IMAGING SYSTEM, ENDOSCOPE, AND CONTROL DEVICE

An imaging system includes: an imaging unit configured to generate a video signal; a control device configured to control the imaging unit; a first signal line configured to transmit a predetermined power supply voltage to the imaging unit; and a second signal line configured to transmit the video signal to the 284 control device. The imaging unit includes an imaging element including a pixel portion configured to generate the video signal according to a light reception amount and output the generated video signal to the second signal line, and a first detector configured to detect a voltage value of a power supply voltage that has reached the imaging unit via the first signal line as a voltage value of a first power supply voltage and output the voltage value to the second signal line.

BACKGROUND

1. Technical Field

The present disclosure relates to an imaging system, an endoscope, and a control device that generate image data by imaging the inside of a subject.

2. Related Art

Hitherto, there is known a technology of driving an imaging element in an optimum state regardless of an individual difference between imaging elements or an individual difference between cables by adjusting a power supply voltage for driving the imaging element provided at a distal end portion of an insertion portion to be inserted into a subject to an appropriate value according to the imaging element in an endoscope (for example, see JP 6397603 B2). With this technology, an A/D conversion circuit provided inside the imaging element measures the power supply voltage supplied from a control device to the imaging element via a signal line, and outputs the power supply voltage measurement result to the control device. The control device compares the power supply voltage measurement result input from the imaging element via the signal line with an optimum value, and adjusts a value of the power supply voltage to be output to the imaging element in such a way that the value of the power supply voltage approaches the optimum value.

SUMMARY

In some embodiments, an imaging system includes: an imaging unit configured to generate a video signal by imaging a subject; a control device configured to control the imaging unit; a first signal line configured to transmit a predetermined power supply voltage to the imaging unit; and a second signal line configured to transmit the video signal to the284control device. The imaging unit includes an imaging element including a pixel portion configured to generate the video signal according to a light reception amount and output the generated video signal to the second signal line, and a first detector configured to detect a voltage value of a power supply voltage that has reached the imaging unit via the first signal line as a voltage value of a first power supply voltage and output the voltage value to the second signal line, and the control device includes: a power source configured to supply a voltage value of a second power supply voltage to the imaging element via the first signal line; a second detector configured to detect a current value in the first signal line; a third detector configured to detect the voltage value of the second power supply voltage supplied by the power source; a calculator configured to calculate a resistance value of the first signal line based on the voltage value of the first power supply voltage, the current value, and a voltage detection value of the second power supply voltage detected by the third detector; and a power source controller configured to adjust the voltage value of the second power supply voltage to be supplied to the imaging element by the power source based on the current value, the resistance value, and a voltage value of a target power supply voltage in the imaging element, and supply the adjusted second power supply voltage to the first signal line.

In some embodiments, an endoscope includes: an imaging unit configured to generate a video signal by imaging a subject; a connector that is connectable to a control device; a first signal line configured to transmit a predetermined power supply voltage to the imaging unit; and a second signal line configured to transmit the video signal to the control device. The imaging unit includes an imaging element including a pixel portion configured to generate the video signal according to a light reception amount and output the generated video signal to the second signal line, and a first detector configured to detect a voltage value of a power supply voltage that has reached the imaging unit via the first signal line as a voltage value of a first power supply voltage and output the voltage value to the second signal line, and the connector includes: a power source configured to supply a second power supply voltage to the imaging element via the first signal line; a second detector configured to detect a current value in the first signal line; a calculator configured to calculate a resistance value of the first signal line based on the voltage value of the first power supply voltage, the current value, and a voltage detection value of the second power supply voltage; and a power source controller configured to adjust the voltage value of the second power supply voltage to be supplied to the imaging element by the power source based on the current value, the resistance value, and a voltage value of a target power supply voltage which is an optimum value of the power supply voltage in the imaging element, and supply the adjusted second power supply voltage to the first signal line.

