JP2006212187A - Electronic endoscope system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic endoscope system capable of highly precisely detecting the distal end position of a flexible tube and also the shape of the flexible tube in a body cavity without being affected by the drive control signals of an imaging element or the like. <P>SOLUTION: The electronic endoscope system comprises: an endoscope provided with the flexible tube having the imaging element on the distal end; a magnetic field generation means for successively and continuously generating a magnetic field in at least a first direction and a second direction orthogonal to each other; a position detection means arranged at a prescribed position inside the flexible tube and provided with at least one position detection sensor for detecting the relative position of the prescribed position to the magnetic field generation means by generating an induction current by using the magnetic field; and a control means for controlling the drive of the magnetic field generation means so as to generate the magnetic field in a charge storage period by the imaging element. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic endoscope system for detecting a shape of an endoscope, particularly a medical endoscope, when a flexible tube is inserted into a lumen.

  In recent years, various systems for detecting the shape of a medical insertion tool inserted into a body cavity have been proposed in the medical field. For example, an endoscope system using a magnetic field generation device that generates a magnetic field by passing an alternating current through a coil and a position detection sensor that detects the magnetic field generated by the magnetic field generation device with a coil or the like has been proposed. In the endoscope system, the tip position of the flexible tube is detected based on the magnitude of the induced current generated by the position detection sensor arranged at the tip of the flexible tube of the endoscope. Then, by tracing the locus of each detection result, the shape of the entire flexible tube in the body cavity is detected. The endoscope system described above is disclosed in, for example, Patent Document 1 below.

JP 2001-145598 A

  As a type of endoscope system, an electronic endoscope system that captures an image of a body cavity with an image sensor provided at the distal end of a flexible tube is known. It is also possible to detect the position of the distal end of the flexible tube in the body cavity and the shape of the entire flexible tube using the configuration described in Patent Document 1 for such an electronic endoscope system.

  However, when the configuration described in Patent Document 1 is applied to the electronic endoscope system as described above, the image sensor is driven and controlled with respect to a detection signal corresponding to the induced current generated by the position detection sensor. The drive control signal may have a relatively high level. For this reason, if a detection signal is output from the position detection sensor while the image sensor is being driven, noise is mixed into the detection signal due to the influence of the drive control signal of the image sensor, which hinders accurate position detection. There is a fear.

  Moreover, it is strongly desired that the flexible tube be reduced in diameter so as to alleviate the physical and mental pain of the subject. Therefore, in the electronic endoscope system having the configuration described in Patent Document 1, in order to further reduce the diameter of the flexible tube, a signal line for transmitting a drive control signal, a signal line for transmitting a detection signal, Inevitably be placed close together. Therefore, there is a high possibility that noise is mixed in the detection signal, and further improvement has been desired.

  Therefore, in view of the above circumstances, the present invention can detect the tip position of the flexible tube and the shape of the flexible tube in the body cavity with high accuracy without being affected by the drive control signal of the imaging device. An object of the present invention is to provide an electronic endoscope system that can perform the above-described operation.

  In order to solve the above problems, an electronic endoscope system according to a first aspect of the present invention includes an endoscope having a flexible tube having an imaging element at a tip, at least a first direction and a second direction orthogonal to each other. The magnetic field generating means for generating the magnetic field successively in the direction of and the relative position of the predetermined position with respect to the magnetic field generating means are detected by generating an induced current using the magnetic field, which is arranged at a predetermined position in the flexible tube And a position detecting means having a position detecting sensor for controlling the driving of the magnetic field generating means so that the magnetic field is generated during a charge accumulation period by the image sensor.

  According to the first aspect of the present invention, the position detection by the position detection sensor is executed during the charge accumulation period of the image sensor, more specifically during the non-transmission of the drive control signal of the image sensor. Therefore, there is no possibility that noise is mixed into the position detection signal due to the influence of the drive control signal having a higher intensity than the position detection signal transmitted from the sensor. Therefore, the relative position of the flexible tube tip with respect to the magnetic field generating means can be detected with high accuracy.

  According to the electronic endoscope system of the second aspect, the electronic endoscope system further includes operation means for instructing position detection by the position detection means, and the control means sets the magnetic field generation means in response to an instruction from the operation means. The drive can be controlled.

