JP2006068113A - Endoscope system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To switch to white balance in accordance with a normal light observation and a narrow band light observation. <P>SOLUTION: In a white balance circuit 25, a white balance correction value calculation part 81 switches the calculation method of a white balance correction value corresponding to mode detection signals which are control signals from a mode switching circuit. In particular, the white balance of the first time by normal light: (R correction value) = (G average value)/(R average value), (B correction value) = (G average value)/(B average value), and the white balance of the second time by narrow band light: (R correction value) = (prescribed fixed value), (B correction value) = (G average value)/(B average value). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an endoscope apparatus that captures an image of a living tissue and performs signal processing.

  2. Description of the Related Art Conventionally, endoscope apparatuses that irradiate illumination light and obtain an endoscopic image in a body cavity have been widely used. In this type of endoscope apparatus, an electronic endoscope having an image pickup unit that guides illumination light from a light source device into a body cavity using a light guide or the like and picks up an image of a subject using the return light is used. An image signal from the imaging means is signal-processed to display an endoscopic image on an observation monitor and observe an observation site such as an affected area.

  When performing normal biological tissue observation in an endoscopic device, the light source device emits white light in the visible light region, and irradiates the subject with surface sequential light through a rotating filter such as RGB, for example. A color image is obtained by synchronizing the return light of the light with a video processor and processing the image, or a color chip is arranged in front of the imaging surface of the imaging means of the endoscope, and the return light of the white light is converted to RGB by the color chip. A color image is obtained by picking up an image by separation and processing the image with a video processor.

On the other hand, in a living tissue, the light absorption characteristics and the scattering characteristics differ depending on the wavelength of the irradiated light. For example, in Japanese Patent Application Laid-Open No. 2002-95635, illumination light in the visible light region has a narrow spectral bandwidth. A narrow-band optical endoscope apparatus that irradiates a living tissue with RGB surface sequential light and obtains tissue information of a desired deep portion of the living tissue has been proposed.
JP 2002-95635 A

  In normal light observation, white balance is acquired in order to correct variations in various optical characteristics. In white balance, a correction value for multiplying the R signal and B signal is obtained, and the RGB signal output during white light observation can be made uniform. Thereby, the influence on the color tone reproducibility by the variation can be suppressed.

  In narrow-band light observation (NBI observation), it is necessary to acquire white balance before starting the inspection, as in normal light observation. As a result, variations in the optical filter for narrow band light can be corrected, and color tone reproducibility is stabilized.

  The irradiation light in narrowband light observation (NBI observation) was conventionally three-band R, G, B narrowband light, but in order to stabilize the reproducibility of mucosal information by narrowband light, When changing to 2 bands of band light, video signal with R light cannot be obtained with frame sequential type narrow band light, so G signal output is divided by R signal output with the same white balance correction value as normal light. Therefore, there arises a problem that the correction value for the R signal cannot be calculated. Further, even with simultaneous narrow-band light, there are two signals obtained by conversion from YCrCb, and since the R signal is not included, the same correction value calculation method as that for normal light cannot be employed.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an endoscope apparatus capable of switching to white balance according to normal light observation and narrow-band light observation.

The endoscope apparatus of the present invention is
An illumination light supply means for supplying illumination light including a visible light region, an endoscope having an imaging means for illuminating the subject with the illumination light and imaging the subject with return light, and an imaging signal from the imaging means In an endoscope apparatus provided with signal processing means for processing,
Band limiting means for limiting the illumination light to narrow band light of a plurality of discrete band areas and irradiating the subject,
White balance means for performing white balance processing on the imaging signal of the subject by the illumination light,
The white balance means is
First white balance correction value calculating means for calculating a first white balance correction value for the illumination light;
A signal replacement means for replacing an imaging signal of a predetermined band of the narrowband light with a predetermined level signal;
Correction value calculation means for calculating a second white balance correction value for the imaging signal replaced by the signal replacement means.

