JP2011110272A - Endoscope apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endoscope apparatus which includes an endoscope insertion portion for irradiating a region to be observed with exciting light, the endoscope apparatus accurately acquiring information on distance between the distal end of the endoscope insertion portion and the region to be observed with a simple configuration. <P>SOLUTION: A fluorescent mark M arranged close to the region to be observed is imaged. The information on distance between the distal end of the endoscope insertion portion and the region to be observed is acquired based on the signal strength of the imaged fluorescent mark M. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an endoscope apparatus including an endoscope insertion portion that is inserted into a body cavity and irradiates an observation portion with excitation light.

  Conventionally, endoscope systems for observing tissue in a body cavity are widely known, and a normal image is obtained by imaging a portion to be observed in a body cavity by irradiation with white light, and this normal image is displayed on a monitor screen. Electronic endoscope systems have been widely put into practical use.

  Moreover, as an endoscope system as described above, for example, in Patent Document 1, an autofluorescence image emitted from an observed part by irradiation of excitation light is captured together with a normal image to obtain autofluorescence images. There has been proposed a fluorescence endoscope system that displays the above image on a monitor screen.

  In addition, as a fluorescence endoscope system, for example, ICG (Indocyanine Green) is introduced into the body in advance, and the fluorescence image of the blood vessel is detected by irradiating the observation part with excitation light and detecting the fluorescence of ICG in the blood vessel Some have also been proposed.

  Here, in the above endoscope system, there is a case where it is desired to obtain distance information between the distal end of the endoscope insertion portion inserted into the body cavity and the observed portion.

  Conventionally, as a distance measuring device used for medical equipment, a measuring ruler, an ultrasonic distance measuring device, a laser distance measuring device, and the like have been proposed.

  Further, for example, in Patent Document 2, a laser spot light of red or infrared is irradiated to an observed part, reflected light of the spot light is imaged by two image sensors, and an optical path incident on the image sensor is detected. A method for obtaining the distance from the difference has been proposed.

JP 2005-204905 A Japanese Patent No. 3191932

  However, the measurement ruler has a problem of invasion to a living body and a problem of reflection in an imaging system, and the ultrasonic distance measuring apparatus and the laser distance measuring apparatus have a problem that the apparatus becomes large and the cost increases.

  Further, in the method described in Patent Document 2, when white light that is illumination light for observation and spot light for distance measurement are simultaneously irradiated, similar spot light is generated due to a reflected component of white light, and an accurate distance is obtained. This causes problems that cannot be measured. In addition, since a subject having various color components is included in a normal image, it is very difficult to recognize only the reflected light portion of the spot light. In other words, the method described in Patent Document 2 has a problem that distance cannot be measured during normal image capturing.

  Also, for example, when controlling the intensity of the excitation light irradiated to the observed part according to the distance information between the distal end of the endoscope insertion part and the observed part, the excitation light Although the intensity needs to be controlled, the method described in Patent Document 2 cannot measure the distance because red or infrared laser spot light does not appear in the fluorescence image.

  The present invention has been made in view of the above problems, and in an endoscope apparatus including an endoscope insertion portion that irradiates an observation portion with excitation light, the distal end of the endoscope insertion portion and the observation portion It is an object of the present invention to provide an endoscope apparatus that can accurately acquire distance information between the two and a distance between them.

  The fluorescence endoscope apparatus of the present invention is inserted into a body cavity and is emitted from an observed part by irradiation of excitation light by the endoscope inserting part that irradiates the observed part with excitation light. In a fluorescence endoscope apparatus including an imaging unit that receives fluorescence and captures a fluorescence image of an observed part, the imaging part images a fluorescent label installed in the vicinity of the observed part. And a distance information acquisition unit that acquires distance information between the distal end of the endoscope insertion unit and the observed portion based on the signal intensity of the fluorescent marker imaged by the unit.

  Further, in the fluorescence endoscope apparatus of the present invention, the distance information acquisition unit is assumed that correction data resulting from the cosine fourth law of the optical system of the imaging unit is set in advance, and the signal intensity of the fluorescent label is Thus, the distance information can be acquired based on the corrected signal intensity corrected using the correction data.

  In addition, the distance information acquisition unit assumes that correction data resulting from the illuminance distribution of the excitation light irradiated to the fluorescent label is set in advance, and corrects the signal intensity of the fluorescent label using the correction data The distance information can be acquired based on the completed signal strength.

