Intraoral imaging system

Abstract

An intraoral imaging system according to one embodiment comprises an imaging device and a processing device. The imaging device includes an imaging unit that acquires imaging data and a control unit. The control unit has a storage area that temporarily stores the imaging data. The control unit and the processing device automatically perform restoration processing after communication between the control unit and the processing device has been interrupted. The recovery processing includes: processing by the processing device that detects restoration of communication, establishes a plurality of virtual communication paths between the control unit and the processing device, and transmits a control signal for discarding residual data at the storage area to the control unit; and processing by the control unit that executes processing for discarding the residual data in response to reception of the control signal.

Description

Intraoral Imaging System

[0001] The present disclosure relates to intraoral imaging systems.

[0002] An intraoral imaging system is known that includes an imaging device having an imaging unit that is placed in the oral cavity and detects radiation transmitted through an object such as a tooth, and a processing device electrically connected to the imaging device. In the intraoral imaging system disclosed in Patent Document 1, a unit (processing device) configured by a computer receives an output signal from a sensor (imaging unit of the imaging device) placed in the patient's oral cavity and transmits a signal to the sensor to operate the CMOS detector of the sensor. In this way, in the above system, the processing device and the imaging device are configured to be able to communicate with each other.

[0003] JP 2011-255192 A

[0004] In the intraoral imaging system described above, communication between the imaging device and the processing device may be temporarily interrupted due to external electromagnetic interference or other factors. In such cases, data temporarily stored in the storage area of ​​the imaging device to be transmitted to the processing device may be corrupted depending on the timing of the communication interruption, making reliability unguaranteed. Therefore, to safely and properly resume data transfer between the imaging device and the processing device, it is necessary to reset (erase) the data temporarily stored in the storage area of ​​the imaging device. The simplest method for doing this is to have a user (e.g., a doctor) manually insert and remove a physical communication cable connecting the imaging device and the processing device. However, since the imaging device is placed in the patient's oral cavity during imaging, manually inserting and removing the communication cable connecting the imaging device and the processing device is time-consuming and burdensome for the user and also places a burden on the patient. For example, if the imaging device is removed from the patient's oral cavity to insert or remove the communication cable and then re-inserted in the patient's oral cavity, the need to reposition the imaging device places a burden on the patient. Therefore, to resume imaging without burdening the patient, an automatic recovery mechanism that does not require manual intervention is required. Furthermore, an automatic recovery mechanism may be required by medical device standards (for example, standards described in technical reports such as IEC TR 60601-4-2).

[0005] Another possible approach is to provide a device (e.g., a circuit controlled by a microcontroller) that mediates communication between the imaging device and the processing device. When a communication interruption between the imaging device and the processing device is detected, the device emulates the above-mentioned connection and disconnection of the communication cable, thereby eliminating the need for manual physical connection and disconnection of the communication cable. However, this approach may result in the device itself malfunctioning due to external electromagnetic interference. Furthermore, providing such an additional device may result in problems such as an increase in the complexity and size of the circuitry of the intraoral imaging system. Furthermore, the electromagnetic waves emitted by the entire intraoral imaging system may increase, potentially exceeding the specified values ​​for medical devices. While the above-described approach automates the recovery process for resuming data transfer after a communication interruption, it may also result in various secondary problems, as described above.

[0006] Therefore, one aspect of the present disclosure aims to provide an intraoral imaging system that can suppress the occurrence of secondary problems and can automatically perform processing to safely resume data transfer processing in the event of a communication interruption.

[0007] The present disclosure includes the following intraoral imaging systems [1] to

[12] .

[0008] [1] An intraoral imaging system comprising: an imaging device; and a processing device electrically connected to the imaging device, wherein the imaging device has an imaging unit that detects radiation that has passed through an object in the oral cavity to acquire imaging data; and a control unit configured to be able to communicate with the processing device and control the imaging unit, wherein the control unit has a memory area that temporarily stores the imaging data to be transmitted to the processing device, and the control unit and the processing device are configured to automatically execute a recovery process after communication between the control unit and the processing device is interrupted, wherein the recovery process includes: a process by the processing device detecting the recovery of the communication after the communication has been interrupted, and after the recovery of the communication is detected, establishing multiple virtual communication paths between the control unit and the processing device, and after the multiple communication paths are established, sending a control signal to the control unit to discard residual data remaining in the memory area; and a process by the control unit executing a process to discard the residual data in response to receiving the control signal.

[0009] The intraoral imaging system described in [1] above is configured to automatically execute a recovery process when communication between the control unit and the processing device is temporarily interrupted. Specifically, when communication between the control unit and the processing device is interrupted and then restored, multiple virtual communication paths are established between the control unit and the processing device, a control signal for discarding residual data remaining in the storage area of ​​the control unit is sent to the control unit, and processing for discarding the residual data remaining in the storage area is automatically executed based on the control signal. According to this configuration, after communication between the control unit and the processing device is restored, instead of immediately resuming the data transfer process from the control unit to the processing device that was being performed before the communication interruption, the storage area can be reset by discarding the residual data remaining in the storage area of ​​the control unit based on an explicit command (control signal) from the processing device. This allows the recovery process for safely resuming normal data transfer processing to be automatically executed without human intervention. Furthermore, the intraoral imaging system described above can realize a mechanism for automating the recovery process without the need for additional devices. As a result, the intraoral imaging system described above can prevent secondary problems (such as the increase in complexity and size of the intraoral imaging system that can arise from the addition of additional devices as described above, and the increase in electromagnetic waves emitted by the entire intraoral imaging system), and can automatically perform processing to safely resume data transfer processing in the event of a communication interruption.

[0010] [2] In the intraoral imaging system of [1], the control unit empties the memory area by transmitting the residual data to the processing device via the multiple communication paths in response to receiving the control signal.

[0011] According to the configuration [2] above, since it is not necessary to implement a function for discarding residual data in the control unit, the functional configuration of the control unit can be simplified.

