JP2010279507A - Electronic endoscopic system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic endoscopic system capable of acquiring an image of high precision by preventing the occurrence of an interline flicker. <P>SOLUTION: The electronic endoscopic system includes an imaging means arranged to the leading end of a flexible tube inserted into the body for photographing an observation object to form an image signal, an operation means for moving the leading end of the flexible tube, a displacement quantity detecting means for detecting the mechanical displacement quantity of the operation means, and a brightness restricting means for restricting the brightness of the image signal formed by the imaging means on the basis of the displacement quantity detected by the displacement quantity detecting means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electronic endoscope system, and more particularly to clip processing in an electronic endoscope system.

  In order to diagnose or treat a patient's body, an electronic endoscope having a solid-state image sensor such as a CCD at the tip, and an electronic endoscope that processes an image signal generated by the solid-state image sensor and outputs it to a monitor An electronic endoscope system including a mirror processor is widely known and put into practical use. When in-vivo observation is performed using such an electronic endoscope system, for example, the tip of the electronic endoscope and the subject approach each other and a certain amount of light is generated, thereby causing a subject image on the monitor screen. In some areas, halation (a state in which the screen turns white) may occur.

  Patent Document 1 describes an electronic endoscope system that can eliminate such halation. In the electronic endoscope system of Patent Document 1, histogram data based on an image signal is generated in a histogram processing circuit included in a processor, and halation is detected based on the generated histogram data. When halation occurs, the halation can be eliminated by closing the aperture and reducing the amount of light incident on the light guide.

JP 2002-58640 A

  By the way, in the case where the tip of the electronic endoscope is moved in a state where halation has occurred in the subject, or when the halation occurs in the subject to which the tip of the electronic endoscope has been moved, A phenomenon called interline flicker may occur. Interline flicker is flickering between lines that occurs in the horizontal direction on the screen, and is a phenomenon that is particularly likely to occur in an LCD (Liquid Crystal Display). In the electronic endoscope system of Patent Document 1, although the halation generated as described above can be eliminated, it is necessary to adjust the light amount by the diaphragm after detecting the halation, so it takes time to eliminate the halation. For this reason, if the tip of the electronic endoscope is moved at high speed, interline flicker occurs on the display screen before halation is eliminated, which hinders in-vivo observation and treatment.

  Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide an electronic endoscope system capable of preventing the occurrence of interline flicker and acquiring a highly accurate image.

  In order to solve the above-described problems, according to the present invention, an imaging means that is arranged at the distal end of a flexible tube inserted into the body and shoots an observation target to generate an image signal, and for moving the distal end of the flexible tube Luminance limit that limits the luminance of the image signal generated by the imaging means based on the operation means, the displacement amount detection means for detecting the mechanical displacement amount in the operation means, and the displacement amount detected by the displacement amount detection means Means for providing an electronic endoscope system.

  With this configuration, the luminance of the image signal can be limited according to the movement of the operation means, and the occurrence of interline flicker on the display screen can be prevented. Moreover, by limiting the luminance based on the mechanical displacement amount of the operating means for operating the movement of the distal end of the flexible tube, the luminance can be quickly limited, and the structure and control of the system are complicated. The above-described effect can be realized without realizing the above.

  Further, the brightness limiting means limits the brightness of the image signal based on the first brightness limit value when the displacement detected by the displacement detection means is equal to or less than a predetermined threshold, and detects the displacement. When the displacement detected by the means is larger than a predetermined threshold, the luminance of the image signal may be limited based on the second luminance limit value. Further, the second luminance limit value may be smaller than the first luminance limit value.

  The second luminance limit value may be set based on a display device on which an image signal is displayed. By configuring in this way, it is possible to limit the luminance according to the characteristics of the display device.

  The operation means may be a rotatable operation lever, and the displacement amount detection means may detect a displacement amount of the rotation angle of the operation lever.

