JP3576024B2 - Image communication device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a captured image communication device that transmits two-dimensional image data obtained by an imaging device such as a CCD camera to an external device.
[0002]
[Prior art]
Conventionally, when transmitting a two-dimensional image captured by a CCD camera or the like to an external device, the image data is converted into a video signal of a predetermined standard by compressing the image data using an image compression technique such as MPEG2. (See, for example, Nikkei Electronics, 1998, No. 3-9, pp. 133-154).
[0003]
On the other hand, in recent years, for example, a device such as a pipe for entering a small structure in which no human can enter, inspecting the inside thereof, or collecting attached matter inside the device, has a size of about several cm. Micromachines of a size have been developed. A small camera such as a CCD camera is incorporated in such a micromachine, so that the operator of the micromachine can remotely control the micromachine while monitoring an image in a structure taken by the small camera.
[0004]
[Problems to be solved by the invention]
By the way, in order to provide such a micromachine with a communication function and to operate the micromachine cordlessly, it is necessary to incorporate a communication device for transmitting a two-dimensional image captured by a small camera into the micromachine.
[0005]
If this communication device is configured to transmit a captured image using the above-described conventional image compression technology, there is a problem that a circuit becomes large and power consumption increases, and it cannot be incorporated in a micromachine. . In other words, in order to incorporate a communication device for picked-up images into a micromachine, it is necessary to reduce the size and power consumption of the circuit. However, in the conventional image compression technology, it is essential to mount a large-scale memory (see the above-mentioned reference). (See pages 140 to 141) Also, the operation clock for image compression becomes extremely high, and thus such demands cannot be met.
[0006]
When image data is transmitted using the above-described conventional image compression technology, an image captured by a camera is once compressed, decompressed, and displayed on a display. There is also a problem that the resolution of the obtained image is deteriorated compared to the resolution of the camera.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and in a device for transmitting a two-dimensional image captured by an imaging device such as a CCD camera, the device is reduced in size, reduced in power consumption, and improved in resolution of a communication image. Therefore, it is intended to enable the incorporation into a micromachine.
[0008]
Means for Solving the Problems and Effects of the Invention
According to a first aspect of the present invention, there is provided a captured image communication apparatus, wherein the imaging control unit drives an imaging unit including a plurality of two-dimensionally arranged imaging elements in accordance with an external imaging command. Then, a horizontal synchronization signal and an output timing signal are output to the captured image output means, so that the captured image output means outputs image information. The captured image output means captures an image captured by the imaging means for each horizontal scanning line in accordance with a horizontal synchronization signal input from the imaging control means, and outputs the captured image of the captured horizontal scanning line to an output timing signal. In synchronization with the above, the image information is sequentially quantized into n-bit image information in pixel units and output. The image information output from the captured image output means is sequentially stored in the captured image storage means under the control of the write / read control means.
[0009]
The writing / reading control means sequentially reads out the image information stored in the captured image storage means in synchronization with a readout timing signal input from the communication means, and the communication means stores the read out image information into one. For each horizontal scanning line, the data is transmitted to an external device while being converted into packet data for data communication, and an imaging command transmitted from the external device is received. Then, the imaging command received by the communication unit is transferred to the imaging control unit by the imaging command transfer unit, and the imaging control unit is used to drive the imaging unit.
[0010]
Therefore, in the captured image communication apparatus of the present invention, the two-dimensional image captured by the image capturing means is sequentially stored in the captured image storage means for each horizontal scanning line in synchronization with the horizontal scanning signal, and The captured image thus read is read out by the communication means for each horizontal scanning line, converted into packet data for data communication by the communication means, and transmitted to an external device. Operates as a so-called buffer that only temporarily stores captured images before transmission.
[0011]
In particular, according to the present invention, the captured image storage means operating as a buffer in this way is configured by at least two storage elements capable of storing image information for one horizontal scanning line output from the captured image output means. The writing / reading control means simultaneously writes and reads the image information while sequentially changing the storage element for writing the image information and the storage element for reading the image information in the captured image storage means.