In some embodiments, provided is a control device electrically connectable to an imaging unit configured to generate a video signal by imaging a subject by using a first signal line configured to transmit a predetermined power supply voltage to the imaging unit and a second signal line configured to transmit the video signal. The control device includes: a power source configured to supply a second power supply voltage to the imaging unit via the first signal line; a second detector configured to detect a current value in the first signal line; a third detector configured to detect a voltage value of the second power supply voltage; a calculator configured to calculate a resistance value of the first signal line based on a voltage value of a first power supply voltage that has reached the imaging unit via the first signal line and that is detected in the imaging unit, the current value, and a voltage detection value of the second power supply voltage detected by the third detector; and a power source controller configured to adjust the voltage value of the second power supply voltage to be supplied to the imaging unit by the power source based on the current value, the resistance value, and a voltage value of a target power supply voltage which is an optimum value of the power supply voltage in the imaging unit, and supply the adjusted second power supply voltage to the first signal line.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an endoscope system including an imaging device will be described as a mode for carrying out the present disclosure (hereinafter, referred to as “embodiment”), but the present disclosure is not limited thereto, and for example, an in-vehicle camera, a surgical microscope, a machine vision camera, and a monitoring camera including an imaging device can also be applied. Further, the disclosure is not limited by these embodiments. Further, in the description of the drawings, the same reference signs denote the same parts. Furthermore, it should be noted that the drawings are schematic, and a relationship between a thickness and a width of each member, a ratio of each member, and the like are different from actual ones. Further, the drawings include portions having different dimensions and ratios.

First Embodiment

Configuration of Endoscope System

FIG.1is a diagram schematically illustrating an overall configuration of an endoscope system according to a first embodiment. An endoscope system1illustrated inFIG.1images the inside of a subject such as a patient by inserting an insertion portion of an endoscope into the subject, and displays a display image based on a video signal obtained by the imaging on a display device. A user such as a doctor observes the display image displayed on the display device. The endoscope system1includes an endoscope2, a light source device3, a display device4, and a control device5.

Configuration of Endoscope

First, a configuration of the endoscope2will be described.

The endoscope2generates a video signal (raw data) obtained by imaging the inside of a body of a subject, and outputs the generated video signal to the control device5. The endoscope2includes an insertion portion21, an operating unit22, and a universal cord23.

The insertion portion21is inserted into the subject. The insertion portion21has an elongated shape having flexibility. The insertion portion21includes a distal end portion24incorporating an imaging device100to be described later, a bendable bending portion25including a plurality of bending pieces, and an elongated flexible tube portion26connected to a proximal end side of the bending portion25and having flexibility.

The distal end portion24is implemented using glass fiber or the like. The distal end portion24includes a light guide (not illustrated) forming a light guide path for illumination light supplied from the light source device3, an illumination optical system provided at a distal end of the light guide, and the imaging device100to be described later.

The operating unit22includes a bending knob221that bends the bending portion25in a vertical direction and a horizontal direction, a treatment tool insertion portion222that inserts a treatment tool such as a biopsy forceps, a laser scalpel, or an inspection probe into a body cavity, and a plurality of switches223that are operation input units that input an operation instruction signal for a peripheral device such as an air supply unit, a water supply unit, or a gas supply unit in addition to the light source device3and the control device5or a pre-freeze signal that instructs the imaging device100to capture a still image. The treatment tool inserted from the treatment tool insertion portion222comes out from an aperture (not illustrated) via a treatment tool channel (not illustrated) of the distal end portion24.

The universal cord23incorporates at least a light guide and a cable assembly including one or more cables. The cable assembly is a signal line for transmitting and receiving signals between the endoscope2and the light source device3, and the control device5, and includes a signal line for transmitting and receiving a captured image (image data), a signal line for transmitting and receiving a timing signal for driving the imaging device100(a synchronization signal and a clock signal), a signal line for supplying power to the imaging device100, and the like. The universal cord23includes a connector27detachable from the light source device3. A coil-shaped coil cable27aextends in the connector27, and a connector28detachably attached to the control device5at an extending end of the coil cable27ais provided.

Configuration of Light Source Device

Next, a configuration of the light source device3will be described.

The light source device3supplies the illumination light for the endoscope2to irradiate the subject under the control of the control device5. The light source device3is implemented by using, for example, a halogen lamp, a laser diode (LD), a white light emitting diode (LED), and the like. The light source device3supplies the illumination light to the distal end portion24of the insertion portion21via the connector27, the universal cord23, and the insertion portion21. Here, the illumination light is either white light or special light (for example, narrow band imaging (NBI) or infrared light).

Configuration of Display Device

Next, a configuration of the display device4will be described.

The display device4displays the display image based on an imaging signal input from the control device5under the control of the control device5. The display device4is implemented by using a display panel such as organic electro luminescence (EL) or liquid crystal.

Configuration of Control Device

Next, a configuration of the control device5will be described.