  The electronic endoscope system may further include synchronization signal generation means for generating a synchronization signal, and the displacement amount detection means may detect the displacement amount based on the synchronization signal. With this configuration, it is possible to detect the amount of displacement of the operating means at a predetermined time, and it is possible to limit the luminance based on the magnitude and speed of the movement of the tip.

  Further, the displacement amount detection means may detect the displacement amount when halation occurs in the image signal generated by the imaging means. With such a configuration, it is possible to reduce the burden on the processing unit and increase the efficiency by limiting the luminance only when there is a high possibility that interline flicker will actually occur.

  Therefore, according to the electronic endoscope system of the present invention, it is possible to prevent the occurrence of interline flicker by setting the luminance limit value of the image signal according to the movement of the tip of the electronic endoscope.

It is a figure which shows schematic structure of the electronic endoscope system in embodiment of this invention. It is a block diagram which shows the structure of the initial stage signal processing circuit in embodiment of this invention. It is a schematic diagram which shows the structure of the operation part of the electronic endoscope in embodiment of this invention. It is a flowchart which shows the flow of the brightness | luminance limiting value setting process in embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of an electronic endoscope system 1 according to an embodiment of the present invention. As shown in FIG. 1, the electronic endoscope system 1 includes an electronic endoscope 10, a processor 20, and a monitor 30. In this embodiment, the electronic endoscope system 1 is a medical electronic endoscope system for performing observation and treatment in a patient's body.

  The electronic endoscope 10 is electrically and optically connected to an insertion portion 10a made of a long flexible tube inserted into a patient's body, an operation portion 10b grasped by an operator, and a processor 20. Part 10c. A light guide 11 for propagating light supplied from the processor 20 from the connection portion 10c of the electronic endoscope 10 to the distal end of the insertion portion 10a and emitting the light to an observation site via a light distribution lens (not shown) extends. Exist. Further, an objective lens 12 for forming an image of the light reflected from the observation site on the light receiving surface of the image sensor at the distal end of the insertion portion 10a, and an imaging for generating an image signal based on the subject image formed on the light receiving surface. A CCD 13 as an element is arranged.

  The operation unit 10b of the electronic endoscope 10 includes various operation buttons (not shown) such as a freeze button for freezing an image acquired by the CCD 13, and an operation lever 14 for moving the distal end of the insertion unit 10a. And an angle sensor 15 for detecting the rotation angle of the operation lever 14 is provided. The angle sensor 15 is a rotation angle sensor attached to the shaft of the operation lever 14, and outputs a voltage corresponding to the detected angle to the angle detection circuit 16 provided in the connection portion 10 c of the electronic endoscope 10. Further, the connection unit 10c is provided with the angle detection circuit 16 described above and an initial signal processing circuit 17 that performs processing described later on the image signal generated by the CCD 13 to generate a video signal.

  The processor 20 includes a system control circuit 21 that performs overall control of the processor 20, a lamp 22 that generates illumination light to be supplied to the electronic endoscope 10, and a light emitted from the lamp 22 to converge the light of the electronic endoscope 10. Various operation buttons including a condenser lens 23 coupled to the guide 11, a video signal processing circuit 24 for performing predetermined processing such as noise reduction on the video signal received from the electronic endoscope 10, and a main power switch are arranged. The front panel 25 is provided. The monitor 30 is a display device that displays an image based on the video signal processed by the video signal processing circuit 24.

  In-body cavity observation in the electronic endoscope system 1 is performed as follows. First, when a surgeon turns on a main power switch (not shown) provided on the front panel 25 of the processor 20, the lamp 22 is turned on under the control of the system control circuit 21. Then, the light emitted from the lamp 22 enters the incident end of the light guide 11 provided in the electronic endoscope 10 via the condenser lens 23. The light incident on the incident end of the light guide 11 passes through the light guide 11 and is emitted from the emission end at the distal end of the insertion portion 10a to the observation site in the body. Then, the emitted light is reflected by the observation site and imaged on the light receiving surface of the CCD 13 via the objective lens 12.

