JPH089359A - Scramble system for still image transmitter - Google Patents

Abstract

PURPOSE:To provide the secrecy of image data between two persons or the secrecy of image data to the third person in pay center service by easily scrambling images while keeping compatibility with normal communication. CONSTITUTION:When the communication to an opposite terminal is started, the data in a coordinate table and also a communication command are transmitted together with a flag showing the image data are in a scramble mode, and succeedingly the data in the transmission buffer area of a buffer memory 10 are successively transmitted. When a system is turned to a receiving state, a CPU9 detects the flag showing the scramble mode from the communication command received by a line I/F 11 and recognizes whether the image data to be transmitted are scrambled or not. When those data are scrambled, coordinate data are stored in the coordinate table, and the storage address of a macro- block for an image memory 5 is generated based on the table.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scramble system of a still image transmission device, and more particularly, to an image in an image communication terminal in which a still image is compressed and transmitted, and a receiving side decompresses and reproduces the image. Data scrambling method.

[0002]

2. Description of the Related Art FIG. 6 shows a general JPEG (Joint Photo
FIG. 3 is a diagram showing a system configuration of a still image communication terminal conforming to graphic coding Experts Group), in which 31 is a camera for capturing an image, 32 is an A / D conversion unit for digitizing the image data, and 33 is an image. A memory control signal generation unit that generates a control signal for the memory 35, and 34 denotes an image memory 35.
, 35 is an image memory for storing a transmission image and a reception image, 36 is a D / A conversion unit for returning the data in the image memory 35 to an analog signal,
37 is a display, 38 is a codec for compressing / expanding image data, 39 is a CP for controlling the system
U (central processing unit), 40 is a buffer memory for temporarily storing compressed image data, and 41 is a line I / F (interface) for inputting / outputting with a telephone line.

First, the general operation of conventional transmission will be described. The image captured by the camera 31 is digitized by the A / D converter 32, and the memory control signal generator 3
3 and the control signal and the address generated by the memory address generation unit 34, the data is written in the image memory 35. Next, the memory control signal generation unit 33 sequentially reads the data according to the address generated by the memory address generation unit 34 and transfers the data to the codec 38. The codec 38 sequentially performs compression processing when one block (= 8 × 8 pixels) of data is accumulated and writes the data in the buffer memory 40. This operation is repeated for the number of pixel data for one screen, and the compression processing of one image is completed.

On the other hand, the CPU 39 confirms the state of the line,
If data can be transmitted, one packet of data is sequentially read from the buffer memory 40 from the beginning, converted into a communication format, and then output to the line through the line I / F 41. Also, when receiving, follow the reverse process of sending,
First, the packet data received from the line I / F 41 is C
By the processing of the PU 39, the data is returned from the communication format to the data of the internal processing, and only the image data is extracted and written in the buffer memory 40. The codec 38 sequentially reads this data from the beginning, and sequentially performs decompression processing when one block of data is taken in.

The memory control signal generator 33 and the memory address generator 34 receive the image data output from the codec 38 and write it in the image memory 35. The transmitted image is reproduced (restored) to the received image by generating the address generated at this time exactly the same as the address generated at the time of transmission. Here, in the JPEG block interleave method, the transmission order of data is defined as the transmission order of blocks within one macroblock and the transmission order of macroblocks. If this order is different between the transmitting side and the receiving side, that is, the order of the addresses generated by the memory address generation unit 34 is different, the received image data cannot be reproduced (restored) correctly even if the codec specifications are the same.

As shown in FIG. 7, the transmission order of macroblocks in JPEG starts from the upper left of the image and progresses in the horizontal direction in sequence, and when it reaches the right end of the image, it sequentially progresses from the left end of the lower stage to the horizontal direction. The order is to go ahead. Further, generally, the data of 8 × 8 pixels in one block is also accessed in the same order as the macro block as shown in FIG.

FIGS. 9A and 9B show the image memory DRA.
FIG. 9 is a diagram showing an example (periodic expression) of the circuit configuration of the memory address generation unit in FIG. 8 for generating the transmission order of macroblocks when M is used, in which 50 is an intra-block horizontal dot counter (HDC). , 51 is an in-block vertical dot counter (VDC), 52 is an in-macroblock block counter (BC), 53 is a horizontal macroblock counter (HMBC), and 54 is a vertical macroblock counter (VDC).
MBC), 55 is a multiplexer.

