JPH01302983A - Displaying device for still picture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The explanation will be given in the following order.

A. Industrial application field B　Invention + Already necessary C Conventional technology D Problems to be solved by the invention E. Means to solve the problem (Figure 1) F. Effect G Example G1 First embodiment (Figures 1 to 4) G2 Other embodiments Effect of H invention A. Industrial application field The present invention relates to a still image display device.

B. Summary of the Invention This invention enables appropriate display even if the image size is different by performing mask processing when implementing so-called videophone using, for example, a general public telephone line. It is.

C. Conventional technology To implement a videophone, transmitting the video signal as is would require a broadband dedicated line. It is difficult to use it easily.

Therefore, for personal videophone calls, ordinary public telephone lines must be used;
There is only about z. Therefore, in this case, the image is a still image, and its video signal is time-axis expanded and transmitted.

Also, if all pixels of one frame of the still image are transmitted,
This requires a considerable amount of time and is not practical. Therefore, pixels are thinned out at an appropriate rate and transmitted.

Therefore, in consideration of the above, the following standards have been devised.

That is, first, the screen mode (screen format) is as shown in FIG.

When switching to i-mode (5th pixel) Number of horizontal pixels: 160 pixels Number of vertical pixels: 100 pixels Gradation degree: 16 or more gradations 11 When in mode B (Figure 5 B) Number of horizontal pixels: 96 pixels Number of vertical pixels: 100 Pixel gradation, 16 gradations or more Note that if the gradation is 16 gradations, one pixel can be expressed with 4 bits, so the amount of image data in mode A is 160 pixels x 100 pixels x 4 bits. 64, and in bit mode B, it becomes 96 pixels x 100 pixels x 4 bits - 38.4 k bits.

Next, the signal format for transmitting image data is as shown in FIG.

That is, when the line with the other party is connected, when the sender presses the image sending key on the videophone call, a message is sent from the sender to the receiver for a period of time TI, for example, TI = 0.
A dual tone signal DLTN is sent out for 4 seconds. This signal DLTN is a signal for forcibly switching the videophone on the receiving side from the normal call mode to the image reception mode.

Therefore, this signal DLTN converts the alternating signal Sc of the color subcarrier frequency f C (-3,579545 MHz) in the NTSC system into a frequency f,, f2, for example, f, = f c/1784; 2006 Hz --
---・S.

f2=fc/2192=1633Hz...
S2, respectively, and the divided signals S1. This is a constant level signal mixed with S2. Therefore, this signal DLTN has signal components of frequencies f, , f2 for a period T.

Since the signal is continuous over the entire length of the signal, the receiving side can easily and reliably identify it as a voice signal or the like.

Then, period T is followed by period T2, for example, T2=0.
There is a no-signal period of 4 seconds.

Next, period T2 is followed by period T3, for example, T3γ0.1
A frame synchronization signal FSYN is sent out for a period of seconds. This signal FSYN is a cue signal that serves as a reference for the timing of subsequent signals, and is also a signal that serves as a reference for the frequency and phase of subsequent signals. Therefore, the signal PSYN changes the signal Sc to a frequency f3, for example, f3=fc/2048=17487...
...S3 is the frequency-divided signal S3, and
This is a signal in which a signal S3 with a phase of 0° and a signal S3 with a phase of 180° are combined in a predetermined order. Also, signal F
The level of SYN is the maximum level of this series of transmitted signals. Note that the period T3 is strictly a 176 cycle period (=0.1 second) of the signal S3.

Subsequently, the amplitude calibration signal ACAL is sent out for a period T4, for example 'r4=0.07 seconds. This signal AC
AL is a signal for correcting the level of subsequent signals in the videophone on the receiving side in response to variations in the transmission gain of the telephone line. Therefore, the signal ACAL is a signal obtained by amplitude and phase modulation of the signal S3 to a predetermined level (16 gradations) and phase (0° or 180°),
Delivered over 128 cycles. Therefore, period T4 is a period of 128 cycles of signal S3.

Furthermore, the identification code ID is sent in the following period T5. This code ID indicates the mode of the image to be transmitted, the communication capability of the video telephone on the transmitting side, etc. using a binary code of "o" and "1".

Therefore, the identification code ID is O according to the binary code 0'' or 1'' of the signal S3.

Or it is a 180° phase modulated signal, code I
The length of period D (the length of period T5) is an integral multiple of 64 cycles of signal S3.

