JPH06319075A - Still picture transmitter - Google Patents

Abstract

PURPOSE:To automate the switching of resolution in accordance with the existence of picture motion at the time of continuously transmitting a still picture. CONSTITUTION:When a system completes the transmission of the data of a still image, a motion detecting part 3 detects the motion of the picture by the operation of picture data stored in a transmission buffer memory 5 and picture data stored in a field memory 2 and compares the maximum value of detection values with a reference value (threshold). At the time of judging the existence of motion, the whole picture data of the memory 2 are copied to the memory 5 and then picture processing is executed in accordance with the transmission procedure of a convensional continuous picture mode. At the time of judging no existence of motion as the result of motion detection, '1' is added to the count value of a counter in the motion detection part 3 without copying the picture data of the memory 2 to the memory 5 and the picture data of the memory 2 are successively transmitted in accordance with the counter value of the detection part 3. Consequently a still picture improved at its resolution can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an international standardization work group JPEG (Joint Pictur) for color still image coding systems.
In a still image transmission device conforming to the e Expert Group), the present invention relates to a still image transmission device that automatically changes the resolution adapted to the movement of a subject. The present invention relates to a still image transmission apparatus that automatically changes the resolution by updating the image when there is movement during transmission and transmitting data that raises the resolution when there is no movement.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram for explaining an embodiment of a conventional still image transmission apparatus. In the figure, 21 is an A / D converter, 22 is a transmission memory controller, 23 is a transmission buffer memory, 24 is an encoder of the codec section, 2
5 is a line control circuit, 26 is a decoder of the codec section, 2
Reference numeral 7 is a reception buffer memory, 28 is a reception memory controller, 29 is a display changeover switch, 30a is a D / A converter, 30b is a video signal processing circuit, and 31 is a display.

First, the operation will be outlined. A video signal to be transmitted, which is input from a video camera or the like, is converted into digital data by the A / D converter 21 and passed to the transmission memory unit. The transmission memory unit writes the image data in the transmission buffer 23 according to the image capture control signal generated by the memory controller 22. Further, the fetched image data is sequentially read from the address generated by the memory controller 22 according to the required resolution and passed to the codec section.
The codec section performs compression / encoding in accordance with the JPEG format, and this data is used as data of the image that has been previously captured in the transmission buffer memory 23, and the line control section 2
It is output to the line via 5.

On the other hand, the received data is image data which is compressed / encoded by the line control unit 25 and passed to the decoder 26 of the codec unit. The decoder 26 decodes this image data according to the JPEG format.
Decompress and pass to the receiving memory section. In the reception memory unit, the image data sequentially sent from the codec unit is written into the reception image buffer memory 27 at the address generated by the reception memory controller 28. Transmission buffer memory 2
3 and the image data in the reception buffer memory 27 are switched by the display changeover switch 29 to which image is to be displayed, and then converted into analog video signals by the D / A converter 30a and the video signal processing circuit 30b, and the display 31. Is displayed in.

Now, here, horizontal 384 dots or 7
Considering a conventional JPEG system having two kinds of resolution modes of 68 dots and two kinds of resolution modes of vertical 240 lines or 480 lines, at the time of transmitting image data, each resolution is read from the transmission buffer memory 23. The data to be read, the data to be ignored, and the order of reading are determined by the address generated by the transmission memory controller 22.

FIGS. 8 to 11 show a conventional JPEG 1
FIG. 8 is a diagram for explaining the transmission position and order of image data in a macroblock. FIG. 8 shows 384 dots × 240 lines, FIG. 9 shows 384 dots × 480 lines, and FIG.
8 dots x 240 lines, Figure 11 shows 768 dots x 48
Each case of 0 line is shown. That is, FIGS. 8 to 11 show the order of the image data read from the transmission buffer memory 23 per macroblock and written in the reception buffer memory 27 according to the generation address. It should be noted here that the received image data has the same resolution as the transmission buffer memory 23 because the address to be written in the reception buffer memory 27 is determined by the resolution. In that case, the data of the previous image is lost.