  In addition, a plurality of fluorescent labels may be arranged at a predetermined interval, and the distance information acquisition unit may acquire distance information based on the signal intensity of the fluorescent label and the signal intensity of the interval.

  In addition, a fluorescent label can be provided on a treatment instrument installed in the vicinity of the observed portion.

  An irradiation intensity control unit that controls the irradiation intensity of the excitation light can be provided based on the distance information acquired by the distance information acquisition unit.

  According to the fluorescence endoscope apparatus of the present invention, the fluorescent marker installed in the vicinity of the observed portion is imaged, and based on the signal intensity of the captured fluorescent label, the endoscope insertion portion tip, the observed portion, Thus, accurate distance information between the distal end of the endoscope insertion portion and the observed portion can be accurately acquired with a simpler configuration.

  Further, in the fluorescence endoscope apparatus of the present invention, the correction data resulting from the cosine fourth law of the optical system of the imaging unit and the correction data resulting from the illuminance distribution of the excitation light irradiated to the fluorescent label are set in advance. When the distance information is acquired based on the corrected signal intensity obtained by correcting the signal intensity of the fluorescent label using the correction data, it is possible to acquire more accurate distance information.

In addition, when a plurality of fluorescent labels are arranged at predetermined intervals and distance information is acquired based on the signal intensity of the fluorescent label and the signal intensity of the interval, for example, the signal distance of the fluorescent label If the distance information is acquired based on the result of subtracting the signal strength of the interval from
Signals based on background fluorescence emitted from around the fluorescent label can be removed, and distance information with higher accuracy can be acquired.

  In addition, when the fluorescent label is provided on a treatment instrument installed in the vicinity of the observed portion, the distance information can be acquired with an existing apparatus without preparing a special instrument or the like.

  Further, when the irradiation intensity of the excitation light is controlled based on the distance information acquired by the distance information acquisition unit, the observation unit is irradiated with more than necessary excitation light. It is possible to prevent damage and to obtain sufficient fluorescence intensity from the observed portion.

Schematic configuration diagram of a rigid endoscope system using an embodiment of an endoscope apparatus of the present invention Schematic configuration diagram of hard insertion part Schematic configuration diagram of the imaging unit The block diagram which shows schematic structure of an image processing apparatus and a light source device The figure which shows schematic structure of forceps The figure which shows an example of the mark provided in forceps The figure which shows an example of the state by which the hard insertion part and forceps were inserted in the body cavity The figure which shows an example of the fluorescence image containing a normal image and a mark image The flowchart for demonstrating the acquisition method of the distance information in one Embodiment of the endoscope apparatus of this invention. Diagram showing the distance between the hard insertion section tip and the observed section Intensity changes C1 and C2 of the fluorescence image signal due to the cosine fourth power law of the lens of the first imaging system, and intensity changes D1 and D2 of the fluorescence image signal due to the illuminance distribution of the excitation light irradiated to the observed portion Figure showing an example The figure which shows an example of the look-up table which matched the distance information of the front-end | tip of a hard insertion part, and a to-be-observed part, and the correction | amendment fluorescence image signal. The figure which shows other embodiment of a mark

  Hereinafter, a rigid endoscope system using an embodiment of an endoscope apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 is an external view showing a schematic configuration of a rigid endoscope system 1 of the present embodiment.

  As shown in FIG. 1, the rigid endoscope system 1 according to the present embodiment guides the normal light and excitation light emitted from the light source device 2 and the light source device 2 that emits white normal light and excitation light. A rigid mirror imaging apparatus that irradiates the observation unit and captures a normal image based on reflected light reflected from the observed portion by irradiation of normal light and a fluorescent image based on fluorescence emitted from the observed portion by irradiation of excitation light 10, an image processing device 3 that performs a predetermined process on the image signal captured by the rigid endoscope imaging device 10, and a normal image and a fluorescence image of the observed portion based on the display control signal generated in the image processing device 3. And a monitor 4 for display.

  As shown in FIG. 1, the rigid endoscope imaging apparatus 10 includes a hard insertion portion 30 that is inserted into the abdominal cavity and an imaging unit 20 that captures a normal image and a fluorescence image of the observed portion guided by the hard insertion portion 30. And.

  In addition, as shown in FIG. 2, the rigid endoscope imaging apparatus 10 has a hard insertion portion 30 and an imaging unit 20 that are detachably connected. The hard insertion portion 30 includes a connection member 30a, an insertion member 30b, a cable connection port 30c, an irradiation lens 30d, and an imaging lens 30e.

