Image transmitting device, image transmitting / receiving system, and program

Abstract

To improve noise resistance compared to a case where a lock signal from an image receiving device is input directly to a transmission circuit of an image transmitting device. [Solution] A VBO transmission circuit 110 receives a LOCKN signal 12 from an image receiving device 20 as a transmission-side LOCKN signal 21 via a LOCKN signal masking unit 130. When the transmission-side LOCKN signal 21 changes from H level to L level, the VBO transmission circuit 110 transmits transmission data 11, in which a clock signal is superimposed on image data, to the image receiving device 20. The LOCKN signal masking unit 130 receives the LOCKN signal 12 from the image receiving device 20, and outputs an H-level transmission-side LOCKN signal 21 to the VBO transmission circuit 110 only if the H level continues for a preset time or longer, even if the received LOCKN signal 12 changes from L level to H level.

Description

[Technical Field]

[0001] The present disclosure relates to an image transmission device, an image transmission / reception system, and a program. [Background technology]

[0002] Patent Document 1 discloses a data communication control device that controls a VBO receiver using an analog front end that converts analog signals into digital signals, thereby reducing the number of transmission paths and suppressing the effects of noise compared to a case where control is always performed based on multiple control signals input via multiple transmission paths.

[0003] Patent Document 2 discloses a data communication device that is capable of transmitting data other than a lock signal from a receiving circuit to a transmitting circuit via the same signal line. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-063375 [Patent Document 2] Japanese Patent Application Publication No. 2019-110449 Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present disclosure is to provide an image transmitting device, an image transmitting / receiving system, and a program that have improved noise resistance compared to when a lock signal from an image receiving device is directly input to a transmission circuit of an image transmitting device. [Means for solving the problem]

[0006] An image transmitting device according to a first aspect of the present disclosure includes a transmitting circuit that transmits transmission data, in which a clock signal is superimposed on image data, to an image receiving device when an input lock signal changes from a first logic state indicating that communication is not established to a second logic state indicating that communication is established; and a lock signal masking unit that receives the lock signal from the image receiving device, and outputs the lock signal of the first logic state to the transmitting circuit only if the first logic state continues for a predetermined time or longer, even if the received lock signal changes to the first logic state after becoming the second logic state.

[0007] An image transmission device of a second aspect of the present disclosure is the image transmission device of the first aspect, wherein the lock signal masking unit outputs a lock signal of the first logic state to the transmission circuit when the period during which the lock signal is in the first logic state continues for a period longer than the period during which the logic state of the lock signal is predicted to be affected by the generated noise.

[0008] An image transmission / reception system according to a third aspect of the present disclosure includes an image receiving device including: a receiving circuit that extracts a clock signal from transmission data transmitted from an image transmitting device, acquires image data from the transmission data using the extracted clock signal, and, when the clock signal can be extracted from the transmission data, changes a lock signal indicating whether communication is established or not from a first logic state indicating that communication is not established to a second logic state indicating that communication is established; and a lock signal transmission control unit that, when the lock signal output from the receiving circuit changes from the second logic state to the first logic state, outputs a signal that changes in a predetermined manner as a lock signal to the image transmitting device; The image transmitting device includes a transmitting circuit that transmits transmission data in which a clock signal is superimposed on image data to the image receiving device when an input lock signal changes from the first logic state to the second logic state, and a lock signal masking unit that receives the lock signal from the image receiving device and outputs a lock signal of the first logic state to the transmitting circuit when the received lock signal changes in a predetermined manner.

[0009] An image transmitting and receiving system of a fourth aspect of the present disclosure is the image transmitting and receiving system of the third aspect, wherein when the lock signal output from the receiving circuit changes from the second logic state to the first logic state, the lock signal transmission control unit outputs to the image transmitting device a lock signal in which the first logic state continues for a predetermined time or more; The lock signal masking unit outputs a lock signal of the first logic state to the transmission circuit when the period during which the lock signal is in the first logic state continues for a predetermined time or longer.

[0010] A fifth aspect of the image transmission / reception system of the present disclosure is the image transmission / reception system of the fourth aspect, wherein when the lock signal output from the receiving circuit changes from the second logic state to the first logic state, and the period in which the lock signal is in the first logic state continues for a period longer than the period predicted for which the logic state of the lock signal is affected by the generated noise, the lock signal transmission control unit outputs a lock signal to the image transmitting device, in which the first logic state continues for a predetermined period of time or longer.