  According to the present invention, there is an effect that it is possible to switch to white balance according to normal light observation and narrow band light observation.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIGS. 1 to 19 relate to Embodiment 1 of the present invention, FIG. 1 is an external view showing an external configuration of an endoscope apparatus, FIG. 2 is a view showing a front panel of the light source apparatus of FIG. 1, and FIG. FIG. 4 is a block diagram showing the configuration of the endoscope apparatus of FIG. 1, FIG. 5 is a block diagram showing the configuration of the rotary filter of FIG. 4, and FIG. 6 is a rotary filter of FIG. 7 is a diagram showing the spectral characteristics of the first filter set, FIG. 7 is a diagram showing the spectral characteristics of the second filter set of the rotary filter of FIG. 5, and FIG. 8 is a diagram of the biological tissue observed by the endoscope apparatus of FIG. FIG. 9 is a diagram illustrating a layer-direction structure, FIG. 9 is a diagram illustrating a state in which illumination light from the endoscope apparatus of FIG. 4 reaches the biological tissue in the layer direction, and FIG. 10 is transmitted through the first filter set of FIG. FIG. 11 is a first diagram showing each band image by frame sequential light, and FIG. 11 is a frame sequential that has passed through the first filter set in FIG. FIG. 12 is a third diagram showing each band image by frame sequential light transmitted through the first filter set of FIG. 6, and FIG. 13 is a second filter set of FIG. FIG. 14 is a second diagram showing each band image by plane-sequential light transmitted through the second filter set of FIG. 7, and FIG. 15 is FIG. FIG. 16 is an external view showing an external configuration of a first modification of the endoscope apparatus of FIG. 1, and FIG. 17 is a second modification of the endoscope apparatus of FIG. FIG. 18 is a configuration diagram showing a configuration of a simultaneous endoscope apparatus which is a modification of the endoscope apparatus of FIG. 4, and FIG. 19 is a configuration of the white balance circuit of FIG. FIG.

  As shown in FIG. 1, an endoscope apparatus 1 according to the present embodiment includes an electronic endoscope 3 having a CCD 2 to be described later as an imaging means that is inserted into a body cavity and images tissue in the body cavity, and an electronic endoscope. 3 includes a light source device 4 for supplying illumination light to a video processor 7 and a video processor 7 for processing an image signal from the CCD 2 of the electronic endoscope 3 and displaying an endoscope image on the observation monitor 5.

Front panels 4a and 7a are provided in front of the light source device 4 and the video processor 7. The front panel 4a of the light source device 4 has a narrow-band light observation mode in the endoscope apparatus 1 as shown in FIG. A narrow-band light observation mode display unit 4b is provided, and a white balance switch 7c is provided on the front panel 7a of the video processor 7 to instruct acquisition of the white balance of the image pickup signal from the CCD 2, as shown in FIG. In addition, a narrow band light observation mode display unit 7b for notifying the narrow band light observation mode in the endoscope apparatus 1 is provided.

  In an endoscopic inspection by the electronic endoscope 3 using the light source device 4 and the video processor 7, it is necessary to acquire white balance before the inspection. In this case, at the distal end of the insertion portion 3 a of the electronic endoscope 3. A white balance process is performed by attaching a cylindrical white cap 45 whose inside is whitened.

  On the other hand, when performing inspection using special observation light such as narrow-band light, it is necessary to perform white balun processing twice in total for each of normal light and special light.

  However, since the white balance process is performed once during normal endoscopic examination using normal light, the white cap 45 is removed from the distal end of the insertion portion 3a of the electronic endoscope 3 before the second white balance process is completed. As a result, the second white balance process may not be performed normally.

  Therefore, in this embodiment, the narrow band light observation mode is notified by the narrow band light observation mode display units 4b and 7b provided on the front panels 4a and 7a, so that the white balance processing by the narrow band light is being executed. The narrow-band light observation mode display units 4b and 7b are visible.

  As shown in FIG. 4, the video processor 7 is configured to be able to encode an endoscopic image and output it to the image filing device 6 as a compressed image.

  The light source device 4 includes a xenon lamp 11 that emits illumination light, a heat ray cut filter 12 that blocks heat rays of white light, a diaphragm device 13 that controls the amount of white light that passes through the heat ray cut filter 12, and illumination light. A rotation filter 14 for converting the surface sequential light, a condensing lens 16 for condensing the surface sequential light via the rotation filter 14 on the incident surface of the light guide 15 disposed in the electronic endoscope 3, and the rotation filter 14. And a control circuit 17 for controlling the rotation of the motor.