The control device5controls each unit of the endoscope system1. The control device5performs various types of image processing on the video signal input from the endoscope2and outputs the video signal to the display device4. In addition, the control device5controls the light source device3to supply the illumination light to the endoscope2.

Main Part of Endoscope System

Next, a configuration of main parts of the endoscope2and the control device5described above will be described.FIG.2is a block diagram illustrating a functional configuration of main parts of the endoscope2and the control device5in the endoscope system1.

Main Part of Endoscope

First, a functional configuration of the main part of the endoscope2will be described.

The endoscope2includes the imaging device100, a transmission cable200incorporated in the universal cord23, and the connector28.

First, the imaging device100will be described.

The imaging device100is arranged at the distal end portion24of the endoscope2, generates the video signal (raw data) by imaging the inside of the subject, and outputs the video signal to the control device5via the transmission cable200of the universal cord23and the connector28. The imaging device100includes an optical system110and an imaging element120.

The optical system110condenses reflected light of the illumination light reflected by the subject to form a subject image on a light receiving surface of the imaging element120. The optical system110is implemented by using one or more lenses and the like.

The imaging element120receives the subject image formed by the optical system110, generates a pixel signal by performing photoelectric conversion, and generates a digital video signal (raw data) by performing A/D conversion processing, signal processing, and the like on the pixel signal. Then, the imaging element120outputs the video signal to the connector28via the transmission cable200. The imaging element120is implemented by using an image sensor such as a complementary metal oxide semiconductor (CMOS) image sensor or a charge coupled device (CCD) image sensor. The imaging element120includes a pixel portion121, an A/D converter122, a signal processor123, a memory124, and an imaging controller125.

The pixel portion121includes a plurality of pixels arranged in a two-dimensional matrix. The pixel portion121is implemented by using a photoelectric conversion element (photodiode) or the like. The pixel portion121outputs a pixel signal of each pixel to the A/D converter122under the control of the imaging controller125. Furthermore, the pixel portion121is driven according to a power supply voltage input from the control device5via the transmission cable200.

Under the control of the imaging controller125, the A/D converter122performs A/D conversion processing on the pixel signal input from the pixel portion121based on a reference voltage Vreftransmitted from a control unit57of the control device5via the transmission cable200to be described later, and outputs the pixel signal to the signal processor123. The reference voltage Vrefcan also be generated inside the imaging element120based on any of power supply voltages VDD1 to VDD3. Furthermore, under the control of the imaging controller125, the A/D converter122performs A/D conversion on a voltage value of a first power supply voltage that has reached the imaging element120via the transmission cable200and is to be transmitted to the control unit57of the control device5to be described later as being detected in the imaging element120(hereinafter, simply referred to as “reaching voltage value Vcis”), and outputs a result of the A/D conversion to the signal processor123. Specifically, under the control of the imaging controller125, the A/D converter122outputs a result of performing A/D conversion on the reaching voltage value Vcisto the signal processor123in a current consumption fluctuation period between a blanking period of the imaging element120and a pixel reading period. The A/D converter122is electrically connected to each of a signal line201, a signal line202, and a signal line203of the transmission cable200described later. The A/D converter122is implemented by using an A/D conversion circuit or the like.

Under the control of the imaging controller125, the signal processor123performs various types of signal processing on the digital pixel signal input from the A/D converter122to generate the digital video signal, and outputs the video signal to the transmission cable200. Here, the various types of signal processing include noise reduction processing, amplification processing, and the like. In addition, the signal processor123outputs the reaching voltage value Vcisinput from the A/D converter122to the transmission cable200under the control of the imaging controller125. The signal processor123is implemented using a noise reduction circuit, an output amplifier circuit, and the like.

The memory124is implemented by using a read only memory (ROM), a random access memory (RAM), or the like, and records various types of information regarding the imaging element120. The memory124records various programs to be executed by the imaging element120, data being processed, identification information for identifying the imaging element120, performance information (a drive voltage and a drive current) of the imaging element120, defective pixel information such as a black defect and white defect in the pixel portion121, and the like.

The imaging controller125controls operation of each unit included in the imaging element120according to a control signal input from the control device5via the transmission cable200. Here, the control signal includes, for example, a synchronization signal (a vertical synchronization signal or a horizontal synchronization signal), a clock signal, a mode signal for instructing the operation of the imaging element120, and the like. The imaging controller125outputs a pixel signal from each pixel of a predetermined read line in the pixel portion121to the A/D converter122according to the control signal input from the control device5via the transmission cable200. The imaging controller125includes a timing generator (TG), a vertical scanning circuit, a horizontal scanning circuit, and the like.