In such a system, a mode in which still images are continuously transmitted / received when the subject moves (hereinafter referred to as continuous image mode), and 1 when there is no motion
A mode for sending images by pressing the send button etc. (hereinafter referred to as still image mode) (the receiving side forcibly receives when data is sent), etc., and switching the resolution of the image to be sent It has been devised so that you can select and maintain a more balanced balance between movement and resolution.

[0008]

As described above, in the conventional still image transmission apparatus, every time an image is transmitted,
Whether to send in continuous image mode or still image mode,
Also, it was necessary to select the resolution from the operation panel or the like. Therefore, transmitting a moving subject in the continuous image mode, and switching a completely stationary subject such as a document to the still image mode in the meantime not only causes troublesome switching operation, but also The receiving side also changes the mode frequently and is unsightly.
Also, considering the case of transmitting images such as documents using the continuous image mode without switching the mode,
Even though the subject is not moving, that is, nothing has changed as the image to be transmitted, the image data is updated on the receiving side, and the display on the display changes sequentially,
It may be difficult to see small characters. Furthermore, when transmitting only in the still image mode without using the continuous image mode, a stationary subject such as a document is good, but since the presence of a moving subject cannot be communicated to the other party, the moving image transmission device can be used. In comparison, the existence value of the continuous image mode itself in a still image transmission device characterized by high definition and low bit rate transmission is lost.

The present invention has been made in view of the above situation, and a motion detecting unit is provided in the transmitting unit, and when there is motion during continuous transmission of still images, the image is updated as usual. An object of the present invention is to provide a still image transmission device in which resolution switching is automated by sending data that raises the resolution when there is no movement.

[0010]

In order to achieve the above object, the present invention provides (1) a set of field memories in a still image transmission apparatus having a resolution switching level in accordance with a predetermined image data transmission format. And a set of transmission memory banks, and when the transmission of one still image data captured in the transmission memory is completed, a motion is detected from the image data of the field memory to be transmitted next, and the motion is detected. Of the maximum value of, the maximum value is compared with the reference value, the determination means for determining whether the reference value is exceeded or not, and the number of times when the reference value is not exceeded by the determination means However, the variable means for varying the position (address thinning method) for reading the image data to be transmitted in the memory according to the count value, and the new image data received while leaving the previously received image data. In the case where the reference value is exceeded by the receiving means for changing the position (how to decimate the address) for writing the received image data into the receiving memory and the judging means, the image data is transferred from the field memory to the transmitting memory. And a transmission means for transmitting (writing) and transmitting the new image data, and automatically changing the resolution according to the movement of the subject during continuous transmission of still images,
Alternatively, (2) a still image transmission apparatus having a switching level of resolution according to a predetermined image data transmission format is provided with two sets of transmission memory banks, and one still image data captured in one of the transmission memories. When the transmission is completed, the image data to be transmitted next is loaded into the other transmission memory, the motion of the image is detected from the data in the two memories, the maximum value of the motion is obtained, and the maximum value is calculated. Judgment means for comparing reference values and judging whether or not the reference value is exceeded, and when the judgment value does not exceed the reference value, the number of times is counted, and the count value is transmitted in the memory. Variable means for varying the position (how to decimate the address) for reading the image data, and the position for writing the newly received image data while leaving the previously received image data. When the reference value is exceeded by the capturing means for varying the (address decimation) into the receiving memory and the determining means, the two transmitting memory banks are switched and the newly captured image data is displayed. The present invention is characterized by having a transmission means for transmitting, and automatically changing the resolution according to the movement of the subject during continuous transmission of still images.