[0012]
Also, the time required for one period of the horizontal synchronizing signal required for the captured image output means to output the image information for one horizontal scanning line, the communication means converts the image information for one horizontal scanning line into packet data, If the time is shorter than the time required for transmission to the apparatus, the writing / reading control means writes the image information to the captured image storage means faster than the reading speed of the image information from the captured image storage means. In the present invention, since the speed is higher and the captured image storage means overflows, the time required for one cycle of the horizontal synchronizing signal is converted by the communication means into image data for one horizontal scanning line into packet data. The period of the horizontal synchronization signal and the output timing signal output from the imaging control unit to the captured image output unit is set so as to be equal to or longer than the time required for transmission to the external device. It is constant.
[0013]
As a result, according to the present invention, it is possible to transmit an image captured by the imaging unit to an external device in real time without compression, and the external device transmits the image data transmitted from the captured image communication device to the external device. Based on this, it is possible to reproduce the image picked up by the image pickup means without deteriorating (in other words, at the same resolution as that of the image pickup means).
[0014]
Further, the captured image storage means for storing image information for image communication may store, for example, two or three horizontal scanning lines out of the images captured by the imaging means. The storage capacity of image information can be extremely reduced as compared with a case where a captured image is compressed using a compression technique. Therefore, according to the present invention, it is possible to reduce the size of the storage element constituting the captured image storage means and its peripheral circuits, and to further reduce the size of the captured image communication device. Further, since the circuit scale can be reduced in this way, power consumption can be reduced.
[0015]
As described above, according to the present invention, it is possible to reduce the size, reduce the power consumption, and increase the resolution of a communication image of the captured image communication device, so that it can be easily incorporated into the above-described micromachine. Become like
Here, as the period of the output timing signal for preventing the captured image storage unit from overflowing, the communication bit rate when the communication unit transmits image information is set to fc [Hz]. ], The speed of the output timing signal may be set to be smaller than fc / n [Hz]. Specifically, when the captured image output unit generates 8-bit image information in pixel units, the output speed of the image information by the captured image output unit is set to fc / 9 [Hz] or fc / 10 [Hz]. The time required for the output speed of the image information to be reduced and the time required for the captured image output means to output the image information for one horizontal scanning line depends on the communication bit rate of the image information for one horizontal scanning line. , And the time required for transmission after adding various kinds of communication information such as a header may be set to be longer than the time required for transmission.
[0016]
The time required for the captured image output means to output image information for one horizontal scanning line is not only the output speed of the image information, but also the horizontal synchronization signal of the captured image output means which does not quantize the image information. In order to prevent overflow of the captured image storage means, the communication means sets the blanking period of the horizontal synchronizing signal for one horizontal scanning line to prevent overflow of the captured image storage means. Is set based on the deviation between the time required to convert all image information into packet data and transmitting it to the external device and the time required for the captured image output means to output all image information for one horizontal scanning line. You may do so.
[0017]
On the other hand, the captured image storage means only needs to be able to store image information for at least two horizontal scanning lines out of the images captured by the imaging means, but the captured image storage means stores the image information for two horizontal scanning lines. With this configuration, the operation timing of the captured image output unit and the operation timing of the communication unit must be adjusted so that the storage element for writing image information and the storage element for reading image information do not overlap with each other. It is conceivable that circuit design becomes difficult.
[0018]
Therefore, more preferably, the picked-up image storage means is constituted by three storage elements capable of storing image information for one horizontal scanning line. It is preferable that writing and reading of image information be performed while sequentially changing these three storage elements for writing, holding, and reading of image information for one horizontal scanning line.
[0019]
In other words, in this case, a storage element for storing image information for one horizontal scanning line is left in addition to a storage element for writing and reading of image information by the write / read control means. Even if the operation timing of the captured image output unit and the operation timing of the communication unit deviate from each other, there is no need to simultaneously write and read image information from the same storage element, which facilitates circuit design.
[0020]
On the other hand, according to the present invention (claim 1), the communication unit receives an imaging command transmitted from an external device, and the imaging command transfer unit transfers the received imaging command to the imaging control unit. The driving of the imaging unit by the imaging control unit can be controlled on the external device side. For this reason, according to the present invention, the external device can control the exposure time and the like of the imaging unit when the imaging control unit drives the imaging unit. It is necessary to synchronize the transfer timing of the imaging command on the imaging command transfer means side with the reception timing of the imaging command on the imaging control means side.