The intra-block horizontal dot counter 50 counts the number of horizontal pixels in the block. The block vertical dot counter 51 counts the number of dots in the block in the vertical direction. The block counter 52 in the macro block counts the number of blocks forming the macro block. The horizontal macroblock counter 53
Count the number of horizontal macroblocks in the image. The vertical macroblock counter 54 counts the number of vertical macroblocks in the image. Above counter 50 ~
54 is connected sequentially.

Here, 1 from the memory control signal generator 33
Pixel address count enable signal (hereinafter ACEN
Is input), the HDC 50 is incremented by one. When this value becomes 7, carry (c
y ₁ ) is output, and VDC51 is incremented by 1 at the next ACEN. Further, when this value becomes 7, carry (cy ₂ ) is output, and when both cy ₁ and cy ₂ outputs become active, cy ₁₂ is output, and BC5 is output at the next ACEN.
2 is incremented by 1. At this stage, counting of one block (8 × 8 pixels) is completed.

Here, it is assumed that the pixel structure 384 (horizontal) × 2
A 40 (vertical) image with color components Y: U:
If the block interleave method of V = 2: 1: 1 is used, the count value of BC52 is 2 + 1 + 1 = 4.
And cy ₃ is output with a count value of 3, and cy ₁ and cy
_{When both 2} and cy ₃ are active, cy ₁₂₃ is output. Then, at the next ACEN, HMBC53 is incremented by one. The number of macroblocks in the horizontal direction is 3
Since 84/16 = 24, the carry (cy ₄ ) of the HMBC 53 is output with the number of blocks of 23, and cy ₁ and cy ₂
Cy and cy ₃ and cy ₄ are both active
₁₂₃₄ is output.

Then, at the next ACEN, the VMBC 54 is incremented by one. Further, since the number of macroblocks in the vertical direction is 240/8 = 30, the carry (cy ₅ ) of the VMBC 54 is output with the number of blocks 29, and the outputs of cy ₁ , cy ₂ , cy ₃ , cy _4, and cy ₅ are output. When both are active, cy ₁₂₃₄₅ is output. This is codec 3
It becomes an end flag of data exchange with 8, and at this stage, counting of all the pixels of the image ends.

If the count outputs (A _{0 to} A ₁₇ ) obtained as described above are stored in the image memory 35 as shown in FIG. 10, for example, A ₁₂ A ₁₁ A ₁₀ A ₉ A ₈ A ₆ A ₂ A ₁
Column addresses of the luminance signal (Y) by arranging the A ₀ is, Column addresses of the color difference signals by arranging the _{A 12 A 11 A 10 A 9} A 8 A 2 A 1 A 0 A 7 (U, V) is generated And A ₁₇ A ₁₆ A ₁₅ A ₁₄ A ₁₃ A ₅ A ₄ A ₃
ow address can be generated. This is the multiplexer 55
Output from the memory control signal generator 33 by
The output is switched according to the timing of the AM row address strobe signal (not shown) and the timing of the column address strobe signal (not shown). With such a configuration, continuous address generation as shown in FIGS. 7 and 8 is performed.

On the other hand, the compressed data output from the codec at the time of transmission is temporarily stored in the transmission buffer area of the buffer memory 40, as shown in FIG. It is read out, converted into a communication format, and then output to the line. Further, the received data is deformatted in the communication format by the CPU 39 and then sequentially stored in the reception buffer area of the buffer memory 40 as shown in FIG.

[0014]

In the conventional still image communication terminal system, when communicating between the same terminals or in a center service or the like, it is possible to send and receive an image that can be seen only to a specific partner (terminal). If you want to provide a high degree of confidentiality, both parties must register a personal identification number, etc., and then recognize it during communication to enable data access, or use communication procedures or image compression methods between terminals. There was no other way but to eliminate the compatibility of data with other standard terminals by changing to the original method (terminal) that is effective only in. According to these methods, there is a problem that the data can be accessed by anyone other than the person who knows the personal identification number, and if the unique method is used, the data cannot be connected to other standard terminals.

The present invention has been made in view of such a situation, and enables scrambling of an image easily while maintaining compatibility with normal communication, and confidentiality of image data between two parties. Another object of the present invention is to provide a scramble system for a still image transmission device that realizes the concealment of image data to a third party of a pay center service.