  As shown in FIG. 5, the rotary filter 14 has a disk-like structure and has a double structure with the center as a rotation axis. The outer diameter portion has an overlap suitable for color reproduction as shown in FIG. An R1 filter unit 14r1, a G1 filter unit 14g1, and a B1 filter unit 14b1 constituting a first filter set for outputting the surface sequential light having the spectral characteristics are arranged, and the inner diameter portion is as shown in FIG. A G2 filter unit 14g2, a B2 filter unit 14b2, and a light shielding filter unit 14Cut constituting a second filter set for outputting narrow-band surface-sequential light having discrete spectral characteristics from which desired layer structure information can be extracted are arranged. Has been.

  Then, as shown in FIG. 4, the rotary filter 14 is rotated by the drive control of the rotary filter motor 18 by the control circuit 17, and is moved in the radial direction (moving perpendicular to the optical path of the rotary filter 14 and rotating. The first filter group or the second filter group of the filter 14 is selectively moved on the optical path) by the mode switching motor 19 in accordance with a control signal from a mode switching circuit 42 in the video processor 7 described later.

  Note that power is supplied from the power supply unit 10 to the xenon lamp 11, the diaphragm device 13, the rotary filter motor 18, and the mode switching motor 19.

  The video processor 7 correlates with a CCD driving circuit 20 that drives the CCD 2, an amplifier 22 that amplifies an imaging signal obtained by imaging the body cavity tissue with the CCD 2 via the objective optical system 21, and an imaging signal that passes through the amplifier 22. A process circuit 23 that performs double sampling, noise removal, and the like, an A / D converter 24 that converts an imaging signal that has passed through the process circuit 23 into image data of a digital signal, and image data from the A / D converter 24 is white. A white balance circuit (WB) 25 that performs balance processing, a selector 26 and synchronization memories 27, 28, and 29 for synchronizing frame sequential light by the rotary filter 14, and synchronization memories 27, 28, and 29 An image processing circuit 30 that reads out each image data of the frame sequential light stored in the image processing unit and performs gamma correction processing, contour enhancement processing, color processing, and the like; From the D / A circuits 31, 32, 33 for converting the image data from the processing circuit 30 into analog signals, the encoding circuit 34 for encoding the image data from the image processing circuit 30, and the control circuit 17 of the light source device 4 And a timing generator (TG) 35 that inputs a synchronization signal synchronized with the rotation of the rotation filter 14 and outputs various timing signals to the circuits.

  Further, the electronic endoscope 2 is provided with a mode change switch 41, and an output of the mode change switch 41 is output to a mode change circuit 42 in the video processor 7. The mode switching circuit 42 of the video processor 7 outputs a control signal to the white balance circuit (WB) 25, the dimming circuit 43, the dimming control parameter switching circuit 44, and the mode switching motor 19 of the light source device 4. It has become. The dimming control parameter switching circuit 44 outputs a dimming control parameter corresponding to the first filter group or the second filter group of the rotary filter 14 to the dimming circuit 43, and the dimming circuit 43 is output from the mode switching circuit 42. Based on the control signal and the dimming control parameter from the dimming control parameter switching circuit 44, the diaphragm device 13 of the light source device 4 is controlled to perform appropriate brightness control.

  As shown in FIG. 8, the body cavity tissue 51 often has an absorber distribution structure such as blood vessels that differ in the depth direction. A large number of capillaries 52 are mainly distributed near the surface of the mucosa, and blood vessels 53 that are thicker than capillaries are distributed in the middle layer deeper than this layer, and thicker blood vessels 54 are further distributed in the deep layers. become.

  On the other hand, the depth of light in the depth direction of the body cavity tissue 51 depends on the wavelength of the light, and the illumination light including the visible range is blue (B) as shown in FIG. In the case of light with such a short wavelength, the light reaches the surface layer only due to the absorption and scattering characteristics in the living tissue, and the light emitted from the surface is observed by being absorbed and scattered in the depth range up to that. Is done. In the case of green (G) light, which has a wavelength longer than that of blue (B) light, it reaches deeper than the range where blue (B) light deepens, absorbs and scatters within that range, and exits from the surface. Light is observed. Still further, red (R) light having a wavelength longer than that of green (G) light reaches a deeper range.

