GB1580002A

GB1580002A - Processing video signals

Info

Publication number: GB1580002A
Application number: GB2236578A
Authority: GB
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1977-06-04
Filing date: 1978-05-25
Publication date: 1980-11-26
Also published as: FR2393495A1; DE2725364B2; DE2725364A1; DE2725364C3; FR2393495B1

Description

(54) PROCESSING VIDEO SIGNALS (71) We, ROBERT BOSCH GmbH, of Robert-Bosch-Strasse 7, 6100 Darmstadt, Federal Republic of Germany, a German Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to a method of reproducing pictures from a recorded video signal.

Video magnetic tape recording devices are generally of two kinds; those in which each field is recorded upon the magnetic tape along a track whose direction is at an angle to the longitudinal direction of the tape, and those in which a field is recorded in a plurality of adjacent tracks. Whilst the still reproduction of individual pictures is possible in the case of the first mentioned device, in the magnetic tape recording devices of the second type a reproduction of still pictures is not readily possible. For removing this disadvantage it has already been proposed (U.K. Patent Application No. 42128/77), (Serial No. 1568870) during the reproduction process of the magnetic tape recording device, to read into a picture store those video signals corresponding to the picture to be reproduced, so that these stored signals can then be repeatedly read out from the picture store for producing a still picture. It is found, however, that when practising electronic editing of recorded video signals the location of precise cutting positions after individual pictures is a very tedious operation.

According to the present invention there is provided a method for the simultaneous display of a plurality of individual pictures of a video signal recorded upon a record carrier, wherein after reproduction from the record carrier each of a selected plurality (up to a maximum of m2 where m is an integer greater than one) of individual pictures in a picture sequence of the recorded video signal is read into a picture store in such manner that only each mth picture element is read-in both in the horizontal and vertical directions and wherein the contents of the picture store are repeatedly read out for obtaining a plurality of compressed pictures simultaneously in the form of a static display upon the picture screen of a video display device.

The invention has the advantage that it is possible to display upon the picture screen of the video display device not merely one individual picture, but a plurality of pictures of the recorded video signal simultaneously.

Using this technique it is possible, for example when carrying out electronic editing work, to determine the cutting positions with substantially greater speed and certainty because of the common display.

Embodiments of the invention will now be described with reference to the accompanying drawing, wherein: Fig. 1 shows a picture sequence of a video signal reproduced from a record carrier plotted with respect to time, and Fig. 2 shows various display arrangements of selected compressed pictures of the picture sequence upon a picture screen.

In Fig. 1 there is shown a schematic diagram of a picture sequence of a video signal reproduced from a video magnetic tape recording device. The picture sequence comprises a plurality of individual pictures. In this diagram it is immaterial whether fields or frames are being considered. Consequently the present specification simply uses the expression "picture" to cover both. The individual pictures of this picture sequence are indicated by the picture numbers 1, 2, 3, etc.

In such a picture sequence reproduced from a record carrier, each individual picture which is to be stored in a picture store is subjected to compression. The picture compression is effected in such manner that only each mth picture element, both in the horizontal and vertical directions, is taken from the picture which is to be stored and is read into the picture store. In the present practical example the integer in m=2. Under this condition the picture to be stored in the picture store is compressed in the ratio 1:4 thus allowing three further compressed pictures to be read into the same picture store.

After the reading in of a succession of four pictures into the picture store, the store content is repeatedly read out for the purposes of static display upon the picture screen of a video display device. For example, in this practical example the control of the reading out operation is effected so that a quartet of pictures (Fig. 2) is visible upon the picture screen of the video display device. If a succession of four consecutive pictures (integer n=l) is read into the picture store, a quartet of pictures is obtained on the screen as shown in Fig. 2a. In the display of Fig. 2a, the reading out of the picture store is effected in a sequence in which picture number 1 appears at the top left hand side, picture number 2 at the top right hand side, picture number 3 at the bottom left hand side, and picture number 4 at the bottom right hand side.

