Interactive television system and method for viewer control of multiple camera viewpoints in broadcast programming

An interactive television system has a set-top box adapted for use with a television and a remote control handset. The set-top box is connected to receive a television broadcast that is filmed using multiple cameras situated at various camera viewpoints. The television broadcast has a primary channel, with which the viewer is familiar as carrying the desired television program, and multiple virtual channels associated with the primary channel. The virtual channels carry video signals from the multiple different cameras covering the event. The remote control handset has dedicated camera control buttons for selecting corresponding virtual channels to allow the viewer to choose a desired camera viewpoint. The dedicated camera control buttons are arranged in an intuitive pattern that correlates to the camera viewpoints.

TECHNICAL FIELD 
This invention relates to interactive television, and more particularly, to 
a system and method for viewer control of multiple camera viewpoints in 
broadcast programming. This invention further relates to a remote control 
handset used in the interactive television system. 
BACKGROUND OF THE INVENTION 
Conventional broadcast programming has traditionally been limited to a 
single video stream broadcast from the television or cable company to a 
viewer's television. Although multiple cameras may have been used to cover 
the event, the program's producer selects which camera to use at which 
point in the program so that only one video stream is broadcast to the 
viewer. For example, when broadcasting sporting events, such as baseball 
games or tennis matches, the sports network typically employs multiple 
cameras to adequately cover the action. The multiple cameras enable ready 
replay of key plays, such as a runner sliding into home plate or a diving 
backhand volley, from many different angles. The producer relies on his or 
her creativity and experience to timely select the appropriate camera 
viewpoint which best conveys the sporting event. 
The viewer, on the other hand, has no control over what he/she is viewing. 
Conventional broadcast systems are not interactive and thus, the viewer is 
forced to watch the single video stream compiled by the program's 
producer. As a result, the viewer cannot independently choose to watch the 
action from the home plate camera in anticipation of a close call at home 
plate. 
With the advances made in fiber optics, digital communications, and other 
broadcast-related technologies, the number of available channels to end 
viewers is ever increasing. Today, there are approximately 40-70 channels. 
By the year 2000, the number of channels is expected to reach 500. 
As the number of available channels increases, it has become possible to 
make available multiple camera signals for control by the viewer. In such 
systems, a channel is reserved for each camera video signal. For example, 
suppose a musical concert event required three camera viewpoints: one 
camera facing center stage, a second camera facing at an angle toward the 
stage, and a third camera portably roving near the stage for close-ups on 
the musicians. The three cameras would be assigned to channels, say, 
150-152. If the viewer wanted to watch a close-up of the lead singer, the 
viewer changes to channel 152 using the television control panel or a 
conventional remote control handset having a number keypad and a channel 
up/channel down key. If the viewer wanted a full view of the stage, the 
viewer would change to channel 150, and so forth. 
This method for viewer interaction is not, however, very convenient for the 
viewer. The viewer must consciously remember which channels show which 
camera viewpoints. Three viewpoints for a concert might be manageable. 
But, six or more viewpoints in a fast paced basketball game or tennis 
match might leave the viewer frustrated and seemingly behind the action of 
every play. 
The present invention provides an interactive system and method which is 
intuitive to operate so that the viewer can expertly manipulate the camera 
viewpoints as desired. 
SUMMARY OF THE INVENTION 
According to one aspect of this invention, an interactive television system 
is provided which permits viewer control of multiple camera viewpoints 
during a television broadcast. The television broadcast is filmed using 
multiple cameras situated at various camera viewpoints, such as at a 
sporting event where many different cameras are employed to capture the 
action from several angles. The television broadcast has a primary channel 
which the viewer is familiar, and multiple virtual channels associated 
with the primary channel. These virtual channels carry video signals from 
the different cameras. The viewer need not be aware of the virtual 
channels, but simply assumes that he/she has tuned to the primary channel 
where various camera angles can be manipulated. 