  During normal observation, the mode switching circuit in the video processor 7 is controlled by a control signal so that it is located on the optical path of the illumination light in the R1 filter 14r1, G1 filter 14g1, and B1 filter 14b1 as the first filter set of the rotary filter 14. The mode switching motor 19 is controlled.

The R1 filter unit 14r1, the G1 filter unit 14g1, and the B1 filter unit 14b1 during normal observation of the tissue 51 in the body cavity are overlapped with each other as shown in FIG.
(1) A band image having shallow layer and middle layer tissue information as shown in FIG. 10 is captured in the imaging signal captured by the CCD 4 by the B1 filter unit 14b1.
(2) Further, the image signal picked up by the CCD 4 by the G1 filter 14g1 is picked up with a band image having a shallow layer and medium layer tissue information including a lot of tissue information in the middle layer as shown in FIG.
(3) Further, the image signal picked up by the CCD 4 by the R1 filter 14r1 picks up a band image having middle layer and deep layer tissue information including a lot of deep layer tissue information as shown in FIG.

  Then, the video processor 7 synchronizes these RGB image signals and performs signal processing, so that an endoscopic image having a desired or natural color reproduction can be obtained as an endoscopic image.

  On the other hand, when the mode switching switch 41 of the electronic endoscope 3 is pressed, the signal is input to the mode switching circuit 42 of the video processor 7. The mode switching circuit 42 outputs a control signal to the mode switching motor 19 of the light source device 4, thereby moving the first filter set of the rotary filter 14 that was on the optical path during normal observation to light the second filter set. The rotary filter 14 is driven with respect to the optical path so as to be disposed on the path.

The G2 filter unit 14g2, the B2 filter unit 14b2, and the light-shielding filter unit 14Cut at the time of narrow band light observation of the body cavity tissue 51 by the second filter set have a narrow spectral characteristic of the illumination light as shown in FIG. Because each wavelength band does not overlap with a band sequential light,
(4) A band image having tissue information in a shallow layer as shown in FIG. 13 is picked up on the image pickup signal picked up by the CCD 4 by the B2 filter unit 14b2,
(5) Further, a band image having tissue information in the middle layer as shown in FIG. 14 is picked up on the image pickup signal picked up by the CCD 4 by the G2 filter unit 14g2.

  On the other hand, the white balance circuit 25 includes a white balance correction unit 80 and a white balance correction value calculation unit 81 as shown in FIG.

  In the endoscope apparatus 1 of the present embodiment, the white balance is acquired by attaching a cylindrical white cap 45 whose inner side is whitened to the tip of the insertion portion 3a of the electronic endoscope 3 before the examination.

  Specifically, when the white balance switch 7C provided on the front panel 7a of the video processor 7 is pressed with the white cap 45 attached to the distal end of the insertion portion 3a of the electronic endoscope 3, the light source device 3, the first filter set of the rotary filter 14 is arranged on the optical path, and the white balance circuit 25 of the video processor 7 acquires the first white balance by the normal light. When the white balance with the normal light is acquired, the second filter set of the rotary filter 14 is arranged on the optical path in the light source device 3, and the second time due to the narrowband light in the white balance circuit 25 of the video processor 7. White balance is acquired. During the first and second acquisition of white balance, the narrowband light observation mode display unit 4b provided on the front panel 4a of the light source device 3 and the narrowband light observation provided on the front panel 7a of the video processor 7 are used. The mode display portion 7b is lit with a predetermined color.

  Note that the color that lights during the first white balance acquisition may be different from the color that lights during the second white balance acquisition, for example, during the first white balance acquisition. The color to be turned on is green, and the color that is turned on during the second white balance acquisition is white.

  In the white balance circuit 25, the white balance correction value calculation unit 81 switches the white balance correction value calculation method according to the mode detection signal that is a control signal from the mode switching circuit 42.

In particular,
First white balance with normal light:
(R correction value) = (G average value) / (R average value), (B correction value) = (G average value) / (B average value)
Second white balance with narrowband light:
(R correction value) = (predetermined fixed value), (B correction value) = (G average value) / (B average value)
The white balance correction unit 80 multiplies the corresponding input signal by the correction value of each signal and outputs the result.