On the other hand, if the succession of four pictures read into the picture store comprise only each second picture of the picture sequence reproduced from the record carrier (n=2), a display is obtained as shown in Fig.

2b. Similarly, a picture screen display is obtained as shown in Fig. 2c if the succession of four pictures read into the store comprise only each fifth picture of the picture sequence reproduced from the record carrier (n=5).

Preferably the method is carried out in such manner that the integers m and n are independently adjustable.

To summarise, the arrangement described above thus permits the simultaneous display upon the picture screen of a video display device of a selected plurality of successive individual pictures of a recorded video signal.

In the arrangement, of each nth individual picture in a sequence of pictures, only each mth picture element in the horizontal and vertical direction is selected, and these picture elements are read into a picture store. By the use of this mode of picture compression it is possible to read into a picture store a number (up to a maximum of m2) of pictures of the picture sequence. For the- purpose of simultaneous display upon the picture screen of a video display device, the contents of the picture store are repeatedly read out.

WHAT WE CLAIM IS: 1. A method for the simultaneous display of a plurality of individual pictures of a video signal recorded upon a record carrier, wherein after reproduction from the record carrier each of a selected plurality (up to a maximum of m2 where m is an integer greater than one) of individual pictures in a picture sequence of the recorded video signal is read into a picture store in such manner that only each mth picture element is read-in both in the horizontal and vertical directions and wherein the contents of the picture store are repeatedly read out for obtaining a plurality of compressed pictures simultaneously in the form of a static display upon the picture screen of a video display device.

2. A method as claimed in claim 1, wherein the selected plurality of pictures comprises each nth picture in the sequence.

3. A method as claimed in claim 2, wherein the integers n and m are independently adjustable.

4. A method as claimed in claim 1, substantially as described herein with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. three further compressed pictures to be read into the same picture store. After the reading in of a succession of four pictures into the picture store, the store content is repeatedly read out for the purposes of static display upon the picture screen of a video display device. For example, in this practical example the control of the reading out operation is effected so that a quartet of pictures (Fig. 2) is visible upon the picture screen of the video display device. If a succession of four consecutive pictures (integer n=l) is read into the picture store, a quartet of pictures is obtained on the screen as shown in Fig. 2a. In the display of Fig. 2a, the reading out of the picture store is effected in a sequence in which picture number 1 appears at the top left hand side, picture number 2 at the top right hand side, picture number 3 at the bottom left hand side, and picture number 4 at the bottom right hand side. On the other hand, if the succession of four pictures read into the picture store comprise only each second picture of the picture sequence reproduced from the record carrier (n=2), a display is obtained as shown in Fig. 2b. Similarly, a picture screen display is obtained as shown in Fig. 2c if the succession of four pictures read into the store comprise only each fifth picture of the picture sequence reproduced from the record carrier (n=5). Preferably the method is carried out in such manner that the integers m and n are independently adjustable. To summarise, the arrangement described above thus permits the simultaneous display upon the picture screen of a video display device of a selected plurality of successive individual pictures of a recorded video signal. In the arrangement, of each nth individual picture in a sequence of pictures, only each mth picture element in the horizontal and vertical direction is selected, and these picture elements are read into a picture store. By the use of this mode of picture compression it is possible to read into a picture store a number (up to a maximum of m2) of pictures of the picture sequence. For the- purpose of simultaneous display upon the picture screen of a video display device, the contents of the picture store are repeatedly read out. WHAT WE CLAIM IS:

1. A method for the simultaneous display of a plurality of individual pictures of a video signal recorded upon a record carrier, wherein after reproduction from the record carrier each of a selected plurality (up to a maximum of m2 where m is an integer greater than one) of individual pictures in a picture sequence of the recorded video signal is read into a picture store in such manner that only each mth picture element is read-in both in the horizontal and vertical directions and wherein the contents of the picture store are repeatedly read out for obtaining a plurality of compressed pictures simultaneously in the form of a static display upon the picture screen of a video display device.