[0012] [3] The intraoral imaging system of [2], wherein the processing device discards the residual data received from the control unit.

[0013] The residual data remaining in the storage area may be corrupted depending on the timing of the communication disconnection, etc. According to the configuration [3] above, by discarding such residual data whose reliability is not guaranteed, only data whose reliability is guaranteed can be used on the processing device side.

[0014] [4] The intraoral imaging system of [3], wherein the processing device further discards corresponding data that has been received from the control unit before the residual data and corresponds to the residual data.

[0015] When the residual data is discarded, the data corresponding to the residual data (i.e., the corresponding data received before the residual data) also becomes unnecessary. According to the configuration [4] above, such unnecessary corresponding data can be automatically and efficiently discarded together with the residual data.

[0016] [5] An intraoral imaging system according to any one of [2] to [4], wherein the processing device determines that the memory area is empty based on the length of a non-reception period during which no data is received from the control unit after the control signal is sent to the control unit.

[0017] According to the configuration [5] above, by taking into consideration the length of the non-reception period during which no data is transmitted from the control unit to the processing device, it is possible to easily and accurately determine whether the storage area has become empty.

[0018] [6] The intraoral imaging system of [5], wherein the control signal is a signal requesting that the residual data be transmitted to the processing device, the non-reception period is a period during which the control unit transmits a negative response indicating that there is no residual data to the processing device in response to each of the multiple control signals repeatedly transmitted from the processing device to the control unit, and the processing device determines that the memory area has become empty when the non-reception period exceeds a predetermined first period.

[0019] According to the configuration [6] above, when the non-reception period during which a negative response is sent from the control unit to the processing device exceeds a predetermined period (first period), it becomes possible to more reliably determine that the storage area has been emptied (i.e., it becomes possible to resume normal data transfer processing after the storage area has been reliably emptied).

[0020] [7] An intraoral imaging system according to any one of [2] to [4], wherein the control signal is a signal requesting the transmission of a predetermined unit data amount of data to the processing device, the control unit transmits the first data of the remaining data corresponding to the unit data amount to the processing device in response to receiving the control signal, and the processing device determines that the memory area has become empty when a predetermined second period has elapsed from the time when the first control signal was transmitted to the control device.

[0021] According to the configuration [7] above, it is possible to easily and accurately determine whether the memory area has become empty based on the time elapsed from the time when the first of multiple control signals sent from the processing device to the control device until all of the remaining data in the control device is transferred to the processing device.

[0022] [8] The intraoral imaging system of [7], wherein the second period is set to a period longer than the period required to transmit the residual data corresponding to the maximum amount of data that may remain in the storage area to the processing device.

[0023] According to the configuration [8] above, by setting the second period to a period longer than the longest period that may be required to empty the storage area, it is possible to more reliably determine that the storage area has been emptied (i.e., to resume normal data transfer processing after the storage area has been reliably emptied).

[0024] [9] An intraoral imaging system according to any one of [1] to [8], wherein when the control unit detects a disconnection of communication between the control unit and the processing device, the control unit prohibits the input of newly acquired imaging data by the imaging unit into the memory area until the memory area becomes empty.

[0025] According to the configuration [9] above, the storage area can be emptied reliably and safely by prohibiting newly acquired imaging data from being input into the storage area while the process of emptying the storage area is being executed.

[0026]

[10] An intraoral imaging system according to any one of [1] to [9], wherein the imaging device operates using power supplied from the processing device even after communication between the control unit and the processing device is disconnected.

[0027] According to the configuration

[10] above, there is no need for an external power supply using a battery or AC adapter to operate the imaging device, so the above-mentioned recovery process can be automated and the intraoral imaging system can be made smaller.

[0028]

[11] The intraoral imaging system according to any one of [1] to

[10] , wherein the control unit is communicably connected to the processing device via USB communication.

[0029] According to the configuration

[11] , data communication between the control unit and the processing device and power supply to the imaging device can be suitably performed via USB communication. Furthermore, if a temporary disconnection of USB communication occurs, the above-mentioned mechanism can automatically execute processing to safely resume data transfer processing.

[0030]

[12] An intraoral imaging system according to any one of [1] to

[11] , wherein the memory area temporarily stores the imaging data to be transmitted to the processing device on a first-in, first-out basis.

[0031] If the storage area is a first-in, first-out (FIFO) storage area, it is not possible to transfer the next data without skipping the data remaining in the storage area (i.e., potentially corrupted data) when communication is interrupted. The intraoral imaging system described above can employ the FIFO storage area because the recovery process described above is automatically performed before resuming normal data transfer. Furthermore, employing the FIFO storage area as a storage area readout method simplifies the process of accessing the storage area.

[0032] According to one aspect of the present disclosure, an intraoral imaging system can be provided that can suppress the occurrence of secondary problems and can automatically perform processing to safely resume data transfer processing in the event of a communication interruption.

[0033] FIG. 1 is a configuration diagram of an intraoral imaging system according to an embodiment. FIG. 2 is a cross-sectional view of an imaging unit shown in FIG. 1. FIG. 3 is a diagram illustrating an example of a functional configuration of the intraoral imaging system. FIG. 4 is a diagram illustrating an example of a hardware configuration of a processing device. FIG. 5 is a sequence diagram illustrating an example of an operation of the intraoral imaging system. FIG. 6 is a sequence diagram illustrating an example of a recovery process after communication is interrupted in the intraoral imaging system.

[0034] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the following description, the same or equivalent elements will be designated by the same reference numerals, and redundant description will be omitted.

[0035] [Configuration of Intraoral Imaging System] As shown in Fig. 1 , the intraoral imaging system 100 includes an imaging device 1 and a processing device 10. The imaging device 1 is placed in the oral cavity and detects radiation (e.g., X-rays) that has passed through an object such as a tooth. The imaging device 1 is electrically connected to the processing device 10 via a cable 9 provided in the imaging device 1. The imaging device 1 and the processing device 10 transmit and receive signals (i.e., communicate) via the cable 9. In the intraoral imaging system 100, when the imaging device 1 detects radiation that has passed through the object, an electrical signal (imaging data) generated thereby is transmitted from the imaging device 1 to the processing device 10, and an image of the object (radiographic image) is generated by the processing device 10 based on the electrical signal.