  Thus, in this embodiment, since the white balance method is switched between normal light and narrowband light, even when the number of bands of irradiation light by narrowband light is two, the correction value of the R signal cannot be calculated. The state can be avoided and the white balance can be acquired. In addition, it can be clearly seen that the white balance is operating, and it is possible to visually grasp what operation is being performed by color-coding.

  In this embodiment, white balance acquisition processing is performed by lighting in the narrow-band light observation mode display units 4b and 7b. However, the present invention is not limited to this, and as shown in FIG. 16, the light source device 3 and the video processor Speakers 61 and 62 may be provided in 7 to notify by sound. In this case, during the acquisition of the first and second white balances, even if an announcement is made with the same sound, or during the acquisition of the first white balance and between the acquisition of the second white balance It is good also as a different sound from the sound which generate | occur | produces. It can be recognized as a sound that the white balance is operating, and it is possible to grasp what operation is being performed now without looking at the device.

  Further, as shown in FIG. 17, a message window 63 may be displayed on the observation monitor 5, and a message such as “white balance operation in progress” may be displayed on the message window 63. During the first and second acquisition of white balance, the same wording is announced, for example, “in white balance operation”, or the wording displayed during the first white balance acquisition, for example “white balance” The display wording may be changed, for example, the wording displayed during “1 operation” and the second white balance acquisition, for example, “white balance 1 operation”. Further, words such as “white balance in operation” may be displayed during white balance acquisition, and words such as “white balance inactive” may be displayed while white balance is not acquired. The fact that the white balance is operating is displayed on the observation monitor 5 as character information, which makes it easier to recognize it as visual.

  Note that, in the endoscope apparatus 1 of the above-described embodiment, an explanation will be given by taking as an example a frame sequential endoscope apparatus in which the light source device 4 supplies the frame sequential light and the video processor 7 synchronizes the plane sequential image information to form an image. However, the present invention is not limited to this, and can also be applied to a simultaneous endoscope apparatus.

  That is, as shown in FIG. 18, the light source device 4a for supplying white light, the electronic endoscope 3a having the color chip 100 on the front surface of the imaging surface of the CCD 2, and the image pickup signal from the electronic endoscope 3a are processed. The present embodiment can also be applied to the simultaneous endoscope apparatus 1a including the video processor 7a.

  In the light source device 4a, the amount of white light from the xenon lamp 11 via the heat ray cut filter 12 is controlled by the diaphragm device 13 and emitted to the incident surface of the light guide 15 disposed in the electronic endoscope 3a. A narrow band limiting filter 14a for converting into narrow band light having discrete spectral characteristics as shown in FIG. 7 is detachably provided on the white light path.

  In the electronic endoscope 3 a, an image of the body cavity tissue 51 is captured by the CCD 2 via the color chip 100.

  In the video processor 7a, the image data from the A / D converter 24 is separated into the luminance signal Y and the color difference signals Cr and Cb by the Y / C separation circuit 101, converted into RGB signals by the RGB matrix circuit 102, and the white balance circuit. 25 is output. Other configurations and operations are the same as those of the endoscope apparatus of FIG.

  The white balance circuit 25 acquires white balance for each of the RGB signals from the RGB matrix circuit 102 as shown in FIG. The white balance acquisition method at this time is the same as in this embodiment.

  FIG. 20 is a configuration diagram showing the configuration of the white balance circuit according to the second embodiment of the present invention.

  Since the second embodiment is almost the same as the first embodiment, only different points will be described, and the same components are denoted by the same reference numerals and description thereof will be omitted.

  In the field sequential endoscope apparatus 1 shown in FIG. 4, the white balance circuit 25 of this embodiment includes an R / G / B signal generator 82 as shown in FIG. The generation unit 82 obtains white balance in the same manner as in the first embodiment after replacing the R signal according to the observation mode in response to the input of the frame sequential R / G / B signal.

That is, in the R / G / B signal generator 82,
Normal light: R signal ← R signal Narrow band: R signal ← G signal is replaced and output to the white balance correction unit 80, and the white balance correction unit 80 acquires the white balance.

