JPS61206395A - Stereoscopic television image transmitting system - Google Patents

Abstract

PURPOSE:To compress a right and left difference signal, namely a parallax signal by dividing the peripheral section of the screen of right and left images to a large block and the center section of the screen to a small block, and transmitting one image in a corresponding block, the data of parallax deviation and a difference signal for both blocks. CONSTITUTION:A signal obtained from decoders 2, 4 is once written in field memories 18-28, the parallax deviation of the right and left images is defected at every block, to make a reference for one image, and to input the other image to analog calculators 30-34 after shifting the position of the image shifted by the parallax deviation and to obtain outputs YDELTA=YL-YR, IDELTA=IL-IR, and QDELTA=QL-QR corresponding to the parallax. On a brightness YL and a chromaticy IL, QL, a chroma synthesis and a time base compression of (1-alpha) are carried out. Also on the luminance signal of a parallax signal and the chromaticy signal, similarly, the time base compression of alpha' is performed. The luminance signal and the chroma signal obtained in such a manner are synthesized by the time base. The synthesized Y, C outputs are recorded to betacam and M system VTR as they are.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the transmission of stereoscopic television image signals, and more specifically, in consideration of the visual characteristics of one human being, two channels corresponding to the left and right eyes are transmitted. 3D television signal band 1
This is intended to be compressed and transmitted in the preview signal band of the channel.

[Conventional technology]

When reproducing a three-dimensional image, two images corresponding to the left and right visual fields of humans
Two video signals are required.

Conventionally, in order to realize a stereoscopic image, simultaneous transmission of two video signals and synchronized recording and playback using two VTRs were required. However, this method not only doubles the line size, but also requires two VTRs, which is a cost problem. It had various drawbacks, such as the need for special circuits and transmission techniques.

To this end, it has already been proposed to appropriately compress transmission information by utilizing the properties of stereoscopic images.

For example, the invention described in Japanese Patent Application No. 59-285798 filed by one applicant divides the screen into blocks of equal size, moves the left image for each block, calculates the difference from the right image, and Find a shift vector that minimizes the difference, extract the difference signal between the left image and right image based on this vector, perform data compression, and transmit this difference signal between the left and right images and the above shift vector together with the left image signal. This is what I am trying to do.

Originally, the left image and the right image are views of the same subject with a slight difference in left and right sides. Therefore, since this left-right difference signal is the difference after almost all the slight left-right differences have been removed, it has a level close to zero in most areas, making it possible to significantly compress the amount of data.

[Problem that the invention seeks to solve]

The present invention focuses on human visual characteristics, that is, the distribution of gaze points when humans look at a television screen, and the characteristic of stereoscopic images that the parallax between left and right images exists only in the foreground, and that the foreground is concentrated in the center of the screen. This is an attempt to further compress the left-right difference signal, that is, the parallax signal.

[Means for solving problems]

In order to solve the above-mentioned problems, in the stereoscopic television image transmission system according to the present invention, when transmitting the stereoscopic television image signal, the left and right images of the stereoscopic television are divided into one large block at the periphery of the screen and one at the center of the screen. is divided into small blocks, and the parallax shift between the images of both blocks is detected for the block of one of the left and right images and the block of the other image located at the same corresponding position on the screen, and the parallax shift data is obtained. is obtained, and a difference signal is obtained between the shifted image in which the parallax shift portion in the block of the one image is shifted by the parallax shift data, and the image on the other side in the corresponding block. The f-side image, the parallax shift data, and the difference signal are transmitted for each block.

〔Example〕

Examples of the present invention will be described in detail below.

FIG. 1 is a diagram explaining the principle of obtaining two video outputs by arranging two cameras at positions corresponding to parallax. Here, the video output of the left camera is assumed to be so, and the video output of the right camera is assumed to be vR.

The video output example shown in FIG.
This is an example of two video outputs. In other words, the solid line is VR (
Right camera output), the broken line is V and left camera output),
As is clear from this figure, binocular parallax exists only in the near field, and the time difference is extremely small, at most IILsec or less. Therefore, the difference signal between the left and right images (that is, the disparity signal) is close to 0 for a distant view, and has a constant component only for a close view that causes parallax.