[0036] 2 , the imaging device 1 includes a wiring board 2, an image sensor 3, a fiber optical plate (FOP) 4, a scintillator 5, a control circuit 6, a communication module 7, a case 8, and a cable 9. The image sensor 3 is mounted on one main surface of the wiring board 2. The image sensor 3 is, for example, a solid-state imaging element such as a CMOS image sensor. The FOP 4 is disposed on the image sensor 3. The scintillator 5 is disposed on the FOP 4.

[0037] The control circuit 6 and the communication module 7 are mounted on the other main surface of the wiring board 2. The control circuit 6 is configured with an integrated circuit such as an FPGA (field-programmable gate), an ASIC (application specific integrated circuit), a CPLD (complex programmable logic device), or a CPU (central processing unit). The control circuit 6 performs various controls in the imaging device 1. The communication module 7 communicates with the processing device 10 in accordance with instructions from the control circuit 6. The communication module 7 receives various data transmitted from the processing device 10. The communication module 7 is an integrated circuit such as a USB (universal serial bus) controller. As an example, the communication module 7 is a USB controller that communicates with the processing device 10 in accordance with the USB standard.

[0038] The case 8 houses the wiring board 2, the image sensor 3, the FOP 4, the scintillator 5, the control circuit 6, and the communication module 7. Of the walls of the case 8, a wall 8a along the scintillator 5 is the wall onto which radiation is intended to be incident. An end of a cable 9 that passes through a wall of the case 8 opposite to the wall 8a is electrically connected to the wiring board 2.

[0039] The cable 9 is a wired cable, such as a USB (Universal Serial Bus) cable. The imaging device 1 is powered by the processing device 10 via USB bus power, for example. That is, the imaging device 1 operates using power supplied from the processing device 10 via the USB cable (cable 9).

[0040] As shown in FIG. 3 , the imaging device 1 includes an imaging unit 20 and a control unit 30. The imaging unit 20 detects radiation transmitted through an object in the oral cavity and acquires imaging data. In this embodiment, the imaging unit 20 is configured to include the image sensor 3, FOP 4, and scintillator 5 described above. The control unit 30 is configured to be able to communicate with the processing device 10 and controls the imaging unit 20. In this embodiment, the control unit 30 is configured to include the control circuit 6 and communication module 7 described above. The control unit 30 communicates with the imaging unit 20, the processing device 10, and controls the imaging unit 20. The imaging unit 20 is electrically connected to the control unit 30 via wiring (not shown) within the case 8. The imaging unit 20 and the control unit 30 transmit and receive signals (i.e., communicate) via the wiring. The control unit 30 is configured to be able to communicate with the processing device 10 via a wire. Specifically, the control unit 30 is configured to be able to communicate with the processing device 10 via a cable 9 (see FIG. 1 ).

[0041] In the imaging device 1 configured as described above, when the case 8 is placed in the oral cavity and radiation that has passed through the object passes through the wall 8a of the case 8 and enters the scintillator 5, fluorescence corresponding to the intensity of the incident radiation is emitted in the scintillator 5. When the fluorescence is guided by the FOP 4 and enters the image sensor 3, an electrical signal corresponding to the intensity of the incident fluorescence is generated in the image sensor 3, and the electrical signal is transmitted to the processing device 10 via the cable 9.

[0042] As shown in FIG. 3 , the control unit 30 includes a programmable logic device (PLD) 31, a USB controller 32, and a memory 33. The USB controller 32 includes an endpoint 34 and a receive buffer 36. In this embodiment, the PLD 31 and the memory 33 are configured by a control circuit 6. Note that the function of the PLD 31 may be realized by a logic circuit such as an FPGA or an ASIC. The USB controller 32 is configured by a communication module 7. The memory 33 and the endpoint 34 function as a storage area M that temporarily stores image data to be transmitted to the processing device 10. The receive buffer 36 is a storage area prepared for receiving control signals (in this embodiment, a bulk-in request, which will be described later) and the like from the processing device 10. Note that the receive buffer 36 may be configured by multiple receive buffers (e.g., a bulk-in request receive buffer, a bulk-out request receive buffer, a control transfer transmit / receive buffer, etc.) according to the purpose.

[0043] The PLD 31 is connected to the imaging unit 20 (image sensor 3) so as to be able to input and output information. The PLD 31 has a function of dividing imaging data obtained by the imaging unit 20 into multiple packets and transferring each packet to the USB controller 32. Each packet is a predetermined unit data amount (for example, 512 bytes). Furthermore, for example, the PLD 31 controls the imaging process of the imaging unit 20 in response to a command (for example, an instruction to acquire imaging data) received from the processing device 10 via the USB controller 32.

[0044] The USB controller 32 is connected to the PLD 31 so as to be able to input and output information. The USB controller 32 is also configured to be able to communicate with the processing device 10 via USB communication. The USB controller 32 has the function of storing packets received from the PLD 31 in an endpoint 34, converting the packets stored in the endpoint 34 into a data format suitable for USB communication, and transferring the converted data to the processing device 10. In this embodiment, a bulk transfer method is used as the USB transfer method between the processing device 10 and the USB controller 32. In this case, the imaging data, which is a large amount and a fixed amount of data, can be transferred to the processing device 10 while maintaining the reliability of the imaging data.

[0045] The memory 33 is connected to the PLD 31 so as to be able to input and output information to and from the PLD 31. The memory 33 temporarily stores the imaging data input from the PLD 31, for example, by a first-in first-out (FIFO) method.