  In this embodiment, a single-plate simultaneous type is applied as a color imaging method, and yellow (Ye), cyan (Cy), magenta (Mg), and green (G) color elements are on a checkered pattern on the light receiving surface of the CCD 13. Complementary color filters (not shown) arranged in a pattern are arranged corresponding to each pixel on the light receiving surface. In the CCD 13, an image signal of a subject image corresponding to the intensity of light transmitted through the complementary color filter is generated by photoelectric conversion, and an image signal for one frame is sequentially read out at a predetermined time interval by a color difference line sequential method. . In this embodiment, an interline transfer type CCD is used, and image signals for one frame are sequentially read out at intervals of 1/30 seconds, for example, in correspondence with the NTSC vertical synchronization frequency. It is sent to the signal processing circuit 17.

  In the initial signal processing circuit 17, a video signal including a luminance signal and a color difference signal is generated from the image signal generated by the CCD 13. FIG. 2 is a block diagram showing a configuration of the initial signal processing circuit 17. As shown in FIG. 2, the initial signal processing circuit 17 includes an A / D conversion circuit 110, a DSP circuit 120, a control circuit 130, and a synchronization signal generation circuit 140.

  The image signal output from the CCD 13 is A / D converted by the A / D conversion circuit 110 and output to the DSP circuit 120. The DSP circuit 120 performs a predetermined process on the input image signal after A / D conversion to generate a video signal. The predetermined processing includes, for example, gain adjustment and resolution adjustment for each color, white balance and black balance adjustment, gamma correction, enhancement processing, and the like. The DSP 120 includes a clipping circuit 125, and clips the luminance value of the image signal within a predetermined range based on a luminance limit value Hc described later.

  The synchronization signal generation circuit 140 generates a synchronization signal for controlling the timing of angle detection in the angle detection circuit 16 in the luminance limit value setting process described later. The control circuit 130 controls the above-described circuits in the initial signal processing circuit 17 and outputs a drive signal to the CCD 13 as a CCD driver for driving the CCD 13. Then, the video signal generated by the initial signal processing circuit 17 is sent to the video signal processing circuit 24 of the processor 20.

  In the video signal processing circuit 24 of the processor 20, the luminance signal component in the received video signal is subjected to noise reduction processing or the like, and the NTSC composite video in which the luminance signal, color difference signal, and decoded synchronization signal with reduced noise are multiplexed is multiplexed. A video signal such as a signal is generated. The video signal is output from the processor 20 to the monitor 30, and a subject image based on the video signal is displayed on the monitor 30. Thereby, the surgeon and the diagnostician can observe the state in the body cavity of the patient from the subject image displayed on the monitor 30.

  Further, during the in-vivo observation as described above, the distal end of the insertion portion 10a can be moved by operating the operation lever 14 provided in the operation portion 10b of the electronic endoscope 10. As a result, the light receiving surface of the CCD 13 can be directed in a desired direction, and an observation site located in the desired direction can be observed. FIG. 3 is a schematic diagram for explaining the configuration of the operation lever 14 of the operation unit 10b and the movement of the distal end of the insertion unit 10a. The operation lever 14 is connected to a pulley (not shown) built in the operation unit 10b, and the pulley can be rotated by rotating the operation lever 14. A pair of operation wires 14a and 14b extending to the tip of the insertion portion 10a where the CCD 13 is disposed are wound around the pulley. Then, by operating the operation lever 14 and rotating the pulley, the two operation wires 14a and 14b are pushed and pulled simultaneously, and the distal end of the insertion portion 10a moves.

  Specifically, for example, when the operation lever 14 is rotated in the direction indicated by the arrow A in FIG. 3, one operation wire 14a is pulled in the direction of the arrow A ′, and the other operation wire 14b is moved in the direction of the arrow A ″. 3, the distal end of the insertion portion 10a is curved, and the light receiving surface of the CCD 13 can be directed upward, similarly, in the direction opposite to the arrow A in FIG. When the operation lever 14 is rotated, the operation wire 14a is pushed out in the direction of the arrow A ″, and the operation wire 14b is pulled in the direction of the arrow A ′, whereby the distal end of the insertion portion 10a is in the state shown in FIG. It can be bent in the opposite direction.