  According to the electronic endoscope system of the third aspect, the magnetic field generation means can further generate a magnetic field in a third direction orthogonal to the first direction and the second direction.

  According to the electronic endoscope system of the fourth aspect, a plurality of position detection sensors may be arranged at substantially equal intervals along the length direction of the flexible tube. Thereby, not only the position of the distal end of the flexible tube but also the shape of the entire flexible tube in the body cavity can be efficiently detected in a short time.

  According to the electronic endoscope system according to claim 5, as the position detection means, a probe including a position detection sensor at least at the distal end and configured to be inserted through a forceps channel provided in a flexible tube is used. be able to. Alternatively, according to the electronic endoscope system of the sixth aspect, the position detection sensor can be disposed in the flexible tube.

  According to the electronic endoscope system of the seventh aspect, the foot switch can be used as the operation means.

  According to the electronic endoscope system of the eighth aspect, it is desirable that the control unit drives and controls the magnetic field generation unit at a predetermined interval. Thereby, when the position detection means includes only one position detection sensor, it is also possible to detect the movement trajectory of the position detection sensor, that is, the shape of the flexible tube in the body cavity. Further, when the position detection means includes a plurality of position detection sensors, a change in the shape of the flexible tube in the body cavity can be detected at any time.

  According to the electronic endoscope system according to claim 9, by configuring the endoscope to hold predetermined information related to the endoscope, the control unit corresponds to the information, and The predetermined period can be set.

  According to the electronic endoscope system of the tenth aspect, the electronic endoscope system includes the display unit that displays the image captured by the image sensor and the detection result by the position detection unit.

  According to the electronic endoscope system of the present invention, since the position detection timing is set outside the drive control signal transmission period for the image sensor, the image sensor can be driven even if a flexible tube having a small diameter is used. Without being affected by a control signal or the like, the tip position of the flexible tube, and further, the shape of the flexible tube in the body cavity can be detected with high accuracy.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an electronic endoscope system 1 according to the present invention. The electronic endoscope system 1 includes a magnetic field generator 2, an electronic endoscope 3, a position detection probe 4, a processor 5, and a monitor 9.

  The magnetic field generator 2 is installed in advance around the subject when performing endoscopic observation and endoscopic treatment. The magnetic field generator 2 has three coils that generate magnetic fields in the X, Y, and Z directions orthogonal to each other. Then, by supplying an alternating current to each coil, an alternating magnetic field is generated in each of the X, Y, and Z directions.

  The electronic endoscope 3 includes a main body 3a having a grip portion on which an operation member (not shown) is disposed, and a flexible tube 3b inserted into the body cavity of the subject. The electronic endoscope 3 includes a light guide 11 that transmits irradiation light from the processor 5 to the endoscope 3, information unique to the electronic endoscope 3 (for example, identification information such as a lot number and information on the total length of the flexible tube 3b). ROM 12 in which the light guide exit end 11a is stored, a light distribution lens 13 for irradiating the body cavity of the subject with the light, and an objective lens for condensing the light from the body cavity of the subject. 15, an imaging element 17 for imaging the body cavity of the subject via the objective lens 15, and a forceps channel 18.

  The position detection probe 4 includes a position detection sensor 4a at the tip. The position detection sensor 4 a has a uniaxial coil and is configured such that an induced current is generated by the magnetic field generated by the magnetic field generator 2.

  Endoscopic observation and endoscopic treatment for a subject using the electronic endoscope system 1 are executed as follows.

  The system controller 23 drives and controls the light source unit 21 to illuminate the body cavity. Specifically, the light source unit 21 includes a light source 47 that is a lamp that emits white light, a substantially disc-shaped dimming diaphragm 49 that adjusts the amount of light output from the light source 47, a motor 51 that rotationally drives the dimming diaphragm 49, A motor drive / control unit 53 that drives / controls the rotationally driven motor 51, a light source power source 55 that supplies power to the light source 47, and a lens 57 that guides light emitted from the light source 47 to the light guide incident end 11b. An RGB color filter 59, a motor 61 for rotationally driving the RGB color filter, and a motor drive / control unit 63 for driving / controlling the motor 61 are provided between the light source 47 and the dimming diaphragm 49, and the irradiation light is sequentially supplied. , Red, green and blue colors have been adjusted. The light of each color incident on the light guide incident end 11 b illuminates the body cavity via the light guide 11 and the light distribution lens 13.

