JPS58210777A - Picture transmitter - Google Patents

Abstract

PURPOSE:To display a still picture of even an object in motion with high precision as a double image-free frame picture and to improve the picture quality of a still picture transmitter by storing an interlaced frame picture. CONSTITUTION:A TV signal obtained by an image pickup is digitized and a picture signal with a specific one-frame period is stored in a frame memory 4. At the same time, it is inputted to a motion detecting circuit 5 and compared with the picture signal stored in the frame memory 4, and motion/still information is stored in a motion area 6. The contents of the memories 4 and 6 are transmitted to a receiving terminal through a transmission control circuit 7. The picture signal of the 1st field is stored at a part 10a unconditionally on the reception side. For a motion area separated by a motion area separating circuit 8 from the picture signal of the 2nd field, an interpolated signal generated by an interpolating circuit 11 which processes the picture signal of the 1st field stored at the part 10a is selected by a switch 9 and the transmitted picture signal is selected in a still area and stored at a part 10b. Thus, the picture signal stored in the frame memory 10 is read repeatedly and a switch 12 is operated, field by field, to obtain a television signal consisting of two fields; when the signal is converted into an analog signal, even a motion picture is displayed on a monitor 14 as a flicker-free frame still picture.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image transmission apparatus, and more particularly to an image transmission apparatus suitable for encoding and transmitting a television signal including the movement of a subject.

There is a still image transmission device that stores an image signal transmitted through a narrowband transmission path in an image memory and repeatedly reproduces the image signal. Normal television signals are scanned with 2:1 interlace, and when one frame is stored and displayed repeatedly, if the subject moves, images at different times by the field period will be displayed as double images. This results in an unsightly image. Therefore, conventional still image transmission devices transmit and store field images and repeatedly reproduce them.

As a result, an image was displayed with a reduced resolution, with the number of scanning lines being 1/2 of that of the standard TV.

The purpose of the present invention is to solve the above problems and store interlaced frame images, even if they are moving images.
An object of the present invention is to provide an image transmission device capable of displaying frame images that do not become superimposed images.

In order to achieve the above object, the present invention divides an image signal of one frame interlaced in n:1 into two into a first field and a second image signal of other (n-1) fields.
The presence or absence of movement of the subject is determined for one frame of image signal. This determination result is transmitted to the receiving end, and for areas determined to have movement, the image signals of other (n-1) fields are interpolated from the image signal of the first field, and there is no change. For the area determined as such, one frame of image signal is created from n fields of image signals, and the image signal is repeatedly displayed. That is, in the dynamic domain,
Instead of displaying a different image of the subject moving in each field cycle, the image of the first field is displayed repeatedly n times, and in a still area, a high-resolution image can be displayed using n fields. Figure 1 shows one of the television images.
As an example, a moving circle is displayed as one frame image consisting of two fields.

In the first field, there are circles in areas A and H, and in the second field, the circles move to areas B and C.

In this case, in area A, the first field is circular, the second field is the background, and a 30 Hz flicker occurs. The same applies to area C. Therefore, the moving areas A, B, and C are extracted from the difference between the image signal stored in the frame memory and the image signal of the current frame, and are transmitted to the receiving side. On the receiving side, using the separately transmitted image signal, for the moving areas A, B, and C, the image signal of the first field is used to interpolate the image signal of the scanning line of the second field, Always the first field image, i.e. circle A
, B and background C are displayed. On the other hand, for the stationary region, the first
Display the image of the field and the second field. This allows high-resolution images to be displayed in static areas without flickering or double images.

Hereinafter, the present invention will be explained in detail by way of an example.

FIG. 2 is a diagram showing the configuration of an embodiment of an image transmission device according to the present invention. In the figure, a TV joy signal imaged by a camera 1 is digitized by an A/D converter 2, and is digitized by a transmission control circuit 7. An image signal of one predetermined frame period is stored in the frame memory 4 via the switch 3 in response to a command from the frame memory 4 . At the same time, the motion detection circuit 5 also inputs the motion detection circuit 5 and compares it with the image signal stored in the frame memory 4, thereby storing motion presence/absence information in the motion area memory 6.