  Thus, the movement of the distal end of the insertion portion 10a is interlocked with the movement of the operation lever 14, and the magnitude and speed at which the operation lever 14 is operated is the magnitude of the movement at the distal end of the insertion portion 10a. And reflected in speed. That is, when the operation lever 14 is moved quickly, the distal end of the insertion portion 10a also moves quickly. In addition to the operation wires 14a and 14b, another pair of operation wires are provided, and each of them is wound around a pulley and interlocked with the operation lever, whereby the distal end of the insertion portion 10a is bent in four directions, up, down, left and right. Is also possible.

  Here, as described above, when the tip of the insertion portion 10a is moved by the operating lever 14 in a state where halation has occurred in the subject image, or the subject image to which the tip of the insertion portion 10a has been moved is halated. In such a case, interline flicker occurs in the video displayed on the monitor 30. In order to prevent the occurrence of such interline flicker, it is desirable to quickly eliminate halation when the distal end of the insertion portion 10a is moved at high speed. Therefore, in the electronic endoscope 10 according to the present embodiment, the luminance limit value setting process for setting the luminance limit value Hc used for the clipping process is performed based on the movement of the operation lever 14.

FIG. 4 is a flowchart showing the brightness limit value setting process in the present embodiment. This process is executed under the control of the control circuit 130 of the electronic endoscope 10. In the present process, first, as an initial value, the brightness limit value Hc in the clip circuit 125 is set to 110 (IRE), the first angle _{R 1} in the angle detection circuit 16 is set to 0 (S101).

  Subsequently, based on the synchronization signal generated from the synchronization signal generation circuit 140, it is determined whether or not it is time to detect the angle of the operation lever 14 (S102). In the present embodiment, the speed of movement of the subject is detected from the difference in the rotation angle of the operation lever 14 for a predetermined time (for example, 1 second). Therefore, the synchronization signal generation circuit 140 generates a synchronization signal at a predetermined time interval (for example, an integer multiple of the vertical synchronization signal in the initial signal processing circuit 17) and outputs the synchronization signal to the angle detection circuit 16 via the control circuit 130. Then, the angle detection circuit 16 detects the output value from the angle sensor 15 in synchronization with this synchronization signal.

If it is determined that it is not the timing for angle detection based on the synchronization signal (S102: No), the process proceeds to S109, and based on the luminance limit value Hc set in the clip circuit 125. Image processing including clip processing is performed. If the observation is continued (S110: No), the process returns to S102. If not (S110: Yes), the process ends. On the other hand, based on the synchronization signal, when it is determined that it is time to perform the angle detection (S102: Yes), the second angle _{R 2} is detected (S103). Second angle R ₂ is the rotation angle of the operation lever 14 detected by the angle sensor 15 at a timing based on the synchronization signal. Here, the output voltage from the angle sensor 15 is detected by the angle detection circuit 16 under the control of the control circuit 130. Then, the rotation angle R ₂ of the operation lever 14 is calculated from the output voltage detected by the angle detection circuit 16.

Subsequently, a difference R ₀ between the _second angle R ₂ obtained in S103 and the first angle R ₁ is obtained. Here, the first angle R ₁ is the rotation angle of the operation lever 14 detected before the second angle R ₂ , and becomes the initial value 0 when this processing is first performed. Yes. Further, the difference R ₀ indicates how much the operation lever 14 has been rotated at a predetermined time. As described above, the rotation of the operation lever 14 is interlocked with the movement of the distal end of the insertion portion 10a. Therefore, when the value of the difference R ₀ is large, it indicates that the movement of the tip of the insertion unit 10a (that is, the movement of the subject) is large, and when the value of the difference R ₀ is small, the movement of the tip of the insertion unit 10a (that is, Indicates that the movement of the subject is small.