In order to create a three-dimensional effect, the subject needs to be large enough to create a sense of parallax. Now, Figure 3 (A)
Consider an example of an image in which nine rectangular parallelepipeds each having a length of 6g5ec are lined up at intervals of Igsec, such as the CR7 image shown in FIG. If the parallax at this time is 1 tilesee as shown in FIGS. 3(B) and 3(C), a parallax shift output as shown in FIG. 3(D) is obtained. In other words, there is a signal for 834 seconds ((
6+1)X9=83) 14 JLsec(18X O
, 8 = 14) (The reason is that 80
In this example, it is assumed that there is no correlation at all between the pixels corresponding to the parallax shift, but as an actual example, this difference can be considered as a type of one-dimensional predicted DPCM signal. .

It is known that one-dimensional predictive DPCM can compress the original image by 50% or less, and when applied to the examples shown in Figures 3 (A) to (D), 2
) It can be seen that it can be compressed as follows. However, the image considered in this example is extremely special, and in reality it may be possible to compress it further. Therefore, the compression ratio α for the disparity signal is
can be considered to be about 10% at most.

As mentioned above, parallax exists only in the foreground and includes positional deviation. If this positional shift is detected and a parallax signal is obtained using a position-corrected signal, the differential output can be further reduced. At this time, in the present invention, a gaze point distribution (see the explanation of FIG. 5 described later) is applied to detect the parallax.

FIGS. 4(A) to 4(D) show the principle of parallax shift detection,
In FIG. 4(A), the solid line is an image obtained by the left camera, and the broken line is an image obtained by the right camera. Figure 4 (B)
is the video output Vt, (left camera output), as shown in Figure 4 (C
) shows the video output VR (right camera output), and Fig. 4 (D) shows the parallax shift (Vt, -VR) due to the left and right camera outputs. , it is determined that there is an object in the foreground that causes parallax.

As mentioned above, the basic concept of this idea is to obtain more compression by calculating the difference using a signal that has been corrected for the displacement and position of the parallax object.

The transmission method and detection procedure will be explained below.

Figures 5 (A) and (B) show the distribution of gaze points on the television screen in the high-definition television system (MUSE system) and the current television system (525 system), respectively. In this figure, the ellipse represents the movement of the line of sight. It shows a range, and there is a 99.73% probability that the line of sight will be concentrated within this range.

As is clear from Figure 5 (B), on current TVs, the line of sight is concentrated in the center of the screen, and as is clear from Figure 5 (A), on high-definition TVs, the gaze point spreads horizontally. There is. Therefore, based on the fact that binocular parallax only exists in the near field (objects within about 10 meters), and because the near field generally exists in the center of the screen, we focused on disparity information in the center of the screen where the line of sight is concentrated. This means that the receiving side only has to faithfully reproduce this information.

From the above, in one embodiment of the present invention, the current 5
The screen is divided into a plurality of positional deviation detection blocks as shown in FIG. 6 for the X.25 system and as shown in FIG. 7 for the high definition television (NUSE) system.

That is, in the central part of the screen where high three-dimensional resolution is required, the blocks for detecting parallax are set smaller than in the peripheral parts of the screen. As an example, a parallax detection block is determined by taking the reciprocal ratio of the density of the gaze points. By doing so, it becomes possible to transmit a three-dimensional image that adapts to the movement of a person's line of sight when watching television.

An example of the detection results of the parallax within each block shown in FIGS. 6 and 7 is shown in FIG. 8. In this figure, a is the horizontal parallax position, b is the horizontal parallax shift (parallax vector), and C is The length of the parallax object in the horizontal direction, d is the line number where parallax starts in the vertical direction (vertical parallax position), and e is the length of the parallax object in the vertical direction.As described later, information on these positions is transmitted. and multiplexed and transmitted during the vertical retrace period.

To actually detect the parallax shift b, the difference between corresponding pixels within a block is taken. Also, images where there are many parallax objects within the same block (i.e.

For images with very high frequency components), transmit a signal representing the parallax for the object with the largest parallax, or the average parallax.For example, in the case of an image of a fine leaf, the average parallax is transmitted. It is preferable to convert it into a signal and transmit it.

Next, specific bit allocation will be explained.

Regarding a+C shown in Figure 8, there is a relationship in which C can be small if position Na is shifted to the right, and 8 bits (258 types of position display possible) are selected for a+C in the 525 system. do. In the MUSE method, 9 bits are used as a+C. Similarly, b is 6 bits in the 525 method (6 bits in the NUSE method), and 6 bits in the 525 method (7 bits in the MuSE method) are used for ct+e for quantization, similar to a+C. Assign levels. As a result, in the 525 system, a+b+c+d=20 bits (22 bits in the MUSE system).