The interactive television system includes a set-top box, which is adapted 
for use with a television, and a remote control handset that is remotely 
coupled to the set-top box. The set-top box is connected to receive the 
primary and virtual channels. The remote control handset has dedicated 
camera control buttons for selecting corresponding virtual channels to 
thereby permit the viewer to choose a desired camera viewpoint. The 
dedicated camera control buttons are arranged in a correlating pattern to 
the camera viewpoints so that selection of a desired viewpoint is 
intuitive to the viewer. Preferably, the dedicated camera control buttons 
are arranged according to directional components of a compass. In this 
arrangement, the viewer simply depresses the "north" button when he/she 
wishes to view the sporting event from the north side, and so on. 
The interactive television system of this invention therefore provides 
intuitive operation whereby the viewer tunes to a single station, and then 
expertly manipulates the camera viewpoints as desired using the designated 
camera control buttons. This arrangement is further advantageous as it 
permits rapid camera change to keep up with the action. The viewer need 
not remember which channel carries which viewpoint. Additionally, the 
viewer is relieved of having to punch various numbers on the keypad or 
up/down buttons to switch camera angles, which is often times too slow.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows an interactive television system 20 according to this 
invention. The interactive television system 20 includes a television 22, 
a set-top box 24, and a remote control handset 26. The set-top box 24 is 
coupled to receive television broadcasts from a cable or television 
company, and feeds the broadcast signals to the television 22 for display. 
As is customary, the set-top box controls which broadcast is displayed on 
the television. 
The remote control handset 26 has conventional channel changing buttons in 
the form of numeric keypad 28 and an up channel/down channel button 30. A 
volume control button 32 is also shown. Other buttons, such as power and 
VCR control keys, are not shown, but may also be provided on remote 
control handset 26. According to one aspect of this invention, remote 
control handset 26 also has designated camera control buttons 34 and a 
mode select button 36, which are be described below in more detail. 
This invention is particularly concerned with television broadcasts which 
are filmed using multiple cameras situated at various camera viewpoints. 
The television broadcast has a primary channel which the viewer is 
familiar with, and multiple virtual channels associated with the primary 
channel. A "virtual channel" is an otherwise normal channel that carries a 
video stream like the primary channel, but the identity of the channel 
itself is hidden from the viewer. The virtual channels are used to carry 
video signals from the different cameras. The viewer does not need to be 
aware of the virtual channels, but instead simply assumes that he/she has 
tuned to the primary channel where various camera angles can be 
manipulated. 
It would be helpful for purposes of continuing discussion to provide a 
example entailing a familiar sporting event. Suppose a sports network 
broadcasts live coverage of a baseball game. The sports network has a 
primary channel, say channel 20, which the viewer tunes into to watch the 
baseball game. The viewer tunes to the primary channel using the channel 
changing buttons 28 or 30. Set-top box 24 includes a channel number 
display 38 which shows the primary channel number "20". 
To adequately cover the baseball game, the sports network positions 
multiple cameras around a baseball field to provide varied viewpoints. The 
multiple viewpoints help capture all of the action, as well as provide 
different replay angles of critical plays, such as a grand slam. 
FIG. 2 shows an example camera arrangement around baseball field 40. The 
action on the baseball field is monitored by seven cameras 42-48. Center 
field camera 42 captures the action from the center field perspective. 
Camera 43 provides overhead visuals from a blimp or dome. First base 
camera 44 monitors action from behind first base as well as a view of the 
home dugout. Third baseline camera 45 provides a view of the entire field 
and particularly, down the third baseline. Home plate camera 46 provides a 
catcher's perspective and shows the types of pitches being hurled at a 
batter. First baseline camera 47 covers the entire field and down the 
first baseline. Third base camera 48 observes action from behind third 
base as well as a view of the visitors' dugout. 
The video streams generated by the cameras are carried on separate channels 
which are simultaneously broadcast to the viewer's home. The program's 
producer assigns the cameras to corresponding channels in a manner 
compatible with directional control afforded by the camera control buttons 
34 on remote control handset 26. For instance, suppose the program 
producer assigns a composite signal (i.e., the signal produced and edited 
by the program staff that is traditionally available on television) to 
channel 120. The video signals produced by cameras 42-48 are assigned to 
respective channels 121-127. Channels 120-127 can be referred to as 
"virtual channels" because the actual identity of channel remains hidden 
from the viewer who believes that he/she is watching the sports channel 
"20". 