Next, the transmission cable200will be described.

The transmission cable200is implemented by using a plurality of signal lines. Specifically, the transmission cable200includes at least the signal line201, the signal line202, the signal line203, a signal line204, a signal line205, and a signal line206. The signal line201transmits the power supply voltage VDD1 input from the control device5to the imaging element120. The signal line202transmits the power supply voltage VDD2 input from the control device5to the imaging element120. The signal line203transmits the power supply voltage VDD3 input from the control device5to the imaging element120. The signal line204transmits, to the imaging element120, the control signal input from the control device5, and transmits, to the control device5, the reaching voltage values of the power supply voltages VDD1 to VDD3 that are input from the imaging element120and have reached the imaging element120. The signal line205transmits a video signal Voutinput from the imaging element120to the connector28. The signal line206transmits the reference voltage Vrefinput from the control unit57of the control device5to the imaging element120.

The connector28is detachably connected to the control device5. The connector28includes at least an analog front end unit281(hereinafter, referred to as an “AFE unit281”) and a signal processor282.

The AFE unit281performs processing such as noise removal on the video signal Vouttransmitted from the signal line205or the reaching voltage value Vcis, and outputs the video signal Voutor the reaching voltage value Vcisto the signal processor282.

The signal processor282performs predetermined signal processing, such as format conversion processing, gain-up processing, or D/A conversion processing, on the video signal Voutor the reaching voltage value Vcisinput from the AFE unit281, and outputs the video signal Voutor the reaching voltage value Vcisto the control device5.

Main Part of Control Device

Next, the main part of the control device5will be described.

The control device5includes a power source51, a current detector52, a voltage detector53, a power source controller54, an image processor55, a memory56, and the control unit57.

Under the control of the power source controller54, the power source51adjusts a power supply voltage input from an external power supply to the plurality of power supply voltages VDD1 to VDD3, and outputs the power supply voltages VDD1 to VDD3 to the transmission cable200(the signal lines201to203). The power source51is implemented by using, for example, a smoothing circuit, a rectifier circuit, a transformer, or the like. Hereinafter, the voltage value of the power supply voltage VDD1 supplied from the power source51to the signal line201will be described as a voltage value Vout1of a second power supply voltage. Hereinafter, the power supply voltage VDD1 output from the power source51to the signal line201will be described. Although the voltage value of the power supply voltage VDD2 and the voltage value of the power supply voltage VDD3 output to the signal line202and the signal line203, respectively, are described as a voltage value Vout2of the second power supply voltage and a voltage value Vout3of the second power supply voltage, respectively, in a case where any one of the voltage value Vout1the voltage value Vout2, and the voltage value Vout3of the second power supply voltage is referred to, it is simply described as the voltage value Vout.

The current detector52is electrically connected to each of the signal lines201to203. The current detector52detects a current value of each of the signal lines201to203and outputs the detection result to the control unit57. The current detector52is implemented by using an ammeter or the like.

The voltage detector53is electrically connected to each of the signal lines201to203. The voltage detector53detects the voltage value Voutof each of the signal lines201to203and outputs the detection result to the control unit57as the voltage detection value Vmon. The voltage detector53is implemented by using a voltmeter or the like.

Under the control of the control unit57, the power source controller54adjusts the voltage values of the plurality of power supply voltages output from the power source51to predetermined voltage values and outputs the voltage values to the power source51. The power source controller54is implemented by using a memory and hardware such as a central processing unit (CPU).

The image processor55performs various types of image processing on the video signal input from the signal processor282of the connector28, and outputs the video signal to the display device4. Here, the various types of image processing include demosaic processing, white balance adjustment processing, γcorrection processing, and the like. The image processor55is implemented by using a memory and hardware such as a field programmable gate array (FPGA) or a graphics processing unit (GPU).

The memory56records various types of information regarding the control device5, image data corresponding to the video signal, data being processed, and the like. The memory56further includes a program recording unit581that records various programs to be executed by the control device5. The memory56is implemented by using a volatile memory, a nonvolatile memory, or the like. The memory56may be implemented by using a memory card or the like that is detachable from the outside.