Regarding the number of pixels within the horizontal IH period in the 525 system, sampling is performed at a frequency four times that of the subcarrier, and the effective number of pixels that can be displayed on the TV screen is 80% of the total.
Suppose that.

This will be approximately 720 pixels. From this point of view, in FIG. 6, the horizontal direction is divided into four blocks, and it can be seen that 8 bits (1 to 25B) for a+C are sufficient.

Similarly, in the case of a high-definition television, the brightness signal band is 2
Since the frequency is 0 MHz, when sampling at 40 MHz, the total number of samples is multiplied by 0.8 (80%), resulting in approximately 2033 effective pixels. Therefore, in the case of a high-definition television, the lateral force direction of the screen is divided into eight blocks, and it is sufficient to use 9 bits (1 to 512) as a+C.

Necessary parallax shift data is transmitted to the IH within the vertical retrace period. The transmission capacity within IH is 364 bits for teletext broadcasting, for example. In addition, in the 525 method, 1
The number of bits required to transmit location information is 20 bits)
6 (blocks), or a total of 320 bits, and IH
It is fully possible to transmit the data within On the other hand, MUSE
As for the system, the band is 8 MHz and can transmit twice the pit rate (that is, 720 bits in IH). In this case, the required number of bits is also 22 bits) x 32 (
block) = 704 bits, which is sufficient to transmit within IH.

FIG. 9 shows the data transfer timing, and the data to be transmitted is inserted into the retrace period preceding the image signal in each field. By doing so, more processing time can be taken on the receiving side, thereby making it possible to simplify the entire apparatus.

Next, a specific digital transmission system will be explained.

FIG. 1O is a block diagram of the transmission encoder. First, the left and right camera outputs v and v are respectively input to the decoder 2.4 and separated into a luminance component and chromaticity components I and Q. Regarding these chromaticity components I and Q, C on high-definition television is
In addition to using w and CN, it is also possible to use RY and BY.

For these signals, a high frequency cut is performed to match the band of the transmission system or recording VTR in order to perform signal processing and time axis compression. Now, when the compression rate is α, the passband is multiplied by (l−α). As mentioned above, this α is about θ˜0.1. Regarding color signals,
A compression ratio α' suitable for the color signal is selected. However, it is also possible to select the compression ratio α for the luminance signal and the compression ratio α′ for the color signal to be equal.

The signal obtained from the decoder 2.4 is once written into the field memory 18 to 2, and the parallax shift between the left and right images is detected for each block using the method described above, and one image is used as a reference, and the other image is After shifting the position of the part of the image that is shifted by the amount of shift, the analog computing unit 30 ~
34 and the output corresponding to the parallax YΔ=YL−YR,
rΔ; ■Se rR, Qa = QL QR is obtained.

In this embodiment, the left video signal is used as a reference, and its luminance Y and chromaticity It, , Qt are chroma-synthesized and subjected to time axis compression of (l-α). As for the chromaticity signal, time axis compression of α' is similarly performed (of course, it is also possible to take α=α'), and this situation is shown in FIG.

The luminance signal and chroma signal obtained in this way are
The 6 time-axis synthesized Y and C outputs can be recorded as they are on a β cam or M system VTR. Also,
When signal processing is performed using an NTSC type encoder, it is possible to send the signal to a transmission line. Furthermore,
1 inch, 3/4V.

It is also possible to record on 1/2β and VHS VTRs.

FIG. 12 shows a decoder demodulator, with input signals as
In addition to signals obtained from YC separation VTRs, composite signals, etc. will be introduced. However, when introducing a composite signal, Y/C separation is performed. These signals are a combination of the left camera output and the parallax output, and time axis separation is first performed.

For left camera output Y and C, respectively l/
The time axis extension of (1-α) and 1/ (1-α′) is
The parallax signals Y4 and CL are subjected to time axis extension by l/α and l/α', respectively, and the CL and CΔ times signals are subjected to I/Q demodulation. signal and analog computing unit 88-1
In addition to 02, get the right camera output.

Since the disparity signal is differenced by shifting the signal by the disparity on the transmission side, it is necessary to add the disparity signal and the left camera signal to the arithmetic unit on the demodulation side, and then perform 2-correction by the shifted amount. The shift data is superimposed on the IH of the vertical retrace period in advance. In order to perform the function of extracting this data, a "deviation data 1 line separation circuit 66" shown in the upper part of FIG. 12 is used. The separated data is written to memory. Then, under the control of the CPU, the shift data is sent to the field memories 88 to 9B for each block determined based on the gaze point distribution.