Subsequently, it is determined whether or not the absolute value of the obtained difference R ₀ is larger than a threshold value R _m (S105). Threshold R _m, in consideration of the occurrence of inter-flicker, which is the upper limit of the tolerance range determined by experiment or the like (e.g., 10 degrees). When the absolute value of the difference R ₀ is larger than the threshold value R _m (S105: Yes), the luminance limit value Hc is set to the low luminance limit value Hx (S106).

  Here, the low brightness limit value Hx is a brightness limit value when the distal end of the insertion portion 10a is moved at high speed, and is set to a value lower than the normal brightness limit value (110 (IRE)). In the present embodiment, the low luminance limit value Hx is set based on the specifications of the monitor 30 connected to the processor 20. Interline flicker is generated differently depending on the monitor specifications on which the subject image is displayed. For example, in the case of an LCD monitor or when processing for increasing the gain is performed on the monitor, interline flicker is likely to occur. Also, when special image processing is performed on the monitor, the occurrence of interline flicker may be affected. Therefore, in the electronic endoscope 10, the low luminance limit value Hx is set in advance for each type of monitor and is stored in a memory (not shown) provided in the connection unit 10c. Specifically, the low luminance limit value Hx corresponding to an LCD monitor that is likely to generate interline flicker is a low value (for example, 70 (IRE)), and the low luminance limit value Hx corresponding to a CRT monitor is a high value ( For example, 95 (IRE)).

These low luminance limit values Hx are appropriately selected and read according to the type of monitor connected. Specifically, when the monitor 30 is connected to the processor 20 for the first time, a monitor selection screen for allowing the operator to select which type of monitor is connected is displayed on the display screen of the monitor 30. When the operator selects a monitor type using a keyboard or the like, information on the selected monitor type is sent from the system control circuit 21 of the processor 20 to the control circuit 130 of the electronic endoscope 10. Then, initiated luminance limit value setting process at S105, if the absolute value of the difference R ₀ is determined to be larger than the threshold value R _m based on the information about the type of the monitor 30, corresponding to the monitor 30 The low brightness limit value Hx (for example, 70 (IRE)) to be read is read out and set as the brightness limit value Hc.

On the other hand, when the absolute value of the difference R ₀ is equal to or smaller than the threshold value R _m (S105: No), the luminance limit value Hc is set to 110 (IRE) as with the initial value (S107). Subsequently, at S108, the second angle _{R 2} is a first angle _{R 1.}

In subsequent S109, the initial signal processing circuit 17 performs image processing including clip processing based on the luminance limit value Hc set in S106 or S107. Specifically, when the value of the difference R ₀ is larger than the threshold value, that is, when it is determined that the distal end of the insertion portion 10a has moved at high speed, the luminance limit value Hc in the image signal, that is, a high luminance of 70 (IRE) or more. Part is deleted. On the other hand, when the value of the difference R ₀ is equal to or smaller than the threshold value, that is, when it is determined that the movement of the distal end of the insertion portion 10a is small, the high luminance portion having the luminance limit value Hc, that is, 110 (IRE) or more is deleted. The

  Then, the control circuit 130 repeats the processing from S102 to S109 until it is determined in S110 that the observation is ended. Then, based on the difference in the rotation angle of the operation lever 14, the value of the luminance limit value Hc in the clip circuit 125 of the initial signal processing circuit 17 is set.

  As described above, in this embodiment, when the tip of the electronic endoscope 10 is moved at high speed, that is, when interflicker is likely to occur, the luminance limit value in the clip circuit 125 is automatically lowered. The high luminance portion of the image, that is, the portion including halation is deleted. Accordingly, it is possible to quickly prevent the occurrence of interline flicker affected by halation and provide a highly accurate image. Further, when the movement of the tip of the electronic endoscope 10 becomes small, the brightness limit value Hc is set again to the normal value (110 (IRE)), so that the tip does not move. It is possible not to delete the high luminance part unnecessarily.