[0011] An image transmitting and receiving system of a sixth aspect of the present disclosure is the image transmitting and receiving system of the third aspect, wherein, when the lock signal output from the receiving circuit changes from the second logic state to the first logic state, the lock signal transmission control unit outputs to the image transmitting device a lock signal that changes between the first logic state and the second logic state a preset number of times and then becomes the first logic state; The lock signal masking unit outputs a lock signal of the first logic state to the transmitting circuit when the lock signal changes between the first logic state and the second logic state a predetermined number of times or more and then becomes the first logic state.

[0012] An image transmission / reception system of a seventh aspect of the present disclosure is the image transmission / reception system of the third aspect, wherein the image transmission device further includes an adding unit that adds an error detection code to image data to be transmitted to the image reception device; the image receiving device further includes a detection unit that detects errors in the image data using an error detection code added to the image data acquired by the receiving circuit; When the detector detects an error in the image data, the lock signal transmission controller outputs a signal that changes in a preset manner to the image transmitter as a lock signal.

[0013] A program according to an eighth aspect of the present disclosure includes, in an image transmitting device including a transmitting circuit that transmits transmission data in which a clock signal is superimposed on image data to an image receiving device when an input lock signal changes from a first logic state indicating that communication is not established to a second logic state indicating that communication is established, the program includes: receiving the lock signal from the image receiving device; and outputting a lock signal of the first logic state to the transmitting circuit only if the first logic state continues for a predetermined time or longer, even if the received lock signal changes to the first logic state after being in the second logic state. [Effects of the Invention]

[0014] According to the image transmitting device of the first aspect of the present disclosure, noise resistance can be improved compared to when the lock signal from the image receiving device is input directly to the transmitting circuit of the image transmitting device.

[0015] According to the image transmission device of the second aspect of the present disclosure, even if the logical state of the lock signal is affected by the occurrence of noise, it is possible to prevent the transmission circuit from receiving an erroneous lock signal.

[0016] According to the image transmitting and receiving system of the third aspect of the present disclosure, noise resistance can be improved compared to when the lock signal from the image receiving device is input directly to the transmission circuit of the image transmitting device.

[0017] According to the image transmitting and receiving system of the fourth aspect of the present disclosure, even if the logical state of the lock signal is affected by the occurrence of noise, it is possible to prevent the transmission circuit from receiving an erroneous lock signal.

[0018] According to the image transmitting and receiving system of the fifth aspect of the present disclosure, even if the logical state of the lock signal is affected by the occurrence of noise, it is possible to prevent the transmission circuit from receiving an erroneous lock signal.

[0019] According to the image transmitting and receiving system of the sixth aspect of the present disclosure, even if the logical state of the lock signal is affected by the occurrence of noise, it is possible to prevent the transmission circuit from receiving an erroneous lock signal.

[0020] According to the image transmission / reception system of the seventh aspect of the present disclosure, it is possible to notify the image receiving device of the result of error detection in image data by using a lock signal to the image transmitting device.

[0021] According to the program of the eighth aspect of the present disclosure, noise resistance can be improved compared to when the lock signal from the image receiving device is input directly to the transmission circuit of the image transmitting device. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 10 is a block diagram showing the configuration of an image transmission / reception system as a comparative example. [Figure 2] 1 is a block diagram illustrating a configuration of an image transmission / reception system according to an embodiment of the present disclosure. [Figure 3] 10 is a timing chart for explaining an operation at the time of initialization of an image transmission / reception system according to an embodiment of the present disclosure. [Figure 4] 10 is a timing chart for explaining the operation when short noise is superimposed on the LOCKN signal 12. [Figure 5] 10 is a timing chart for explaining the operation when an error is detected in the case where the LOCKN signal 12 is set to H level for a period longer than the noise period. [Figure 6] 10 is a timing chart for explaining the operation when an error is detected when the LOCKN signal 12 is changed between H level and L level a predetermined number of times. DETAILED DESCRIPTION OF THE INVENTION

[0023] Next, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0024] A communications standard called V-by-One (registered trademark) is sometimes used when transmitting and receiving image data. V-by-One uses a clock-embedded method in which the transmitting side transmits a data signal and clock information as a pair of differential signal transmission data to the receiving side. When transmitting and receiving image data using this clock-embedded method, the receiving side extracts the clock signal and image data from the received transmission data by performing a CDR (clock data recovery) training process on the transmission data from the transmitting side. This process makes it difficult for skew to occur between the clock signal and image data with V-by-One, enabling high-speed image data transmission.