  The connection member 30a is provided on one end side 30X of the hard insertion portion 30 (insertion member 30b). For example, the connection member 30a is fitted into an opening 20a formed on the imaging unit 20 side, so that the imaging unit 20 and the hard insertion portion 30 are fitted. Are detachably connected.

  The insertion member 30b is inserted into the abdominal cavity when photographing inside the abdominal cavity, and is formed of a hard material and has, for example, a cylindrical shape with a diameter of approximately 10 mm. The insertion member 30b accommodates a lens group for forming an image of the observed portion. The normal image and the fluorescent image of the observed portion incident from the other end 30Y are the imaging lens 30e and the above-described lens. The light is emitted to the imaging unit 20 side of the one end side 30X through the lens group.

  A cable connection port 30c is provided on the side surface of the insertion member 30b, and the optical cable LC is mechanically connected to the cable connection port 30c. Thereby, the light source device 2 and the insertion member 30b are optically connected via the optical cable LC.

  The irradiation lens 30d is provided on the other end side 30Y of the hard insertion portion 30, and irradiates the observed portion with normal light and excitation light guided by the optical cable LC. In addition, a light guide for guiding normal light and excitation light from the cable connection port 30c to the irradiation lens 30d is accommodated in the insertion member 30b (not shown), and the irradiation lens 30d is guided by the light guide. The light to be observed is irradiated with normal light and excitation light.

  FIG. 3 is a diagram illustrating a schematic configuration of the imaging unit 20. The imaging unit 20 includes a first imaging system that captures a fluorescent image of the observed portion formed by the lens group in the hard insertion portion 30 and generates a fluorescent image signal of the observed portion, and the hard insertion portion 30. And a second imaging system that generates a normal image signal by capturing a normal image of the observed portion formed by the lens group. These imaging systems are divided into two optical axes orthogonal to each other by a dichroic prism 21 having a spectral characteristic that reflects a normal image and transmits a fluorescent image.

  The first imaging system is an excitation light cut filter 22 that cuts the excitation light emitted from the hard insertion portion 30 and transmitted through the dichroic prism 21, and the dichroic prism 21 and the excitation light cut filter 22 that are emitted from the hard insertion portion 30. The first imaging optical system 23 that forms an image of the fluorescent image L4 that has passed through the first imaging optical system 23, and the high-sensitivity imaging device 24 that images the fluorescent image L4 imaged by the first imaging optical system 23.

  The second imaging system is a normal image formed by the second imaging optical system 25 and a second imaging optical system 25 that forms a normal image L3 emitted from the hard insertion portion 30 and reflected by the dichroic prism 21. An image sensor 26 that captures the image L3 is provided.

  The high-sensitivity imaging element 24 detects light in the wavelength band of the fluorescent image L4 with high sensitivity, converts it into a fluorescent image signal, and outputs it. The high sensitivity image sensor 24 is a monochrome image sensor.

  The image sensor 26 detects light in the wavelength band of the normal image, converts it into a normal image signal, and outputs it. On the image pickup surface of the image pickup element 26, color filters of three primary colors red (R), green (G) and blue (B), or cyan (C), magenta (M) and yellow (Y) are arranged in a Bayer array or a honeycomb. It is provided in an array.

  In addition, the imaging unit 20 includes an imaging control unit 27. The imaging control unit 27 performs CDS / AGC (correlated double sampling / automatic gain control) processing and A / D on the fluorescence image signal output from the high-sensitivity imaging device 24 and the normal image signal output from the imaging device 26. A conversion process is performed and output to the image processing apparatus 3 via the cable 5 (see FIG. 1).

  As shown in FIG. 4, the image processing apparatus 3 includes a normal image input controller 31, a fluorescence image input controller 32, an image processing unit 33, a memory 34, a video output unit 35, an operation unit 36, a TG (timing generator) 37, and a CPU 38. And a distance information acquisition unit 39.

  The normal image input controller 31 and the fluorescence image input controller 32 include a line buffer having a predetermined capacity, and temporarily store the normal image signal and the fluorescence image signal for each frame output from the imaging control unit 27 of the imaging unit 20. To remember. Then, the normal image signal stored in the normal image input controller 31 and the fluorescent image signal stored in the fluorescent image input controller 32 are stored in the memory 34 via the bus.