[0011]

According to the structure of the invention of claim 1, the image to be transmitted next is written in the field memory. From this image data and the image data in the transmission buffer memory that has already been transmitted, the motion detection unit determines whether or not there is a motion in both images. If there is a movement, the image data in the field memory is copied to the transmission buffer memory, and the transmission operation similar to the previous time is started. When it is determined that there is no movement, it counts the number of times (what number of images), ignores the image data in the field memory, and determines the image of the part of the image data that has not been transmitted yet in the transmission buffer memory. The data is read according to the address generated by the transmission memory controller and sequentially passed to the encoder of the codec section. After that, a series of transmission operations similar to the conventional one are performed.

On the other hand, the receiving unit is
From the data sent from the line, it is recognized whether the received image data is moving or not with respect to the previously received image data, and if there is, the same receiving operation as the previous time is performed. To do. If not, an address that has not been written is generated by the reception memory controller based on the number of times, and the decompressed image data is sequentially received from the decoder of the codec unit and written in the reception buffer memory. As described above, since the resolution of the image data transmitted according to the movement of the subject is automatically determined, the operation for switching the resolution and the transmission mode is not required, and the operation can be simplified. At the same time, the receiving side can increase the resolution of the image each time it receives an image in the case of a subject with almost no motion, and obtain a finer image. As described above, the images are sequentially updated, and an image in which motion is prioritized is obtained.

According to the configuration of the second aspect of the present invention, the image to be transmitted next is taken into the transmission buffer memory of the one of the two sets of transmission buffer memories, which is different from the one to which the previous data was transmitted. From this image data and the image data in the transmission buffer memory that has already been transmitted, the motion detection unit determines whether or not there is a motion in both images. If there is a movement, the data is read from the transmission buffer memory of the one that newly captured the image data, and the same transmission operation as the previous time is started. If it is determined that there is no movement, it counts the number of times (what number of images), the image data in the transmission buffer memory of the one that newly captured the image data is ignored, and the transmission of the one that was transmitted last time is performed. The image data of the portion of the image data in the buffer memory that has not been transmitted is read from the address generated by the transmission memory controller and sequentially passed to the encoder of the codec unit. After that, a series of transmission operations similar to the conventional one are performed.

On the other hand, the receiving unit, in the line control circuit,
From the data sent from the line, the received image data recognizes whether there is movement or not with respect to the previously received image data, and if there is, the same receiving operation as the previous time I do. If not, an address that has not been written is generated by the reception memory controller based on the number of times, and the decompressed image data is sequentially received from the decoder of the codec unit and written in the reception buffer memory. As described above, since the resolution of the image data transmitted according to the movement of the subject is automatically determined, the operation for switching the resolution and the transmission mode is not required, and the operation can be simplified. At the same time, the receiving side can increase the resolution of the image each time it receives an image in the case of a subject with almost no motion, and obtain a finer image. As described above, the images are sequentially updated, and an image in which motion is prioritized is obtained.

[0015]

Embodiments will be described below with reference to the drawings. FIG. 1 is a block diagram for explaining an embodiment of a still image transmission apparatus according to the present invention. In the figure, 1 is an A / D converter, 2 is a field memory, 3 is a motion detection unit, and 4 is a transmission memory controller. 5, 5 is a transmission buffer memory, 6 is an encoder, 7 is a line controller, 8 is a decoder, 9 is a reception buffer memory, 10 is a reception memory controller, 11
Is an image data interpolation circuit, 12 is a display changeover switch,
13a is a D / A converter, 13b is a video signal processing circuit, and 14 is a display.

The video signal digitized by the A / D converter 1 is always written in the field memory 2 in real time with 768 dots × 480 lines. When the system finishes transmitting one piece of still image data, the motion detection unit 3 calculates an image by calculating the image data in the transmission buffer memory 5 and the image data in the field memory, which are written at this point. Motion is detected and the maximum amount is compared with a reference value (threshold). As a result, if it is determined that there is movement, the image data in the field memory is copied to the transmission buffer memory in its entirety, and thereafter processed according to the conventional transmission procedure in the continuous image mode. At this time, the image data in the transmission buffer memory is JP
In accordance with the EG format, addresses are read out per macroblock in the order of addresses as shown in FIG. 2 and passed to the codec section. However, it is assumed that the resolution of the continuous image mode described here is 384 dots × 240 lines.