[0025] In V-by-One, when the receiving side completes the CDR training process and becomes able to extract a clock signal from the transmission data, the receiving side notifies the transmitting side using a LOCKN signal that communication has been established. Specifically, when the LOCKN signal is at a high level (hereinafter abbreviated as H level), it indicates that the clock signal cannot be extracted from the transmission data, that is, communication has not been established. On the other hand, when the LOCKN signal is at a low level (hereinafter abbreviated as L level), it indicates that the clock signal can be extracted from the transmission data, that is, communication has been established. Then, the transmitting side checks the logic of the LOCKN signal from the receiving side and, when it confirms that it is at L level, which indicates that communication has been established, it performs an operation of including image data in the transmission data and transmitting it to the receiving side.

[0026] However, if the logic of the LOCKN signal changes to a high level after communication between the transmitter and receiver is established, indicating that communication is no longer established, the transmitter will halt the transfer of image data and restart CDR processing. Because the LOCKN signal is a single-ended signal, it has low noise resistance. Therefore, if noise is superimposed on the LOCKN signal while the image data is being transmitted from the transmitter to the receiver, causing the LOCKN signal, which should be low, to go high, the transmitter will execute CDR training processing even though the CDR on the receiver is in a normal locked state. This results in the problem of image data transfer being interrupted even though it should not have been interrupted. Therefore, improved noise resistance is required to prevent image data transfer from being interrupted even when noise is superimposed on the LOCKN signal.

[0027] Before describing the configuration of the image transmission / reception system of this embodiment, a configuration of an image transmission / reception system to which the technology of the present disclosure is not applied will be described as a comparative example with reference to FIG.

[0028] 1, the image transmission / reception system of this comparative example is composed of an image transmission device 810 and an image reception device 820. The image transmission device 810 includes a VBO (V-by-One) transmission circuit 110 and a CRC (Cyclic Redundancy Check) adding unit 120. The image reception device 820 includes a VBO reception circuit 210 and a CRC error detection unit 220.

[0029] Such an image transmission / reception system is used, for example, to transmit and receive image data between an image capturing device or a scanner device and a signal processing unit, and between the signal processing unit and an image display device, etc.

[0030] The CRC adding unit 120 adds a CRC code, which is an error detection code, to image data to be transmitted to the image receiving device 820. Specifically, the CRC adding unit 120 adds the remainder obtained when dividing the image data by a preset generating polynomial as a CRC code to the image data.

[0031] The VBO transmission circuit 110 transmits transmission data 11, in which a clock signal is superimposed on image data, to the image reception device 820, and receives a LOCKN signal 12 from the image reception device 820. Here, when the logic state of the LOCKN signal 12 is H level, this indicates that the image reception device 820 has not completed CDR training processing and has not been able to extract a clock signal from the transmission data 11, i.e., communication has not been established (a link has not been established). When the logic state of the LOCKN signal 12 is L level, this indicates that the image reception device 820 has completed CDR training processing and has been able to extract a clock signal from the transmission data 11, i.e., communication has been established. Specifically, this LOCKN signal 12 is a lock signal that indicates the lock state of a CDR PLL (Phase Locked Loop) circuit mounted in the VBO reception circuit 210.

[0032] Therefore, when the input LOCKN signal 12 changes from an H level, which is a logical state indicating that the link is not established, to an L level, which is a logical state indicating that the link is established, the VBO transmission circuit 110 transmits transmission data 11, in which a clock signal is superimposed on image data, to the image receiving device 820.

[0033] The VBO receiving circuit 210 extracts a clock signal from the transmission data 11 transmitted from the image transmitting device 810, and uses the extracted clock signal to acquire image data from the transmission data 11. When the VBO receiving circuit 210 is in a state where it can extract the clock signal from the transmission data 11, it changes the LOCKN signal 12, which indicates whether communication has been established, from an H level, which is a logical state indicating that communication has not been established, to an L level, which is a logical state indicating that communication has been established.

[0034] The CRC error detection unit 220 detects errors in the image data using an error detection code added to the image data acquired by the VBO receiving circuit 210. Specifically, the CRC error detection unit 220 extracts the CRC code added to the image data received by the VBO receiving circuit 210 and checks whether the image data is corrupted by checking whether the extracted CRC code matches the remainder when the image data is divided by a preset generating polynomial. If the CRC error detection unit 220 detects an error in the received image data, it notifies the downstream circuit that there may be an error in the received image data by sending an error notification.