The contents of the frame memory 4 and the motion area memory are transmitted to the back end via the transmission control circuit 7.

On the receiving side, the image signal of the first field is unconditionally stored in a predetermined portion 10a of the frame memo 1710. On the other hand, for the motion area separated by the motion area separation circuit 8, the image signal of the second field is stored in the first field of the frame memory.
The interpolation signal created by the interpolation circuit 11 from the image signal of the first field stored in the field portion 10a is selected by the switch 9, and the transmitted image 7 signal is selected in the still area and stored in the frame memory 10. It is stored in the second field portion 10b. By repeatedly reading out the image signal stored in the frame memory 10 in this way and switching the switch 12 for each field, a television signal consisting of two fields is obtained, which is converted back to an analog signal by the D/A converter 13 and then monitored. 14, a frame still image without flicker can be displayed even if it is a moving image.

In the embodiment described above, an example was described in which an image signal of one frame period is unconditionally transmitted to the receiving end, but considering that motion information is being transmitted and that the receiving end also has a frame memory, By transmitting only the image signal of the changed portion and substituting the contents of the frame memory for the rest, the amount of transmitted information can be significantly reduced.

For example, in the above-mentioned embodiment, the transmission control circuit 7 transmits the image signal of the first field for the area where there is a change, and the image signal of the second field for the area where there is no change!
shall transmit a signal. At the receiving end, if the transmitted image signal is of the first field, a predetermined area of the first field of the frame memory 10a is updated, and the second field is also updated using the interpolated value. If the transmitted image is of the second field, frame memory 1
Update only the second field of 0b. For this reason, is the amount of data transmitted mentioned above? It becomes possible to compress the data to 1/2 of that in the c embodiment.

FIG. 3 shows the configuration of the main part of another embodiment of the present invention that transmits only the changed portion. In the figure, a frame memory 4 is divided into field memories 4a and 4b. 'In addition, the motion presence/absence information detected by the change detection circuit 5 is stored in the motion area memory 17, and the information that was determined to be motion last time and no motion this time is stored in the negation circuit 15 and the AND circuit 1.
6 and stored in the second motion area memory 18. In the transmission control circuit 20, the motion area memo IJ 17
The image signal of the first field is transmitted for the area determined to have movement, and the image signal of the second field is transmitted for the area determined to be shading in the second motion area memory 18.

At the receiving end, it is determined whether the transmitted image signal is the first field or the second field from the pixel position '+n information separated by the motion area separation circuit 21. 23, the first field 10a of the frame memory is updated, and the interpolation circuit 22 interpolates the image signal of the second field.
A predetermined area of the second field iob of the frame memory is updated via the switch 24. On the other hand, for the image signal determined to be the second field by the motion area separation circuit,
The second field 10b of the frame memory is updated via the switch 25.

In the embodiment shown in FIG. 3, the changed area and a part of the previous changed area are transmitted, and other areas are transferred to the frame memory
Using the image signal stored in 0, the latest field image is displayed in the moving image part, and the frame image consisting of two fields is displayed in the still part, so a high quality still image can be displayed. Furthermore, since the amount of transmitted data is proportional to the changing portion of the image, it is possible to significantly shorten the transmission time.

It is clear that these embodiments can be applied not only to black and white television signals but also to color television signals.

According to the present invention, even for a moving subject, a high-quality still image can be displayed as a frame image that does not cause double images, so there is an effect that the image quality of the still image transmission device can be improved.

[Brief explanation of the drawing]

Figure 1 is an example of an image displayed on a television monitor.
FIGS. 2 and 3 are configuration diagrams of an embodiment of the image transmission apparatus of the present invention.

Claims (1)

[Claims] 1, n:l (n is an integer of 2 or more) interlace-scanned television signal consisting of n fields,
field and other (n-1) fields.
a motion detection circuit that divides the television signal into a group of image signals and determines whether or not there is movement in the television signal; The receiving end has a frame memory and an interpolation circuit, and for the motion area, it interpolates the image signal of the (n-1) field from the transmitted image signal of the first field. An image transmission device characterized in that it repeatedly reproduces a television signal consisting of n fields interlaced.