[0046] The endpoint 34 is a buffer area that temporarily stores, for example, by a FIFO method, imaging data to be transmitted to the processing device 10. The endpoint 34 includes a plurality of transmission buffers 35 (four transmission buffers 35 in this embodiment). Each transmission buffer 35 stores one piece of data corresponding to a unit data amount (i.e., the data for one packet described above).

[0047] An example of the operation of the imaging data transfer process within the imaging device 1 will be described. The imaging data acquired by the imaging unit 20 (image sensor 3) is sent to the PLD 31 of the control unit 30. The PLD 31 divides the received imaging data into multiple packets. If there is no free space in the endpoint 34 (i.e., if data is stored in all of the transmission buffers 35), the PLD 31 stores the packets in the memory 33. On the other hand, if there is free space in the endpoint 34 (i.e., if there is free space in any of the transmission buffers 35), the PLD 31 transmits the packet to be transmitted (if one or more packets are stored in the memory 33, the first packet stored in the memory 33) to the USB controller 32. The USB controller 32 stores the packet received from the PLD 31 in the endpoint 34 (free transmission buffer 35). Through the above process, the data (data divided into multiple packets) constituting the imaging data to be transmitted to the processing device 10 is stored in the multiple transmission buffers 35. In addition, any imaging data that does not fit into the endpoint 34 is temporarily stored in memory 33 until there is space in the endpoint 34, and when there is space in the endpoint 34, the data is automatically replenished (moved) to the endpoint 34 by the processing of the PLD 31 and USB controller 32 described above.

[0048] [Configuration of Processing Device] The processing device 10 is configured by a computer device such as a PC or a tablet terminal. As an example, the processing device 10 is configured by a computer 200 having the hardware configuration shown in FIG. 4. The computer 200 includes a processor 201, a memory 202, an auxiliary storage device 203, an input device 204, an output device 205, and a communication device 206. The processor 201 is, for example, a central processing unit (CPU). The memory 202 is, for example, a random access memory (RAM) and a read-only memory (ROM). The auxiliary storage device 203 is, for example, a semiconductor memory, a hard disk drive (HDD), a solid state drive (SSD), etc. The input device 204 is, for example, a keyboard, a mouse, a touch panel, etc. The output device 205 is, for example, a display, a speaker, etc. The communication device 206 is, for example, a network card, a wireless communication module, etc.

[0049] 3, the processing device 10 has an application 11 and a device driver 12. The application 11 and the device driver 12 are part of a program pre-stored in the auxiliary storage device 203. Various processes of the processing device 10, which will be described later, are realized by reading such programs into the memory 202 and executing them in the processor 201.

[0050] The application 11 is a program (application software) for executing processes such as issuing imaging instructions to the imaging device 1, acquiring imaging data from the imaging device 1, and displaying a radiographic image on the output device 205 (such as a display) based on the acquired imaging data. Generally, USB communication is classified into three layers: the top layer, the middle layer, and the physical layer, and the application 11 is software that operates on the top layer.

[0051] The device driver 12 is a program that executes the exchange of data (packets) via USB communication. In the above-described classification of USB communication, the device driver 12 is software that operates at an intermediate layer. The device driver 12 is a USB device driver (e.g., WinUSB) that is installed as a standard API (Application Program Interface) in an OS (Operating System) such as Windows (registered trademark). The application 11 executes imaging instructions, data transfer requests, and the like to the USB controller 32 (imaging device 1) via the device driver 12 by utilizing library functions (e.g., various functions such as WinUsb_ReadPipe, which will be described later) provided by the device driver 12.

[0052] [Data Transfer Processing] An example of processing for transferring imaging data (data constituting one captured image captured by the image sensor 3) from the USB controller 32 (imaging device 1) to the processing device 10 will be described with reference to FIG. 5 .

[0053] In step S1, the processing device 10 starts the data transfer process. As an example, the application 11 first establishes multiple virtual communication paths (pipes) for sending and receiving data between a buffer (a storage area used for data transfer) provided in the processing device 10 and a buffer (i.e., the endpoint 34 and the receiving buffer 36) of the imaging device 1, and instructs the device driver 12 to receive imaging data from the USB controller 32. For example, the application 11 performs the above instruction by executing the WinUsb_ReadPipe function provided by the device driver 12.

[0054] In step S2, the processing device 10 (device driver 12) transmits a data transfer request via USB communication to the USB controller 32. As an example, the device driver 12 transmits a transfer request (bulk-in request) for the first data stored in the endpoint 34 (the first packet of multiple packets stored in the multiple transmit buffers 35) to the USB controller 32. The bulk-in request is received by the receive buffer 36 of the USB controller 32.

[0055] In step S3, when the USB controller 32 receives the Bulk-in request and the data to be transferred to the processing device 10 is stored in the endpoint 34, the USB controller 32 transmits the first data (packet) stored in the endpoint 34 to the processing device 10. Furthermore, when the processing device 10 has successfully received the data corresponding to the Bulk-in request, the USB controller 32 transmits an acknowledgement (ACK) to the USB controller 32. Furthermore, when subsequent data exists in the memory 33, the first data (packet) of the subsequent data is transferred from the PLD 31 to the USB controller 32, and the transmission buffer 35 that has been emptied by the transmission of the data is automatically replenished. On the other hand, when the data to be transferred to the processing device 10 is not present in the endpoint 34, the USB controller 32 transmits a negative acknowledgement (NACK) to the processing device 10, indicating that there is no data to be transmitted.