[0021]
Then, if the imaging command transfer means is configured to transfer the imaging command to the imaging control means as it is immediately after the communication means receives the imaging command from the external device, the transfer timing and the imaging control means side Therefore, a synchronization signal for synchronizing the reception timing of the imaging command is required, and the device configuration becomes complicated.
[0022]
Therefore, in order to eliminate the need for such a synchronization signal, as described in claim 5, the data length of the imaging command received by the communication means from the external device is determined by the imaging control means. The number of bits is set in advance so that the number of bits is smaller than the number of horizontal synchronization signals per cycle of the vertical synchronization signal for outputting information, and the imaging command transfer unit starts transferring the imaging command in synchronization with the vertical synchronization signal. In addition, the imaging command is transferred in units of 1 bit in synchronization with the horizontal synchronization signal, and the imaging control means side transfers one bit of the imaging command transferred from the imaging command transfer means to the horizontal synchronization signal. And the driving control of the imaging means based on all the bit data of the captured imaging command is performed in synchronization with the vertical synchronization signal.
[0023]
According to this configuration, it is not necessary to generate a dedicated synchronization signal in order to synchronize the transfer timing of the imaging command on the imaging command transfer unit side and the reception timing of the imaging command on the imaging control unit side. The device configuration can be simplified.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, FIG. 1 is a schematic configuration diagram illustrating a captured image communication device 2 and peripheral devices according to an embodiment to which the present invention is applied.
[0025]
The captured image communication device according to the present embodiment is incorporated in a self-propelled micromachine 2 together with various actuators such as an electrostatic actuator and a piezoelectric actuator (not shown) and a drive device thereof, and captures an image of the surroundings to convert the captured image into a micro image. The signal is transmitted to an external device (control device for a micromachine) 4 by a wave, and includes a CCD camera 10 for capturing an ambient image, an RF circuit 30 for performing microwave communication with the control device 4, and a CCD camera 10. The captured image is converted into serial data for communication and output to the RF circuit 30, and the image to be transferred to the CCD camera 10 upon receiving the camera control command signal (imaging command) received by the RF circuit 30. And a communication control LSI 40.
[0026]
The RF circuit 30 not only performs communication between the captured image communication device and the control device 4, but also performs communication between the control device 4 and another device (such as a driving device for various actuators) incorporated in the micromachine 2. The communication is also performed. Further, on the control device 4 side, an RF circuit 6 for performing wireless communication using microwaves with the RF circuit 30 on the side of the micromachine 2 is provided, and the RF circuit 6 is controlled by the communication control unit 8. Is done.
[0027]
When receiving the transmission data from the micromachine 2 via the RF circuit 6, the communication control unit 8 outputs the received data to a host computer (not shown) so that the operation state of the micromachine 2 and the imaging by the CCD camera 10 are performed. Images and the like are displayed on the display, and various command signals to the micromachine 2 input from the host computer are transmitted from the RF circuit 6 to the micromachine 2 side.
[0028]
As a result, the image data transmitted by the captured image communication device of the present embodiment to the control device 4 via the RF circuit 30 is captured by the host computer of the control device 4 and displayed on the display. The second operator can drive and control the micromachine 2 while viewing the display image.
[0029]
Next, FIG. 2 is a block diagram showing a configuration of the CCD camera 10 and the image communication control LSI 40 which are main parts according to the present invention.
As shown in FIG. 2, the CCD camera 10 captures an image signal for one horizontal scanning line from the CCD sensor 12 in accordance with a horizontal synchronization signal HP and a CCD sensor 12 in which an image sensor (CCD in this embodiment) is two-dimensionally arranged. The horizontal shift register 14 sequentially shifts this pixel by pixel in accordance with the pixel clock PCK as an output timing signal, and outputs the image signal output from the horizontal shift register 14 by n bits (8 bits in this embodiment). An A / D converter 16 that quantizes (in other words, A / D converts) the image information into the image information, and an image signal for one horizontal scanning line captured by the horizontal shift register 14 based on the vertical synchronization signal VP and the horizontal synchronization signal HP. A vertical shift register 18 for sequentially shifting in the column direction, and a reference clock CKO input from the outside (in this embodiment, A horizontal synchronizing signal HP, a vertical synchronizing signal VP, and a pixel clock PCK are generated on the basis of 500 kHz) and output to each of the above-described units, and also used for camera control from the control device 4 transferred from the image communication control LSI. And a CCD control circuit 20 for driving (exposure) the CCD sensor 12 based on the command CMD in synchronism with the vertical synchronizing signal VP to capture a surrounding image. ing.