[0035] When the LOCKN signal 12 changes from H level to L level after starting transmission of the transmission data 11 to the image receiving device 820, the VBO transmission circuit 110 determines that CDR training has been completed in the image receiving device 820, and transmits image data with a clock signal superimposed thereon to the image receiving device 820 as the transmission data 11. Furthermore, when the LOCKN signal 12 changes from L level to H level while transmitting the transmission data 11 to the image receiving device 820, the VBO transmission circuit 110 determines that an unlocking of the CDR circuit has occurred in the image receiving device 820, and stops transmitting the transmission data 11. Then, the VBO transmission circuit 110 resumes the CDR training process.

[0036] Here, the LOCKN signal is a single-ended signal, and therefore has lower noise resistance than the transmission data 11, which is a differential signal. Therefore, if some kind of noise occurs between the image transmitting device 810 and the image receiving device 820, there is a possibility that the logic state of the LOCKN signal 12 will momentarily change from L level to H level. If the VBO transmitting circuit 110 detects that the LOCKN signal 12 has become H level even for a moment, it determines that the CDR circuit in the image receiving device 820 has lost lock, and stops transmitting the transmission data 11.

[0037] [One embodiment of the technology of the present disclosure]

[0038] Therefore, in the image transmission / reception system of this embodiment, the following configuration is adopted to improve noise resistance compared to when the LOCKN signal from the image receiving device is directly input to the transmission circuit of the image transmitting device.

[0039] The configuration of an image transmission / reception system according to an embodiment of the present disclosure is shown in Fig. 2. In Fig. 2, the same components as those shown in Fig. 1 are denoted by the same reference numerals, and the description thereof will be omitted.

[0040] The image transmitting and receiving system of this embodiment is made up of an image transmitting device 10 and an image receiving device 20, as shown in FIG.

[0041] The image transmitting device 10 includes a VBO transmitting circuit 110, a CRC adding unit 120, and a LOCKN signal masking unit 130. The image receiving device 20 includes a VBO receiving circuit 210, a CRC error detecting unit 220, and a LOCKN signal transmission control unit 230.

[0042] The image transmitting device 10 has a configuration in which a LOCKN signal masking unit 130 is added to the image transmitting device 810 shown in Fig. 1. The image receiving device 20 has a configuration in which a LOCKN signal transmission control unit 230 is added to the image receiving device 820 shown in Fig. 1.

[0043] The VBO transmission circuit 110 in this embodiment transmits transmission data 11, in which a clock signal is superimposed on image data, to the image receiving device 20. The VBO transmission circuit 110 also receives the LOCKN signal 12 from the image receiving device 20 as a transmission-side LOCKN signal 21 via a LOCKN signal masking unit 130. The VBO transmission circuit 110 transmits the transmission data 11, in which a clock signal is superimposed on image data, to the image receiving device 20 when the input transmission-side LOCKN signal 21 changes from an H level, which is a logical state indicating that a link is not established, to an L level, which is a logical state indicating that a link is established.

[0044] The LOCKN signal masking unit 130 receives the LOCKN signal 12 from the image receiving device 20, and outputs an H-level transmitting side LOCKN signal 21 to the VBO transmitting circuit 110 only when the received LOCKN signal 12 changes in a preset manner, even if the received LOCKN signal 12 becomes L level and then changes to H level.

[0045] If the LOCKN signal 12 received from the image reception device 20 changes in a preset manner, the LOCKN signal masking unit 130 outputs an error notification to a downstream circuit.

[0046] Furthermore, when the CRC error detection unit 220 in this embodiment detects an error in the received image data, it sends an error notification to the subsequent circuit and outputs an H-level error signal 23 to the LOCKN signal transmission control unit 230.

[0047] When the receiving-side LOCKN signal 22 output from the VBO receiving circuit 210 changes from L level to H level, the LOCKN signal transmission control unit 230 outputs a signal that changes in a preset manner to the image transmitting device 10 as the LOCKN signal 12. Also, when the CRC error detection unit 220 detects an error in the image data and the error signal 23 becomes H level, the LOCKN signal transmission control unit 230 outputs a signal that changes in a preset manner to the image transmitting device 10 as the LOCKN signal 12.