[0056] In step S4, the processing device 10 (device driver 12) determines whether a response (data corresponding to the bulk-in request or a NACK) has been received normally from the USB controller 32. While the data transfer process is proceeding normally, the response of step S3 generally reaches the processing device 10, resulting in a "YES" determination in step S4. However, the data transfer process may be interrupted midway due to the application 11's circumstances. For example, the application 11 may instruct the device driver 12 to interrupt the data transfer (reception of data from the USB controller 32). Furthermore, data transfer between the processing device 10 and the USB controller 32 may be forcibly interrupted due to a communication interruption caused by external electromagnetic interference. In such a case, the response of step S3 does not reach the processing device 10, resulting in a "NO" determination in step S4. Note that external electromagnetic interference may be interference from the environment external to the intraoral imaging system 100 or from a device other than the intraoral imaging system 100. Examples of sources of interference include electrostatic discharge, RF radiated electromagnetic fields, lightning surges, transients / bursts, electrically induced interference by RF radiated electromagnetic fields, voltage dips, momentary power outages, and magnetic proximity.

[0057] If the determination result in step S4 is "YES", the processing device 10 (device driver 12) determines whether or not the desired amount of data has been obtained (step S5). For example, if the volume of data transmitted in one data transfer (data for one captured image) is a predetermined fixed value, the processing device 10 can determine whether or not the desired amount of data has been obtained by determining whether or not the total volume of the multiple data (packets) received up to that point has reached the fixed value.

[0058] If it is determined that the desired amount of data has not been obtained (step S5: NO), the processing device 10 executes the process of step S2 again and requests the USB controller 32 to transfer the next data (packet). On the other hand, if it is determined that the desired amount of data has been obtained (step S5: YES), the processing device 10 (application 11) determines that the desired amount of imaging data has been received successfully, and ends the transfer process.

[0059] If the determination result in step S4 is "NO," the processing device 10 executes error processing (step S6). As an example, the device driver 12 first notifies the application 11 of error information indicating that data communication with the USB controller 32 has ended before the processing related to the initial data transfer request (the request instructed by the application 11 in step S2) is completed. Subsequently, in response to receiving the error information, the application 11 ends the data transfer processing started in step S1 and inquires of the device driver 12 about the reason for the end of the data communication. For example, the application 11 executes the GetLastError function provided by the OS (Windows) to obtain information related to the last error that occurred (i.e., information indicating the reason for the end of the data communication).

[0060] In step S7, the processing device 10 (application 11) determines whether the reason for the termination of the data communication is a disconnection of USB communication between the processing device 10 and the USB controller 32. For example, the application 11 can make this determination based on whether information about the target device (i.e., information about the USB device of the imaging device 1 connected to the processing device 10 via the cable 9) is present in a list obtained by a device manager of the OS (Windows). Specifically, if the target device is not present in the list even though there is no physical disconnection of the cable 9, it is highly likely that USB communication between the processing device 10 and the USB controller 32 has been disconnected due to external electromagnetic interference or the like. Therefore, the application 11 can determine that USB communication with the USB controller 32 has been disconnected if the target device is not included in the list. Note that if the OS is Linux (registered trademark), the application 11 can make the same determination as above based on whether the target device is present in a list obtained by executing the lsusb command.

[0061] If it is determined that the reason for the termination of data communication between the processing device 10 and the USB controller 32 is not a disconnection of USB communication (i.e., a disconnection of USB communication has not occurred) (step S7: NO), it can be determined that the termination of the data communication (i.e., the interruption of processing of the initial data transfer request) was an intentional termination (e.g., a termination based on an instruction from the application 11 as described above). In this case, the termination of the data communication is a planned termination, so no problems resulting from the disconnection of USB communication have occurred. Therefore, in this case, the processing device 10 (application 11) terminates the series of processes without executing the recovery process (FIG. 6) described below.

[0062] On the other hand, if it is determined that the reason for the termination of data communication between the processing device 10 and the USB controller 32 is a disconnection of USB communication (i.e., a disconnection of USB communication has occurred) (step S7: YES), the disconnection of USB communication may have occurred due to unexpected electromagnetic interference or the like, as described above. In this case, depending on the timing of the USB communication disconnection, the residual data stored in the storage area M (e.g., part of the data being transferred) may have been corrupted. Therefore, it is preferable to start a new imaging process without using such unreliable residual data. However, if the data transfer process is resumed while residual data remains in the storage area M, as described above, the transfer starts from the first data in the endpoint 34, and the residual data is transmitted to the processing device 10 before the image data obtained by the new imaging process. If the residual data is used on the processing device 10, a correct radiographic image cannot be reconstructed on the processing device 10, which may result in an unexpected error. For these reasons, to reliably avoid the occurrence of the above-mentioned malfunctions after the data transfer process is resumed, the residual data remaining in the storage area M must be discarded (reset and erased). Therefore, in this embodiment, when a disconnection of the USB communication between the control unit 30 and the processing device 10 is detected (step S7: YES), the control unit 30 and the processing device 10 are configured to automatically execute a process (recovery process) for safely resuming the data transfer process. An example of the recovery process will be described with reference to FIG. 6 .

[0063] [Recovery Processing] In step S11, the processing device 10 (application 11) determines whether USB communication has been restored. For example, if the OS is Windows, the application 11 can make this determination by using several functions included in the Setup API and the WinUsb_QueryInterfaceSettings function and the WinUsb_QueryPipe function included in the WinUSB API. The application 11 repeatedly executes the determination processing of step S11 until it confirms that USB communication has been restored (i.e., until the determination result of step S11 becomes "YES").

[0064] When the processing device 10 detects that USB communication has been restored after communication between the USB controller 32 and the processing device 10 was disconnected (step S11: YES), it establishes multiple virtual communication paths (pipes) for sending and receiving data between the USB controller 32 and the processing device 10, and instructs the device driver 12 to receive data (i.e., residual data remaining in the memory area M) from the USB controller 32 (step S12).