The control unit57controls each unit included in the endoscope system1. The control unit57is implemented by using a memory and hardware such as a central processing unit (CPU) or an FPGA. The control unit57includes a calculator571.

The calculator571calculates a resistance value R of the signal line201of the transmission cable200based on the reaching voltage value Vcisinput from the imaging element120, a current value I input from the current detector52, and the voltage detection value Vmon. In addition, the calculator571calculates the resistance value R of the signal line201of the transmission cable200a plurality of times in a predetermined period, and calculates an average value of the plurality of calculation results as the resistance value R of the signal line201of the transmission cable200. Specifically, the calculator571calculates the resistance value R of the signal line201of the transmission cable200based on the reaching voltage value Vcisinput from the imaging element120and the current value I input from the current detector52for each blinking period of the imaging element120based on a vertical synchronization signal VDinput from the control unit57. Similarly to the signal line201, the calculator571calculates a resistance value of each of the signal line202and the signal line203of the transmission cable200, but a detailed description thereof is omitted in order to simplify the description.

Processing in Endoscope System

Next, processing executed by the endoscope system1will be described.FIG.3is a flowchart illustrating an outline of processing executed by the control device5.FIG.4is a timing chart illustrating a relationship between the reaching voltage value Vcis, the vertical synchronization signal VD, the current value I, and the resistance value R of the transmission cable200at the time of processing executed by the endoscope system1. InFIG.4, (a) from the top illustrates the reaching voltage value Vcis, (b) illustrates the vertical synchronization signal VD, (c) illustrates the current value I, and (d) illustrates the voltage value Voutof the power supply voltage supplied to the imaging element by the power source51. InFIG.4, the current value I and the resistance value R in the signal line201of the transmission cable200are described. However, since similar processing is executed in the other signal lines202and203, a detailed description is omitted.

As illustrated inFIG.3, first, under the control of the imaging controller125, the A/D converter122detects the power supply voltage VDD1 supplied from the control device5via the signal line201of the transmission cable200as the reaching voltage value Vcisthat has reached the imaging element120(Step S101). In this case, as illustrated inFIG.4, the A/D converter122adds an elapsed time (for example, times t1, t2, t3, and t4) elapsed from the vertical synchronization signal VDas time information and outputs the time information and the reaching voltage value Vcisto the signal processor123every time the reaching voltage value Vcis(P1, P2, P3, and P4) is detected at a predetermined interval under the control of the imaging controller125. At this time, under the control of the imaging controller125, the signal processor123outputs the time information and the reaching voltage value Vcisto the control device5via the signal line201of the transmission cable200every time the reaching voltage value Vcisand the time information are input from the A/D converter122.

Subsequently, the current detector52detects the current value I of the signal line201of the transmission cable200(Step S102). Specifically, as illustrated inFIG.4, the current detector52detects the current value I of the current flowing through the signal line201at predetermined intervals under the control of the control unit57, and outputs the detection result to the control unit57. In this case, every time the current value I (P11, P12, P13, and P14) is detected, the current detector52adds an elapsed time (for example, times t1, t2, t3, and t4) elapsed from the vertical synchronization signal VDas the time information and outputs the current value I and the time information to the control unit57.

Thereafter, the control unit57determines whether or not one imaging frame of the imaging element120has ended based on the vertical synchronization signal VDsupplied to the imaging element120(Step S103). In a case where the control unit57determines that one imaging frame of the imaging element120has ended (Step S103: Yes), the endoscope system1proceeds to Step S104to be described later. On the other hand, in a case where the control unit57determines that one imaging frame of the imaging element120has not ended (Step S103: No), the endoscope system1returns to Step S101described above.

Next, the calculator571calculates the resistance value of the signal line201of the transmission cable200based on the reaching voltage value Vcisinput from the imaging element120, the current value I input from the current detector52, and the voltage detection value Vmon(Step S104). Specifically, assuming that the resistance value of the signal line201is R, the reaching voltage value is Vcis, the current value flowing through the signal line201is I, and the voltage detection value of the power supply voltage supplied by the power source51and detected by the voltage detector53is Vmon, the resistance value R of the signal line201is calculated based on the following Equation (1).

In addition, the calculator571calculates the resistance value R of the signal line201based on the reaching voltage value Vcisand the current value I at the same time recorded in the memory56. In this case, the calculator571calculates the resistance value R of the signal line201a plurality of times for each same time based on the reaching voltage value Vcisand the current value I at the same time recorded in the memory56, and calculates the average value of the plurality of calculation results as the resistance value of the signal line201.