[0048] In this embodiment, when the receiving-side LOCKN signal 22 output from the VBO receiving circuit 210 changes from L level to H level, the LOCKN signal transmission control unit 230 outputs a signal that remains at H level for a predetermined time, for example, 10 ms or more, as the LOCKN signal 12 to the image transmitting device 10.

[0049] The LOCKN signal masking unit 130 receives the LOCKN signal 12 from the image receiving device 20, and even if the received LOCKN signal 12 changes from an L level to an H level, outputs an H-level transmitting side LOCKN signal 21 to the VBO transmitting circuit 110 only if the H level continues for a preset time, for example, 10 ms or more.

[0050] Here, 10 ms is an example of a time longer than the time it is predicted that the logic state of LOCKN signal 12 will be affected by the generated noise. For example, if the time it takes for the logic state of LOCKN signal 12 to be affected by noise is on the order of several ms, then 10 ms is set as a time that is sufficiently longer than the time it is predicted that the logic state of LOCKN signal 12 will be affected by the generated noise, as described above. Furthermore, if it is predicted that the time it takes for the logic state of LOCKN signal 12 to be affected by noise is even longer, then it is sufficient to set a time of about several tens of ms as a time that is sufficiently longer than the time it is predicted that the logic state of LOCKN signal 12 will be affected by noise.

[0051] Alternatively, as another configuration, when the receiving-side LOCKN signal 22 output from the VBO receiving circuit 210 changes from L level to H level, the LOCKN signal transmission control unit 230 may output to the image transmitting device 10 a LOCKN signal 12 that changes between H level and L level a preset number of times and then becomes H level. In this case, the LOCKN signal masking unit 130 is set to output an H-level transmitting-side LOCKN signal 21 to the VBO transmitting circuit 110 when the LOCKN signal 12 changes between H level and L level a preset number of times or more and then becomes H level.

[0052] For example, when the receiving-side LOCKN signal 22 output from the VBO receiving circuit 210 changes from L level to H level, the LOCKN signal transmission control unit 230 may output to the image transmitting device 10 a LOCKN signal 12 that changes between H level and L level 100 times and then becomes H level. In this case, the LOCKN signal masking unit 130 is set to output an H-level transmitting-side LOCKN signal 21 to the VBO transmitting circuit 110 when the LOCKN signal 12 changes between H level and L level 100 times or more and then becomes H level.

[0053] In this embodiment, a configuration will be described in which the LOCKN signal masking unit 130 is provided in the image transmitting device 10 and the LOCKN signal transmission control unit 230 is provided in the image receiving device 20. However, if the LOCKN signal masking unit 130 operates to set the transmitting-side LOCKN signal 21 to H level when the H level state of the LOCKN signal 12 continues for a preset time or longer, noise resistance can be improved even with a configuration in which only the LOCKN signal masking unit 130 is provided in the image transmitting device 10. However, in such a configuration, errors in the image data detected by the CRC error detection unit 220 will not be transmitted to the image transmitting device 10 side.

[0054] Next, the operation of the image transmitting and receiving system of this embodiment will be described with reference to the timing charts of FIGS.

[0055] First, the operation at the time of initialization of the image transmission / reception system of this embodiment will be described with reference to the timing chart of FIG.

[0056] First, at time T1 in the initial state, the LOCKN signal masking unit 130 selects the LOCKN signal 12 received from the image receiving device 20 and outputs it as is as the transmitting-side LOCKN signal 21. In addition, the LOCKN signal transmission control unit 230 selects the receiving-side LOCKN signal 22 from the VBO receiving circuit 210 and outputs it as the LOCKN signal 12.

[0057] In this state, a CDR training process is started between the image transmitting device 10 and the image receiving device 20.

[0058] Then, when the CDR training process is completed at time T2, the VBO receiving circuit 210 sets the receiving-side LOCKN signal 22 to H level. Then, the LOCKN signal transmission control unit 230 sets the LOCKN signal 12 to H level. As a result, the LOCKN signal masking unit 130 sets the transmitting-side LOCKN signal 21 to H level, and the VBO transmitting circuit 110 recognizes that the CDR training process is completed.

[0059] After that, as the CDR training process is completed, the LOCKN signal masking unit 130 fixes the transmitting side LOCKN signal 21 to the L level at time T3. Then, image data is transmitted and received between the image transmitting device 10 and the image receiving device 20 via the transmission data 11.

[0060] The operation when short noise is superimposed on the LOCKN signal 12 in this state will be described with reference to the timing chart of FIG.