On the other hand, when it is determined as a result of the motion detection that there is no motion, the image data in the field memory is not copied to the transmission buffer memory 5, and the counter in the motion detecting section 3 is incremented by one. . That is, the previous image data remains in the transmission buffer memory 5.
This data is 768 dots × 480 lines, and the resolution of the image transmitted at one time in the continuous image mode is 384 dots × 240 lines, so that the data of 3/4 capacity is discarded. . Therefore, these data are sequentially transmitted according to the counter value of the motion detection unit 3 (the number of times it is determined that there is no motion). Also in this case, since the format of one image data conforms to JPEG, even if the receiving side does not have the function of the present invention, a normal received image can be obtained without any problem (however, In this case, the resolution of the received image is always 384 dots × 240 lines).

FIGS. 3 to 5 are views for explaining the address generation within one macroblock when there is no motion detection. FIG. 3 shows the case where the count value for motion detection is 1, FIG.
Shows the case where the count value is 2, and FIG. 5 shows the case where the count value is 3. The difference in how to read the image data in the transmission buffer memory within one macroblock depending on the count value of the motion detection unit will be described below. First, when the count value is 1, to increase the resolution in the vertical direction, the transmitting side reads as shown in FIG. 3, and the receiving side generates the same address as the transmitting side without erasing the previous data, If the data is embedded there, a still image with a resolution of 384 dots × 480 lines can be obtained when two screens are received in the continuous image mode. When the count value further reaches 2, the resolution is increased in the horizontal direction this time, so that the data of the address of FIG. 4 is sequentially read and transmitted from the transmitting side. However, in the image generated on the receiving side, even-numbered lines are 76
Since there are 8 dots and 384 dots in the odd line, which causes inconvenience when displaying on the display, the data at the position x in the figure is interpolated by the data interpolation circuit 11 and displayed. As a result, when three screens are received in continuous image mode, 768 dots × 240 lines and 768 dots × 48
A still image with an intermediate resolution of 0 lines is obtained.

Next, when the count value becomes 3, as shown in FIG.
By sending the data at the X position, which was a problem with, the receiving side has a maximum resolution of 76 for this system.
A still image of 8 dots × 480 lines can be obtained. By the way, when the count value exceeds 3, by switching the mode, it is possible to unconditionally capture new image data and repeat the above-mentioned procedure, and thereafter, whether to stop the transmission and reception of the image data until the motion is detected. You can choose. As described above, according to the present invention, a moving image is updated one screen at a time as in the conventional continuous image mode.
Images with no motion can be transmitted with priority given to the motion of the subject.
Even in the continuous image mode, it is possible to obtain a still screen in which the resolution is sequentially increased without being updated one by one as in the conventional case. In the present embodiment, the resolution is set to two levels for both horizontal and vertical for simplification of the description, but this is not particularly limited, and no matter how many steps are set according to the system configuration, the motion detection is performed accordingly. It is obvious that the present invention can be applied only by changing the maximum value of the count values of.