  The light of each color reflected in the body cavity forms an optical image on the light receiving surface of the image sensor 17 via the objective lens 15. The image sensor 17 is driven and controlled by the image sensor control / drive unit 29 in synchronization with a timing signal transmitted from the timing controller 27 under the control of the system controller 23. The timing signal is synchronized with the irradiation timing of light of each color emitted from the light source unit 21. The image sensor 17 generates an image signal corresponding to the optical image in synchronization with the drive control signal from the image sensor control / drive unit 29 and periodically transmits the image signal to the pre-stage image signal processing unit 31 of the processor 5.

  The pre-stage image signal processing unit 31 performs processing such as A / D conversion on the image signal. The image signal output from the pre-stage image signal processing unit 31 is sequentially stored in the second image memory 33 as image data relating to each color. The stored image data corresponding to each color is output simultaneously to the subsequent image signal processing unit 45 in synchronization with the timing signal transmitted from the timing controller 27. The timing signal is transmitted corresponding to the cycle of the monitor 9, for example. The post-stage image signal processing unit 45 performs processing such as D / A conversion on the image data, and outputs it to the monitor 9 as a moving image.

  FIG. 2 shows an example of the screen of the monitor 9. The image data output from the post-stage image signal processing unit 45 is displayed as the main image 9a on the screen of the monitor 9, for example. The surgeon identifies a lesioned part while confirming the main image 9a, and performs a treatment such as collection of a living tissue using forceps. The above is the description of endoscopic observation and endoscopic treatment for the subject using the electronic endoscope system 1.

  Next, detection of the tip position of the flexible tube 3b, which is one of the main features of the present invention, will be described in detail. When detecting the position of the distal end of the flexible tube 3b in the body cavity, the operator first starts the position detection probe until the position detection sensor 4a disposed at the distal end of the position detection probe 4 is positioned at the distal end of the flexible tube 3b. 4 is inserted into the forceps channel 18. Here, the position detection probe 4 is marked at a position located near the forceps channel insertion opening when the position detection sensor 4a reaches the distal end of the flexible tube 3b. Therefore, the operator can easily determine whether or not the position detection sensor 4a is positioned at the distal end of the flexible tube 3b depending on whether or not the marked site is positioned at the forceps channel insertion port. . Even when the position detection probe 4 is not marked, the time when the position detection probe 4 appears in the main image 9a in the screen of the monitor 9 is regarded as the time when the position detection sensor 4a reaches the tip of the flexible tube 3b. Good.

  The system controller 23 drives and controls each component in the processor 5. When the electronic endoscope 3 is connected to the processor 5, the system controller 23 executes the following processing in advance. That is, the system controller 23 reads information unique to the endoscope 3 from the ROM 12, and determines the timing for generating the magnetic field based on information regarding the total length of the flexible tube 3b among the unique information. In the present embodiment, the system controller 23 determines the period of magnetic field generation based on the information related to the total length of the flexible tube 3b read from the ROM 12.

  When the foot switch 19 is operated by the operator, the system controller 23 transmits a control signal for generating a magnetic field to the control calculation unit 37 at a timing described below. FIG. 3 is a timing chart regarding each part in the processor 5 that is driven and controlled by the system controller 23. FIG. 3A shows the illumination timing of red, green, and blue light emitted from the light source unit 21. In FIG. 3 (1), the period of H shows the lighting period of each light of red, green, and blue. FIG. 3B shows the drive timing of the image sensor 17 that is driven and controlled by the image sensor control / drive unit 29 under the control of the system controller 23. In FIG. 3B, a drive control signal at the time of rising, more specifically, a signal instructing readout of the charge accumulated in each pixel is transmitted from the image sensor control / drive unit 29 to the image sensor 17. Therefore, in FIG. 3B, the period H is a readout period in which the charges read from each pixel of the image sensor are transmitted to the previous image signal processing unit of the processor 5 as an image signal. In FIG. 3B, a period L is a charge accumulation period in which the image sensor receives light reflected in the body cavity and accumulates charges. FIG. 3 (3) shows the ON / OFF state of the foot switch 19. In FIG. 3 (3), a period H is a period in which the foot switch 19 is operated and is in the ON state.