[0065] Like step S1, step S12 is a process for starting data transfer processing from the USB controller 32 to the processing device 10, but its purpose is different from that of step S1. Specifically, step S1 is a process for starting normal data transfer processing (process for obtaining radiographic image data from the imaging device 1 to be displayed on the processing device 10). In contrast, step S12 is a process for starting preprocessing for safely resuming normal data transfer processing (i.e., a process for resetting data that may have been corrupted due to the disconnection of USB communication and whose reliability cannot be guaranteed). More specifically, step S12 is intended to empty (reset) memory area M by reading out residual data that was stored in memory area M at the time of the disconnection of USB communication (i.e., a series of data that was scheduled to be transmitted to the processing device 10 in the data transfer processing that was started before the USB disconnection). In other words, the processing device 10 (application 11) is configured to perform processing (in this embodiment, a discarding processing to be described later) on the residual data received from the USB controller 32 by the data transfer processing started by the processing of step S12, which is treated differently from the data received from the USB controller 32 by the normal data transfer processing.

[0066] The processes of steps S13 and S14 are the same as the processes of steps S2 and S3 described above. In step S13, the processing device 10 (device driver 12) transmits a data transfer request via USB communication to the USB controller 32. That is, the device driver 12 transmits a transfer request (bulk-in request) for the first data stored in the endpoint 34 (the first packet of multiple packets stored in the multiple transmit buffers 35) to the USB controller 32. The bulk-in request is received by the receive buffer 36 of the USB controller 32. The transfer request (bulk-in request) transmitted in step S13 functions as a control signal for discarding the residual data remaining in the storage area M.

[0067] In step S14, in response to receiving the bulk-in request (control signal), the control unit 30 executes processing to discard the residual data remaining in the storage area M. In this embodiment, if data to be transferred to the processing device 10 is stored in the endpoint 34, the USB controller 32 transmits the first data (packet) stored in the endpoint 34 to the processing device 10. If the processing device 10 has successfully received the data corresponding to the bulk-in request, the processing device 10 transmits an acknowledgement (ACK) to the USB controller 32. If subsequent data exists in the memory 33, the first data (packet) of the subsequent data is transferred from the PLD 31 to the USB controller 32, and the transmission buffer 35, which has been emptied by the transmission of the data, is automatically replenished. On the other hand, if data to be transferred to the processing device 10 does not exist in the endpoint 34, the USB controller 32 transmits a negative acknowledgement (NACK) to the processing device 10.

[0068] In step S15, the processing device 10 (device driver 12) determines whether data (packets) have been received from the USB controller 32. If data has been received (step S15: YES), the device driver 12 executes the process of step S13 again and requests the USB controller 32 to transfer the next data. On the other hand, if the device driver 12 receives a negative acknowledgement (NACK) indicating that there is no data (step S15: NO), the processing device 10 proceeds to the determination process of step S16.

[0069] In step S16, the processing device 10 (device driver 12) determines whether the endpoint 34 has become empty. As described above, one packet (data stored in one transmission buffer 35) is transferred each time a bulk-in request is executed. If there is remaining data in the memory 33, the remaining data is automatically stored in the empty transmission buffer 35. Therefore, in this embodiment, the determination that "the endpoint 34 has become empty" means that all of the data (residual data) stored in the storage area M (the endpoint 34 and the memory 33) at the time of disconnection of the USB communication has been transferred. Two examples of the determination process in step S16 will be described below. However, the determination method in step S16 is not limited to the following two examples.

[0070] (First Example) In step S16, the processing device 10 (device driver 12) may determine that the storage area M has become empty based on the length of a non-reception period during which no data is received from the USB controller 32 after the processing device 10 has transmitted a bulk-in request (step S13) to the USB controller 32. In this embodiment, the bulk-in request is a signal requesting transmission of residual data remaining in the endpoint 34 (i.e., the storage area M) to the processing device 10. The non-reception period is a period during which the USB controller 32 transmits a negative acknowledgement (NACK) indicating that there is no remaining data to the processing device 10 (device driver 12) in response to each of a plurality of bulk-in requests repeatedly transmitted from the processing device 10 to the USB controller 32. For example, the processing device 10 may determine that the endpoint 34 has become empty if the non-reception period exceeds a predetermined first period.

[0071] According to the first example, it is possible to easily and accurately determine whether the endpoint 34 has become empty by considering the length of the non-reception period during which no data is transmitted from the USB controller 32 to the processing device 10. Furthermore, in this embodiment, when the non-reception period during which a negative acknowledgement (NACK) is transmitted from the USB controller 32 to the processing device 10 exceeds a predetermined period (first period) (timeout), it is possible to more reliably determine that the storage area M has become empty (i.e., normal data transfer processing can be resumed after the storage area M has been reliably emptied).

[0072] (Second Example) In this embodiment, the bulk-in request is a signal requesting the transmission of data (packets) of a predetermined unit data amount (512 bytes in this embodiment) to the processing device 10. Furthermore, the USB controller 32 is configured to transmit, in response to receiving the bulk-in request, the first data (packet) of the residual data remaining in the storage area M, which corresponds to the unit data amount. If the data amount of the residual data is greater than the unit data amount, the first data includes a portion of the residual data. If the data amount of the residual data is equal to or less than the unit data amount, the first data includes the entire residual data. Therefore, in step S16, the processing device 10 (device driver 12) may determine that the storage area M has become empty if a predetermined second period has elapsed since the time when the first bulk-in request of the multiple bulk-in requests (i.e., the bulk-in requests transmitted in each of the multiple repeated executions of step S13) was transmitted to the USB controller 32 (i.e., the time when step S13 was first executed). For example, the second period is set to a period longer than the period (longest period) required to transmit the remaining data corresponding to the maximum amount of data that may remain in the memory area M (in this embodiment, data for one captured image) to the processing device 10. Note that the longest period can be calculated based on, for example, the amount of data for one captured image (the above-mentioned maximum amount) and the effective transfer speed of USB communication in the intraoral imaging system 100.

[0073] According to the second example, it is possible to easily and accurately determine whether the storage area M has become empty based on the time elapsed since the time the first bulk-in request was sent. Furthermore, in this embodiment, by setting the second period to a period longer than the longest period that may be required to empty the storage area M, it is possible to more reliably determine that the storage area M has become empty (i.e., to resuming normal data transfer processing after the storage area M has been reliably emptied).