[0030]
Here, the CCD sensor 12 corresponds to the imaging means of the present invention. In the present embodiment, as shown in FIG. 3, the number of pixels in the row direction is 302, and the number of pixels in the column direction is 352. The number of pixels is 100,000 pixels of 302 × 352, and is composed of 272 × 347 signal pixels, 28 × 347 black reference pixels, and other dummy pixels. Further, the CCD sensor 12 of the present embodiment is a color image sensor, and signal pixels are provided with respective color filters of yellow Ye, cyan Cy, magenta Mg, and green Gr.
[0031]
Further, the CCD control circuit 20 corresponds to an imaging control unit of the present invention. In the present embodiment, the A / D converter is generated by dividing the frequency of the reference clock CKO to generate a pixel clock PCK of 250 kHz. The output speed of the image information from 16 is set to 250 kHz.
[0032]
Further, the CCD control circuit 20 also generates a horizontal synchronizing signal HP and a vertical synchronizing signal VP. As shown in FIG. 4A, the horizontal synchronizing signal HP has a horizontal blanking period of 50 pixel clocks (50 PCK). And a video signal valid period for 302 pixel clocks (302 PCK), and constitutes one horizontal scanning period (1H). During the video signal valid period, the A / D converter 16 outputs a front signal for two pixel clocks (2 PCK). A video signal including a porch period, a video signal period of 272 pixel clocks (272 PCK), and a back porch period of 28 pixel clocks (28 PCK) is output.
[0033]
Also, as shown in FIG. 4B, a vertical blanking period for 20 horizontal scanning periods (20H) is set in the vertical synchronization signal VP. Then, the vertical synchronizing signal VP rises in the 196th horizontal blanking period, and then falls when the 175.5 horizontal scanning period (175.5H) has elapsed. The period is defined as an odd field valid signal period, rises during the first horizontal signal valid period, and then falls after the elapse of the 175.5 horizontal scanning period (175.5H). It is defined as a field valid signal period.
[0034]
Incidentally, the falling edge of the even field valid signal period and the rising edge of the odd field valid period are, as shown in FIG. 4 (b-1), the falling edge at which the horizontal synchronizing signal HP enters the horizontal blanking period. On the other hand, it is controlled at a timing delayed by two pixel clocks (2PCK).
[0035]
Further, in the present embodiment, the vertical shift register 18 instructs the A / D converter 16 to sequentially scan two rows of adjacent image pickup elements for one horizontal scanning line from the first row of the CCD sensor 12 during the odd field effective period. The electric charges accumulated in the upper and lower imaging elements are mixed and quantized, and during the even field effective period, the adjacent imaging elements 2 are sequentially supplied to the A / D converter 16 from the second row of the CCD sensor 12. The operation is performed by a well-known field accumulation driving method, in which electric charges accumulated in upper and lower two imaging elements are mixed and quantized by using one row as one horizontal scanning line.
[0036]
Further, the A / D converter 16 starts the quantization of the image signal at the rising edge of the pixel clock PCK generated by the CCD control circuit 20 based on the reference clock CKO, as shown in FIG. In the image communication control LSI 40 described below, the falling edge of the pixel clock PCK is used to capture the image information at the timing when the image information per pixel output from the A / D converter 16 is determined. At the same timing as the edge, image information output from the A / D converter 16 is fetched.
[0037]
In the present embodiment, the horizontal shift register 14, the A / D converter 16, and the vertical shift register 18 in the CCD camera 10 function as a captured image output unit of the present invention.
Next, the image communication control LSI 40 receives a vertical synchronizing signal VP and a horizontal synchronizing signal HP from the CCD camera 10 and a line memory 42 as a captured image storing means for storing image information output from the A / D converter 16. The CCD interface 44 as write / read control means for controlling writing of image information to the line memory 42 and reading of image information from the line memory 42, and from the line memory 42 via the CCD interface 44 The image information for one horizontal scanning line is read out, converted into packet data (serial data) for data communication at a predetermined communication bit rate (2.5 Mbps in this embodiment), and output to the RF circuit 30. A command CMD for camera control is received via the transmitting unit 46 and the RF circuit 30 and is transmitted to the C By outputting the D interface 44, and a data reception unit 48. which is transferred from the CCD interface 44 to the CCD control circuit 20 of the CCD camera 10 side. Note that the data transmitting unit 46 and the data receiving unit 48 correspond to the communication unit of the present invention.
