System for Combining image signals

A system for combining images has VTRs for storing a plurality of image signals and a signal generator for generating a key signal representing a combining position in each of the image signals. The key signals are added to the image signals. The composed image signals are combined with each other at the combining position based on the key signals.

FIELD OF THE INVENTION 
The present invention relates to a system for combining image signals 
(video signal) to form a continuous image where a display area of a 
combined image is optionally selected. 
BACKGROUND OF THE INVENTION 
In order to selectively display image (video) signals taken by a plurality 
of cameras, there has been a head switching method in which a desired 
image is selected from the image signals at a predetermined time interval. 
There has been another method in which a desired position of a desired 
image is combined with a desired position of another image to display a 
continuous image derived from a plurality of image signals. 
If the image signal taken by the several cameras in which a continuous 
significant scene is included, it is desirable that the separate image 
signals can be combined with each other to form the continuous scene with 
accuracy, and the scene can be optionally and continuously scrolled in a 
display. 
Such a system is effective to increase the display effect of a simulation 
device or game machines. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a system in which separate 
positions in separate image signals can be combined to form a continuous 
image, and a scene in the continuous image can be scrolled in a display. 
According to the present invention, there is provided a system for 
combining images comprising storing means for storing a plurality of image 
signals, generator means for generating a key signal representing a 
combining position in each of the image signals, composing means for 
composing the key signals with the image signals, and combining means for 
combining the image signals at the combining position based on the key 
signals. 
The system further has a standard signal generator for generating standard 
signals for controlling operating timing of the generator means and 
combining means.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
An image combining system of the present invention comprises signal 
composing unit and an image combining unit. 
Referring to FIG. 1 showing the signal composing unit, two cameras are used 
to take pictures to produce a first image source FS and a second image 
source SS, respectively. Both image sources are stored in the first and 
second VTRs 4 and 5. The image sources are NTSC signals. A standard signal 
generator 1 produces a standard signal A of a NTSC signal which is applied 
to the first and second VTRs 4 and 5. Based on the standard signal A, the 
first and second VTRs 4 and 5 produce first and second image signals B and 
C, respectively. The image signals B and C are applied to composing 
sections 6 and 7, respectively. The image signals are produced at a timing 
in synchronism with the standard signal A. 
The standard signal of the standard signal generator 1 is further applied 
to a key signal generator 2 which produces a first key signal F and a 
second key signal G for determining split positions of the image sources 
FS and SS at every field. The first and second key signals F and G are 
applied to the composing sections 6 and 7 to be added to the image signals 
B and C, respectively. 
A timing signal generator 3 is applied with the standard signal to produce 
timing signals D and E which are applied to the composing sections 6 and 
7. The timing signals determine timings for adding the key signals F and G 
to the image signals B and C. The first and second key signals F and G are 
added to the image signals B and C at timings D and E shown in FIG. 3, and 
first and second image signals H and I composed with the key signals F and 
G are produced from the composing sections 6 and 7. 
The operation of the image combining unit will be described. FIG. 3 shows 
waveforms of the respective output signals A to I. The first and second 
image signals B and C produced based on the image sources FS and SS and 
the standard signal A are composed with the first and second key signals F 
and G in accordance with the timing signals D and E. The system is so 
designed that the timing signals are produced at predetermined timings 
near a vertical blanking interval of each image signal. Therefore, the key 
signals F and G for splitting the image sources are located near the 
vertical blanking. Thus, the first and second image signals H and I added 
with the key signals F and G are produced. 
In each of the image signals H and I, signals between the vertical blanking 
interval and the key signal are eliminated in order to simplify the 
construction of a split signal (key signal) detecting circuit. 
FIGS. 2a to 2c show a concrete example of key signals for combining two 
images. As shown in FIG. 2b, the first image source FS is combined with 
the second image source SS. As shown in FIG. 2c, the first key signal F 
has an upgoing edge which is positioned at a center of the overlapped 
portions of the images, and has a downgoing edge which is positioned at 
the right edge of the first image. The second key signal G has an upgoing 
edge positioned at the left edge of the second image and a downgoing edge 
positioned at the center of the overlapped portions. 
FIG. 2b shows a display area of one picture of the combined image. 
As the key signal, a digital code can be used. 
FIG. 4 shows the image combining unit of the system. The unit comprises a 
first image VTR 4a in which the first image signal H is stored, and a 
second image VTR 5a storing the second image signal I. The first and 
second image VTRs 4a and 5a are applied with the standard signal A of a 
standard signal generator 1a and image signals H and I are applied to a 
combining section 14 in accordance with the timing in synchronism with the 
standard signal A. 
The image signals H and I are further applied to key signal detectors 8 and 
9 which detect key signals F and G in the image signals H and I and derive 
the key signals from the image signals. The output signals are applied to 
key signal generating sections 10 and 11 which produces key signals J and 
K as position signals to determine position for combining image signals. 