    The B signal may be assigned to the R signal, or signal data prepared in advance separately from the output of the CCD 2 may be used.

  The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the scope of the present invention.

1 is an external view showing an external configuration of an endoscope apparatus according to Embodiment 1 of the present invention. The figure which shows the front panel of the light source device of FIG. The figure which shows the front panel of the video processor of FIG. 1 is a configuration diagram showing the configuration of the endoscope apparatus of FIG. The block diagram which shows the structure of the rotation filter of FIG. The figure which shows the spectral characteristics of the 1st filter set of the rotation filter of FIG. The figure which shows the spectral characteristics of the 2nd filter set of the rotation filter of FIG. The figure which shows the layer direction structure of the biological tissue observed with the endoscope apparatus of FIG. The figure explaining the arrival state to the layer direction of the biological tissue of the illumination light from the endoscope apparatus of FIG. FIG. 6 is a first diagram showing each band image by frame sequential light transmitted through the first filter set in FIG. 6. 2nd figure which shows each band image by the surface sequential light which permeate | transmitted the 1st filter set of FIG. 3rd figure which shows each band image by the field sequential light which permeate | transmitted the 1st filter set of FIG. FIG. 7 is a first diagram showing each band image by frame sequential light transmitted through the second filter set in FIG. 7. 2nd figure which shows each band image by the field sequential light which permeate | transmitted the 2nd filter set of FIG. The block diagram which shows the structure of the white balance circuit of FIG. 1 is an external view showing an external configuration of a first modification of the endoscope apparatus of FIG. 1 is an external view showing an external configuration of a second modification of the endoscope apparatus of FIG. The block diagram which shows the structure of the simultaneous endoscope apparatus which is a modification of the endoscope apparatus of FIG. 18 is a block diagram showing the configuration of the white balance circuit of FIG. The block diagram which shows the structure of the white balance circuit based on Example 2 of this invention.

Explanation of symbols

1 ... Endoscope device 2 ... CCD
DESCRIPTION OF SYMBOLS 3 ... Electronic endoscope 4 ... Light source device 5 ... Observation monitor 6 ... Image filing device 7 ... Video processor 10 ... Power supply part 11 ... Xenon lamp 12 ... Heat ray cut filter 13 ... Diaphragm device 14 ... Rotary filter 15 ... Light guide 16 ... Condensing lens 17 ... Control circuit 18 ... Rotary filter motor 19 ... Mode switching motor 19
DESCRIPTION OF SYMBOLS 20 ... CCD drive circuit 21 ... Objective optical system 22 ... Amplifier 23 ... Process circuit 24 ... A / D converter 25 ... White balance circuit 26 ... Selector 27, 28, 29 ... Synchronization memory 30 ... Image processing circuit 31, 32, 33 ... D / A circuit 34 ... encoding circuit 35 ... timing generator 41 ... mode switching switch 42 ... mode switching circuit 43 ... dimming circuit 44 ... dimming control parameter switching circuit 80 ... white balance correction unit 81 ... white balance correction value Calculation Department Agent Patent Attorney Susumu Ito

Claims (3)

An illumination light supply means for supplying illumination light including a visible light region, an endoscope having an imaging means for illuminating the subject with the illumination light and imaging the subject with return light, and an imaging signal from the imaging means In an endoscope apparatus provided with signal processing means for processing,
Band limiting means for limiting the illumination light to narrow band light of a plurality of discrete band areas and irradiating the subject,
White balance means for performing white balance processing on the imaging signal of the subject by the illumination light,
The white balance means is
First white balance correction value calculating means for calculating a first white balance correction value for the illumination light;
A signal replacement means for replacing an imaging signal of a predetermined band of the narrowband light with a predetermined level signal;
An endoscope apparatus comprising: a correction value calculation unit that calculates a second white balance correction value for the imaging signal replaced by the signal replacement unit. The endoscope apparatus according to claim 1, wherein the signal replacement unit replaces an imaging signal in a predetermined band region of the narrowband light with a predetermined fixed value. The endoscope apparatus according to claim 1, wherein the signal replacement unit replaces an imaging signal in a predetermined band of the narrowband light with an imaging signal in a predetermined band of the illumination light.

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