FIG. 6 is a diagram showing another embodiment of the still image transmitting apparatus according to the present invention, in which 15 is a switch A, 16
Is a transmission buffer memory A, 17 is a transmission buffer memory B, 18 is a switch B, and other parts having the same functions as those in FIG. Now, considering the case where the image data taken in the transmission buffer memory A16 is being transmitted, the video signal digitized by the A / D converter 1 is the transmission buffer of the one that does not always transmit still data in real time. It is written in the memory B17 with 768 dots × 480 lines. When the system has finished transmitting one still image data, the motion detection unit 3
However, the motion of the image is detected by calculating the image data of the transmission buffer memory A16 and the image data of the transmission buffer memory B17 at this time, and the maximum amount thereof is compared with the reference value (threshold value). As a result, if it is determined that there is movement, the switch A15 determines that the transmission buffer memory A1
The switch B18 is switched to the transmission buffer memory B17 side on the 6 side, and thereafter, the transmission buffer memory B17
The image data taken in is processed in accordance with the conventional continuous image mode transmission procedure. At this time, the image data in the transmission buffer memory A / B is read in the order of addresses as shown in FIG. 2 per macroblock according to the JPEG format, and passed to the encoder 6 of the codec section. However, the resolution of the continuous image mode described here is
It is assumed that there are 384 dots × 240 lines.

On the other hand, if it is determined as a result of the motion detection that there is no motion, the switches A15 and B18 are not switched, and the counter in the motion detecting section 3 is incremented by one. That is, the previous image data remains in the transmission buffer memory A connected to the encoder 6. This data is 768 dots x 480 lines, and the resolution of the image transmitted at one time in the continuous image mode is 3
Since it is 84 dots × 240 lines, the data of 3/4 capacity is discarded. Therefore, these data are sequentially transmitted according to the counter value of the motion detection unit (the number of times it is determined that the motion cannot be performed). Also in this case, since the format of one image data conforms to JPEG, even if the receiving side does not have the function of the present invention, a normal received image can be obtained without any problem (however, in that case). , The resolution of the received image is always 38
4 dots x 240 lines).

The difference in the method of reading the image data of the transmission buffer memory within one macroblock depending on the count value of the motion detector will be described with reference to FIGS. First, when the count value is 1, to increase the resolution in the vertical direction, the transmitting side reads as shown in FIG. 3, and the receiving side generates the same address as the transmitting side without erasing the previous data. If data is filled in, a still image with a resolution of 384 dots × 480 lines will be obtained when two screens are received in the continuous image mode. When the count value further reaches 2, the resolution is increased in the horizontal direction this time, so that the data of the address of FIG. 4 is sequentially read and transmitted from the transmitting side. However, in this case, the image generated on the receiving side has 768 dots for even lines and 384 dots for odd lines, which causes inconvenience when it is displayed on the display. Interpolate and display. As a result, when three screens are received in continuous image mode, 768 dots × 240 lines and 76
A still image with an intermediate resolution of 8 dots × 480 lines is obtained.

Next, when the count value becomes 3, FIG.
By sending the data at the X position, which was a problem with, the receiving side has a maximum resolution of 76 for this system.
A still image of 8 dots × 480 lines can be obtained. By the way, when the count value exceeds 3, by switching the mode, it is possible to unconditionally capture new image data and repeat the above-mentioned procedure, and thereafter, whether to stop the transmission and reception of the image data until the motion is detected. You can choose. As described above, according to the present invention, a moving image is updated one screen at a time as in the conventional continuous image mode.
Images with no motion can be transmitted with priority given to the motion of the subject.
Even in the continuous image mode, it is possible to obtain a still screen in which the resolution is sequentially increased without being updated one by one as in the conventional case. In the present embodiment, the resolution is set to two levels for both horizontal and vertical for simplification of the description, but this is not particularly limited, and no matter how many steps are set according to the system configuration, the motion detection is performed accordingly. It is obvious that the present invention can be applied only by changing the maximum value of the count values of. (Below margin)

[0024]

As is apparent from the above description, the present invention has the following effects. (1) Effect corresponding to claim 1: One set of field memories, means for detecting movement of an object, and means for varying data read / address of the transmission buffer memory and data write address of the reception buffer memory thereby. In the continuous image mode, if there is a motion in the continuous image mode, if there is a motion, 1
It operates so as to update the screen for each screen, and when there is no movement, the transmitting side sequentially transmits the data for increasing the resolution for each screen transmission, and the receiving side sequentially stores the received image data. This eliminates the need to switch between transmission modes and resolutions depending on the subject, and during meetings involving telecom conferences that also perform simultaneous voice communication, documents and video images, etc. There are no interruptions, and smooth meetings can be expected. (2) Effect corresponding to claim 2: Two sets of transmission buffer memories, means for detecting the movement of the subject, and means for varying the data reading and address of the transmission buffer memory and the data writing address of the reception buffer memory. By providing and, the same effect as that of claim 1 is achieved.