[0038]
Here, the line memory 42 includes three storage elements (a first memory 51 and a second memory 52) each of which can store image information for one horizontal scanning line among image information output from the A / D converter 16. , Third memory 53).
The CCD interface 44 has write enable signals WE1, WE2, and WE3 that permit writing of image information to the memories 51 to 53, respectively, and reads that allow reading of image information from the memories 51 to 53, respectively. A WE / RE generating circuit 61 for generating enable signals RE1, RE2 and RE2, a DIADR generating circuit 62 for generating a write address DIADR of image information to a memory in which writing of image information is permitted by a write enable signal; A DOADR generating circuit 63 for generating a read address DOADR of image information for a memory to which reading of image information is permitted by a read enable signal, and a command CMD input from the data receiving unit 48 are transferred to the CCD control circuit 20. CMD output circuit as imaging command transfer means 4 and are provided.
[0039]
The CCD interface 44 also incorporates a frequency divider that divides the reference clock CKO and generates a write strobe signal DISTRB of 250 kHz, which is the same as the pixel clock PCK generated by the CCD control circuit 20. By outputting the written write strobe signal DISTRB to the line memory 42, the writing timing of the image information to the memory to which the writing of the image information is permitted is controlled. The write strobe signal DISTRB is also input to the DIADR generation circuit 62, and the DIADR generation circuit 62 updates the write address DIADR in synchronization with the write strobe signal DISTRB.
[0040]
On the other hand, for example, as shown in FIG. 5, when transmitting packet data for one horizontal scanning line, the data transmitting unit 46 generates additional information F1, F2, F3 such as a header and a flag to be added to the head of the packet data. Then, when it becomes necessary to read the image information from the line memory 42, an enable signal ENB for permitting the reading of the image information for one horizontal scanning line from the line memory 42 is output to the CCD interface 44. A read strobe signal DOSTRB is output as a read timing signal in synchronization with the generation of the packet data. When reading the image information from the line memory 42 via the CCD interface 44, the data transmitting section 46 temporarily lengthens the cycle of the read strobe signal DOSTRB in order to secure a zero insertion time. Here, the zero insertion is an operation of inserting zero into the transmission data in order to identify the actual data part and the head / end part of the packetized transmission data.
[0041]
The enable signal ENB from the data transmission unit 46 is input to the WE / RE generation circuit 61. The WE / RE generation circuit 61 receives the enable signal ENB and outputs a read enable signal to the line memory 42. Start. The read strobe signal DOSTRB is output to the line memory 42 via the CCD interface 44, and controls the timing of writing image information to a memory to which reading of image information is permitted. The read strobe signal DOSTRB is also input to the DOADR generation circuit 63, and the DOADR generation circuit 63 updates the read address DOADR in synchronization with the read strobe signal DOSTRB.
[0042]
Next, FIG. 6 is a time chart showing signals for accessing the line memory 42 output from the CCD interface 44.
As shown in FIG. 6, the DIADR generation circuit 62 repeatedly generates the write address DIADR in synchronization with the horizontal synchronization signal HP output from the CCD camera 10, and also outputs the value of the write address DIADR to the reference clock CKO. Are sequentially changed from the minimum address to the maximum address of each of the memories 51 to 53 in synchronization with the write strobe signal DISTRB generated from the above. When the CCD camera 10 starts outputting image information in synchronization with the vertical synchronizing signal VP, the WE / RE generation circuit 61 generates a write enable signal WE1 for the first memory 51, and outputs the image information from the CCD camera 10. Is written to the first memory 51. After that, the WE / RE generation circuit 61 switches the write enable signal output to the line memory 42 in the order of WE2 → WE3 → WE1... In synchronization with the horizontal synchronization signal HP, and outputs one horizontal signal output by the CCD camera 10. The writing destination of the image information for the scanning line is changed in the order of the second memory 52 → the third memory 53 → the first memory 51.