When the viewer first tunes to the primary sports network channel "20", the 
composite video stream is initially displayed on the television. The 
composite video stream is created by the program's producer and staff from 
the multiple camera viewpoints. It presents the baseball game in the same 
manner available in conventional television systems, including: data 
overlays for scores or statistics, audio from the commentators, and cuts 
to various camera angles to timely capture the action. 
If the viewer wishes to choose another camera viewpoint independently from 
what the program producer is displaying, the viewer simply pushes one of 
the dedicated camera control buttons 34 on the remote control handset 26. 
The camera control buttons are arranged in a correlating pattern to the 
camera viewpoints. One preferred arrangement is a directional layout along 
compass coordinates as shown in FIG. 3. Here, camera control buttons 34 
include a "northwest" oriented button 50, a "north" oriented button 51, a 
"northeast" oriented button 52, an "east" oriented button 53, a 
"southeast" oriented button 54, a "south" oriented button 55, a 
"southwest" oriented button 56, and a "west" oriented button 57. 
The camera control buttons 34 correlate to the camera viewpoints at the 
baseball field 40 in an intuitive fashion. For example, the "north" button 
51 can be assigned to select the viewpoint from center field camera 42 
situated at the north end of the ballpark. The "south" button 55 can be 
assigned to select the viewpoint from home plate camera 46 situated at the 
south end of the baseball field. The following table 1 summarizes the 
correlation between the camera control buttons and the camera positions 
about the baseball field 40, as well as the corresponding channel carrying 
the video stream. 
TABLE 1 
______________________________________ 
Direction 
Button Camera (Number and Viewpoint) 
Channel 
______________________________________ 
NW 50 Composite -- edited by producer 
120 
from all cameras 
N 51 42 -- Center Field 121 
NE 52 43 -- Blimp 122 
E 53 44 -- 1st Base 123 
SE 54 45 -- 3rd Baseline 124 
S 55 46 -- Home Plate 125 
SW 56 47 -- 1st Baseline 126 
W 57 48 -- 3rd Base 127 
______________________________________ 
As evident from table 1, the dedicated camera control buttons offer the 
viewer intuitive, intelligent control of the various camera viewpoints. If 
the viewer wants to watch the pitch, the viewer simply hits the "south" 
button 55 to watch from the home plate viewpoint taken through camera 46. 
If the viewer wants to see whether a hit ball slices foul down the first 
baseline, the viewer can immediately press the "southwest" button 56 to 
observe the 1st baseline taken through camera 47. In a very short time, 
the viewer learns to instinctively switch to the desired camera viewpoint 
without conscious effort because of the intuitive correlation between the 
camera control buttons and camera viewpoints. 
Although the composite signal is described as being carried on a virtual 
channel 120, it may alternatively be carried on the primary channel "20". 
In this manner, the primary channel carries the traditional composite 
signal created by the program's producer, while the independent camera 
viewpoints are carried on the virtual channels. The broadcast or cable 
company would provide as part of the broadcast video signal appropriate 
information which coordinates the composite signals and independent camera 
viewpoints as belonging to the same broadcast program. 
FIG. 4 shows a functional block diagram of the remote control handset 26 
and set-top box 24. Remote control handset 26 comprises a channel changing 
signal generator 60 which generates channel changing signals in response 
to depression of the channel changing buttons 28 and 30. Remote control 
handset 26 further comprises a camera control signal generator 62 which 
generates unique camera control signals in response to depression of the 
camera control buttons 34. A modal control signal generator 64 is also 
provided to generate a modal control signal in response to actuation by 
modal select button 36, which is described below in more detail. 
The signals generated in the remote control handset are transmitted via 
conventional infrared or radio communication techniques (as indicated by 
jagged arrow 66) to a receiver 68 in set-top box 24. Decoder 70 deciphers 
the transmitted signal. If the transmitted signal involves channel 
changing information, the set-top box changes the primary channel and the 
number of the primary channel is displayed on the primary channel number 
display 72. If the transmitted signal involves volume control or other 
television operating settings, the decoder 70 informs the appropriate 
control circuits (not shown) to adjust the television as desired. 