Then, image data is transmitted in a period T6 following the period T5. In this case, this image data is transmitted by the signal S
3 using image data and transmitting the modulated signal Sm.

However, at this time, as shown in Figure 7 (this figure is 16
), one cycle of the signal Sm (S3) is assigned to the image data of one pixel, and the amplitude and phase of the one cycle are modulated according to the image data of one pixel, and the pixel is black. At the level (0th gradation),
The signal Sm has a phase of 0°, a maximum amplitude, and a white level (15th
gradation), the amplitude is maximized when the phase is 180°.

Note that even when the amplitude of the signal Sm is the minimum, the amplitude is O
Therefore, the signal Sm is not interrupted even at the minimum amplitude, and the signal S3 exists as a carrier signal. Furthermore, when the gradation is 16 or more, the amplitude of the signal Sm is subdivided in the same manner as described above.

Therefore, in the case of mode, one screen is 160 pixels x 1
00 pixels, T 6 = 160 x 100 x 1/ f 3; 9.
It will be 2 seconds. In addition, in the case of mode B, T6=9
6 X100 Xi/f 3; 5.5 seconds.

References: Specifications such as Japanese Patent Application No. 155145/1982 and Drawing D Problems to be Solved by the Invention By the way, in the above-mentioned videophone, it is possible to support two modes, screen mode A and mode B, with different image sizes. equipment is desired.

In this case, the image for mode A, which has a large image size (
The image for mode B (96 pixels x 10 pixels) is the size of the display screen - the cup.
0 pixel) may be displayed in the center of the display screen.

However, in the case of mode B, mode B
For example, if you display an image in mode A after displaying an image in mode A, if you do not perform some processing on the area other than the screen based on the image data, that is, the area of 32 pixels x 100 pixels on each side of the screen, the mode The old mode A image remains on both sides of the image, resulting in an unsightly screen as a whole.

E. Means for Solving the Problems Therefore, in this invention, for example, FIGS.
As shown in the figure, when the screen mode is mode B, the masking circuit performs masking processing on the screen other than the mode B image.

F When displaying image data with an image size smaller than the display screen as action image data, the parts other than the image part to be displayed are
For example, if the image is masked in gray, one still image display device can appropriately display the image even if the image size is different.

G Example GI First Example FIG. 1 shows an example of this invention.

However, in this example, the adapter is configured in the form of an adapter that connects to a normal telephone to realize a videophone call, but the specific values are as described above.

In Figure 1, (11) is a general public telephone line, (1
2> is a regular telephone, (13) is an audio tape recorder used when you want to save image data, (14)
indicates a video printer for obtaining a still image sent from the other party as a hard copy, and the above means (11) to
(14) is connected to this videophone adapter through connectors (21) to (24).

In addition, (31) is an image pickup tube that takes an image of one's own face, etc.;
4) is a 4-bit A/D converter, (39) is a mask circuit for masking the display screen in screen mode B, (35) is a 4-bit D/A converter, (38)
) is a 4-inch flat picture tube that displays an image, (41)
is a memory for storing image data to be sent to the other party, (4
2) is a memory that stores image data sent from the other party, (43) is its memory controller, and memories (41) and (42) are so-called video RAMs.
160 addresses x 1 corresponding to 160 pixels x 100 pixels, which is one screen of mode A.
It has a capacity of address 00. Also, the memory controller (
43) is composed of a gate array, and Memo! J (4
1), (42) It forms the signals necessary for writing and reading, and also performs some video signal processing.

Furthermore, (44) shows a digital modulation circuit that converts the image data to be sent to the other party into a modulated signal Sm. data to signal Sm
It is converted into .

In addition, (52) is a detection circuit that detects the dual tone signal DLTN sent from the other party, (53) is a similar detection circuit, and (55) is a received calibration signal that corrects the level of the received signal based on CAL. gain control amplifier, (56
) is a demodulation circuit, (71) is a system controller composed of a microcomputer for controlling the operation of the entire device, and this system controller (71) has a plurality of LEDs (72) that display the operating status. and keys (switches) for inputting the operation mode (73A) ~ (
73F) is connected.

Furthermore, (81) shows a forming circuit for a mask clock. This forming circuit (81) itself is a one-chip IC for forming NTSC synchronization signals used in general video cameras, etc., and therefore, this forming circuit (81)
) has a crystal oscillator, and the color subcarrier signal Sc (frequency f
c), vertical and horizontal synchronization pulses Pv.