[0016]

In order to achieve the above object, the present invention provides: (1) In a terminal for communicating a still image based on a still image compression / expansion method, the horizontal / vertical direction is calculated from the number of pixels of the image. The number of macroblocks arranged in each direction is calculated, and a generating unit that randomly generates coordinates that are a combination of positions in each direction and a coordinate table that stores the coordinates generated by the generating unit are provided. A generation unit that sequentially refers to the coordinates of the coordinate table for each macroblock to generate a read address (cutout position) of the macroblock from the image memory, and indicates that the coordinate table is scrambled by a communication command at the time of transmission. When the image is received, the transmission means for transmitting together with the flag and the flag indicating that the scramble has been transmitted are recognized, and the If it is a amble, the storage means for storing the coordinate data sent subsequently to the coordinate table and the coordinates of this table are sequentially referred to for each macroblock when the image is expanded, and the macroblock to the image memory is referred to. Generating means for generating a write address of
Alternatively, (2) in a terminal that performs still image communication, when packetizing compressed image data at the time of transmission, randomly generating an order (cutout position) for reading packets of image data in the transmission data buffer Means and
Transmitting means for converting the sequence generated by the generating means into a table and transmitting to the partner terminal together with a flag indicating that the data is scrambled, and generating means for generating an address to be read from the transmission data buffer for each packet according to the data in the table. At the time of reception, a flag indicating that the scramble has been sent is recognized, and if it is scrambled, a storage unit that stores the table data that is sent subsequently is stored in the table, and sequentially according to the table data. The reception data buffer has a generation means for generating an address for storing the packet data.

[0017]

According to the scramble system of the still image transmission apparatus of the present invention having the above-mentioned configuration, (1) by setting the scramble mode, the cut-out address of the macro block from the image memory can be changed for each macro block at the time of transmission. Then, the start address (coordinate data) is transmitted together with the flag indicating scrambling. The receiving side recognizes the flag indicating the scramble, and if it is scrambled, the storage address of the macro block in the image memory is generated based on the table of the transmitted start address (coordinate data). As a result, it is possible to easily scramble the image while maintaining compatibility with normal communication, and the confidentiality of the image data between the two parties and the confidentiality of the image data with respect to the third party of the pay center service are reduced. realizable.

(2) By setting the scramble mode, at the time of transmission, the cut-out address of the packet data from the transmission buffer memory is changed for each packet, and the address data is transmitted together with the scramble flag. The receiving side recognizes the flag indicating scrambling, and if it is scrambling, stores the packet data in the receiving buffer memory based on the table of the sent address data. As a result, the image can be easily scrambled while maintaining the compatibility with the normal communication, and the confidentiality of the image data between the two parties,
The confidentiality of the image data with respect to the third party of the pay center service can be realized.

[0019]

Embodiments will be described below with reference to the drawings. FIG. 1 is a configuration diagram for explaining an embodiment of a scramble system of a still image transmission apparatus according to the present invention.
1 is a camera, 2 is an A / D converter, 3 is a memory control signal generator, 4 is a memory address generator, 5 is an image memory, 6
Is a D / A converter, 7 is a display, 8 is a codec,
9 is a CPU (central processing unit), 10 is a buffer memory,
Reference numeral 11 is a line I / F (interface), and 12 is a packet number table.

A still image transmitting apparatus according to claim 1 includes a camera 1 for inputting an image, an A / D converter 2 for digitizing the image signal, and an image memory 5 for storing the digitized image data. , A D / A conversion unit 6 for returning the data in the image memory to analog, a display 7 for displaying an image, a memory control signal generation unit 3 for controlling the image memory 5, and a memory address generation for generating an address of the memory Unit 4, a codec 8 for compressing / decompressing image data, a buffer memory 10 for temporarily storing the compressed / decompressed image data, and a CPU for controlling the system
9 and a line I / F 11 for performing input / output with the line.

2A and 2B are block diagrams of the memory address generator in FIG. 1, in which 20 is a horizontal dot counter (HDC) in the block and 21 is a vertical dot counter (VDC) in the block. , 22 is a block counter (BC) in the macroblock, 25 is a multiplexer, 26
Is a macroblock counter (MBC), and 27 is a macroblock address table (MBAT).

The in-block horizontal dot counter 20 counts the number of horizontal pixels in the block. The intra-block vertical dot counter 21 counts the number of dots in the block in the vertical direction. The intra-macroblock counter 22 counts the number of blocks forming the macroblock. The macroblock counter 26 counts the number of macroblocks. The macroblock address table 27 stores the cutout address for each macroblock.