[0061] 4, it can be seen that external noise is superimposed on the LOCKN signal 12 at time T4. However, even if the LOCKN signal 12 momentarily goes high, the LOCKN signal masking unit 130 does not change the logic state of the transmitting LOCKN signal 21 unless the LOCKN signal 12 remains high for 10 ms or more. Therefore, at time T4, the logic state of the transmitting LOCKN signal 21 remains low, and the occurrence of noise is ignored. As a result, the VBO transmission circuit 110 continues to transmit image data to the image receiving device 20 via the transmission data 11 without being affected by the generated noise.

[0062] In this way, in the image transmission / reception system of this embodiment, noise resistance is improved compared to when the receiving side LOCKN signal 22 output from the VBO receiving circuit 210 of the image receiving device 20 is input directly to the VBO transmitting circuit 110.

[0063] Next, the operation when an error is detected in the CRC error detection unit 220 of the image receiving device 20 will be described with reference to the timing chart of FIG.

[0064] 5, at time T5, the CRC error detector 220 detects an error in the image data and sets the error signal 23 to H level. Therefore, the LOCKN signal transmission controller 230 determines that an error has occurred, sets the LOCKN signal 12 to H level at time T6, and keeps the H level state for 10 ms or more.

[0065] Then, because the LOCKN signal 12 has been at H level for 10 ms or more, at time T7 the LOCKN signal masking unit 130 switches from a fixed L level to a selected LOCKN signal 12. As a result, the LOCKN signal masking unit 130 changes the transmitting side LOCKN signal 21, which had been fixed at L level, to H level.

[0066] Therefore, the VBO transmission circuit 110 determines that the image receiving device 20 is no longer able to receive image data normally, stops transmitting image data, and starts CDR training processing. The VBO reception circuit 210 then changes the receiving-side LOCKN signal 22 to H level. The LOCKN signal transmission control unit 230 then selects the receiving-side LOCKN signal 22 and outputs it as the LOCKN signal 12.

[0067] When the CDR training process started as described above is completed, image data is transmitted and received between the image transmitting device 10 and the image receiving device 20 via the transmission data 11, as shown in FIG. 3.

[0068] In Fig. 5, when an error is detected, the LOCKN signal 12 is kept at H level for a period longer than the noise time. In contrast, the timing chart in Fig. 6 shows the operation when an error is detected, when the LOCKN signal 12 is changed between H level and L level a predetermined number of times, for example, 100 times or more, within a preset period.

[0069] The timing chart shown in Fig. 6 differs from the timing chart shown in Fig. 5 only in that, at time T5, error signal 23 becomes H level, causing LOCKN signal transmission control section 230 to change LOCKN signal 12 between H level and L level 100 or more times before setting it to H level. Other operations in Fig. 6 are the same as those in the timing chart of Fig. 5, and therefore description thereof will be omitted.

[0070] In the above-described embodiment, the LOCKN signal masking unit 130 and the LOCKN signal transmission control unit 230 are configured as hardware. However, the technology of the present disclosure is not limited to such a configuration. The LOCKN signal masking unit 130 and the LOCKN signal transmission control unit 230 may each be configured as a processor such as a CPU, and the operations of the LOCKN signal masking unit 130 and the LOCKN signal transmission control unit 230 may be realized by running a program stored in a storage device or the like on the processor.

[0071] In each of the above embodiments, the term "processor" refers to a processor in a broad sense, and includes general-purpose processors (e.g., CPU: Central Processing Unit, etc.) and dedicated processors (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.).

[0072] Furthermore, the operations of the processor in each of the above embodiments may be performed not only by a single processor but also by multiple processors located at physically separate locations working together. Furthermore, the order of the operations of the processor is not limited to the order described in each of the above embodiments and may be changed as appropriate.

[0073] In this embodiment, the term "system" includes both a system made up of multiple devices and a system made up of a single device.

[0074] The techniques of this disclosure are also applicable to programs and program products.