  In the present embodiment, the angle sensor 15 is attached to the operation lever 14, and the movement of the distal end portion is detected from the difference in the rotation angle of the operation lever 14 that is interlocked with the movement of the distal end of the electronic endoscope 10. Thus, the system can be configured with a simple structure by controlling the brightness limit value based on the mechanically measured value of the rotation angle of the operation lever 14. In addition, since it is not necessary to perform image processing to detect halation, the burden on the processing unit can be reduced.

  The above is the embodiment of the present invention, but the present invention is not limited to this embodiment, and various modifications are possible within the scope of the technical idea of the present invention. For example, in the above-described embodiment, the initial signal processing circuit 17 of the electronic endoscope 10 is configured to perform clip processing. However, the video signal processing circuit 24 of the processor 20 may perform the processing. . In this case, the system control circuit 21 performs the brightness limit value setting process as in the above-described embodiment based on the detection result in the angle detection circuit 16, and performs the clip process based on the required brightness limit value.

  In the above embodiment, the low luminance limit value Hx is selected according to the type of monitor connected to the processor 20, but the present invention is not limited to this. For example, by using a predetermined fixed value (for example, 75 (IRE)) as the low brightness limit value Hx, the brightness limit value setting process can be further simplified. In addition, the operator may arbitrarily set the low brightness limit value Hx. In this case, the low luminance limit value Hx can be arbitrarily set using an operation button or the like on the front panel 25 of the processor 20.

  Furthermore, in the said embodiment, when the front-end | tip of the insertion part 10a of the electronic endoscope 10 moves at high speed, it is set as the structure which reduces the brightness | luminance limiting value Hc. However, first, it may be configured to detect whether halation has occurred and to perform the processing of S102 to S108 in the luminance limit value setting processing only when halation has occurred. With this configuration, the load on the processing unit is reduced and the efficiency is improved by performing the angle detection and the brightness limit value setting process only when there is a high possibility that interline flicker will actually occur. Can do.

DESCRIPTION OF SYMBOLS 1 Electronic endoscope system 10 Electronic endoscope 14 Operation lever 15 Angle sensor 16 Angle detection circuit 17 Initial signal processing circuit 20 Processor 21 System control circuit 24 Video signal processing circuit 30 Monitor 120 DSP circuit 125 Clip circuit 140 Synchronization signal generation circuit

Claims (7)

An imaging means arranged at the tip of a flexible tube to be inserted into the body and imaging an observation target to generate an image signal;
Operating means for moving the tip of the flexible tube;
A displacement amount detecting means for detecting a mechanical displacement amount in the operation means;
An electronic endoscope system comprising: a luminance limiting unit that limits a luminance of an image signal generated by the imaging unit based on a displacement amount detected by the displacement amount detecting unit. The luminance limiting unit limits the luminance of the image signal based on a first luminance limiting value when the displacement detected by the displacement detection unit is equal to or less than a predetermined threshold.
The luminance of the image signal is limited based on a second luminance limit value when the amount of displacement detected by the displacement amount detector is larger than a predetermined threshold. Electronic endoscope system.   The electronic endoscope system according to claim 2, wherein the second brightness limit value is smaller than the first brightness limit value.   4. The electronic endoscope system according to claim 2, wherein the second luminance limit value is set based on a display device on which the image signal is displayed. The operating means comprises a rotatable operating lever,
The electronic endoscope system according to any one of claims 1 to 4, wherein the displacement amount detection means detects a displacement amount of a rotation angle of the operation lever. Synchronization signal generating means for generating a synchronization signal;
6. The electronic endoscope system according to claim 1, wherein the displacement amount detection unit detects the displacement amount based on the synchronization signal.   7. The displacement amount detection unit according to claim 1, wherein the displacement amount detection unit detects the displacement amount when halation occurs in the image signal generated by the imaging unit. 8. Electronic endoscope system.

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