A case where an image having a structure of 384 × 240 pixels is handled by a block interleave system of color components Y: U: V = 2: 1: 1 will be described below. First, when the system is in the transmission state, the CPU 9 calculates the number of horizontal macroblocks and the number of vertical macroblocks of the image. In this case, the number of horizontal macroblocks is 384/16 = 24, and the number of vertical macroblocks is 240/8 = 30.

Here, the horizontal position of an arbitrary macroblock is x (0≤x≤23), and the vertical position is y (0
If ≦ y ≦ 29), the CPU 9 randomly generates a combination of (x, y) and sequentially writes it in the MBAT 27. Since this image is composed of 24 × 30 = 720 macroblocks in total, 720 (x, y) are MBA.
It is stored in T27. As a result, the order of reading macroblocks from the image memory 5 is determined.

For example, (2,2), (5,3), (4,
If 1), ... Are stored, the macroblocks are read in the order shown in FIG. The reading order in the block is the same as the conventional one, as described above with reference to FIG. Therefore, in the case of normal communication not in the scramble mode, the data in this table may be set as shown in FIG.

Next, the memory control signal generator 3 starts transferring data from the image memory 5 to the codec 8.
When the memory control signal generation unit 3 outputs the address count enable signal ACEN for one pixel, the HDC 2
One is incremented by 0. When this value reaches 7, carry (cy ₁ ) is output and VD is output at the next ACEN.
C21 is incremented by 1. Furthermore, this value is 7
When it becomes, a carry (cy ₂ ) is output, and when both the outputs of cy ₁ and cy ₂ become active, cy ₁₂ is output, and BC22 is incremented by 1 at the next ACEN. At this stage, counting of one block (8 × 8 pixels) is completed.

Here, since one macroblock is composed of four blocks, a carry (cy ₃ ) is output when the count value of the BC 22 reaches 3. When both cy ₁ , cy ₂ and cy ₃ are active, cy ₁₂₃ is output, and MBC26 is output at the next ACEN.
Will count up one. The count value of the MBC 26 is registered at the position of the pointer by using it as the pointer of the MBAT 27 described above (x,
y) can be read.

If the count value thus obtained and the table data are stored in, for example, an image memory as shown in FIG. 10, A ₁₂ A ₁₁ A ₁₀ A ₉ A ₈ A ₆ A ₂ A ₁
Column addresses of the luminance signal (Y) by arranging the A ₀ is, Column addresses of the color difference signals by arranging the _{A 12 A 11 A 10 A 9} A 8 A 2 A 1 A 0 A 7 (U, V) is generated And A ₁₇ A ₁₆ A ₁₅ A ₁₄ A ₁₃ A ₅ A ₄ A ₃
ow address can be generated. This is the multiplexer 25
Output from the memory control signal generator 3 by
It is switched and output according to the timing of the M row address strobe signal (not shown) and the timing of the Column address strobe signal (not shown). With such a configuration, random address generation can be performed in macroblock units as shown in FIGS. 3 and 8.

The data read from the image memory 5 is
It is compressed by the codec 8 and stored in the transmission buffer area of the buffer memory 10. When communication with the partner terminal is started, the image data sent from now on is sent together with a flag indicating that the image data is in the scramble mode.
The AT27 data is transmitted together with the communication command. After that, subsequently, the data in the transmission buffer area of the buffer memory 10 is sequentially transmitted.

On the other hand, when the system is in the receiving state, the CP
U9 detects the scramble mode flag from the communication command received on the line I / F 11, and thereafter recognizes whether the image data transmitted is scrambled or not. If scrambled,
Then, the table data of MBAT 27 received next is set to the MB.
Store in AT27. If it is not scrambled, the default table for the normal mode is loaded into the MBAT 27 as shown in FIG.

Thereafter, the sequentially sent data is stored in the reception buffer area of the buffer memory 10. The codec 8 reads this data, decompresses it, and writes it in the address generated by the memory address generation unit 4 according to the timing of the memory control signal generation unit 3. The process of generating the address at this time is similar to that at the time of transmission. As a result, the scrambled image data is reproduced on the receiving side as the original normal image.

As described above, according to the first aspect of the present invention, the variable means for arbitrarily changing the address generation at the time of reading the data from the image memory at the time of transmission, and the start address of the macroblock are changed. Transmitting means for transmitting the table together with the flag indicating the scramble by the communication command, and at the time of reception, recognize the flag indicating the scramble, and if it is scramble, store the data of the start address of this macroblock in the table,
A configuration is provided that includes a generation unit that generates a write address to the image memory from this data.