If the transmitted signal is a camera control signal, it is forwarded to 
virtual channel selector 74 which is connected to all of the channels 
coming from the cable company. In our continuing example, FIG. 4 shows 
virtual channels 120-127 which carry the video streams from the cameras at 
the baseball game. Virtual channel selector 74 switches among the virtual 
channels in response to the selected camera control buttons depressed by 
the viewer. 
Suppose, for example, the viewer wants to watch the lead off runner on 
first base. The viewer might depress the "west" button 57 to watch from 
the third base camera 48. The depressed "west" button causes generation of 
a unique camera control signal which is transmitted to set-top box 24. The 
camera control signal is received and decoded and ultimately passed onto 
virtual channel selector 74. In response to the signal, the virtual 
channel selector switches from the present camera angle to virtual channel 
127 which is carrying the video stream from third base camera 48. 
It is noted that the virtual channel selector 74 changes the virtual 
channel without affecting the primary channel number "20" being shown on 
the primary channel number display 72. In this manner, the change of 
camera viewpoints is transparent to the viewer. The viewer believes that 
he/she is still watching the sports network on channel "20", even though 
the set-top box is switching among multiple channels all the time. The 
intuitive, transparent control of camera viewpoints afforded by this 
invention is advantageous because the viewer does not have to expressly 
change channels or memorize the various channels which carry the different 
camera viewpoints. 
FIG. 5 shows preferred steps in a method for controlling multiple camera 
viewpoints during a television broadcast according to the techniques of 
this invention. Steps 80 and 82 establish the environment for one 
preferred use of this invention. At step 80, a televised event is covered 
using multiple camera viewpoints, such as the above example baseball game. 
The video stream from each camera is broadcast on a separate channel to 
the viewer's set-top box (step 82). 
At step 84, the viewer selects a desired program, such as the baseball 
game, using the channel changing buttons 28 or 30 on the remote control 
handset 26. At this point, the composite video signal on channel 120 is 
displayed on the television (step 86), although other virtual channels 
might alternatively be used as the default viewpoint. When the viewer 
wishes to change to a new camera viewpoint, the user presses the 
appropriate dedicated camera control button 34 on the remote control 
handset 26 (step 88). This effectuates generation of a unique camera 
control signal which is sent to the set-top box 24, or more precisely, to 
the virtual channel selector 74 which switches to the virtual channel that 
carries the selected camera viewpoint (step 90). As a result, the video 
stream from the new virtual channel is displayed on the television (step 
92). 
Although the interactive television system of this invention allows viewers 
to control the camera viewpoints, the producer might still be inclined to 
present simulcast information on any or all of the channels. Score 
overlays, statistics, and commentator audio can be made available to the 
viewers regardless of which camera viewpoint is selected. 
It is noted that an alternative configuration of the interactive television 
system can allow the viewer to customize the program to his/her tastes. 
For example, the simulcast information might be provided on an entirely 
separate channel which can then be manipulated and combined with the 
selected camera viewpoints in the set-top box according to the viewer's 
preferences. 
FIG. 6 shows another aspect of interactive television system 20 according 
to this invention. Here, television 22 is shown displaying the selected 
virtual channel (i.e., an overhead view of the baseball game taken from 
the blimp camera 43), two selectable option icons 100 and 102, and a modal 
selection icon 104. The option icons 100 and 102 represent alternative 
viewing screens which display information other than video footage of the 
baseball game. For example, the screen associated with option icon 100 
might provide the statistics of a player or entire team and the screen 
associated with option icon 102 might provide the league standings. Many 
other options may also be included, such as the scores of other games, the 
remaining schedule, or up-to-the-minute baseball news. 
The modal select button 36 on remote control handset 26 enables the 
interactive television system to toggle between two modes of operation. In 
a first mode of operation, the dedicated camera control buttons 34 are 
used to cycle through the various option icons 100 and 102 and modal 
selection icon 104. A highlighting indicator 106 is used to visually 
identify the active option icon. 
