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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a television receiver, and more
particularly to a portable television receiver capable of transmitting
image data through a communication channel.
2. Description of the Related Art
Recently, liquid-crystal television sets using a liquid-crystal display
unit in the display section in place of a cathode ray tube (CRT), one of
typical display devices, have become popular because of the relative
lightness and thinness of the device. For example, liquid-crystal display
units are widely used in the fields of car use and sports watching.
Particularly, such miniaturized liquid-crystal television sets which fit
in a breast pocket of the shirt are now on the market. People may go to
work or on a business trip, carrying those TV sets with them to watch a TV
program whenever they want to.
With such conventional liquid-crystal TV sets, however, since TV waves are
received and only the received image data is displayed on the
liquid-crystal display unit, the images that people can see on the
liquid-crystal TV set are limited to those televised.
In these days, people often use the telephone at a going-out place and can
of course transmit only sound to the other party on the phone.
It is unreasonable and inconvenient that people carrying liquid-crystal TV
sets with them can transmit only sound to the other party on the telephone
without transmitting image data.
SUMMARY OF THE INVENTION
Accordingly, the object of the present invention is to provide a portable
television receiver capable of transmitting specific image data together
with sound by means of a communication channel.
According to an aspect of the present invention, there is provided a
portable television receiver comprising: a television tuner; a display
section for displaying the image received by the television tuner; camera
means; means for causing the image taken by the camera means to be
displayed on the display section; means for compressing the image taken by
the camera means; means for modulating the image compressed by the
compressing means into an audio signal; and speaker means for outputting
the image modulated by the modulating means into an audio signal, wherein
the speaker means is pressed against the mouthpiece of a telephone to
transmit the image.
According to another aspect of the present invention, there is provided a
portable television receiver comprising: a case body; a television tuner;
a display section for displaying the image received by the television
tuner; a camera section; means for causing the image taken by the camera
section to be displayed on the display section; means for binarizing the
image taken by the camera section; and a facsimile transmission block
containing a facsimile modem for transmitting the image binarized by the
binarizing means to a facsimile.
According to still another aspect of the present invention, there is
provided a portable television receiver comprising: a case containing: a
television tuner; a display section for displaying the image received by
the television tuner; camera means; means for causing the image taken by
the camera means to be displayed on the display section; means for
compressing the image taken by the camera means; and means for modulating
the image compressed by the compressing means; and a telephone line jack
provided on the case and connected to a telephone line in order to output
the image data modulated by the modulating means.
According to further aspect of the present invention, there is provided a
portable television receiver comprising: a case containing: a television
tuner; means for displaying the image received by the television tuner;
camera means; means for compressing the image taken by the camera means;
means for modulating the image compressed by the compressing means; and
means for demodulating the image modulated by the modulating means; means
for expanding the image demodulated by the demodulating means; and means
for displaying selectively one of the image taken by the camera means and
the image expanded by the expanding means; and a telephone line jack
connected to a telephone line wherein outputting the image modulated by
the modulating means through the telephone line jack to a telephone line
and demodulating by the demodulating means the modulated image inputted
from the telephone line through the telephone line jack enables the
receiver to function as a videophone.
In the present invention, the above-mentioned configuration enables even a
portable television receiver to transmit image data using a communication
channel.
Additional objects and advantages of the invention will be set forth in the
description which follows, and in part will be obvious from the
description, or may be learned by practice of the invention. The objects
and advantages of the invention may be realized and obtained by means of
the instrumentalities and combinations particularly pointed out in the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part
of the specification, illustrate presently preferred embodiments of the
invention, and together with the general description given above and the
detailed description of the preferred embodiments given below, serve to
explain the principles of the invention.