[0043]
On the other hand, when the enable signal ENB is output from the data transmission unit 46, the DOADR generation circuit 63 starts outputting the read address DOADR in synchronization with the horizontal synchronizing signal HP, and outputs the value of the read address DOADR to the data. In synchronization with the read strobe signal DOSTRB from the transmission unit 46, the addresses are sequentially changed from the minimum address of each of the memories 51 to 53 to the maximum address. Then, the WE / RE generation circuit 61 outputs a read enable signal for the memory that has output the write enable signal during the previous horizontal scanning period, in synchronization with the horizontal synchronization signal HP. Therefore, the read enable signal is always output to the memory in which the image information has been written during the previous horizontal scanning period, such as RE1, RE2, RE3, RE1,. , The latest image information is output from the memory after the image information is written.
[0044]
As described above, in the present embodiment, the data transmission unit 46 is configured to convert image data for one horizontal scanning line into packet data at a communication bit rate of 2.5 Mbps and output the packet data. Outputs 8-bit image information at a transmission speed synchronized with the pixel clock PCK of 250 kHz, and furthermore, the blanking period (horizontal blanking period) of the horizontal synchronizing signal HP is reduced to a time corresponding to 50 pixel clocks (50 PCK). Since it is set, the amount of image information output from the CCD camera 10 during the horizontal scanning period and written to a specific memory in the line memory 42 is determined by the data transmission unit 46 during the horizontal scanning period. And the line memory 42 overflows. It is not such.
[0045]
That is, in the present embodiment, the time required for the data transmitting unit 46 to convert image information for one horizontal scanning line into packet data for transmission and transmit the packet data to the RF circuit 30 is represented by the total data amount of the packet data. Total data amount = (data amount of one horizontal scanning line of CCD) + (maximum value of zero insertion) + (data amount for transmission)｝ and communication bit rate (2.5 Mbps) of data transmission unit 46 The transmission speed of the image information from the CCD camera 10 is determined so that the horizontal scanning period 1H during which the CCD camera 10 outputs image information for one horizontal scanning line is longer (preferably equal) with respect to this time. By setting 250 kHz) and the horizontal blanking period (50 PCK), the line memory 42 is prevented from overflowing.
[0046]
Next, the CMD output circuit 64 transfers the command CMD input from the data receiving unit 48 to the CCD control circuit 20. The command CMD has a data length equal to the horizontal synchronization signal HP per one cycle of the vertical synchronization signal VP. Is set to 128 bits, which is smaller than the number of. Then, as shown in FIG. 7A, the CCD control circuit 20 synchronizes the 128-bit command CMD with the CCD in units of 1 bit in synchronization with the horizontal synchronization signal HP input after the rise of the vertical synchronization signal VP. Transfer to the control circuit 20.
[0047]
Further, the CCD control circuit 20 fetches the command CMD transferred bit by bit from the CMD output circuit 64 in synchronization with the horizontal synchronization signal HP. In the next blanking period of the vertical synchronizing signal VP, the CCD sensor 12 controls the exposure time and the like based on all the bit data (128 bits) of the command CMD transferred from the CMD output circuit 64 so far. Is driven to capture a surrounding image.
[0048]
As shown in FIG. 7B, the CMD output circuit 64 starts outputting one-bit data of the command CMD at the rising edge (timing t1) of the horizontal synchronization signal HP, and thereafter, outputs the horizontal synchronization signal HP In the vertical control signal VP during one cycle of the vertical synchronizing signal VP, such that the output data value is changed at the rising edge (timing t1) of the command CMD in accordance with the next data of the command CMD. Transfer to 20. Further, the CCD control circuit 20 captures the bit data of the command CMD output from the CMD output circuit 64 at the falling edge (timing t2) of the horizontal synchronization signal HP.
