of yellow-green, but it is low in brightness and looks dark so that it is hardly noticeable.

In the above description, the case where the VTR and the magnetic tape are used as an example of the image signal transmitting device has been mentioned, but the invention is not limited to this, and various image signals such as VD and still image recording electronic camera are used. It is also possible to use a recording device or medium, and it is also applicable to a transmission system such as CATV or wireless broadcasting.

[0052]

As described above, according to the image signal transmission method and apparatus of the present invention, the following various excellent features are provided. Even if a TV monitor with an aspect ratio of 9:16 is used while maintaining compatibility with the S-VHS type VTR and the standard type (aspect ratio 3: 4) TV monitor that have been conventionally used, A wide image with high image quality can be obtained. When the ID signal indicating the type of the reinforcement signal is also used, a reproduced image of higher quality can be obtained.

The luminance signal vertical high-frequency component, the luminance signal horizontal high-frequency component, and the color signal horizontal high-frequency component are separated from the wide image signal in advance, and two or more of them are time-axis compressed. When the reinforcement signal is obtained by selecting in a predetermined order, a higher quality image can be obtained when recording and reproducing by the S-VHS system VTR. It is possible to expand the usable area of the S-VHS software by using a dedicated decoder or by adopting it in the recorded software. When the device of the present invention is configured with a specific circuit, it can be realized relatively simply and can be easily integrated into an IC.

[Brief description of drawings]

FIG. 1 is a block system diagram showing a signal processing operation of a first embodiment of an image signal transmission method of the present invention.

FIG. 2 is a principle diagram showing an image signal conversion algorithm in the method of the first embodiment of the present invention.

FIG. 3 is a block configuration diagram showing a second embodiment of the image signal transmission device of the present invention.

FIG. 4 is a block system diagram showing a signal processing operation of a second embodiment of the present invention.

FIG. 5 is a signal spectrum diagram for explaining the operation in the second embodiment of the present invention.

FIG. 6 is a principle diagram showing a conversion algorithm of VLPF2 in the second embodiment of the present invention.

FIG. 7 is a schematic diagram showing an arrangement example during transmission of color difference signals in the third embodiment of the present invention.

FIG. 8 is a block diagram showing a third embodiment of the present invention.

FIG. 9 is a schematic diagram of a composite output image obtained in the third embodiment of the present invention.

FIG. 10 is a schematic waveform diagram of an ID code for indicating the type of a reinforcement signal used in the method of the fifth embodiment of the present invention.

FIG. 11 is a block diagram showing a main part of a sixth embodiment of the present invention.

FIG. 12 is a frequency characteristic diagram of a high-frequency emphasis circuit and a high-frequency attenuation circuit used in the sixth embodiment of the present invention.

FIG. 13 is a diagram illustrating TB during reproduction according to the seventh embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration example of a circuit that generates a recording signal that is a C pilot signal.

FIG. 14 is a signal waveform diagram for explaining a generation operation of a recording signal which becomes a pilot signal during reproduction.

FIG. 15 is a schematic diagram showing a projection position of a reinforcement signal when an image based on the EDTV2 broadcasting system is displayed on a conventional TV monitor.

[Explanation of symbols]

 1 image signal transmission device 2 original wide image signal 3,14 VLPF (low-pass filter for vertical scanning signal) 4 VHPF (high-pass filter for vertical scanning signal) 5 main image signal 6 vertical high-frequency reinforcing signal 7 amplitude adjusting means 8, 24, 82 Signal combining means 9, 20 Combined output (display screen) 10 HHPF (horizontal high-pass filter) 12 Frequency converter 16, 18, 29 Time axis compressor 17 Horizontal high-frequency reinforcement signal 22, 27 CVLPF ( Color signal vertical low-pass filter) 25 CHHPF (color signal horizontal high-pass filter) 30 Color signal compression reinforcement signal 33 High-frequency emphasis circuit 34,47 Sync separation circuit 46 Burst sync wave generator 48 Gate generation circuit Sw1, Sw2 switch

Claims (6)

[Claims] 1. An image signal transmission method for converting a wide image signal having an aspect ratio different from a standard into a letterbox signal having a standard aspect ratio and transmitting the letterbox signal, wherein the wide image signal is changed to a luminance signal vertical high range. Component, luminance signal horizontal high frequency component, chrominance signal horizontal high frequency component, at least one high frequency component is extracted, and further time axis compression is performed to generate a reinforcement signal. Image signal transmission, characterized in that it is selectively inserted into the area portion and transmitted, and that the reinforcing signal is combined with the video signal of the main image area of the letterbox signal at the receiving side, if necessary. Method. 2. An image signal transmission method for converting a wide image signal having an aspect ratio different from a standard into a letterbox signal having a standard aspect ratio, and transmitting the letterbox signal. At least two high-frequency components of the signal horizontal high-frequency component and the color signal horizontal high-frequency component are extracted, and further time-axis compressed to generate a plurality of types of reinforcement signals, and the plurality of types of reinforcement signals are subjected to a predetermined sequence. It is sequentially inserted into the upper and lower non-image areas of the letterbox signal and transmitted, and at the receiving side, each reinforcement signal is obtained based on the above-mentioned predetermined sequence, and these reinforcement signals are imaged in the main image area of the letterbox signal. A method for transmitting an image signal, which comprises synthesizing into a signal. 3. An image signal transmission method for converting a wide image signal having an aspect ratio different from a standard into a letterbox signal having a standard aspect ratio and transmitting the letterbox signal. At least two high frequency components of the signal horizontal high frequency component and the color signal horizontal high frequency component are extracted and further time-axis compressed to generate a plurality of types of reinforcement signals, and these reinforcement signals are output above and below the letterbox signal. The index signal indicating the kind of the reinforcement signal is inserted outside the video area of the letterbox signal and transmitted while the image signal is arbitrarily inserted and transmitted in the image area portion. A method of transmitting an image signal, comprising obtaining a reinforcement signal and synthesizing the reinforcement signal with a video signal of a main image area of the letterbox signal. 4. The image signal transmitting method according to claim 1, wherein the amplitude of the reinforcing signal is limited, and the signal is inserted into upper and lower non-image areas of the letterbox signal for transmission and reception. The image signal transmission method, wherein the amplitude-limited reinforcement signal is returned to the original amplitude on the side. 5. The image signal transmission method according to claim 1, wherein the reinforcement signal is pre-emphasized, and then inserted into the upper and lower non-image areas of the letterbox signal for transmission. An image signal transmitting method, characterized in that the reinforcing signal is subjected to de-emphasis processing complementary to the pre-emphasis processing on the receiving side. 6. An image signal transmission device configured to convert a wide image signal having an aspect ratio different from a standard into a letterbox signal having a standard aspect ratio and transmit the letterbox signal. The luminance signal vertical high frequency component from the wide image signal. , At least one high-pass filter that extracts any one of the luminance signal horizontal high-frequency component and the color signal horizontal high-frequency component, and the extracted high-frequency components are individually time-axis compressed. At least one time-base compressor that generates a reinforcement signal, an in-screen rearrangement unit that inserts the reinforcement signal into the upper and lower non-image areas of the letterbox signal and outputs the same, and a receiving side via a predetermined transmission line. An image signal transmission apparatus comprising: a synthesizing unit that synthesizes the reinforcing signal with a video signal of a main image area of the letterbox signal as needed.