FIG. 1 is a perspective view of a portable television receiver according to
a first embodiment of the present invention, viewed from the front;
FIG. 2 is a perspective view of the portable television receiver of the
first embodiment, viewed from the back;
FIG. 3 is a block diagram of the primary portion of the portable television
receiver of the first embodiment;
FIG. 4 is a perspective view for explaining how to operate the portable
television receiver of the first embodiment;
FIG. 5 is a perspective view of a portable television receiver according to
a second embodiment of the present invention, taken from the back;
FIG. 6 is a perspective view of a portable television receiver according to
a second embodiment of the present invention, taken from the front;
FIG. 7 is a perspective view of a portable television receiver according to
a third embodiment of the present invention, viewed from the front;
FIG. 8 is a perspective view of the portable television receiver of the
third embodiment with the camera section removed;
FIG. 9 is a perspective view of the portable television receiver according
to the third embodiment, viewed from the back;
FIG. 10 is a block diagram of the primary portion of the portable
television receiver of the third embodiment;
FIG. 11 is an exploded perspective view of an LCD;
FIG. 12 is an exploded perspective view of a flat fluorescent tube;
FIG. 13 is a flowchart for a binarization process;
FIG. 14 is a diagram for explaining an error diffusion process at a filter
in the binarization process;
FIG. 15 is a perspective view of a portable television receiver according
to a fourth embodiment of the present invention, viewed from the front;
FIG. 16 is a perspective view of the portable television receiver according
to the fourth embodiment, viewed from the back;
FIG. 17 is a drawing to help explain the connection between the portable
television receiver of the fourth embodiment and a telephone line;
FIG. 18 is a block diagram of the primary portion of the portable
television receiver of the fourth embodiment;
FIG. 19 is a diagram of the format for image and sound in the time division
multiplex system;
FIG. 20 is a flowchart for the operation of the control section in the
portable television receiver of the fourth embodiment;
FIG. 21 is a flowchart of the operation of the control section continued
from FIG. 20;
FIG. 22 is a transition diagram of the communication state during
transmission in the fourth embodiment;
FIG. 23 is a transition diagram of the communication state during reception
in the fourth embodiment;
FIG. 24 is a perspective view of an application where a card memory is
applied to the portable television receiver of the fourth embodiment; and
FIG. 25 is a perspective view of an embodiment of a video printer used to
print the image data stored in the card memory applied in FIG. 24.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention will be explained
hereinafter referring to the accompanying drawings.
With reference to FIGS. 1 to 4, a portable television receiver according to
the first embodiment of the present invention will be explained
hereinafter.
First, an arrangement of the first embodiment of the present invention will
be described hereinbelow.
FIGS. 1 and 2 show an outward appearance of the portable television
receiver of the first embodiment, viewed from the front and the back,
respectively. Hereinafter, a case where an analog-telephone ordinary
subscriber's line is used as a communication channel will be described. In
FIG. 1, the portable television receiver 1 is basically composed of a
receiver body 2 and a power supply section 3. The receiver body 2 is made
up of a reinforced plastic enclosure measuring 65 mm in height, 60 mm in
width and 24 mm in thickness. On the front of the body 2, a liquid-crystal
display section 5 and a camera section 6 are integrally provided, as shown
in FIG. 1. On the back of the body 2, a speaker section 8 is integrally
provided, as shown in FIG. 2. A power supply section 3, when attached to
the bottom of the receiver body 2, supplies a specific current to the body
2. Specifically, the power supply section 3 is made up of a battery pack
incorporating dedicated nickel-cadmium (Ni--Cd) batteries. While in the
first embodiment, explanation is given using a battery pack with built-in
dedicated nickel-cadmium batteries as the power-supply section 3 attached
to the bottom of the body 2, the invention is not limited to this example.
For instance, the power-supply section 3 may be composed of a dry-battery
pack containing five size AAA alkaline batteries, an AC adapter using an
AC (alternating current) power supply, or a car adapter using a DC (direct
current) battery in the cigarette lighter of a car. The liquid-crystal
display section 5 is a TFT active matrix liquid-crystal display unit
having a 1.4-inch screen. This display section is provided with a
high-resolution color liquid-crystal display panel having
220.times.279=61380 pixels where each set of pixels corresponding to R
(Red), G (Green), and B (Blue) known as primary colors is arranged in a
delta. The camera section 6, as shown in FIG. 1, is a compact CCD (Charge
Coupled Device) camera installed detachably on the same plane as the
screen of the liquid-crystal display section 5. The camera section 6 is
connected to the receiver body 2 with a video cable. The speaker section 8
is composed of, e.g., a dynamic cone-type loudspeaker, and outputs sound
data from speaker holes 8b made inside a ringed noise-insulating wall 8a
provided on the back of the body 2 as shown in FIG. 2. While in the first
embodiment, explanation is given using a dynamic cone-type loudspeaker as
the speaker section 8, the invention is not restricted to this example.
For instance, a speaker used for the speaker section 8 may be an entire
surface-driven-type electrostatic or flat loudspeaker or a dome
loudspeaker.