Thereafter, under the control of the control unit57, the power source controller54adjusts the power supply voltage to be supplied from the power source51to the imaging element120and outputs the adjusted power supply voltage (Step S105). Specifically, in a case where a voltage value of the power supply voltage VDD1, which is the second power supply voltage, is Vout, and a voltage value of a target power supply voltage, which is an optimum value of the power supply voltage in the imaging element120, is Vtarget, the power source controller54adjusts the power supply voltage to be supplied to the imaging element120by the power source51by using the following Equation (2) and outputs the adjusted power supply voltage.

In this case, as indicated by an arrow A1inFIG.4, the power source controller54outputs the voltage value Voutof the power supply voltage VDD1, which is the second power supply voltage adjusted in the previous frame of the imaging element120, in the next frame of the imaging element120based on the vertical synchronization signal VD.

Subsequently, in a case where an instruction signal for ending inspection of the subject is input (Step S106: Yes), the endoscope system1ends the processing. On the other hand, in a case where the instruction signal for ending the inspection of the subject is not input (Step S106: No), the endoscope system1returns to Step S101described above.

According to the first embodiment described above, the power source controller54adjusts the voltage value Voutof the power supply voltage VDD1 to be supplied from the power source51to the imaging element120based on the current value detected by the current detector52, the reaching voltage value Vciscalculated by the control unit57, the voltage value Vtargetof the target power supply voltage, and the voltage detection value Vmonof the second power supply voltage, and supplies the adjusted voltage value of the power supply voltage VDD1 to the signal line201of the transmission cable200. Therefore, it is possible to operate the imaging element120at an appropriate power supply voltage while preventing a diameter of the signal line201from being increased while maintaining a transmission rate. As a result, a diameter of a power supply line connecting the control device5and the imaging element120can be decreased, and an optimum power supply voltage can be supplied, so that heat generated by the power supply voltage can be minimized to suppress an influence on a body tissue.

Furthermore, according to the first embodiment, since the A/D converter122provided in the imaging element120detects the reaching voltage value Vcis, and it is not necessary to separately provide a detection circuit for detecting the voltage value in the imaging element120, it is possible to prevent an increase in size of the imaging element120.

In addition, according to the first embodiment, since the control unit57calculates the resistance value of the signal line201for each detection based on the time information at the time of detection of each of the reaching voltage value Vcisand the current value I, and the reaching voltage value Vcisand the current value I at the same time, it is possible to accurately calculate the resistance value R of the signal line201.

In addition, according to the first embodiment, since the time information at the time of the detection of the reaching voltage value Vcisby the A/D converter122based on the vertical synchronization signal VDis output to the signal line205of the transmission cable200, the control unit57can accurately calculate the resistance value R of the signal line201.

In addition, according to the first embodiment, since the control unit57calculates the resistance value of the signal line201of the transmission cable200a plurality of times in a predetermined period, and calculates the average value of the plurality of calculation results as the resistance value of the signal line201, it is possible to accurately calculate the resistance value R of the signal line201.

Furthermore, according to the first embodiment, the A/D converter122detects the reaching voltage value Vcisfor each blanking period of the imaging element120, and the control unit57calculates the resistance value R of the signal line201of the transmission cable200based on the reaching voltage value Vcisand the current value I detected by the current detector52for each blanking period. After the resistance value is once calculated, the optimum power supply voltage can be output following the current value detected based on Equation (2).

Second Embodiment

Next, a second embodiment will be described. An endoscope system according to the second embodiment is different from the endoscope2according to the first embodiment described above in terms of a configuration and a procedure to be executed. Hereinafter, the configuration of the endoscope system according to the second embodiment will be described, and then processing executed by the endoscope system will be described. Note that the same components as those of the endoscope system1according to the first embodiment described above are denoted by the same reference signs, and a detailed description thereof will be omitted.

Configuration of Endoscope System

FIG.5is a block diagram illustrating a functional configuration of main parts of an endoscope and a control device in the endoscope system according to the second embodiment. An endoscope system1A illustrated inFIG.5includes an endoscope2A and a control device5A instead of the endoscope2according to the first embodiment described above.