Ph and composite synchronization pulse 5YNC are output.

Then, the synchronization pulse Pv from this forming circuit (81),
Ph is supplied to the deflection circuit (82) to form vertical and horizontal deflection signals, these signals are supplied to the vertical and horizontal deflection coil (310) of the image pickup tube (31), and the pulses Pv and Ph are supplied to the deflection circuit. (83) to form vertical and horizontal deflection signals, which are then fed to the picture tube (83) to form vertical and horizontal deflection signals.
38) to the vertical and horizontal deflection coils (38D). In addition, at this time, the image pickup tube (31) and the picture tube (38
) is overscanned by about 15%, so that the image in mode A is the same size as the screen.

The master, synchronous pulse Pv, Ph are the controller (43
) and the system controller (71) as a signal indicating the timing of the luminance signal, and the signal Sc from the forming circuit 81)
is supplied to the controller (43) and also to the system controller (71), especially the CPU of the system controller (71), as its clock. Furthermore, the signal Sc is connected to the frequency dividing circuit (
84) and is divided into signals 81 to S3,
The signal S3 is supplied to the controller (43) and also to the modulation circuit (44) as a carrier signal.

Furthermore, (91) to (95) are switch circuits,
These switch circuits (91) to (95) are controlled by a system controller (71) through a control signal line (not shown). Further, (74S) is a relay contact, and the relay (74) is also controlled by the system controller (71).

When this device is not in use, the relay contact (74S) is in the state shown in the figure, and the telephone (12) is connected to the line (11) through the contact (74S). Therefore, in this case, the telephone (12
) can be used like a regular telephone and is in call mode, allowing you to talk to the other party.

Further, when the power is turned on in the call mode, the switch circuits (91) to (95) are brought into the state shown in the diagram for the system controller (71). Then, from the image pickup tube (31), NTSC
A luminance signal sy based on the method is extracted, and this signal S
y is connected to the processor circuit (33) through the preamplifier (32).
) is supplied to the A/D converter (3), where it undergoes gamma correction and AGC, etc.
At the same time, the signal Sc from the formation circuit (81) is supplied to the formation circuit (3) through the switch circuit (92).
4) as a clock, and the signal Sy has a frequency fc
The signal is sampled and quantized into a 4-bit parallel digital luminance signal Py.

Then, this signal Py is thinned out to a signal of 160 pixels x 100 pixels in the controller (43) regardless of the screen mode, and this signal is sent to the mask circuit (39) described later.
The signal Sc is supplied as a clock to the converter (35), the signal Py is converted to an analog luminance signal Py, and this signal Sy is supplied to the video amplifier (36). synchronization pulse 5YNC is added, and this synchronization pulse 5
The YNC-added signal Sy is supplied to the picture tube (38).

Therefore, when the power is turned on, the camera enters a mode in which the image being captured by the picture tube (31) can be monitored in a moving image state by the picture tube (38).

And when in this monitor mode, key (73A)
～(73F) “Photograph” key (73B>
When you press , the system controller (71
) controls the controller (43), and the signal Py from the conharc (34) is supplied to the memory (41) through the controller (43), and the controller (43) supplies the memory (41) with the cycle of the signal Sc. A write signal and an address signal are supplied, and image data of 160 pixels x 100 pixels of the signal Py of one field is written and stored in the memory IJ (41).

Then, when the image data is written to the memo 'J (41), a read signal and an address signal are supplied from the controller (43) to the memory (41) at the cycle of the signal Sc, and the image data is stored in the memo 'J (41). The image data is sequentially and repeatedly read out and taken out as a still image signal py, and this signal Py is supplied to the converter (35) through the controller (43) and mask circuit (39). Therefore, the image tube (38) stores the image data stored in the memory (41) as a still image, that is,
The image when the "take" key (73B) is pressed is displayed as a still image.

Also, when this still image is displayed, press the key (73A).
) ~ (73F>"View" key (73A)
), the system controller (7
1), the controller (43) is controlled again to the monitor state, and the image being captured by the image pickup tube (31) is displayed on the picture tube (38) in the form of a moving image.

Therefore, by repeating the operations of keys (73A) and (73B), you can record the image data of the images you need or like! Can be stored in J(41).