The field memory performs address control using this data, corrects the position by the amount of deviation, and reproduces the right camera output. In this way, left and right camera outputs vL and vR are sent out from the encoder.

In the method described above, Y
, I, and Q signals each require l fields of memory (i.e., 3 fields in total), but Y, I,
The required transmission band ratio of each Q signal is at most 2:1:1,
As for memory capacity, 2 fields are sufficient.

As is clear from the above description, the present invention can of course be applied to analog systems as well.

Furthermore, it can also be applied to transmission of black-and-white stereoscopic television.

〔Effect of the invention〕

According to the present invention, television signals for two left and right channels can be transmitted in one channel.

Furthermore, when applied to an analog system, it has the advantage that current video transmission systems and VTRs can be used as is by adopting the same format as existing composite video signals.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the principle of obtaining a stereoscopic video signal, Figure 882 is a diagram showing an example of video output, and Figures 3 (A) to 882 are diagrams showing an example of video output.
(D) is a diagram showing the actual left and right camera projection and parallax shift output, Figures 4 (A) to (D) are diagrams showing the principle of detecting positional discrepancies that occur based on parallax, Figures 5 (A) and (B) is a diagram showing an example of the distribution of points of interest on a high-definition TV and an example of the distribution of points of interest on a 525-scheme TV, respectively. Fig. 6 is a diagram showing a positional deviation detection block for the 525-scheme. Fig. 7 is a diagram showing the position of a high-definition TV. A diagram showing a shift detection block. FIG. 8 is a diagram illustrating an example of parallax detection according to the detection principle shown in FIG. 4. FIG. 9 is a diagram illustrating a data signal sending method. Fig. 10 is a block diagram of a detection Φ transmission system for parallax shift data to which the present invention is applied, Fig. 11 is a diagram illustrating time axis compression, and Fig. 12 is a block diagram of demodulation of a stereoscopic television signal to which the present invention is applied. be. vshi...Left camera output, vR...Right camera output, 2.4...Decoder, 6...Left luminance (Yshi) signal generation circuit, 8...Right luminance (YR) signal generation Circuit, lO...Left color difference (■) signal generation circuit, 12...Right color difference (IR) signal generation circuit, 1
4...Left color difference (Q) signal generation circuit, 16...Right color difference (QR) signal generation circuit, 18-28...Field memory, 30.32.34...Analog computing unit, 3B. ...Chroma synthesis circuit, 38...Difference signal chroma synthesis circuit. 40-4B...Time axis compression circuit, 48.50...Time axis synthesis circuit, 52...IH shift data encoding circuit 54...Shift data synthesis circuit, 56...Encoder, 58...・Difference detection circuit, 80...YC separation signal source, 62...Transmission line or composite VTR164・
・・YIC separation circuit, 66 ・Shift data l line separation circuit, 88.70・
...Time axis separation circuit, 72...Memory/control unit, 74...1/(l-α) time axis expander, 7B...Bow/
(1-α') Time axis expander, 78...100 Time axis expander, 80...11α' Time axis expander, 82.84...I/Q demodulation circuit, 86-9B... field memory. 98.100,102...analog computing unit, 104.
108...Encoder. Patent applicant Japan Broadcasting Association agent
Patent Attorney Yoshi Tani - Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1) When transmitting a stereoscopic television image signal, the left and right images of the stereoscopic television are divided into large blocks at the periphery of the screen and small blocks at the center of the screen, and one of the left and right images is divided into large blocks at the screen periphery and into small blocks at the center of the screen. The parallax shift data is obtained by detecting the parallax shift between the images of both blocks for the block of the image and the block of the other image located at the same corresponding position on the screen, and the parallax shift portion in the block of the one image is calculated. Obtaining a difference signal between the shifted image shifted by the parallax shift data and the other image in the corresponding block, and the one image in the block;
A stereoscopic television image transmission system, characterized in that the parallax shift data and the difference signal are transmitted for each block. 2) The one image and the difference signal are time-base compressed and combined within one horizontal scanning period, and the parallax shift data is multiplexed in a vertical retrace period and transmitted in a television signal band of one channel. A stereoscopic television image transmission system according to claim 1. 3) The stereoscopic television image transmission system according to claim 1 or 2, wherein the blocks are divided into sizes that are inversely proportional to the distribution of gaze points.