  FIG. 3 (4) is a diagram showing timing related to detection of the tip position of the flexible tube 3 b by the system controller 23. In FIG. 3 (4), the period H is a period during which the processing relating to positioning, which will be described in detail below, is performed, that is, a position detection period. As shown in FIGS. 3 (3) and 3 (4), when the foot switch 19 is turned on, the system controller 23 periodically generates a magnetic field by transmitting a control signal related to magnetic field generation to the control calculation unit 37. Let In FIG. 3 (4), the rise time corresponds to the control signal transmission time.

  The system controller 23 transmits a control signal to the control calculation unit 37 at a timing that does not overlap with the readout period. As described above, the period of magnetic field generation is determined based on the information related to the total length of the flexible tube 3b read from the ROM 12. In this embodiment, as shown in FIGS. 3 (2) and 3 (4), the magnetic field generation cycle is set so that a magnetic field is generated each time the image sensor 17 is accumulating charges (every charge accumulation period). .

  When receiving the control signal, the control calculation unit 37 drives the magnetic field generator 2 by supplying an alternating current via the magnetic field generator drive circuit 41. Here, the magnetic field generator drive circuit 41 is configured to be able to supply an alternating current independently to each of the coils corresponding to the X, Y, and Z directions in the magnetic field generator 2. Then, every time a control signal is received, the control calculation unit 37 sequentially supplies an alternating current to each coil so that a magnetic field in a different direction is continuously generated once from the magnetic field generator 2. Even if the magnetic field is generated continuously, the deviation at the time of generation of each magnetic field is set to be very small, and can be regarded as substantially the same timing in practice.

  When a magnetic field is generated, the position detection sensor 4a generates an induced current under the influence of the magnetic field. A signal corresponding to the induced current is transmitted to the amplifier 35 in the processor 5 through the connector 39. The signal amplified to a predetermined level by the amplifier 35 is input to the control calculation unit 37. In the position detection period shown in FIG. 3 (4), at least the processes described above are executed. That is, a signal corresponding to the induced current is always transmitted to the processor 5 during the charge accumulation period of the image sensor 17, in other words, during a period other than when a signal having a relatively high intensity such as a drive control signal or an image signal is transmitted / received. Is done. Therefore, the signal corresponding to the induced current is not affected by the drive control signal or the like, and errors due to noise or the like are reduced, thereby enabling highly accurate position detection.

  The induced current generated by the position detection sensor 4a changes corresponding to the distance between the magnetic field generator 2 and the position detection sensor 4a. That is, the relative position of the position detection sensor 4a with respect to the magnetic generator 2 when the magnetic field is generated can be detected by continuously detecting the induced current when the magnetic field is generated in each of the X, Y, and Z directions. it can. Therefore, the control calculation unit 37 associates each direction of the magnetic field being generated with the magnitude of the input induced current, and generates relative position information of the position detection sensor 4a with respect to the magnetic field generator 2. That is, the relative position information includes the amount of induced current when the magnetic field in the X direction is generated (distance information in the X direction), the amount of induced current when the magnetic field is generated in the Y direction (distance information in the Y direction), and the time when the magnetic field is generated in the Z direction. Is the amount of induced current (distance information in the Z direction).

  The control calculation unit 37 stores the generated relative position information in the first image memory 43 as character data or image data. The stored data is read by the subsequent image signal processing unit 45 and output to the monitor 9 in accordance with a predetermined timing, for example, the frame period of the monitor 9. As a result, the operator can easily confirm the position of the distal end of the flexible tube 3b in the current body cavity.

