Patent ID: 12256171

DESCRIPTION OF THE EMBODIMENTS

In a case where a signal from the other party is present during the conflict determination period that precedes the interval transmitting the non-video data, data signal conflict can be avoided by stopping non-video data transmission.

First Embodiment

FIG.1is a block diagram illustrating an example of a configuration of a first device10and a second device50according to the embodiment. The first device10is an image capturing device, such as a camera, and the second device50is a car navigation device, for example, or an automatic driving device, etc., of a vehicle. The first device10may also be a monitoring camera, and the second device50may also be a control device of the monitoring camera. The first device10and the second device50are connected via an analog transmission cable40. The analog transmission cable40is used to transmit video data obtained by the first device10to the second device50and transmit non-video data, such as a control signal, between the first device10and the second device50.

The first device10includes an image sensor12, a memory14, and a Tx system20. The image sensor12obtains video data of a target by receiving light emitted from the target and converting the brightness of the light into an electrical signal. The memory14is a storage device, such as a flash memory. The Tx system20transmits the video data obtained by the image sensor12to the second device50via the analog transmission cable40.

The Tx system20includes a video transmission circuit24and a Tx data transmission/reception circuit26. The video transmission circuit24transmits video data as an analog signal, and the Tx data transmission/reception circuit26transmits/receives non-video as a digital signal of I2C data, etc., with the second device50. Each of the video transmission circuit24and the Tx data transmission/reception circuit26is controlled by a Tx control part22.

The Tx control part22outputs control signals for respectively controlling the video transmission circuit24and the Tx data transmission/reception circuit26to the video transmission circuit24and the Tx data transmission/reception circuit26, respectively, and outputs a transmission/reception timing setting signal for performing transmission/reception control to the video transmission circuit24and the Tx data transmission/reception circuit26, respectively. In the embodiment, a video period for transmitting the video data and a video blanking period for transmitting the non-video data are in the transmission timing, and the transmission/reception timing setting signal output by the Tx control part22sets the video period and the video blanking period in the transmission timing.

The Tx data transmission/reception circuit26includes a reception part28and a transmission part32. The reception part28receives the digital signal transmitted from the second device50, and the transmission part32transmits the digital signal to the second device50. The reception part28includes a monitoring part30. The monitoring part30controls the transmission part32, so that, in the case where a conflict determination period is provided in the transmission timing and data is transmitted from the transmission side during the conflict determination period, data transfer from the reception side to the transmission side is stopped to avoid signal conflict. In the embodiment, as described above, the video period in which the video data is transmitted and the video blanking period in which the non-video data is transmitted are set in the transmission/reception timing setting signal output by the Tx control part22. However, as described in the following, the conflict determination period is provided in the video blanking period to control transmission to avoid signal conflict.

The memory14stores, for example, a program, such as firmware, controlling the image capturing function of the first device10. The program, such as firmware, stored in the memory14is updated by using the digital signal from the second device50.

The second device50includes an Rx system60, a display52, and a micro control unit (MCU)54. The Rx system60receives the video data, the display52displays the received video data, and the MCU54controls the Rx system60.

The Rx system60includes a video reception circuit62, a Rx data transmission/reception circuit66, a video processing circuit64, and a Rx control part74. The video reception circuit62receives the video data as an analog signal. The Rx data transmission/reception circuit66transmits and receives the digital signal of I2C data, etc., with the first device10. The video processing circuit64processes the received video data into a state able to be displayed on the display52. The Rx control part74is a subordinate control device of the MCU54. The video reception circuit62, the video processing circuit64, and the Rx data transmission/reception circuit66are respectively controlled by the Rx control part74.

The Rx control part74outputs the control signals for controlling the video reception circuit62, the video processing circuit64, and the Rx data transmission/reception circuit66to the video reception circuit62, the video processing circuit64, and the Rx data transmission/reception circuit66, respectively. In addition, the video reception circuit62generates a synchronization signal indicating a difference between the video period and the video blanking period in the Rx system60of the second device50according to the time at which the video signal is received from the first device10, and outputs the synchronization signal to the Rx data transmission/reception circuit66.

The Rx data transmission/reception circuit66includes a reception part68and a transmission part72. The reception part68receives the digital signal transmitted from the first device10, and the transmission part72transmits the digital signal to the first device10. The reception part68includes a monitoring part70. The monitoring part70controls the transmission part72, so that, in the case where a conflict determination period is provided in the transmission timing and data is transmitted from the transmission side during the conflict determination period, data transfer from the reception side to the transmission side is stopped to avoid signal conflict.