As shown in FIG. 1, the receiver body 2 is further provided with various
switches: they include a power switch 11, a power indicator 12, a tuning
button 13, a volume control dial 14, an earphone terminal 15, a video
switch 16, a video-mode select switch 17, and an image taking-in switch
18. The power switch 11 is used to determine whether or not the voltage
supplied from the power-supply section 3 is applied to the portable
television receiver 1. The power indicator 12 is made up of LEDs (Light
Emitting Diodes) and lights up when the power switch 11 is on. The tuning
button 13 is used to increase or decrease the tuning frequency. The volume
control dial 14 is used to control the earphone volume. The earphone
terminal 15 is a terminal for connecting to an earphone also serving as a
wire antenna, and acts as an antenna terminal. The video switch 16 is a
toggle switch for instructing the liquid-crystal display section 5 whether
to display an image on the LCD screen or not. The video-mode select switch
17 is a switch for choosing one, as the image to be displayed on the
liquid-crystal display section 5, among the televised image (the
television mode), the image data taken in by the camera section 6 (the
camera mode), and the image data already stored in a memory (the
transmission mode). The switch changes from the television mode to the
camera mode, and to the transmission mode each time the switch is pressed.
The image taking-in switch 18 is a switch for indicating whether the image
on the liquid-crystal display section 5 is to be stored as the image data
in a particular memory or the image data is to be transmitted in the
transmission mode.
FIG. 3 is a schematic block diagram of the portable television receiver
shown in FIGS. 1 and 2. In FIG. 3, the portable television receiver 1
comprises the power supply section 3, a TV tuner section 4, the
liquid-crystal display section 5, the camera section 6, a modulating
section 7, the speaker section 8, an image compressing section 9, a
control section 10, and a key operation section 10a. The modulating
section 7, the speaker section 8, and the image compressing section 9, the
control section 10, and the key operation section 10a are each connected
to a bus B.
The power supply section 3 is composed of a battery pack containing
nickel-cadmium (Ni--Cd) batteries, as mentioned earlier. The power supply
section 3, when the power switch 11 is turned on, supplies a specific
voltage to each section of the receiver body 2.
The TV tuner section 4 is made up of a tuner 21 and an ADC 22. The tuner 21
selectively receives a particular TV wave and outputs the received signal
to a DD23 (explained later) of the liquid-crystal display section 5. The
tuner also outputs the video signal to a video memory 32 in the image
compressing section 9 via the ADC 22. The ADC 22 converts the analog video
signal supplied from the tuner 21 into a digital signal. In FIG. 3, the
audio signal (AUDIO OUT) demodulated at the tuner 21 is supplied to the
earphone via the earphone terminal 15.
The liquid-crystal display section 5 is composed of a DD (Display Driver)
23 and an LCD (Liquid Crystal Display) 24, as shown in FIG. 3. The DD23 is
a display driving section for driving the LCD 24 to display the image on
the basis of the image signal taken in by the camera section 6 or the
video signal received by the TV tuner section 4. More specifically, the
DD23 converts the supplied video signal into an analog video signal
(analog RGB signal) of a specific number of bits for 220.times.279 pixels
and outputs the converted signal to the LCD 24. The LCD 24 is made up of a
color liquid-crystal display unit having a liquid-crystal panel (not
shown). In the LCD 24 of this embodiment, a compact flat fluorescent tube
(not shown) is used as a backlight (back illumination).
The camera section 6 is composed of a lens 25, a CCD 26, and an ADC 27. The
lens 25 is an optical lens formed of glass or plastic, provided on the
body 2 of the portable television receiver 1. The CCD 26 generates an
electric signal on the basis of the intensity of light focused by the lens
25, and supplies the generated electric signal (analog signal) to the ADC
27. The ADC 27 converts the video signal (analog signal) from the CCD 26
into a signal (digital signal) that can be processed in the image
compressing section 9.
The modulating section 7 is composed of a buffer memory 28 and a data
modulating circuit 29. The buffer memory 28 temporarily stores the
compressed image data to be modulated at the data modulating circuit 29.
The data modulating circuit 29 acts as a modulator which converts the
digital signal held in the buffer memory 28 into a transmission signal
(analog signal) that can be transmitted through a communication channel
(in this case, an analog telephone ordinary subscriber's line). The data
transfer speed of the data modulating circuit 29 in the first embodiment
is set at 1200 bps because the image data is transmitted in sound using an
analog-telephone ordinary subscriber's line.
The speaker section 8 is such that, for example, as shown in FIG. 4, sound
data is supplied to the mouthpiece through the speaker holes 8b (see FIG.
2) made inside the noise-isolating wall 8a by pressing the noise-isolating
wall 8a provided on the receiver body 2 against the mouthpiece of the
handset 101 of a telephone. The noise-isolating wall 8a is formed of an
elastic material such as synthetic rubber.