  In the above description, a series of positioning processes whose main purpose is to detect the tip position of the flexible tube 3b in the current body cavity has been described. In this embodiment, for example, the shape of the flexible tube 3b in the body cavity can be detected by turning on the foot switch 19 when the flexible tube 3b is inserted into the body cavity. When detecting the shape of the flexible tube 3 b in the body cavity, the control calculation unit 37 converts the distance information in the X direction and the Y direction among the generated relative position information into the address of the first image memory 43. Then, distance information in the Z direction is stored in the memory area specified by the address. The control calculation unit 37 executes the above-described series of processing every time it receives a control signal from the system controller 23.

  FIG. 4 is a schematic diagram showing the memory area of the first image memory 43 as a two-dimensional map. In FIG. 4, the numbers surrounded by circles indicate the order in which the relative positions are detected. The numbers indicating the order are handled as header information when stored in the memory, for example. A cell to which each number is attached is a memory area having an address specified by the control calculation unit 37 based on the generated relative position information. Therefore, the data amount in the memory area to which each number is attached corresponds to the distance information in the Z direction.

  The surgeon operates the front panel switch 25 or the operation unit of the endoscope main body 3a at an arbitrary timing to give an instruction to display the shape of the flexible tube 3b on the monitor 9. When receiving the instruction, the system controller 23 transmits a plurality of relative position information stored in the first image memory 43 to the subsequent image signal processing unit 45.

  The post-stage image signal processing unit 45 generates an image related to the shape of the flexible tube 3 b based on the relative position information read from the first image memory 43. Specifically, the address of the memory area in which data is stored is converted into distance information in the X direction and the Y direction. A point specified by distance information in the X direction and the Y direction, that is, a position detection point is interpolated by, for example, a straight line. The interpolation process is performed with reference to the header information. The amount of data stored in the memory area, that is, distance information in the Z direction is converted into a luminance level at the position detection point. Thereby, the two-dimensional image regarding the shape of the flexible tube 3b specified by the X, Y, and Z directions is generated.

  The post-stage image signal processing unit 45 outputs the two-dimensional image generated by performing the above processing to the monitor 9. In FIG. 3, the two-dimensional image is displayed side by side with a main image 9a as a sub-image 9b. In the sub-image 9b, white dots are position detection points developed on two-dimensional coordinates corresponding to the X and Y directions with the origin as the position of the magnetic field generator 2. Each white dot is expressed as a luminance corresponding to distance information in the Z direction. Therefore, the surgeon can easily grasp the shape of the flexible tube 3b by observing the sub-image 9b.

  In this way, in the electronic endoscope system 1, since the shape of the flexible tube 3b is detected using only one position detection sensor 4a, the internal configuration of the flexible tube may be complicated compared to the previous configuration. Absent. In addition, since the shape is detected using a probe that can be inserted through the forceps channel 18, the flexible tube 3b can be kept thin.

  The above is the embodiment of the present invention. The present invention is not limited to these embodiments, and can be modified in various ranges as exemplified below.

  For example, the position detection sensor 4a does not necessarily need to be single. For example, as shown in FIG. 5, it is possible to use a position detection probe 4 'in which a plurality of position detection sensors 4a are arranged at predetermined intervals along the length direction. When the position detection probe 4 ′ having a plurality of position detection sensors 4a is used, the magnetism in each of the X, Y, and Z directions is generated without generating a magnetic field continuously a plurality of times as described above. Relative position information at a plurality of locations of the flexible tube 3b is generated only by generating each time. That is, the shape of the flexible tube 3b in the body cavity can be detected in a short time.

  When the position detection probe 4 'is used, signals corresponding to a plurality of induced currents are simultaneously output from the position detection sensors 4a. Thus, by connecting each position detection sensor 4a and the amplifier 35 of the processor 5 in parallel, the transmission speed can be increased and the processing efficiency can be increased. However, a serial connection may be used as long as the probe itself and the flexible tube 3b are reduced in diameter.

  For example, in the above-described embodiment, it has been described that the system controller 23 executes a series of position detection processes such as driving control of the magnetic field generator 7 in accordance with the operation of the foot switch 19 which is an operation unit. If it is the purpose, it is not necessary to provide operation means. In this case, the system controller 23 executes the position detection process by always generating a magnetic field at a predetermined timing that does not overlap with the transmission timing of the drive control signal of the image sensor and the like.