The key signals J and K are applied to a combination controller 12. The 
combination controller 12 is further applied with an output signal of a 
position and direction setting section 13 which is operated to set a 
position of a combined scene in the display and a direction for moving the 
scene. The controller 12 operates to control a combining operation of the 
image signals in the combining section 14 based on the key signals J and K 
and a position and direction signal from the position and direction 
setting section 12. The controller 14 produces a combined image signal L 
to be reproduced. 
FIG. 6 shows waveforms of output signals of the image reproducing unit. The 
signals A, H, I, F and G are the same signals as those in FIG. 3 of the 
signal composing unit. The combined image signal L is produced in 
accordance with key signals J and K when the position and direction are 
set. 
Referring to FIG. 5 showing the details of the image combining unit, the 
combination controller 12 comprises a writing controller 15 (FIG. 5c) 
applied with the signal A and a reading controller 16 applied with signals 
A, J and K and position and direction signal. 
The combining section 14 comprises an NTSC/RGB converter 17 (FIG. 5a) 
applied with the first image signal H stored in the first image VTR 4a, 
and an NTSC/RGB converter 18 applied with the second image signal I stored 
in the second image VTR 5a. In the converters 17 and 18, the image signals 
H and I of the NTSC signals are converted into the video signals of R 
(red), G (green) and B (blue). The R, G and B video signals of the first 
image signal H are applied to A/D converters 19a, 19b and 19c, 
respectively, in which R, G and B video signals are converted into digital 
signals. Similarly, the R, G and B video signals of the second image 
signal I are applied to A/D converters 20a, 20b and 20c respectively, for 
converting the video signals into digital signals. The converted digital 
signals are applied to a frame memory 21 (FIG. 5b). 
The frame memory 21 has memories 22a and 22b, 23a and 23b, and 24a and 24b, 
selectors 25, 26 and 27. The R video signals of the first image signal (1R 
signal) and the second image signal (2R signal) converted at the A/D 
converters 19a and 20a are stored in the memories 22a and 22b, 
respectively. The G video signals of the first and second image signals 
(1G signal and 2G signal) converted at the A/D converters 19b and 20b are 
stored in the memories 23a and 23b, respectively. The B video signals of 
the first and second image signals (1B signal and 2B signal) converted at 
the A/D converters 19c and 20c are stored in the memories 24a and 24b, 
respectively. Each of the memories is applied with a writing signal from 
the writing controller 15 of the synthetic controller 12. Thus, the 
respective video signals are written and stored in the respective memories 
in accordance with the writing signal. 
The 1R and 2R signals stored in the memories 22a and 22b are selected by 
the selector 25 for the R video signal. The 1G and 2G signals in the 
memories 23a and 23b are selected by the selector 26 for he G video 
signal, and the 1B and 2B signals in the memories 24a and 24b are selected 
by the selector 27 for the B video signal. The selectors are operated in 
accordance with a reading signal from the reading controller 16. 
The video signals selected by the respective selectors are applied to D/A 
converters 28a, 28b and 28c, respectively, in which the digital signals 
are converted into analog signals. The converted analog signal are applied 
to an RGB/NTSC converter 29 in which R, G and B video signals are 
converted into the image signal L of NTSC signal. 
The operation of the image combining unit will be described with reference 
to FIG. 7. When a desired reading position is set in accordance with the 
position and direction setting section 13, the R, G and B video signals 
are controlled in accordance with the reading signals of the reading 
controller 16. 
Since the operations of video signals are the same, the operation of the R 
video signal will be described. 
If a desired reading position is set in the horizontal (H) direction, the R 
signal selector 25 selects the 1R signal stored in the memory 22a, and the 
1R signal is read to the position of the key signal J. Then, the selector 
25 selects the 2R signal in the memory 22b, and the 2R signal is read at 
the position of the key signal K. The first image and the second image are 
overlapped at the predetermined portions and fixed to each other. 
If the direction is set by the section 13, the displaying area in the 
display is changed. As shown in FIGS. 8a, 8b and 8c, if the direction is 
set to the rightword direction, the display area is moved to the right. 
In place of the NTSC system, the high-vision system may be used. If key 
signals are added to both sides of the image, it is possible to select one 
of either sides, or a plurality of image sources. 
In accordance with the present invention, the key signals are added to the 
image signal at every field for determining split and combined positions 
and the image signals are combined based on the key signals. Since the 
combined position of the image signals are optionally set, the split 
positions are continuously selected. Furthermore, the combined image on 
the display area can be scrolled. 
While the presently preferred embodiments of the present invention have 
been shown and described, it is to be understood that these disclosures 
are for the purpose of illustration and that various changes and 
modifications may be made without departing from the scope of the 
invention as set forth in the appended claims.