The image compressing section 9 comprises a buffer memory 30, a data
compressing circuit 31, a video memory (VRAM) 32, and a DAC (Digital to
Analog Converter: D/A converter) 33. The buffer memory 30 temporarily
stores the image data that has undergone data compression at the data
compressing circuit 31. The image data stored in compressed form in the
buffer memory 30 is supplied to the modulating section 7 under the control
of a CPU 35. The data compressing circuit 31 performs a compressing
(encoding) process on the image data stored in the video memory 32 by a
particular encoding method. Specifically, each 8.times.8 pixel block is
compressed by the DCT (Discrete Cosine Transform), quantization, and
Huffman coding techniques, using, e.g., a JPEG (Joint Photographic
(Coding) Experts Group) algorithm, depending on the type of images to be
handled (in this case, still images). This circuit then supplies the
compressed image data to the buffer memory 30, which stores it. In this
case, the data compressing circuit 31 has the capability of converting the
image data to be transmitted in the form of a color video signal for
110.times.160 pixels in up to 4096 colors (12 bits) into a YC signal
consisting of a luminance signal (hereinafter, referred to as signal Y)
corresponding to 220.times.279 pixels and a color signal (hereinafter,
referred to as signal C) corresponding to 4096 colors. The above-mentioned
12 bits of digital image data for 220.times.279 pixels is converted into
12 bits of image data for 110.times.160 pixels. The compression factor of
the compressed image data to be transferred is determined to be nearly
7/100 (nearly 68/1000) in consideration of the picture quality after
compression and expansion. The video memory 32 is composed of a VRAM
(Video RAM), which is a semiconductor image memory for storing the
original image data (digital data) to be compressed at the data
compressing circuit 31. The DAC 33 converts the video signal (digital
signal) of the image data stored in the video memory 32 into a signal
(analog signal) that can be displayed on the liquid-crystal display
section 5, and outputs the converted signal. In the first embodiment,
because an analog data driver is used for the driver for the
aforementioned LCD 24 to provide multi-gradation representation, the DAC
(D/A converter) is required. However, when a digital data driver is used
as the data driver for the liquid-crystal display section 5, the DAC 33 is
not required.
The control section 10 comprises a CPU (Central Processing Unit) 34, a RAM
(Random Access Memory) 35, and a ROM (Read Only Memory) 36. The CPU 34
supplies various control signals via the bus B to the individual circuits
in the portable television receiver 1. The CPU 34 also outputs the
compressed image data supplied via bus B from the image compressing
section 9 to the modulating section 7 via bus B. The RAM 35 is a
semiconductor memory for storing the program data used in a programmed
process executed at the CPU 34, the compressed image and sound data, etc.
The ROM 36 is a semiconductor memory for storing programs and data used in
the portable television receiver 1. The key operation section 10a is
composed of various operation switches including the video switch 16, the
video-mode select switch 17, and the image taking-in switch 18. When a key
switch is pressed, the process corresponding to the key switch is executed
by the CPU 34. The bus B is a common signal path to which the modulating
section 7, the image compressing section 9, the control section 10, and
the key operation section 10a are connected separately, and is made up of
an address bus for specifying an address and a data bus for transferring
data.
The image data dealt with in the first embodiment is the color image data
one screen of which has 110.times.160 pixels in 4096 colors (12 bits). The
amount of image data for one screen comes to 110.times.279.times.12=211200
bits (approximately 25.8 kilobytes). This is simultaneously compressed at
a ratio of approximately 68/1000 by the image compressing process into
14400 bits of image data. These 14400 bits are transferred in units of
1200 bits per second, and consequently still images are transferred
intermittently at a rate of one frame in 12 seconds (=14400.div.1200).
Therefore, the amount of data actually transferred in a second is 17600
bits (approximately 2.15 kilobytes) of image data obtained by dividing
211200 by 12. These 17600 bits of image data is compressed at a ratio of
approximately 68/1000 into an video code including 1200 bits of image
data.
Generally, liquid-crystal display units are much thinner than such image
display means as CRTs and are easy to make more compact and lighter.
Because active matrix LCDs provide minute half-tone control, assure a high
contrast ratio, and achieve a high response speed, as compared with simple
matrix LCDs, the former are effective devices in the fields requiring
multi-gradation color of high picture quality. Particularly, TFT active
matrix LCDs with three terminals provide as high a picture quality as that
of CRTs.
In the first embodiment, to make more use of the features of the
liquid-crystal display unit, a flat fluorescent tube is used as a
backlight, thereby making the unit more compact.
Next, an operation of the first embodiment of the present invention will be
described hereinbelow.