  In addition, when it is known in advance that the insertion state of the flexible tube is two-dimensional, or when cost reduction is intended, the magnetic field generator has two directions orthogonal to each other (X and Y in the above embodiment). The magnetic field may be generated only in the two directions. In this case, the control calculation unit 37 in the above embodiment may store binary data at an address obtained by converting distance information in the X and Y directions.

  Further, the image relating to the shape of the flexible tube can be displayed not only two-dimensionally but also three-dimensionally. Furthermore, the relative position information can be converted into coordinate values and stored in the first image memory.

  In the above-described embodiment, the system controller 23 has been described as setting the period of magnetic field generation based on the endoscope-specific information read from the ROM 12 of the electronic endoscope 3. In the electronic endoscope system according to the present invention, the operator can arbitrarily set the period of magnetic field generation by further operating a front panel switch or the like. Here, if the magnetic field generation cycle is set short, more position detection points can be obtained and a finer bent shape can be detected. If the period of magnetic field generation is set to be long, the processing burden is reduced, and an image relating to the shape of the flexible tube can be displayed more quickly.

  Moreover, in the said embodiment, it demonstrated that the position detection sensor was arrange | positioned at the position detection probe. In the electronic endoscope system according to the present invention, even if the position detection sensor is arranged on the flexible tube itself of the electronic endoscope, the same effects as in the above embodiment can be obtained.

It is a figure showing a schematic structure of an electronic endoscope system of an embodiment of the present invention. It is a figure which shows an example of the screen displayed on the monitor of the electronic endoscope system of embodiment. It is a timing chart regarding each site | part in the processor drive-controlled by a system controller. It is a schematic diagram which shows the memory area of a 1st image memory as a two-dimensional map. It is a figure which shows the other structure of a position detection probe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic endoscope system 2 Magnetic field generator 3 Electronic endoscope 3b Flexible tube 4, 4 'Position detection probe 4a Position detection sensor 5 Processor 17 Image pick-up element 18 Forceps channel 19 Foot switch 23 System controller 37 Control calculating part 41 Magnetic field Generator drive circuit

Claims (10)

An endoscope having a flexible tube provided with an image sensor at the tip;
Magnetic field generating means for sequentially generating magnetic fields sequentially in at least a first direction and a second direction orthogonal to each other;
A position detection means having a position detection sensor disposed at least near the tip in the flexible tube and detecting a relative position of the tip with respect to the magnetic field generation means by generating an induced current using the magnetic field;
An electronic endoscope system comprising: a control unit that drives and controls the magnetic field generation unit so that the induced current is generated during a charge accumulation period of the imaging element. The electronic endoscope system according to claim 1,
It further has operation means for instructing position detection by the position detection means,
The electronic endoscope system according to claim 1, wherein the control unit drives and controls the magnetic field generation unit in accordance with the instruction from the operation unit. The electronic endoscope system according to claim 1 or 2,
The electronic endoscope system according to claim 1, wherein the magnetic field generation unit further generates a magnetic field in a third direction orthogonal to the first direction and the second direction. The electronic endoscope system according to any one of claims 1 to 3,
A plurality of the position detection sensors are arranged at substantially equal intervals along the length direction of the flexible tube. The electronic endoscope system according to any one of claims 1 to 4,
The electronic endoscope system according to claim 1, wherein the position detection means is a probe that includes the position detection sensor at least at a distal end and is configured to be inserted through a forceps channel provided in the flexible tube. The electronic endoscope system according to any one of claims 1 to 4,
The electronic endoscope system, wherein the position detection sensor is disposed in the flexible tube. The electronic endoscope system according to any one of claims 2 to 6,
The electronic endoscope system according to claim 1, wherein the operating means is a foot switch. The electronic endoscope system according to any one of claims 1 to 7,
The electronic endoscope system according to claim 1, wherein the control means drives and controls the magnetic field generation means at a predetermined cycle. The electronic endoscope system according to claim 8, wherein
The endoscope has predetermined information about the endoscope,
The electronic endoscope system, wherein the control means sets the predetermined period corresponding to the information.   The electronic endoscope system according to any one of claims 1 to 9, further comprising display means for displaying an image picked up by the image pickup device and a detection result by the position detection means.

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