Once the modal selection icon 104 is highlighted, the viewer can hit the 
modal select button 36 to toggle to the other mode of operation. In the 
second mode of operation, the camera control buttons 34 are used to switch 
among the virtual channels, in the manner described above. 
FIG. 7 shows a functional block diagram of the remote control handset 26, 
set-top box 24', and a head end server 120 according to another 
implementation of this invention. The construction and operation of remote 
control handset 26 and set-top box 24' are essentially the same as that 
described above with respect to FIG. 4. The only notable difference is 
that the set-top box 24' is implemented without a virtual channel decoder, 
and instead sends the camera control signals over cable 122 to head end 
server 120. 
Head end server 120 services many (e.g., tens to hundreds of thousands) 
viewers. Head end server 120 includes a program selector 124, a camera 
viewpoint selector 126, and a program store 128. The program selector 124 
chooses the appropriate program (such as the baseball game), and the 
camera viewpoint selector 126 chooses the desired camera viewpoint (such 
as the home plate camera). The head end server 120 receives the multiple 
camera video signals directly from a satellite feed, or other source. The 
head end server can then immediately rebroadcast the program to the 
set-top box 24', as is the case for televising live baseball action. If 
the viewer desires to change the camera viewpoint, he/she depresses the 
desired dedicated camera control button to generate an appropriate camera 
control signal within remote control handset 26. The camera control signal 
is transmitted via communication link 66 to set-top box 24', which then 
sends the request to head end server 120. Program selector 124 and camera 
viewpoint selector 126 decode the signal and cause the appropriate video 
signal corresponding to the selected camera viewpoint to be sent back to 
the set-top box for display on the television. 
Alternatively, the head end server 120 can digitally store the program 
received via satellite in program store 128. Here, all video streams from 
all cameras used to film a specific program are digitally stored in 
program store 128. In this interactive environment, the viewer can call up 
for viewing a stored program that has already been run. For example, the 
viewer may wish to watch a baseball game that aired live last week. The 
head end server 120 retrieves the desired video signals from the program 
store. When the viewer wants to change viewpoints, the program selector 
and camera viewpoint selector change the memory pointers to the 
appropriate storage locations to retrieve the selected camera video 
signal. 
FIG. 8 shows preferred steps in a method for controlling multiple camera 
viewpoints using the FIG. 7 interactive television system. At step 130, a 
televised event is covered using multiple camera viewpoints, such as the 
above example baseball game. At step 132, the video streams are provided 
to head end server 120, for example, via satellite. At step 134, the video 
streams of all the different camera viewpoints can be stored in program 
store 128. The head end server transmits one of the video signals (e.g., 
the composite video signal) in real-time, or by reading it from program 
store 128, to set-top box 24' (step 136). 
The camera viewpoint corresponding to the transmitted video signal is 
displayed on the television (step 138). The user changes the camera 
viewpoint by intuitively depressing a particular dedicated camera control 
button on the remote control handset (step 140). This request is sent back 
through the set-top box 24' to head end server 120 (step 142), which then 
switches to the video signal corresponding to the selected camera 
viewpoint (step 144). The new video signal is then transmitted over cable 
122 to set-top box 24' (step 146) for display on the television (step 
148). 
The interactive television system of this invention provides intuitive and 
intelligent operation. The viewer simply tunes to a single station, and 
then manipulates the camera viewpoints as desired using the designated 
camera control buttons. The inconvenience of having to remember which 
channel carries which viewpoint is eliminated. Additionally, the intuitive 
system permits rapid camera change to keep up with the action. The viewer 
is relieved of having to punch various numbers on the keypad or up/down 
buttons to switch camera angles, which is often too slow for the pace of 
the event. 
In compliance with the statute, the invention has been described in 
language more or less specific as to structural and methodical features. 
It is to be understood, however, that the invention is not limited to the 
specific features shown and described, since the means herein disclosed 
comprise preferred forms of putting the invention into effect. The 
invention is, therefore, claimed in any of its forms or modifications 
within the proper scope of the appended claims appropriately interpreted 
in accordance with the doctrine of equivalents.