When image data is stored in memo') (41) (at this time, the still image is displayed on the picture tube (38)) keys (73A) to (7)
3F), press the “Send” key (73C),
Based on this key output, the relay (74) is driven to the left by the system controller (71), and its contact (74S) is connected in a state opposite to that shown in the figure.

Further, the system controller (71) outputs the signal S1. from the frequency dividing circuit (84). S2 is supplied to the adder circuit (45) through the switch circuit (93), and the adder circuit (45) takes out the sum signal of the signals Sl and S2, that is, the dual tone signal DLTN, and this signal DLTN is used for regulating the sending level. Attenuator (46) → Band pass filter (47) that removes unnecessary signal components → Transformer (4
8) → Connect the line (1) through the signal line of the contact (74S).
1).

Then, when this signal DLTN is sent out for a period T1, the circuit (44) which is sent to the system controller (71)
, (93) is controlled to create a no-signal period T2, and then, during periods T3 to T5, a predetermined modulation signal is supplied from the system controller (71) to the modulation circuit (44), and the processing of the modulation circuit (44) is performed. is allowed signal FSYN, AC
AL and ID are sequentially formed and these signals are sequentially sent out to the telephone line (11) through the adder circuit (45) as described above.

Then, in period T6 following period T, a read signal and an address signal are supplied from the controller (43) to the memory (41) at the cycle of signal S3, and the memory IJ (
41) with the period of the signal S3, that is, the signal S3
Image data is read out at a rate of 1 address (4 bits for 1 pixel) per cycle of Sm is similarly sent out to line (11).

In this case, if the mode key (73F) of the keys (73A) to (73F>) specifies mode A, the image data of 160 pixels x 100 pixels will be sent to the signal S.
If mode B is specified, the image data of 96 pixels x 100 pixels at the center of the screen will be sent as signal Sm.
sent out as. In addition, during the period T1 to T6, LE
D (72) blinks to indicate that it is the image data sending mode.

Then, when the period T6 has elapsed and all the image data has been sent out, the relay (74) is no longer driven, and its contact (73S) returns to the state shown in the figure to enter the call mode again.

In addition, while monitoring the video, press the "Shoot" key (7).
3B) If you press the "Send" key (73C) without pressing the key (73B), the image data at the time you press the key (73C) will be stored in the memory (41) in the same way as when you press the key (73B). The image data is then sent out to the line (11) as described above.

Furthermore, while the image data is being sent to the other party in this way, the tape recorder (
13) is in the recording state, the signal DLTN-3m is supplied from the filter (47) through the buffer amplifier (54) to the tape recorder (13), and this signal is recorded on tape.

On the other hand, if image data is sent from the other party during a call, the dual tone signal DLTN located at the beginning of the image data is
However, line (11) → contact (74S) → transformer (51)
The signal DLTN is supplied to the detection circuit (52) and detected through the signal line of the system controller (71).
).

Then, the relay (74) is driven by the system controller (71) based on the detection output, and the contact (74S) is connected in a state opposite to that shown in the diagram, and the system controller (71)
The switch circuits (94) and (95) are connected to the state shown in the figure.

Therefore, subsequently, during the period T3-T5, the signal FSYN~
When the ID is sent, these signals are transmitted to the line (11)
→ Contact (743) → Transformer (48) → Amplifier (5
4) → Switch circuit (94) → Gain control amplifier (55)
The signal S3 from the frequency divider circuit (84) is supplied to the converter (57) through the switch circuit (95), and the demodulated output is supplied to the A/D converter (57). ) as a clock and its demodulated output is digitized, and this digital signal is sequentially supplied to the system controller (
71).

Thus, during period T3, the frame synchronization signal FSYN
Based on the output of the system controller (71), the demodulation circuit (5
The reference phase at the time of demodulation in step 6) is regulated to Oo, and is used as a synchronization signal for the signal after period T4 in the system controller (71). Further, during period T4, the gain of the amplifier (55) is controlled by the output of the system controller (71) based on the calibration signal ACAL, and the subsequent signal level is corrected. Furthermore, during period T5, the identification code I
The image data (
For example, the switch circuits (91) and (92) are connected in a state opposite to that shown in the figure, and a signal indicating whether the image mode is mode 8 or mode B is made. is supplied from the system controller (71) to the controller (43).