[0075] [Note] (((1))) a transmitting circuit that transmits transmission data, in which a clock signal is superimposed on image data, to an image receiving device when the input lock signal changes from a first logic state, which indicates that communication is not established, to a second logic state, which indicates that communication is established; a lock signal masking unit that receives the lock signal from the image receiving device, and outputs the lock signal of the first logic state to the transmitting circuit only if the first logic state continues for a predetermined time or longer, even if the received lock signal changes to the first logic state after being in the second logic state; An image transmitting device comprising: (((2))) The lock signal masking unit outputs a lock signal of the first logic state to the transmission circuit when the period during which the lock signal is in the first logic state continues for a time longer than a time during which the logic state of the lock signal is predicted to be affected by generated noise. The image transmitting device according to (((1))). (((3))) an image receiving device comprising: a receiving circuit that extracts a clock signal from transmission data transmitted from an image transmitting device, acquires image data from the transmission data using the extracted clock signal, and when the clock signal can be extracted from the transmission data, changes a lock signal that indicates whether communication is established or not from a first logic state that indicates that communication is not established to a second logic state that indicates that communication is established; and a lock signal transmission control unit that, when the lock signal output from the receiving circuit changes from the second logic state to the first logic state, outputs a signal that changes in a predetermined manner as a lock signal to the image transmitting device; an image transmitting device including: a transmitting circuit that transmits transmission data, in which a clock signal is superimposed on image data, to the image receiving device when an input lock signal changes from the first logic state to the second logic state; and a lock signal masking unit that receives the lock signal from the image receiving device and outputs a lock signal of the first logic state to the transmitting circuit when the received lock signal changes in a preset manner; An image transmission and reception system having the same. (((4))) the lock signal transmission control unit, when the lock signal output from the receiving circuit changes from the second logic state to the first logic state, outputs to the image transmitting device a lock signal in which the first logic state continues for a predetermined time or longer; the lock signal masking unit outputs the lock signal of the first logic state to the transmission circuit when the period during which the lock signal is in the first logic state continues for a preset time or longer. The image transmission / reception system according to (((3))). (((5))) and when the lock signal output from the receiving circuit changes from the second logic state to the first logic state and the period of time in the first logic state continues for a period longer than a period of time that is predicted to be affected by generated noise, the lock signal transmission control unit outputs to the image transmitting device a lock signal in which the first logic state continues for a predetermined period of time or longer. The image transmission / reception system according to (((4))). (((6))) when the lock signal output from the receiving circuit changes from the second logic state to the first logic state, the lock signal transmission control unit outputs to the image transmitting device a lock signal that changes between the first logic state and the second logic state a predetermined number of times and then becomes the first logic state; the lock signal masking unit outputs a lock signal of the first logic state to the transmission circuit when the lock signal changes between the first logic state and the second logic state a predetermined number of times or more and then becomes the first logic state. The image transmission / reception system according to (((3))). (((7))) the image transmitting device further includes an adding unit that adds an error detection code to image data to be transmitted to the image receiving device; the image receiving device further includes a detection unit that detects errors in the image data using an error detection code added to the image data acquired by the receiving circuit; the lock signal transmission control unit outputs a signal that changes in a preset manner to the image transmission device as a lock signal when the detection unit detects an error in the image data. The image transmission / reception system according to (((3))). (((8))) an image transmitting device including a transmitting circuit that transmits transmission data in which a clock signal is superimposed on image data to an image receiving device when an input lock signal changes from a first logic state indicating that communication is not established to a second logic state indicating that communication is established; outputting a lock signal of the first logic state to the transmitting circuit only when the first logic state continues for a predetermined time or more, even if the received lock signal changes to the first logic state after being in the second logic state; A program that causes a computer to execute the following.

[0076] According to the image transmitting device of (((1))), noise resistance can be improved compared to when the lock signal from the image receiving device is input directly to the transmitting circuit of the image transmitting device. According to the image transmitting device of (((2))), even if the logic state of the lock signal is affected by the occurrence of noise, it is possible to prevent the transmitting circuit from receiving an erroneous lock signal. According to the image transmission / reception system (((3))), noise resistance can be improved compared to when the lock signal from the image receiving device is input directly to the transmission circuit of the image transmitting device. According to the image transmission / reception system of (((4))), even if the logic state of the lock signal is affected by the occurrence of noise, it is possible to prevent the transmission circuit from receiving an erroneous lock signal. According to the image transmission / reception system of (((5))), even if the logic state of the lock signal is affected by the occurrence of noise, it is possible to prevent the transmission circuit from receiving an erroneous lock signal. According to the image transmission / reception system of (((6))), even if the logic state of the lock signal is affected by the occurrence of noise, it is possible to prevent the transmission circuit from receiving an erroneous lock signal. According to the image transmission / reception system of (((7))), it is possible to notify the image receiving device of the result of error detection in image data by means of a lock signal to the image transmitting device. According to the program (((8))), noise resistance can be improved compared to when the lock signal from the image receiving device is input directly to the transmission circuit of the image transmitting device. [Explanation of symbols]