An operation of the control section 10 in FIG. 3 will be explained first.
The program corresponding to the processing effected by the CPU 34 in the
control section 10 is stored in the ROM 36 in the same control section 10.
The portable television receiver 1 of the first embodiment has a mode (the
television mode) in which the TV tuner section 4 receives a television
broadcast and the received broadcast is displayed on the liquid-crystal
display section 5 (i.e., in this mode, the portable television receiver 1
acts as a television set) and a mode (the camera mode) in which the image
data is taken in from the camera section 6.
In the television mode, by turning on the power switch 11 and operating the
tuning button 13, the wave from the desired television station is tuned in
and the televised image is displayed on the liquid-crystal display section
5, as well as the sound is provided through an earphone connected to the
earphone terminal 15. The volume of the earphone is adjusted to the
optimum level with the volume control dial 14. When the user wants to
listen to only the sound in receiving a TV broadcast, he or she can turn
off the televised image on the liquid-crystal display section 5 by
pressing the video switch 16. The image data corresponding to the
televised image is supplied to the video memory 32 via the ADC 22.
To specify the camera mode, the video-mode select switch 17 is pressed. By
doing this, the image data from the camera section 6 is displayed on the
LCD 24 of the liquid-crystal display section 5 (the video through image).
With either mode specified, to record the image appearing on the LCD 24,
the image taking-in switch 18 is pressed. By doing this, the video signal
received at the TV tuner section 4 in the television mode or the image
data taken in from the camera section 6 in the camera mode is converted
into digital data and then stored in the video memory 32. The image data
stored in the video memory 32 is compressed at the data compressing
circuit 31 and then stored in the buffer memory 30.
To specify the transmission mode, the video-mode select switch 17 is
pressed again. Then, the image data already stored in the memory is
selected. As shown in FIG. 4, by pressing the noise-isolating wall 8a
formed on the back of the receiver body 2 against the mouthpiece of the
handset 101 of the telephone now in a busy state, the speaker section 8 is
made ready to output the sound data. In this state, when the image
taking-in switch 18 is pressed, the compressed image data stored in the
buffer memory 30 is outputted to bus B under the control of the CPU 34. A
header (identifier) in a specified format is added to the compressed image
data and then temporarily stored in the buffer memory 28 in the modulating
section 7 via bus B. Next, the data modulating circuit 29 reads the
compressed image data from the buffer memory 28 sequentially, and
modulates the read-out compressed image data. The modulated compressed
image data is outputted in the form of sound data, which is transmitted
through a communication channel (in this case, an analog ordinary
subscriber's line) to the other party.
On the other hand, the image data (digital data) written in the video
memory 32 is D/A converted by the DAC 33, and the converted data is
supplied to the DD 23. The DD 23 displays the image data on the LCD 24.
Each time the video-mode select switch 17 is pressed, the televised image,
the image of the subject from the camera section 6, and the image stored
in the memory are displayed one after another in that order. When the
operator wants to record the image on the calling party side (the image to
be transmitted) appearing on the LCD 24 during telephone conversation, he
or she presses the image taking-in switch 18. This causes the image data
stored in the buffer memory 30 to be stored in the RAM 35. In this case,
as explained in the aforementioned transmission process, the amount of
image data for a compressed single screen is approximately 25.8 kilobytes.
Therefore, if the image data storage area of the RAM 35 has a capacity of
256 kilobytes, it can store nearly 10 screens of image data. When during
communication, the state of the communication channel deteriorates and the
picture quality transmitted worsens seriously, the transmission of the
image data may be stopped automatically.
As has been described above, with the first embodiment, high-quality images
are transmitted through an analog ordinary subscriber's line by
transferring a screen of image data (211200 bits) displayed on the LCD 24
at a rate of one screen in 12 seconds, conforming to the data transfer
speed (1200 bps) of the compressed image data transmitted through the
communication channel. Specifically, because the screen size of the LCD 24
is 1.4 inches and its single screen has 110.times.160 pixels.times.12 bits
(4096 colors)=211200 bits of data, the image data is transferred at a rate
of one frame in 12 seconds. However, as the number of pixels and the
number of colors (the number of gradations) in one screen increase or
decrease as a result of the change of the screen size, the time required
to transfer a single screen of image data is changed. Specifically, for
example, it is assumed that a mode in which the image data is transferred
in 4096 colors is determined to be a normal mode, and a mode in which
representation is made in 65536 colors (16 bits) using the same number of
pixels (110.times.160 pixels) is determined to be a high-quality mode.
When the image | | |