[0049]
As described above, in the captured image communication apparatus of the present embodiment, the image information sequentially output from the CCD camera 10 is stored in the first memory 51 to the third memory in the line memory 42 every one horizontal scanning line. 53, and the data transmitting section 46 sequentially reads out image information for one horizontal scanning line from the first memory 51 to the third memory 53 in which the image information is written, and simultaneously converts the image information into packet data for data communication. While outputting to the RF circuit 30. Further, a blanking period (horizontal blanking period) of a horizontal synchronizing signal HP for determining a cycle at which the CCD camera 10 outputs image information for one horizontal scanning line, and a pixel clock PCK for defining a transmission speed of image information. The cycle is set so that the time per one cycle of the horizontal synchronizing signal HP (horizontal scanning period) is not shorter than the time required for the data transmitting unit 46 to transmit packet data for one horizontal scanning line. Have been.
[0050]
For this reason, according to the present embodiment, it is possible to transmit the image captured by the CCD camera 10 to the control device 4 in real time without compressing the image captured by the CCD camera 10 using the three memories 51 to 53 constituting the line memory 42. That is, the control device 4 can display the image captured by the CCD camera 10 on the display without deteriorating based on the transmission data.
[0051]
Further, in this embodiment, the line memory 42 for storing image information for image communication is constituted by three memories 51 to 53 for storing image information for one horizontal scanning line. Compared to a case where a captured image is compressed using an image compression technique, the storage capacity of image information can be extremely reduced, and the device can be reduced in size and power consumption can be reduced. Therefore, even if the captured image communication device is incorporated in the micromachine 2 as in the present embodiment, it is possible to realize a micromachine capable of obtaining a clear image in real time without increasing the size of the micromachine 2.
[0052]
Further, various command signals are transmitted from the control device 4 to the micromachine 2, and the command CMD for camera control is transferred to the CCD camera 10 via the RF circuit 30 and the image communication control LSI 40. In the image communication control LSI 40, the CMD output circuit 64 that transfers the command CMD to the CCD camera 10 is configured to transfer the command CMD to the CCD camera 10 in units of one bit in synchronization with the horizontal synchronization signal HP. Therefore, there is no need to generate a synchronization signal dedicated to command transfer for synchronizing the CMD output circuit 64 and the CCD control circuit 20 of the CCD camera 10, which can also simplify the device configuration.
[0053]
As mentioned above, although one Example of this invention was described, this invention is not limited to the said Example, You can take various aspects.
For example, in the above embodiment, in order to prevent the line memory 42 from overflowing, both the blanking period of the horizontal synchronization signal HP generated by the CCD control circuit 20 and the period of the pixel clock PCK are adjusted. However, for example, the cycle of the pixel clock PCK is set corresponding to the speed (fc / n) obtained by dividing the communication bit rate fc of the data transmission unit 46 by the number n of bits to be quantized by the A / D converter 16. Alternatively, by making only the blanking period of the horizontal synchronizing signal HP longer, the overflow of the line memory 42 may be prevented. Conversely, the blanking period of the horizontal synchronizing signal HP may be set to a minimum length. Only the pixel clock (in other words, the transmission speed of the quantized image information) on the CCD camera 10 side is determined. By integer, it may be prevented overflow line memory 42.
[0054]
Further, in the above-described embodiment, the description has been made assuming that the imaging camera uses an imaging unit including a CCD sensor. However, the image sensor incorporated in such an imaging camera is not necessarily a CCD (charge coupled device) as an imaging device. It is not necessary to use a CCD sensor using a CMOS image sensor. For example, another image sensor such as a MOS image sensor using a MOS solid-state imaging device may be used.
[0055]
Further, in the above embodiment, the captured image communication device is described as being incorporated in the micromachine. However, according to the captured image communication device of the present invention, the image captured by the camera can be transmitted in real time without compression, and Fields that require a small camera with low power consumption, such as, for example, incorporating a mobile phone or the like and transmitting a captured image to a communication partner because the device can be reduced in size and power consumption can be reduced. In this case, it is possible to obtain the same effect as in the case of incorporating into a micromachine.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating a captured image communication device and a peripheral device thereof according to an embodiment.
FIG. 2 is a block diagram illustrating a configuration of a CCD camera and an image communication control LSI.
FIG. 3 is an explanatory diagram illustrating a pixel configuration of a CCD sensor.
FIG. 4 is a time chart illustrating an operation of the CCD camera.
FIG. 5 is a time chart illustrating an operation of a data transmission unit.
FIG. 6 is a time chart showing an operation of accessing a line memory of the CCD interface.