[0077] 10 Image transmission device 11 Transmission Data 12 LOCKN signal 20 Image receiving device 21 Sender LOCKN signal 22 Sender LOCKN signal 23 Error Signal 110 VBO transmitter circuit 120 CRC assignment section 130 LOCKN signal mask section 210 VBO receiving circuit 220 CRC error detection unit 230 LOCKN signal transmission control unit 810 Image transmission device 820 Image receiving device

Claims

1. a transmitting circuit that transmits transmission data, in which a clock signal is superimposed on image data, to an image receiving device when the input lock signal changes from a first logic state, which indicates that communication is not established, to a second logic state, which indicates that communication is established; a lock signal masking unit that receives the lock signal from the image receiving device, and outputs the lock signal of the first logic state to the transmitting circuit only if the first logic state continues for a predetermined time or more, even if the received lock signal changes to the first logic state after being in the second logic state; An image transmitting device comprising:

2. The lock signal masking unit outputs a lock signal of the first logic state to the transmission circuit when the period during which the lock signal is in the first logic state continues for a time longer than a time during which the logic state of the lock signal is predicted to be affected by generated noise. The image transmitting device according to claim 1 .

3. an image receiving device comprising: a receiving circuit that extracts a clock signal from transmission data transmitted from an image transmitting device, acquires image data from the transmission data using the extracted clock signal, and, when the clock signal can be extracted from the transmission data, changes a lock signal, which indicates whether communication is established or not, from a first logic state, which indicates that communication is not established, to a second logic state, which indicates that communication is established; and a lock signal transmission control unit that, when the lock signal output from the receiving circuit changes from the second logic state to the first logic state, outputs a signal that changes in a predetermined manner as a lock signal to the image transmitting device; an image transmitting device including: a transmitting circuit that transmits transmission data, in which a clock signal is superimposed on image data, to the image receiving device when an input lock signal changes from the first logic state to the second logic state; and a lock signal masking unit that receives the lock signal from the image receiving device and outputs a lock signal of the first logic state to the transmitting circuit when the received lock signal changes in a preset manner; An image transmission and reception system having the same.

4. the lock signal transmission control unit, when the lock signal output from the receiving circuit changes from the second logic state to the first logic state, outputs to the image transmitting device a lock signal in which the first logic state continues for a predetermined time or more; the lock signal masking unit outputs the lock signal of the first logic state to the transmission circuit when the period during which the lock signal is in the first logic state continues for a preset time or longer.

4. The image transmitting and receiving system according to claim 3.

5. When the lock signal output from the receiving circuit changes from the second logic state to the first logic state, and the period of time in the first logic state continues for a period longer than a period of time predicted to be affected by generated noise, the lock signal transmission control unit outputs to the image transmitting device a lock signal in which the first logic state continues for a predetermined period of time or longer.

5. The image transmitting and receiving system according to claim 4.

6. when the lock signal output from the receiving circuit changes from the second logic state to the first logic state, the lock signal transmission control unit outputs to the image transmitting device a lock signal that changes between the first logic state and the second logic state a predetermined number of times and then becomes the first logic state; the lock signal masking unit outputs a lock signal of the first logic state to the transmission circuit when the lock signal changes between the first logic state and the second logic state a predetermined number of times or more and then becomes the first logic state.

4. The image transmitting and receiving system according to claim 3.

7. the image transmitting device further includes an adding unit that adds an error detection code to image data to be transmitted to the image receiving device; the image receiving device further includes a detection unit that detects errors in the image data using an error detection code added to the image data acquired by the receiving circuit; the lock signal transmission control unit outputs a signal that changes in a preset manner to the image transmission device as a lock signal when the detection unit detects an error in the image data.

4. The image transmitting and receiving system according to claim 3.

8. an image transmitting device including a transmitting circuit that transmits transmission data in which a clock signal is superimposed on image data to an image receiving device when an input lock signal changes from a first logic state indicating that communication is not established to a second logic state indicating that communication is established; and outputting a lock signal of the first logic state to the transmitting circuit only when the first logic state continues for a predetermined time or more, even if the received lock signal changes to the first logic state after being in the second logic state; A program that causes a computer to execute the following.

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