Then, during the period T6, a signal Sm is obtained from the amplifier (55), and this signal Sm is supplied to the demodulation circuit (56) to demodulate the analog luminance signal Sy. The luminance signal sy at a level indicating the gradation of the pixel is demodulated, and this signal Sy is supplied to the A/D converter (34) through the switch circuit (91), and the signal S3 from the frequency divider circuit (84) is sent to the switch circuit (91). A/D through circuits (95) and (92)
It is supplied as a clock to the converter (34) and controller (43).

In this way, the brightness signal sy from the demodulation circuit (56) is converted into a digital signal Py (image data) in synchronization with the signal S3 from the frequency dividing circuit (84) in the converter (34), and this signal Py is converted into a digital signal Py (image data) by the controller (34). 43) Receive memo through! J (42) and
The write signal and address signal synchronized with the signal s3 from the frequency dividing circuit (84) from the controller (43) are sent to the memory (
42), and the signal Py is sequentially written and stored in the memo 'J (42).

At this time, the screen mode is determined based on the sent identification code ID, and in the case of mode A, the image data is memo! The data is sequentially written to all addresses of J ('42), and in the case of mode B, it is written to the address area corresponding to the center of the screen.

Further, at this time, at the same time as the signal py is written, the controller (43) supplies the memory (42) with a mode read signal and an address signal at the cycle of the signal Sc, and the image is stored in the memory IJ (42). Data is a memo! The still image signal Py is sequentially and repeatedly read out from all addresses of J (42), and this signal Py is supplied to the D/A converter (35) through the mask circuit (39). Therefore, the image data sent from the other party is displayed on the picture tube (38) as a still image in mode A or mode B in order from the top according to the transmission speed, and when the period T6 ends, the image data is completely displayed. A still image will be displayed.

Note that the period T1 to T6 during which image data is received is processed.
The LED (72) blinks to indicate that it is in the image data reception mode.

Then, when the period T6 ends, the relay (74) is no longer driven, its contact (74S) returns to the state shown in the figure, and the switch circuits (91) to (95) are also brought to the state shown in the figure. Enters call mode.

Note that in this image data reception mode, the period T1~
If the tape recorder (13) is kept in the recording state for T6, the signal DLTN-3m sent from the other party is recorded on the tape.

In this way, when image data is sent from the other party, the image data is stored in the memory (42) and the picture tube (3) is stored.
8) is displayed as a still image.

In addition, if the image data to be sent to the other party is stored in the memory (41) and the image data sent from the other party is stored in the memory (42), the key (73A)
～(731E) “Partner” key (73D)
When you press , image data is read from Memo 'J (42), this read image data is converted to a luminance signal Sy and supplied to the picture tube (38), and the "self" key (73B) is pressed. When you press Memo IJ (4
1), this image data is converted into a luminance signal Sy, and is supplied to the picture tube (38).

Therefore, by using the keys (730) and (731E), it is possible to freely select and display an image to be sent to the other party and an image sent from the other party.

Further, when the telephone (12) is not in use and the signal recorded in the period T1 to T6 is played back on the tape recorder (13), the dual tone signal DLTN located at the beginning of the playback signal is detected by the detection circuit ( 53), and based on the detection output, a switch circuit (92),
(94) and (95) are connected in a state opposite to that shown in the figure.

Therefore, the reproduction signal of the tape recorder (13) is replaced by the signal sent from the line (11) to the amplifier (55).
), and the signal S from the amplifier 55)
m is supplied to the shaping circuit (58) to convert the signal Sm to the signal S
3 is extracted, and this signal S3 is sent to the switch circuit (95
>, (92) is supplied to the converter (34) and controller (43) as a clock during tape playback, and is processed in the same way thereafter, so that the image recorded on the tape is displayed on the picture tube (38). Ru. Therefore, if a tape recorder (13) is provided, still images can be saved as files.

FIG. 2 is a diagram showing a specific example of the mask circuit (39).

In the figure, the 2° bit output terminal of the controller (43) is connected to the 2° bit output terminal of the controller (43) via the AND circuit (100).
The bit output terminal is connected to the AND circuit (101), the 22-bit output terminal is connected to the AND circuit (102) and the OR circuit (105), and the 23-bit output terminal is connected to the AND circuit (103). , are connected to the 2° bit input terminal to the 23 bit input terminal of the D/A converter (35). Then, as shown in FIG. 3, the blanking signal BLK becomes "1" during the horizontal display period in mode A, and the blanking signal B becomes "1" during the horizontal display period in mode B.
LKB is connected from the controller (43) to the switch circuit (10
6) Supplied to.