Next, the invention according to claim 2 will be described. The still image transmission apparatus of the present embodiment has a packet number table 12 added to the configuration shown in FIG.
That is, a camera 1 for inputting an image, an A / D converter 2 for digitizing the image signal, an image memory 5 for storing the digitized image data, and a D for returning the image memory data to analog data. / A converter 6, a display 7 for displaying an image, a memory control signal generator 3 for controlling the image memory 5, a memory address generator 4 for generating a memory address, and compression / expansion of image data. A codec 8, a buffer memory 10 for temporarily storing compressed / decompressed image data, a CPU 9 for controlling the system, and a line I / O for inputting / outputting to / from the line.
F11 and a packet number table 12 for storing a packet number string.

When the system is in the transmission state, the data in the image memory 5 is read out by the memory control signal generating section 3 and the memory address generating section 4 and compressed, and the data shown in FIG.
As described above, the data is sequentially stored in the transmission buffer area of the buffer memory 10. At the time of communication in the normal mode, the CPU 9 sequentially cuts out (packetizes) the data in this buffer, converts it into a communication format, and then the line I / F 11
Although it is transmitted from, CP is first sent in scramble mode.
U9 calculates the number of packets from the amount of data in the transmission buffer area and generates a random number sequence within the range of the number of packets.
(T). For example, compressed image data is 32 Kbytes, and 1 packet = 1 Kbyte
If sent as e, this data is divided into 32 packets. Therefore, the CPU 9 randomly generates a sequence of numbers 0 to 31 and stores it in the PNT 12.

When this operation ends and the communication with the partner terminal is started, first, the data of the PNT 12 on the transmitting side is transmitted together with the communication command together with the flag indicating that the image data to be transmitted is in the scramble mode. Next, the first data of the PNT 12 is read, one packet of data is read from the address of the transmission buffer area obtained by multiplying this value by the address of one packet length = 400H, and converted into the transmission format.
Output from 11 to the line. Next, the second data of the PNT 12 is read and the same operation is performed. If this is repeated 32 times, the data transmission of one image is completed.

On the other hand, when the system is in the receiving state, CP
U9 detects the scramble mode flag from the communication command received on the line I / F 11, and recognizes whether the image data sent thereafter is scrambled or not. If it is scrambled, the data of the subsequently received PNT is stored in the PNT 12.
If it is not scrambled, the default table for the normal mode is loaded into the PNT 12.

Thereafter, the packets sequentially sent generate an address for storing the packet based on the received data of the PNT 12 in the same procedure as that at the time of sending, as shown in FIG. 5B. It is stored in the reception buffer area of the buffer memory 10. Therefore, the compressed image data is descrambled when it is stored in the reception buffer area. The codec 8 reads this data, decompresses it, and writes it in the address generated by the memory address generation unit 4 according to the timing of the memory control signal generation unit 3. As a result, the scrambled image data is reproduced on the receiving side as the original normal image.

As described above, the invention according to claim 2 is
When the compressed image data is packetized from the transmission buffer memory at the time of transmission, the variable means for varying the address cut out as packet data for each packet and the transmission means for transmitting the table of the cutout address together with the flag indicating the scramble by the communication command. When receiving, the flag indicating scrambling is recognized, and if it is scrambling, the data of this table is stored in the table, and according to the cutout address of the packet data,
After that, it has a configuration including a storage means for storing the packet data that is sent in the reception buffer memory.

[0039]