Configuration of Endoscope

As illustrated inFIG.5, the endoscope2A includes an imaging element120A instead of the imaging element120according to the above-described first embodiment in the endoscope2according to the above-described first embodiment. The imaging element120A includes an imaging controller125A, a constant current source126, and a switch127in addition to the configuration according to the first embodiment described above.

The constant current source126is electrically connected to each of signal lines201to203of a transmission cable200A. Under the control of the imaging controller125A, the constant current source126implements power supply voltages VDD1 to VDD3 supplied from the control device5A via the signal lines201to203of the transmission cable200A, and the constant current source126is implemented using a regulator or the like. Note that the constant current source126is grounded via a signal line207and the control device5A. The constant current source126can adjust a current value flowing through the signal lines201to203. Here, in a case where a current value at a timing when a resistance value is calculated is Imonand a current value flowing at a timing when a voltage is adjusted is I, the following relationship holds.

Furthermore, an output voltage Vouthas the following output due to an error α of the voltage detector or the AD converter of the imaging element.

Therefore, in a case where the current value of Imonis small, the influence of the error increases, so that the current value Imonat the timing of resistance calculation can be increased using the constant current source126to increase the accuracy of DC resistance value calculation.

One end of the switch127is electrically connected to each of the signal lines201to203of the transmission cable200A, and the other end is electrically connected to the constant current source126. The switch127electrically connects each of the signal lines201to203of the transmission cable200A and the constant current source126under the control of the imaging controller125A. The switch127is implemented by using a switch, a semiconductor switch, or the like.

The imaging controller125A controls the switch127based on a control signal input from a control unit57A of the control device5A via a signal line204of the transmission cable200A. Specifically, in a calculation period in which the control unit57A calculates a resistance value R of the signal line201of the transmission cable200A, the imaging controller125A stops operation of units other than an A/D converter122and a signal processor123among units included in the imaging element120A. Furthermore, the imaging controller125A drives the switch127under the control of the control unit57A. Specifically, in a case where a determination signal of a determination result indicating that the current value detected by the current detector52is equal to or less than a predetermined threshold is input from a determination portion572of the control unit57A to be described later, the imaging controller125A electrically connects the constant current source126and the signal line201to the switch127.

Configuration of Control Device

Next, a configuration of the control device5A will be described. The control device5A includes the control unit57A instead of the control unit57according to the first embodiment described above. The control unit57A further includes the determination portion572in addition to the configuration of the control unit57according to the above-described first embodiment.

The determination portion572determines whether or not the current value calculated by the calculator571is equal to or less than a predetermined threshold.

Processing in Endoscope System

Next, processing executed by the endoscope system1A will be described.FIG.6is a flowchart illustrating an outline of processing executed by the endoscope system1A.

As illustrated inFIG.6, first, in a calculation period in which the control unit57A calculates the resistance value R of the signal line201of the transmission cable200A, the imaging controller125A stops operation of units other than the A/D converter122and the signal processor123among the units included in the imaging element120A (Step S201).

In Step S204, the control unit57A determines whether or not the current value I of the current flowing through the signal line201of the transmission cable200A, detected by the current detector52is equal to or less than a predetermined threshold. In a case where the control unit57A determines that the current value I of the current flowing through the signal line201of the transmission cable200A, detected by the current detector52is equal to or less than the predetermined threshold (Step S204: Yes), the endoscope system1A proceeds to Step S205described later. On the other hand, in a case where the control unit57A determines that the current value I of the current flowing through the signal line201of the transmission cable200A, detected by the current detector52is not equal to or less than the predetermined threshold (Step S204: No), the endoscope system1A proceeds to Step S206described later.

In Step S205, the imaging controller125A electrically connects the constant current source126and the signal line201of the transmission cable200A to the switch127. After Step S205, the endoscope system1A proceeds to Step S206described later.

According to the second embodiment described above, in the calculation period in which the control unit57A calculates the resistance value R of the signal line201of the transmission cable200A, the imaging controller125A stops operation of units other than the A/D converter122and the signal processor123among the units included in the imaging element120A, so that the accurate resistance value R of the signal line201can be calculated.

In addition, according to the second embodiment, in a case where the control unit57A determines that the current value I of the current flowing through the signal line201of the transmission cable200A, detected by the current detector52is equal to or less than the predetermined threshold, the imaging controller125A electrically connects the constant current source126and the signal line201of the transmission cable200A to the switch127. Therefore, it is possible to increase the current value Imonat the timing of resistance calculation by using the current source to increase the accuracy of DC resistance value calculation. Furthermore, noise generated in the A/D converter122can be reduced, and variation in current consumption can be suppressed.