FIG.2is a diagram explaining an example of the transmission timings of the video data and the non-video data. As shown inFIG.2, in analog video signal transmission, a process in which data (non-video data such as I2C data) other than video is superimposed on the analog signal is used. The transmission/reception of non-video data is performed during the video blanking period, so as not to affect the video signal. When performing transmission without defining the specification at the time of transmitting non-video data, it is necessary to avoid data signal conflict to safely perform communication. In the embodiment, the transmission timing of the data signal at the transmission side (Tx) and the reception side (Rx) is determined in advance, so that signal conflict due to bidirectional communication does not occur during the transmission of non-video data, and data signal conflict is avoided. In addition, when detecting a data signal out of an expected timing, the reception side (Rx) stops the data signal transmission to avoid data conflict.

FIG.3is a diagram explaining an example of camera module control through non-video data transmission. As shown inFIG.2, in analog video signal transmission, a process in which non-video data as a digital signal, such as I2C data, is superimposed on the analog signal is used. The analog video signal obtained by the image sensor12provided in the first device10is transmitted from the Tx system20, which is the transmission side, to the Rx system60, which is the reception side of the second device50, via the analog transmission cable40, and is displayed on the display52as a display device. It may also be that the MCU15or the storage14and the MCU54are not included in the first device10and the second device50, respectively, but are connected via buses.FIG.3illustrates a configuration differing from the configuration ofFIG.1in that the MCU15, the memory14, and the MCU54are not included in the first device10and the second device50, respectively.

In addition, the I2C data as non-video data is an instruction signal to the camera module formed by the image sensor12and the Tx system20, for example, and is a notification signal to the MCU15, for example. More specifically, through the control of the MCU54, the control signal of the camera module, the signal for firmware re-writing, etc., of the camera module, and the command for communication with the MCU15are transmitted from the second device50to the first device10via the Rx control part74. The I2C data is, for example, transmitted via a serial bus, such as a serial peripheral interface (SPI). For example, in the case where the I2C data is a signal for re-writing the firmware of the camera module, through the control of the MCU54, a signal for rewiring new firmware is transmitted from the second device50to the first device10as non-video data and stored in the memory14, and, in the case where the I2C data is a command to the MCU15, for example, the I2C data notifies the MCU15via the serial bus, etc.

In the case where the command to the camera module, the re-writing of the firmware, the command notification to the MCU15, etc., is completed, in accordance with needs, a signal indicating that the re-writing of the firmware is completed is transmitted as I2C data from the Tx system20of the first device10to the MCU54of the second device50via the serial bus, such as SPI.

FIG.4is a block diagram illustrating an example of a detailed configuration of the Rx data transmission/reception circuit66. The Rx data transmission/reception circuit66includes a reception part68and a transmission part72. The reception part68receives the digital signal transmitted from the first device10, and the transmission part72transmits the digital signal to the first device10.

The reception part68includes a reception circuit68A, a reception format68B, and the monitoring part70. The reception circuit68A receives an input signal, which is I2C data, as a signal indicating that the re-writing of the firmware is completed, etc. The reception format68B converts the received I2C data into a format that can be interpreted by the Rx control part74. The monitoring part70provides a conflict determination period during the video blanking period, which is the transmission timing of non-video data, and performs conflict determination in the case where data is transmitted from the transmission side during the conflict determination period. The monitoring part70performing conflict determination outputs a stop control signal for stopping the data transfer from the reception side to the transmission side to the transmission part72, and controls the transmission part72to avoid signal conflict.

The signal for controlling the camera module through the control of the MCU54and the signal for re-writing the firmware of the camera module, etc., are input to the transmission part72via the Rx control part74. The signal input via the Rx control part74is converted into the format of I2C data by a transmission format72C and transmitted to a transmission circuit72A. In the case where transmission is not stopped according to a transmission determiner72B, the transmission circuit72A transmits the input I2C data to the first device10.

A synchronization signal is input from the video reception circuit62to each of the transmission circuit72A and the reception signal62A. In the embodiment, as described above, the video period transmitting video data and the video blanking period transmitting non-video data are set, and the video reception circuit62receives the video data from the first device10during the video period. The synchronization signal output by the video reception circuit62to each of the transmission circuit72A and the reception circuit68A indicates the distinction between the video period and the video blanking period in the Rx system60of the second device50. Each of the transmission circuit72A and the reception circuit68A avoids signal conflict between video data and non-video data by performing I2C data that is non-video data during the video blanking period indicated by the synchronization signal that is input.