As is apparent from the above description, the present invention has the following effects. (1) Effect corresponding to claim 1: At the time of transmission, the number of macroblocks in the horizontal direction and the vertical direction configured from the number of pixels of the image is calculated, and the number of macroblocks in the horizontal and vertical directions is calculated. A combination of coordinates is randomly generated, the coordinates are sequentially stored in the macroblock address table, the coordinate data is sequentially referred to as the image data is read, and the read address of the macroblock is generated. Then, when the communication with the partner terminal is started, the data of the macroblock address table is transmitted together with the scramble mode flag by a communication command prior to the transmission of the image data. At the time of reception, when the communication with the partner terminal is started, the scramble mode flag sent first is detected, and if scrambled, the data of the macro block address table sent subsequently is stored in the macro block address table in order. After that, as in the case of transmission, based on the coordinate data registered in this macroblock address table, the expanded image data is written, and the address of the image memory is generated. If the image data is not scrambled, or if the terminal cannot recognize the scramble mode flag, the image data is restored in the received order in the order from the upper left of the image.
Therefore, it is possible to scramble or not scramble the image depending on the communication partner, so that the image data to be transmitted can be arbitrarily concealed, and the third block can be provided while conforming to the standard of the conventional JPEG block interleave method. This has the effect of preventing information leakage for persons. (2) Effect corresponding to claim 2: At the time of transmission, the number of packets of data composed of the capacity of compressed data is calculated, a number indicating the number of the packet is randomly generated, and this packet number is sequentially assigned to the packet number. The packet number is stored in the table, the packet number is referred to in order as the image data is read, and the read address of the packet is generated. Then, when the communication with the partner terminal is started, the data of the packet number table is transmitted together with the scramble mode flag by a communication command prior to the transmission of the compressed data. At the time of reception, when the communication with the partner terminal is started, the scramble mode flag sent first is detected, and if scrambled, the data of the packet number table sent subsequently is stored in the packet number table in order. After that, based on the packet numbers registered in this packet number table, as in the case of transmission,
The address of the buffer memory for storing the packet of the compressed data sent thereafter is generated. If it is not scrambled, it is stored in the buffer memory in the order of the sent packets and the image can be decompressed and played back as usual, but the terminal that cannot recognize the scramble mode flag or the scramble mode on the sending side In spite of the existence, if the scramble mode flag is not intentionally set, the receiving side stores the packets sent in the buffer memory in the order. Therefore, the arrangement of the compressed data is messed up, the codec cannot decompress, the image to be transmitted can be arbitrarily scrambled, and the information leakage to the third party can be prevented.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of a scramble system of a still image transmission apparatus according to the present invention.

FIG. 2 is a block diagram of a memory address generation unit in FIG.

FIG. 3 is a diagram showing an example of a macroblock cutout order in the present invention.

FIG. 4 is a diagram showing data in a macroblock address table when scrambling is not applied in the present invention.

FIG. 5 is a diagram for explaining a difference between scrambling and non-scrambling according to the present invention.

FIG. 6 is a configuration diagram of a conventional still image transmission device.

FIG. 7 is a diagram showing an example of a conventional macroblock cutout order.

FIG. 8 is a diagram showing an example of the order of cutting out pixels in a conventional block.

FIG. 9 is a block diagram of a conventional memory address generation unit.

FIG. 10 is a diagram showing an example of storing data in an image memory according to the related art and the present invention.

FIG. 11 is a diagram showing an example of a conventional packet cutout order.

[Explanation of symbols]

1 ... Camera, 2 ... A / D converter, 3 ... Memory control signal generator, 4 ... Memory address generator, 5 ... Image memory, 6
... D / A converter, 7 ... display, 8 ... codec,
9 ... CPU (central processing unit), 10 ... buffer memory,
11 ... Line I / F (interface), 12 ... Packet number table.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H04L 9/10 9/12 H04N 1/41 Z 1/44 7/00 H04N 7/00 Z

Claims (2)

[Claims] 1. In a terminal for communicating a still image based on a still image compression / expansion method, a horizontal / horizontal image is calculated from the number of pixels of the image.
The number of macroblocks arranged in the vertical direction is calculated, and a generating unit that randomly generates coordinates that are a combination of positions in each direction and a coordinate table that stores the coordinates generated by the generating unit are provided. A generating unit that sequentially refers to the coordinates of the coordinate table for each macro block and generates a read address of the macro block from the image memory, and transmits the coordinate table together with a flag indicating that the coordinate table is scrambled by a communication command. And a storage means for recognizing a flag indicating that the image is scrambled when the image is received, and if the image is scrambled, storing the coordinate data subsequently sent in a coordinate table, When decompressing an image, the coordinates in this table are referenced in sequence for each macroblock, and the macro memory Scrambling method of a still picture transmission apparatus characterized by having a generating means for generating a write address of the block. 2. A terminal for performing still image communication, wherein, when packetizing compressed image data at the time of transmission, generating means for randomly generating an order of reading packets of image data in a transmission data buffer; Transmitting means for converting the order generated by the generating means into a table and transmitting to the partner terminal together with a flag indicating that the data is scrambled; generating means for generating an address to be read from the transmission data buffer for each packet according to the data of the table. At the time of reception, it recognizes a flag indicating that it is a scramble that has been sent, and if it is scrambled, it stores the table data that has been sent subsequently in a table, and sequentially receives it according to the table data. The data buffer has a generation means for generating an address for storing the packet data. A scramble method for a still image transmission device characterized by: