Television – Two-way video and voice communication
Reexamination Certificate
2001-02-21
2003-07-08
Ramakrishnaiah, Melur (Department: 2643)
Television
Two-way video and voice communication
C348S014070, C348S578000
Reexamination Certificate
active
06590601
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a videophone apparatus forming one terminal of a videophone system that sends and receives picture data as well as voice data over a communication line, more particularly to a videophone apparatus that modifies or replaces a live picture of the user for purposes of courtesy and privacy protection.
In recent years, with the development of communication networks and advances in data compression technology, videophone systems that can communicate (send and receive) not only voice but also pictures over the same line have gradually been spreading. Differing from conventional telephone systems that send and receive only speech, videophone systems have made it possible to converse while seeing the other party's face.
A videophone system and a conventional videophone apparatus will be described below with reference to the drawings.
FIG. 22
is an overall block diagram showing a videophone system using conventional videophone apparatus.
In the videophone system in
FIG. 22
, a videophone apparatus
1
and a videophone apparatus
21
are disposed on opposite sides of a communication network
40
such as a telephone network. The sending and receiving of voice and pictures is thus carried out through the communication network
40
between videophone apparatus
1
and videophone apparatus
21
. The user of videophone apparatus
1
is a speaker
2
(Mr. A); the user of videophone apparatus
21
is a speaker
22
(Mr. B). Speaker
22
(Mr. B) and the background
23
of Mr. B appear on the monitor screen
12
a
of videophone apparatus
1
; speaker
2
(Mr. A) and the background
3
of Mr. A appear on the monitor screen
12
b
of videophone apparatus
21
.
In videophone apparatus
1
and videophone apparatus
21
there are provided: an operation unit (OP)
11
by which the speakers
2
,
22
give instructions to the videophone apparatus
1
and videophone apparatus
21
; a display unit
12
that displays the faces of the far-end speakers
2
,
22
, their backgrounds
3
,
23
, and so on; an imaging unit
13
that images the faces of the speakers
2
,
22
, their backgrounds
3
,
23
, and so on; a handset
14
by which the speakers
2
,
22
input and output their voices; a system control unit (SYSCON)
15
that controls the coding and decoding of voice data and picture data and the operation of the videophone apparatus
1
or
21
overall according to the instructions input from the operation unit
11
; a voice-data coding/decoding unit
16
that codes signals input from the handset
14
and decodes signals sent to the handset
14
; a picture-data coding/decoding unit
17
that codes signals input from the imaging unit
13
and decodes signals sent to the display unit
12
; a transmission control unit (TXCON)
18
that converts signals output from the voice-data coding/decoding unit
16
and picture-data coding/decoding unit
17
to signals for transmission on the communication network
40
, extracts picture data and voice data from incoming transmitted signals on the communication network
40
, and outputs these data to the voice-data coding/decoding unit
16
and picture-data coding/decoding unit
17
; and a line interface unit
19
that carries out adjustments of the signal level, signaling system, and so on in order to adapt the output signals of the transmission control unit
18
to the communication network
40
, and carries out adjustments of the signal level, signaling system, and so on so that signals received from the communication network
40
can be processed inside the videophone apparatus
1
,
21
.
Next, the coding of the transmitted pictures in
FIG. 22
will be explained in more detail.
FIG. 23
is a drawing that shows selected blocks related to the process of coding transmitted pictures in the videophone apparatus
1
in FIG.
22
.
A line-connect/disconnect key (off-hook/on-hook key)
11
a
is provided in the operation unit
11
for the speaker
2
to use to give instructions for the process of connecting the videophone apparatus
1
to the line and the process of disconnecting the videophone apparatus
1
from the line.
The picture-data coding unit
90
is a block that indicates a coding unit used in sending picture data in the picture-data coding/decoding unit
17
in FIG.
22
. Descriptions of the other blocks will be omitted because they duplicate blocks shown in FIG.
22
.
A more detailed description of the picture-data coding unit
90
in
FIG. 23
will now be given.
FIG. 24
is a block diagram showing the internal structure of the picture-data coding unit
90
in FIG.
23
.
The internal structure of the picture-data coding unit
90
in
FIG. 24
also shows the picture signal coding system shown, for example, in ISO-IEC/JTC1/SC29/WG11 MPEG 92/NO245 Test Model 2.
The picture-data coding unit
90
in
FIG. 24
comprises a subtractor
52
, a DCT (discrete cosine transform) circuit
53
, a quantizing circuit
54
, a variable-length coding circuit
55
, a transmit buffer
56
, a dequantizing circuit
61
, an IDCT (inverse discrete cosine transform) circuit
62
, an adder
63
, a memory circuit
64
, a switching circuit
65
, and a motion compensation and prediction circuit
66
.
On instruction from the system control unit
15
, a signal
71
(a digital picture signal) input to the picture-data coding unit
90
from the imaging unit
13
is input to the first input unit (
1
) of the subtractor
52
, the first input unit (
1
) of the motion compensation and prediction circuit
66
, and the second input unit (
2
) of the quantizing circuit
54
. The output
72
of the subtractor
52
is input to the DCT circuit
53
; the output
73
of the DCT circuit
53
is input to the first input unit (
1
) of the quantizing circuit
54
. The output
74
of the quantizing circuit
54
is input to the variable-length coding circuit
55
and is also input to the dequantizing circuit
61
. The output
75
of the variable-length coding circuit
55
is input to the transmit buffer
56
. The output from the first output unit <1> of the transmit buffer
56
is output to the transmission control unit
18
; the output
77
from the second output unit <2> of the transmit buffer
56
is input to the third input unit (
3
) of the quantizing circuit
54
.
The output
81
of the dequantizing circuit
61
is input to the IDCT circuit
62
; the output
82
of the IDCT circuit
62
is input to the first input unit (
1
) of the adder
63
. The output
83
of the adder
63
is input to the first input unit (
1
) of the memory circuit
64
; the output
84
of the memory circuit
64
is input to the second input unit (
2
) of the motion compensation and prediction circuit
66
and the first input unit (
1
) of the switching circuit
65
. The output from the first output unit <1> of the motion compensation and prediction circuit
66
is input to the second input unit (
2
) of the memory circuit
64
.
In addition, a zero signal is furnished to the second input unit (
2
) of the switching circuit
65
, and the output
87
from the second output unit <2> of the motion compensation and prediction circuit
66
is input to the third input unit (
3
) of the switching circuit
65
. The output
85
of the switching circuit
65
is input to the second input unit (
2
) of the subtractor
52
and the second input unit (
2
) of the adder
63
.
The videophone system and videophone apparatus shown in
FIGS. 22
to
24
operate as follows.
A case will be described in which, for example, speaker
2
(Mr. A) uses videophone apparatus
1
to call speaker
22
(Mr. B), who is at videophone apparatus
21
.
First, when the line-connect/disconnect key
11
a
in the operation unit
11
shown in
FIG. 23
is operated by speaker
2
, the system control unit
15
connects videophone apparatus
1
to the communication network
40
by means of the transmission control unit
18
, line interface unit
19
, and so on.
Next, speaker
2
designates the dial number of speaker
22
by means of dial keys or the like (not visible), and a communication line i
Hatano Yoshiko
Kurashita Takuji
Minobe Tadashi
Sugiyama Kazuhiro
Sukeno Junji
Mitsubishi Denki & Kabushiki Kaisha
Ramakrishnaiah Melur
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