In the embodiment, although the video data is transmitted unidirectionally from the first device10to the second device50, the non-video data is transmitted bidirectionally between the first device10and the second device50. As described above, in the embodiment, the monitoring part70of the reception part68performs conflict determination in the case where data is transmitted from the transmission side during the conflict determination period in the video blanking period, and outputs a stop control signal for stopping the data transfer from the reception side to the transmission side to the transmission determiner72B of the transmission part72. The transmission determiner72B receiving the stop control signal stops the transmission of the transmission circuit72A and avoids signal conflict.

FIG.5is a flowchart illustrating an example of a process of transmission/reception control of the non-video data in the monitoring part30of the Tx data transmission/reception circuit26or the monitoring part70of the Rx data transmission/reception circuit66. The process shown inFIG.5is started when the first device10and the second device50respectively become able to communicate.

In Step100, whether data reception from the other party (the Rx data transmission/reception circuit66in the case where the Tx data transmission/reception circuit26is the reception side and the Tx data transmission/reception circuit26in the case where the Rx data transmission/reception circuit66is the reception side) is detected during the conflict determination period in the video blanking period is determined. In Step S100, in the case where data reception is detected, the procedure proceeds to Step S102, and in the case where data reception is not detected, the procedure proceeds to Step S104.

In Step S102, conflict determination is performed, and a stop instruction for stopping data transfer from the reception side to the transmission side is output to the transmission part32or the transmission part72, and the process is ended.

In Step S104, conflict determination is not performed, the stop instruction for stopping data transfer from the reception side to the transmission side is not output, transmission of I2C data according to the transmission part32or the transmission part72is permitted, and the process is ended.

As shown inFIGS.2and5, in the transmission system in which the analog video signal is transmitted between the first device10and the second device50and data other than video (non-video data, such as the I2C data) is superimposed and transmitted bidirectionally during the video blanking period, each device includes the transmission circuit and the reception circuit of non-video data, and is controlled to perform transmission at a non-video data transmission/reception timing set in advance.

In addition, the reception circuit on the reception side includes a signal conflict monitoring part (the monitoring part30or the monitoring part70), stops the transmission according to the transmission part32or the transmission part72when a data signal from the transmission side is detected during the conflict determination period, and permits the transmission according to the transmission part32or the transmission part72when there is no data signal from the transmission side.

FIG.6Ais a diagram explaining an example of the transmission timing of non-video data to the first device10, which is the video data transmission side, from the second device50, which is the video data reception side.FIG.6Bis a schematic diagram illustrating a transmission image of non-video data from the second device50to the first device10.FIG.6Cis a diagram explaining an example of the transmission timing of non-video data to the second device50, which is the video data reception side, from the first device10, which is the video data transmission side.FIG.6Dis a schematic diagram illustrating a transmission image of the non-video data from the first device10to the second device50.

In the embodiment, the transmission and reception of the non-video data can be from either side, as shown inFIGS.6B and6D.

As shown inFIGS.6A and6C, in the embodiment, the conflict determination period is provided at the beginning of line transfer during the video blanking period, the transmission of data signals between the transmission side and the reception side is performed according to the result of the conflict determination. In the embodiment, the prioritized device is determined in advance, and only the prioritized device can transmit a signal during the conflict determination period. As shown inFIGS.6A and6C, the case where the transmission of non-video data from the first device10to the second device50is prioritized is shown, and only the first device10transmits a signal during the conflict determination period.

As shown inFIG.6A, in the case where the monitoring part70of the second device50determines that there is no signal (blank) in the conflict determination period, the data transmission of non-video data to the first device10is executed during a video data reception side data transmission interval ofFIG.6A.

As shown inFIG.6C, in the case where the monitoring part70of the second device50determines that there is a signal, such as a video data transmission side data transfer notification, from the first device10during the conflict determination period, the data transmission from the first device10is prioritized, and the data transmission of non-video data from the second device50is performed after a video data transmission side data transmission interval ofFIG.6Cends.

FIGS.6A and6Cillustrate the case where the transmission of non-video data from the first device10to the second device50is prioritized. However, the case where the transmission of non-video data from the second device50to the first device10is prioritized can also be realized in a similar way. In the case where the transmission of non-video data from the second device50to the first device10is prioritized, only the second device50transmits a signal during the conflict determination period. In the case where the monitoring part30of the first device10determines that there is a signal, such as a data transfer notification, from the second device50during the conflict determination period, the data transmission from the second device50is prioritized, and the data transmission of non-video data from the first device10is performed after a video data reception side data transmission interval ends.