[0074] If it is determined that the endpoint 34 is not empty (step S16: NO), the processing device 10 executes the process of step S13 again and requests the USB controller 32 to transfer the next data (packet). On the other hand, if it is determined that the endpoint 34 is empty (step S16: YES), the processing device 10 (application 11) completes the transfer request (bulk-in request) to the USB controller 32 and proceeds to the process of step S17.

[0075] In step S17, the processing device 10 (application 11) discards the residual data received from the USB controller 32. The processing device 10 (application 11) may also discard corresponding data that was received from the USB controller 32 before the residual data and corresponds to the residual data. The corresponding data is data that was received from the USB controller 32 before the USB communication was disconnected (i.e., while the response was being received successfully in step S4). For example, the corresponding data is data that, together with the residual data, constitutes the same captured image.

[0076] After the above recovery process (steps S11 to S17) is completed, the processing device 10 can safely resume normal data transfer by re-executing step S1 shown in Fig. 5. That is, even if the intraoral imaging system 100 is exposed to electromagnetic interference, the intraoral imaging system 100 can automatically return to its intended operation (e.g., normal data transfer).

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[0098] [009 ... According to the above configuration, after the communication between the USB controller 32 and the processing device 10 is restored, instead of immediately resuming the data transfer process from the USB controller 32 to the processing device 10 that was being performed before the communication was interrupted (i.e., the normal data transfer process similar to the data transfer process started in step S1), the storage area M can be reset by discarding the residual data remaining in the storage area M based on an explicit command (control signal) from the processing device 10. This allows the recovery process for safely resuming the normal data transfer process to be automatically executed without human intervention. Furthermore, the intraoral imaging system 100 can realize a mechanism for automating the recovery process without providing an additional device. As a result, the intraoral imaging system 100 can prevent secondary problems (such as the increase in complexity and size of the intraoral imaging system 100, which may occur due to the addition of additional devices as described above, and the increase in electromagnetic waves emitted by the entire intraoral imaging system 100), and can automatically execute a process (in this embodiment, the recovery process shown in Figure 6) to safely resume the data transfer process when communication between the USB controller 32 and the processing device 10 (device driver 12) is interrupted.

[0078] Furthermore, in response to receiving a control signal (in this embodiment, the Bulk-in request in step S13), the USB controller 32 empties the storage area M by transmitting the residual data remaining in the storage area M to the processing device 10 via the multiple pipes established in step S12. According to the above configuration, the control unit 30 does not need to be equipped with a function for discarding the residual data, and therefore the functional configuration of the control unit 30 can be simplified. More specifically, in this embodiment, residual data whose reliability is not guaranteed can be easily removed simply by having the USB controller 32 execute a normal data transfer operation for transferring the residual data to the processing device 10 based on an instruction from the processing device 10.

[0079] The processing device 10 also discards the residual data received from the USB controller 32 (step S17). As described above, the residual data may be corrupted depending on the timing of the communication disconnection, etc. According to the above configuration, by discarding the residual data whose reliability is not guaranteed, only data whose reliability is guaranteed can be used on the processing device 10 side.

[0080] The processing device 10 also discards the corresponding data that was received from the USB controller 32 before the residual data (step S17). When discarding the residual data, data corresponding to the residual data (i.e., the corresponding data that was received before the residual data) also becomes unnecessary. With the above configuration, such unnecessary corresponding data can be automatically and efficiently discarded together with the residual data.

[0081] Furthermore, the imaging device 1 (imaging unit 20 and control unit 30) continues to operate using power supplied from the processing device 10 even after communication between the USB controller 32 and the processing device 10 is disconnected. In this embodiment, even if USB communication for data transmission and reception between the USB controller 32 and the processing device 10 is disconnected, power supply (bus power) from the processing device 10 to the control unit 30 and the imaging unit 20 via the cable 9 continues. With the above configuration, an external power supply using a battery, an AC adapter, or the like is not required to operate the imaging device 1, which makes it possible to automate the above-described recovery process ( FIG. 6 ) and reduce the size of the intraoral imaging system 100.

[0082] Furthermore, the control unit 30 (USB controller 32) is communicably connected to the processing device 10 via USB communication. According to the above configuration, data communication between the control unit 30 and the processing device 10 and power supply to the imaging device 1 can be preferably performed via USB communication. Furthermore, if a temporary disconnection of USB communication occurs, the above-described mechanism can automatically execute processing to safely resume data transfer processing.

[0083] Furthermore, the endpoint 34 (memory area M) temporarily stores imaging data (packets) to be transmitted to the processing device 10 using a first-in, first-out method. If the endpoint 34 uses a FIFO method, data remaining in the endpoint 34 (i.e., potentially corrupted data) cannot be skipped and the next data cannot be transferred when communication is interrupted. The intraoral imaging system 100 can use the FIFO method because it automatically performs a process of discarding the residual data remaining in the memory area M (e.g., the recovery process shown in FIG. 6 ) before resuming normal data transfer. Furthermore, using the FIFO method as the read method for the endpoint 34 simplifies access processing to the endpoint 34.

[0084] [Modifications] Although several embodiments of the present disclosure have been described above, the present disclosure is not limited to the configurations shown in the above embodiments. The materials and shapes of each component are not limited to the specific materials and shapes described above, and various materials and shapes other than those described above can be used. Furthermore, some of the configurations or processing contents included in each of the above embodiments may be omitted or modified as appropriate, or may be combined in any manner.