[Brief description of drawings]

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

FIG. 2 is a diagram for explaining address generation in one macroblock when there is motion detection in the present invention.

FIG. 3 is a diagram (No. 1) for explaining address generation in one macroblock when there is no motion detection in the present invention.

FIG. 4 is a diagram (No. 2) for explaining the address generation in one macroblock when there is no motion detection in the present invention.

FIG. 5 is a diagram (No. 3) for explaining the address generation in one macroblock when there is no motion detection in the present invention.

FIG. 6 is a diagram showing another embodiment of the still image transmission apparatus according to the present invention.

FIG. 7 is a block diagram of a conventional still image transmission device.

FIG. 8 is a diagram (part 1) for explaining the transmission position and the order of image data in one macroblock by the conventional JPEG.

FIG. 9 is a diagram (No. 2) for explaining the transmission position and the order of image data in one macroblock by the conventional JPEG.

FIG. 10 is a diagram (part 3) for explaining the transmission position and the order of image data in one macroblock by the conventional JPEG.

FIG. 11 is a diagram (No. 4) for explaining the transmission position and the order of image data in one macroblock by the conventional JPEG.

[Explanation of symbols]

1 ... A / D converter, 2 ... Field memory, 3 ... Motion detection unit, 4 ... Transmission memory controller, 5 ... Transmission buffer memory, 6 ... Encoder, 7 ... Line control unit, 8 ... Decoder, 9 ... Reception buffer memory, 10 ... Receiving memory controller, 11 ... Image data interpolating circuit, 12 ... Display changeover switch, 13a ... D / A converter, 13b ... Video signal processing circuit, 14 ... Display.

Claims (2)

[Claims] 1. A still image transmission apparatus having a resolution switching level according to a predetermined image data transmission format, comprising one set of field memories and one set of memory banks for transmission, and being loaded into the memory for transmission. 1
When the transmission of the still image data is completed, the motion is detected from the image data of the field memory to be transmitted next, the maximum value of the motion is obtained, the maximum value is compared with the reference value, and the reference value is set. Determination means for determining whether or not it has been exceeded,
When the judgment means does not exceed the reference value, the number of times is counted, and a varying means for varying the position where the image data to be transmitted in the memory is read according to the count value,
With the previously received image data remaining, the position at which the newly received image data is written is changed and loaded into the receiving memory, and if the judgment value exceeds the reference value, it is sent from the field memory. Still image transmission characterized by having a transmission means for transmitting image data to a memory and transmitting the new image data, and automatically changing the resolution according to the movement of the subject during continuous transmission of still images. apparatus. 2. A still image transmission apparatus having a resolution switching level according to a predetermined image data transmission format, comprising two sets of transmission memory banks, and one set of still image data taken in one transmission memory. When the transmission is completed, the image data to be transmitted next is loaded into the other transmission memory, the motion of the image is detected from the data in the two memories, the maximum value of the motion is obtained, and the maximum value is calculated. Judgment means for comparing reference values and judging whether or not the reference value is exceeded, and when the judgment value does not exceed the reference value, the number of times is counted, and the count value is transmitted in the memory. Variable means for changing the position for reading out the image data, and a receiving memo by changing the position for writing the newly received image data while leaving the previously received image data. And a transmission means for switching the two transmission memory banks to transmit the image data on the newly captured side when the reference value is exceeded by the determination means. A still image transmission device characterized in that the resolution is automatically changed according to the movement of a subject during continuous transmission.