The conflict determination periods inFIGS.6A and6Care respectively set to be shorter than the video data reception side data transmission interval and the video data transmission side data transmission interval. If the conflict determination period is set to be long, the signal conflict between the transmission side and the reception side can be avoided reliably. However, there is a concern that the band used for non-video data transmission may be impaired by the conflict determination period. If the conflict determination period is set to be short, the band used for non-video data transmission is secured. However, there is a concern that it may be difficult to reliably avoid signal conflict. The length of the conflict determination period is determined by whether avoiding signal conflict or securing the band used for non-video data transmission is prioritized.

As described above, according to the embodiment, whether there is a signal from the other party of data transmission is determined in the conflict determination period preceding the video data reception side data transmission interval or the video data transmission side data transmission interval, and data transmission to the other party is performed in the case where a signal is not present during the conflict determination period. As a result, data signal conflict can be avoided in the data transmission of non-video data.

In the embodiment, the transmission/reception timing setting signal setting the video period and the video blanking period in the transmission timing is output by the Tx control part22of the first device10. However, the disclosure is not limited thereto. It may also be that the Rx control part74of the second device50outputs the transmission/reception timing setting signal to the Rx data transmission/reception circuit66, and the Rx data transmission/reception circuit66transmits the transmission/reception timing setting signal, as I2C data, to the first device10. In such case, the first device10controls the transmission of video data and non-video data in accordance with the video period and the video blanking period set in the transmission/reception timing setting signal that is transmitted.

Second Embodiment

Then, the second embodiment is described. The embodiment differs from the first embodiment in the point that the non-video data is transmitted more stably. However, the remaining configuration is the same as the configuration of the first embodiment. Therefore, for the configuration same as the first embodiment, symbols same as those of the first embodiment are labeled, and the detailed description is omitted.

FIG.7Ais a schematic diagram illustrating an example of a transmission timing of non-video data from the second device50, which is the video data reception side, to the first device10, which is the video data transmission side.FIG.7Bis a diagram explaining an example of a transmission timing of the non-video data to the second device50, which is the video data reception side, from the first device10, which is the video data transmission side.

As shown inFIGS.7A and7B, in the embodiment, the point that the conflict determination period is provided at the beginning of the line transfer of the video blanking period is common to the first embodiment. However, the point in which a switching period and a BIAS stable period are provided after the conflict determination period is different from the first embodiment. The switching period is a blank period in which no signal is transmitted and which is provided to smoothly switch to the subsequent video data reception side data transmission interval or video data transmission side data transmission interval. The BIAS stable period is a period which assumes a case where a signal is unstable or a case where various processing delays between the transmission side and the reception side occur and synchronizes the transmission side and the reception side, respectively.

As shown inFIG.7A, in the case where the monitoring part70of the second device50determines that there is no signal (blank) in the conflict determination period, the transmission part72of the second device50executes the data transmission of non-video data to the first device10during the video data reception side data transmission interval ofFIG.7Afollowing the switching period and the BIAS stable period. AlthoughFIG.7Aillustrates the transmission of non-video data from the second device50to the first device10, the same applies to the case where non-video data is transmitted from the first device10to the second device50. That is, in the case where the monitoring part30of the first device10determines that there is no signal (blank) in the conflict determination period, the transmission part32of the first device10executes the data transmission of non-video data to the second device50during the video data transmission side data transmission interval after the switching period and the BIAS stable period.

As shown inFIG.7B, in the case where the monitoring part70of the second device50determines that there is a signal, such as a video data transmission side data transfer notification, from the first device10during the conflict determination period, the data transmission from the first device10is prioritized, and the data transmission of non-video data from the second device50is performed following the switching period and the BIAS stable period after the video data transmission side data transmission interval ofFIG.7Bends.

FIG.7Billustrates the case where the transmission of non-video data from the first device10to the second device50is prioritized, the same applies to the case where the transmission of non-video data from the second device50to the first device10is prioritized. In the case where the monitoring part30of the first device10determines that there is a signal, such as a data transfer notification, from the second device50during the conflict determination period, the data transmission from the second device50is prioritized, and the data transmission of non-video data from the first device10is performed following the switching period and the BIAS stable period after the video data reception side data transmission interval ends.

As described above, according to the embodiment, following the conflict determination period, the switching period and the BIAS stable period are provided. The switching period is provided for smoothly performing switching to the video data reception side data transmission interval or the video data transmission side data transmission interval. The BIAS stable period is provided for assuming the case where the signal is unstable or the case where various processing delays between the transmission side and the reception side occur and synchronizing the transmission side and the reception side, respectively. Accordingly, it is possible to stably transmit non-video data.