[0085] For example, when the control unit 30 detects a disconnection of communication between the USB controller 32 and the processing device 10, it may prohibit the input of newly acquired image data by the imaging unit 20 (image sensor 3) into the storage area M until the storage area M is empty. If the amount of residual data (e.g., the number of packets to be discarded) remaining in the storage area M after the communication disconnection could be accurately determined, even if new image data were input to the storage area M after the communication disconnection, only the amount of data (number of packets) to be discarded would need to be discarded. However, in practice, it is difficult to accurately determine the amount of residual data. Therefore, by prohibiting the input of newly acquired image data by the imaging unit 20 into the storage area M while the process of emptying the storage area M (e.g., the recovery process of FIG. 6 ) is being executed as described above, the storage area M can be emptied reliably and safely. In other words, when residual data and newly input data are mixed, if the boundary between the residual data and the newly input data is not accurately determined, problems may occur, such as some of the residual data remaining or some of the newly input data not to be discarded being mistakenly discarded. However, the above configuration avoids such problems.

[0086] In the above embodiment, a data transfer request (in this embodiment, a bulk-in request) is used as a control signal for discarding the residual data remaining in the storage area M. However, the control signal is not limited to the data transfer request. For example, the control signal may be a command instructing the control unit 30 to discard (delete) the residual data stored in the storage area M. In this case, the control unit 30 may execute a process for internally discarding the residual data stored in the storage area M as a process for discarding the residual data remaining in the storage area M. However, as described above, this requires the control unit 30 to include additional control circuits, programs, etc. for executing the data discarding, which may result in an increase in the size of the control unit 30 or an increase in the amount of electromagnetic waves emitted from the control unit 30. Therefore, from the perspective of avoiding such problems, it is preferable to transfer the residual data from the control unit 30 to the processing device 10 and then delete the residual data on the processing device 10, as in the above embodiment.

[0087] In the above embodiment, the imaging device 1 operates using power supplied from the processing device 10. However, the imaging device 1 may operate using power supplied from another power source. In such a case, a situation may arise in which communication between the USB controller 32 and the processing device 10 is cut off while power supply to the imaging device 1 continues (i.e., a situation in which the storage area M needs to be emptied before normal data transfer processing is resumed).

[0088] In the above embodiment, the control unit 30 and the processing device 10 are connected via USB communication, but the control unit 30 and the processing device 10 may be connected via a communication method other than USB communication. Furthermore, a reading method other than the FIFO method may be adopted as the reading method for the endpoint 34. Furthermore, a transfer method other than the bulk transfer method may be used for data transfer between the control unit 30 (USB controller 32) and the processing device 10.

[0089] In the above embodiment, the imaging device 1 detects radiation (e.g., X-rays) that has passed through an object such as a tooth while being placed inside the oral cavity. However, this is not limiting. For example, only the imaging unit 20 of the imaging device 1 may detect radiation (e.g., X-rays) that has passed through an object such as a tooth while being placed inside the oral cavity. In this case, the control unit 30 may control the imaging unit 20 while being placed outside the oral cavity. For example, the imaging unit 20 and the control unit 30 may be housed in separate housings (cases) and configured to transmit and receive signals (i.e., communicate) via a cable (not shown).

[0090] 1...imaging device, 20...imaging section, 30...control section, 10...processing device, 100...intraoral imaging system, M...storage area

Claims

1. An intraoral imaging system comprising: an imaging device; and a processing device electrically connected to the imaging device, wherein the imaging device has an imaging section that detects radiation that has passed through an object in the oral cavity to obtain imaging data; and a control section configured to be able to communicate with the processing device and controlling the imaging section, wherein the control section has a memory area that temporarily stores the imaging data to be transmitted to the processing device, and the control section and the processing device are configured to automatically execute a recovery process after communication between the control section and the processing device is interrupted, wherein the recovery process includes: a process by the processing device detecting the recovery of communication after the communication has been interrupted, and after the recovery of communication is detected, establishing multiple virtual communication paths between the control section and the processing device, and after the multiple communication paths have been established, sending a control signal to the control section to discard residual data remaining in the memory area; and a process by the control section executing a process to discard the residual data in response to receiving the control signal.

2. The intraoral imaging system of claim 1, wherein the control unit empties the memory area by transmitting the residual data to the processing device via the multiple communication paths in response to receiving the control signal.

3. The intraoral imaging system of claim 2, wherein the processing device discards the residual data received from the control unit.

4. The intraoral imaging system of claim 3, wherein the processing device further discards corresponding data that has been received from the control unit before the residual data and corresponds to the residual data.

5. An intraoral imaging system as described in any one of claims 2 to 4, wherein the processing device determines that the memory area is empty based on the length of a non-reception period during which no data is received from the control unit after the control signal is sent to the control unit.

6. The intraoral imaging system of claim 5, wherein the control signal is a signal requesting that the residual data be transmitted to the processing device, the no-reception period is a period during which the control unit transmits a negative response indicating that there is no residual data to the processing device in response to each of the multiple control signals repeatedly transmitted from the processing device to the control unit, and the processing device determines that the memory area is empty when the no-reception period exceeds a predetermined first period.

7. An intraoral imaging system as described in any one of claims 2 to 4, wherein the control signal is a signal requesting the transmission of a predetermined unit data amount of data to the processing device, the control unit transmits the first data of the remaining data corresponding to the unit data amount to the processing device in response to receiving the control signal, and the processing device determines that the memory area has become empty when a predetermined second period has elapsed from the time when the first control signal was transmitted to the control device.

8. The intraoral imaging system of claim 7, wherein the second period is set to a period longer than the period required to transmit the remaining data corresponding to the maximum amount of data that may remain in the storage area to the processing device.

9. An intraoral imaging system as described in any one of claims 1 to 8, wherein, when the control unit detects a disconnection of communication between the control unit and the processing device, the control unit prohibits the input of newly acquired imaging data by the imaging unit into the memory area until the memory area becomes empty.

10. An intraoral imaging system as described in any one of claims 1 to 9, wherein the imaging device operates using power supplied from the processing device even after communication between the control unit and the processing device is disconnected.

11. An intraoral imaging system according to any one of claims 1 to 10, wherein the control unit is communicatively connected to the processing device via USB communication.

12. An intraoral imaging system according to any one of claims 1 to 11, wherein the memory area temporarily stores the imaging data to be transmitted to the processing device on a first-in, first-out basis.

Images