Third Embodiment

Next, a third embodiment will be described. An endoscope system according to the third embodiment is different from the endoscope system1according to the first embodiment described above in terms of a configuration. Hereinafter, a configuration of the endoscope system according to the third embodiment will be described. Note that the same components as those of the endoscope system1according to the first embodiment described above are denoted by the same reference signs, and a detailed description thereof will be omitted.

Functional Configuration of Main Part of Endoscope System

FIG.7is a block diagram illustrating a functional configuration of a main part of an endoscope and a control device in the endoscope system according to the third embodiment. An endoscope system1B illustrated inFIG.7includes an endoscope2B and a control device5B instead of the endoscope2and the control device5according to the first embodiment described above.

Configuration of Endoscope

First, a configuration of the endoscope2B will be described. The endoscope2B includes a connector28B  instead of the connector28according to the above-described first embodiment. The connector28B includes a power generation unit283, a current detector284, and a voltage detector285in addition to the configuration of the connector28according to the first embodiment described above.

Under the control of a connector controller286, the power generation unit283generates a plurality of power supply voltages (power supply voltages VDD1 to VDD3) from a power supply voltage input from a power source51of the control device5B, and outputs the generated power supply voltages to a transmission cable200(signal lines201to203). The power generation unit283is implemented by using, for example, a smoothing circuit, a rectifier circuit, a transformer, or the like.

The current detector284is electrically connected to each of the signal lines201to203. The current detector284detects a current value of each of the signal lines201to203and outputs the detection result to the connector controller286. The current detector284is implemented using an ammeter or the like.

The voltage detector285is electrically connected to each of the signal lines201to203. The voltage detector285detects a voltage value of each of the signal lines201to203and outputs the detection result to the connector controller286. The voltage detector285is implemented using a voltmeter or the like.

The connector controller286adjusts voltage values of the plurality of power supply voltages output from the power generation unit283to predetermined voltage values and outputs the voltage values to the power generation unit283. The connector controller286is implemented by using a memory or hardware such as an FPGA. A calculator286ais provided. The calculator286ahas the same function as the calculator571described above.

Main Part of Control Device

Next, a configuration of the control device5B will be described.

The control device5B does not include the current detector52and the voltage detector53in the configuration of the control device5according to the first embodiment described above. Furthermore, the control device5B includes a control unit57B instead of the control unit57according to the first embodiment described above. The control unit57B does not include the calculator571of the control unit57according to the first embodiment described above.

According to the third embodiment described above, the same effects as those of the first embodiment described above are obtained, and it is possible to perform an operation at an appropriate power supply voltage while preventing the diameter of the signal line201from being increased while maintaining the transmission rate.

In the third embodiment described above, the power generation unit283, the current detector284, the voltage detector285, and the connector controller286are provided in the connector28B. However, the present disclosure is not limited thereto, and for example, the power generation unit283, the current detector284, the voltage detector285, and the connector controller286may be provided in the operating unit22.

Other Embodiments

Various embodiments can be formed by appropriately combining a plurality of constituent elements disclosed in the endoscope systems according to the first to third embodiments of the present disclosure described above. For example, some constituent elements may be deleted from all the constituent elements described in the endoscope systems according to the embodiments of the present disclosure described above. Furthermore, the constituent elements described in the endoscope systems according to the embodiments of the present disclosure described above may be appropriately combined.

Furthermore, in the endoscope systems according to the first to third embodiments of the present disclosure, the “unit” or “portion” described above can be replaced with “means”, “circuit”, or the like. For example, the control unit can be replaced with control means or a control circuit.

Note that, in the description of the flowcharts in the present specification, the context of processing between steps is clearly indicated using expressions such as “first”, “thereafter”, and “subsequently”, but the order of processing necessary for implementing the disclosure is not uniquely determined by these expressions. That is, the order of processing in the flowcharts described in the present specification can be changed within a range without inconsistency.

Although some of the embodiments of the present application have been described in detail with reference to the drawings, these are merely examples, and the disclosure can be implemented in other forms in which various modifications and improvements have been made based on the knowledge of those skilled in the art, including the aspects described in the section of the present disclosure.

According to the disclosure, it is possible to perform an operation at an appropriate power supply voltage while preventing a diameter of a signal line from being increased while maintaining a transmission rate.