Further, a mode switching signal Ms is taken out from the controller (43), and this signal Ms is supplied to the switch circuit (106) as its control signal, and the switch circuit (106)
The signal BLKA is taken out in the case of mode A, and the signal BLKB is taken out in the case of mode B, and the output of this switch circuit (106) is taken out from the AND circuit (100).
~(103) are commonly supplied. Further, in the controller (43), for example, as shown in FIG.
A mask signal MASK is formed which becomes 1" when LK8=1" and BLKB -"O" In the case of
supplied to

Therefore, in the case of mode A, the signal BLKA is supplied to the AND circuits (100) to (103), and the signal supplied from the switch circuit (107) to the OR circuit (105) is 0'', so the controller The image data 2° to 23 from (43) are supplied as they are to the D/A converter through the AND circuits (101) to (104) and the OR circuit (105). Therefore, in the case of mode A, as shown in FIG. A screen of 160 pixels x 100 pixels of image data as shown in A is obtained.In addition, in the case of mode B, the horizontal display period (
96 pixel period), BLKB - "1", M
Since ASK-"O", the image of mote B is displayed in the center of the screen as shown in FIG. 4B. At this time, in the remaining period, BLKB-"0", MASK-
Since it is "1", only the input terminal 22 of the converter (35) is at the "1" level, and the other input terminals 2°, 2', 2
3 becomes 0'', therefore, during this remaining period, the manual data of the controller (35) becomes '0100', which is the fourth gray level. Therefore, as shown in Figure 4B, the center of the screen has 96 pixels x 100 pixels.
While the pixel image data is displayed, the portions on both sides of the screen, that is, the two areas of 32 pixels x 100 pixels indicated by diagonal lines, become gray at the fourth gradation.

G2 Other Embodiments In the above, the telephone (12) and tape recorder (13) are separate from the device, but they may be integrated. In this case, the telephone (12) and tape recorder (13) may be integrated. You can also transfer it to your phone and display it. Further, although the switch circuits (92) and (95) are described as being separate from the controller (43), they can also be included in the controller (43). Furthermore, in the above, Memo! J (41) and (42) are designed to be able to write and read the signal Py at the same time (this means that
A buffer memory is prepared, and during the horizontal blanking period, image data is transferred between this buffer memory and memory (41) or (42) to make it appear to be simultaneous. You can also do that.

In addition, in the above description, in order to facilitate understanding, a considerable amount of signal processing, including the signal processing of the demodulation circuit (56), is expressed in terms of hardware;
and its software.

Furthermore, in the above description, during the period T6, the received image data is sequentially written into the memory (42) and at the same time, the memo IJ (42) is read out for display, so the display screen is In areas where image data has been received, an image based on the received image data is displayed, but in areas where image data has not yet been received, an old image based on old image data is displayed. However, if such a display is inconvenient, the signals BLKA and BLKB may be changed to "o" in the section of the old image.
In addition, the mask signal MASK may be set to "l". That is, if this is done, the area where image data has not been received becomes gray at the fourth gradation, and the old image is not displayed.

H Effects of the Invention According to this invention, when displaying an image of a smaller image size among a plurality of image sizes, the screen area outside the image area is masked with, for example, gray, so that the image memory is It is possible to display only the necessary images without performing complicated processing on unnecessary image data remaining in the image data, and it is possible to skillfully display a plurality of image data having different image sizes.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an example of the present invention, and FIGS. 2 to 7 are diagrams for explaining the same. (31) is an image pickup tube, (34) is an A/D converter, (3
5) is a D/A converter, (38) is a picture tube, (39)
is the mask circuit, (41), (42) are the memory, (
44) is an amplitude/phase modulation circuit, (56) is a demodulation circuit, (
71) is a scon. Agent Paige Ito
Hide Matsukuma → Niku

Claims (1)

[Claims] In a receiving device that receives image data of a first still image and a second still image smaller than the first still image through a transmission line in an audio band, the image data is stored. It has a memory, a display means for displaying the first and second still images, and a mask circuit, reads the stored data by periodically reading the memory, and reads the stored data. The output data is supplied to the display means through the mask circuit, and when the image data is image data of the second still image, the data is read from the memory corresponding to the outside of the second still image. A still image display device that masks output data with predetermined data.