FIG. 7 is a time chart illustrating an operation of the CMD output circuit 64;
[Explanation of symbols]
2 ... micro machine, 4 ... control device, 6 ... RF circuit, 8 ... communication control unit, 10 ... CCD camera, 12 ... CCD sensor, 14 ... horizontal shift register, 16 ... A / D converter, 18 ... vertical shift register, 20 ... CCD control circuit, 30 ... RF circuit, 40 ... Image communication control LSI, 42 ... Line memory, 44 ... CCD interface, 46 ... Data transmission unit, 48 ... Data reception unit, 51 ... First memory, 52 ... Second memory 53, a third memory, 61, a WE / RE generation circuit, 62, a DIADR generation circuit, 63, a DOADR generation circuit, 64, a CMD output circuit.

Claims (5)

Imaging means comprising a plurality of two-dimensionally arranged imaging elements;
In accordance with a horizontal synchronization signal input from the outside, an image captured by the imaging means is captured for each horizontal scanning line, and the captured images for the captured one horizontal scanning line are sequentially synchronized in pixel units in synchronization with an output timing signal. a captured image output unit that quantizes and outputs the n-bit image information,
The imaging means is driven in accordance with an external imaging instruction to capture a two-dimensional image, and after the imaging, the horizontal synchronization signal and the output timing signal are output to the captured image output means, and the captured image output means is output. Imaging control means for outputting image information from
A captured image storage unit for temporarily storing image information output from the captured image output unit,
In synchronization with the operation of the captured image output means controlled by the imaging control means, the image information output from the captured image output means is sequentially stored in the captured image storage means, and the readout timing externally input Writing and reading control means for sequentially reading image information stored in the captured image storage means in synchronization with a signal;
By outputting the read timing signal to the write / read control means, the image information stored in the captured image storage means is sequentially read out via the write / read control means, and the image information is read out by the horizontal Communication means for transmitting to an external device while converting the data into packet data for data communication for each scanning line, and receiving an imaging instruction transmitted from the external device;
Imaging command transfer means for transferring an imaging command from the external device received by the communication means to the imaging control means,
A captured image communication device comprising:
The captured image storage unit is configured with at least two storage elements capable of storing image information for one horizontal scanning line output from the captured image output unit,
The writing / reading control means is configured to simultaneously perform writing and reading of the image information while sequentially changing a storage element for writing image information and a storage element for reading image information in the captured image storage means. ,
In addition, the horizontal synchronization signal is controlled so that the time per one cycle is equal to or longer than the time required for the communication unit to convert the image information for one horizontal scanning line into packet data and transmit the packet data to an external device. A captured image communication device, wherein a period of a signal and a period of the output timing signal are set. When a communication bit rate at which the communication unit transmits the image information is fc [Hz], a cycle of the output timing signal is set such that a speed of the output timing signal is smaller than fc / n [Hz]. 2. The captured image communication device according to claim 1, wherein: The blanking period of the horizontal synchronization signal, which determines the time from when the captured image output unit outputs the image information for one horizontal scanning line to when the output of the image information starts next, is performed by the communication unit. The time required to convert all image information for one horizontal scan line into packet data and transmit it to an external device, and the time required for the captured image output means to output all image information for one horizontal scan line 3. The captured image communication device according to claim 1, wherein the setting is based on a deviation from time. The captured image storage means includes three storage elements capable of storing image information for one horizontal scanning line, and the writing / reading control means stores the three storage elements in the one horizontal scanning line, respectively. 4. The captured image communication device according to claim 1, wherein the image information is written and read while sequentially changing the image information for writing, holding, and reading. The data length of the imaging command received by the communication unit is a bit number smaller than the number of horizontal synchronization signals per one cycle of a vertical synchronization signal that causes the imaging control unit to output one frame of image information from the captured image output unit. Is set to
The imaging command transfer unit is configured to start transfer of the imaging command in synchronization with the vertical synchronization signal, and to transfer the imaging command in units of 1 bit in synchronization with the horizontal synchronization signal,
The imaging control unit captures one bit of the imaging command transferred from the imaging command transfer unit in synchronization with the horizontal synchronization signal, and controls the imaging unit based on all the bit data of the captured imaging command. 5. The captured image communication device according to claim 1, wherein drive control is performed in synchronization with the vertical synchronization signal.

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