  The image processing unit 33 receives a normal image signal and a fluorescence image signal for each frame read from the memory 34, performs predetermined image processing on these image signals, and outputs them to the bus.

  The distance information acquisition unit 39 acquires distance information between the tip of the hard insertion unit 30 and the observed portion based on the fluorescence image signal output from the imaging unit 20.

  Here, in the rigid endoscope system of the present embodiment, a forceps 6 as shown in FIG. 5A is used. The forceps 6 shown in FIG. 5A includes an operating portion 6a for holding an observed portion or performing a predetermined treatment, an operating portion 6a, a handle portion 6b having a thin cylindrical shape, and an operator operating the operating portion. And an operation unit 6c for performing the operation 6a. A distance measuring mark M is provided on the circumference of the handle 6b at the tip of the forceps 6 as shown in FIG. 5B. In the present embodiment, the mark M is formed in a cylindrical shape by a fluorescent material that emits fluorescence of 800 nm or more and 850 nm or less when irradiated with near infrared excitation light of 750 nm or more and 800 nm or less. For the fluorescent material forming the mark M, it is desirable to use a fluorescent agent such as ICG described later or a material that emits fluorescence in the same wavelength band as the wavelength band of autofluorescence.

  The fluorescent image signal output from the imaging unit 20 includes a signal representing the mark M, and the distance information acquisition unit 39 is based on the intensity of the signal representing the mark M. The distance information between the tip and the observed part is acquired. The operation of the distance information acquisition unit 39 will be described in detail later.

  The video output unit 35 receives the normal image signal and the fluorescence image signal output from the image processing unit 33 via the bus, performs predetermined processing to generate a display control signal, and outputs the display control signal to the monitor 4. Output.

  The operation unit 36 receives input by the operator such as various operation instructions and control parameters. The TG 37 outputs a driving pulse signal for driving the high-sensitivity imaging device 24, the imaging device 26 of the imaging unit 20, and the LD driver 45 of the light source device 2 described later. The CPU 36 controls the entire apparatus.

  As shown in FIG. 4, the light source device 2 condenses the normal light source 40 that emits normal light (white light) L <b> 1 having a broadband wavelength of about 400 to 700 nm and the normal light L <b> 1 emitted from the normal light source 40. The condensing lens 42 and the normal light L1 collected by the condensing lens 42 are transmitted, the excitation light L2 described later is reflected, and the normal light L1 and the excitation light L2 are incident on the incident end of the optical cable LC. And a dichroic mirror 43. For example, a xenon lamp is used as the normal light source 40. A diaphragm 41 is provided between the normal light source 40 and the condenser lens 42, and the amount of the diaphragm is controlled based on a control signal from ALC (Automatic light control).

  Further, the light source device 2 emits near-infrared light of 750 to 800 nm that excites the fluorescent dye ICG to generate fluorescence, as an excitation light L2, and an LD driver 45 that drives the LD light source 44. , A condenser lens 46 that condenses the excitation light L2 emitted from the LD light source 44, and a mirror 47 that reflects the excitation light L2 collected by the condenser lens 46 toward the dichroic mirror 43.

  In the present embodiment, the light having the wavelength band as described above is used as the excitation light L2. However, the excitation light L2 is not limited to the light having the above wavelength band, and the fluorescent material that forms the mark M is used for the subject. It is determined appropriately depending on the type of fluorescent dye to be introduced or the type of biological tissue to be autofluorescent.

  The LD driver 45 controls the intensity of the excitation light output from the LD light source 44 based on the distance information acquired by the distance information acquisition unit 39 of the image processing device 3. That is, the distance information becomes large so that the observed part is not damaged by irradiating the observed part with more excitation light than necessary and sufficient fluorescence intensity is obtained from the observed part. The LD light source 44 is driven and controlled so that the intensity of the excitation light increases and the intensity of the excitation light decreases as the distance information decreases.

  Next, the operation of the rigid endoscope system of this embodiment will be described.

  First, after the hard insertion portion 30 and the cable 5 to which the optical cable LC is connected are attached to the imaging unit 20, the light source device 2, the imaging unit 20, and the image processing device 3 are powered on and driven.

  Next, as shown in FIG. 6, the operator inserts the hard insertion portion 30 and the forceps 6 into the abdominal cavity, the observation portion is sandwiched by the forceps 6, and the distal end of the hard insertion portion 30 is the observation portion. It is installed in the vicinity.

  Then, the normal light L1 emitted from the normal light source 40 of the light source device 2 is incident on the hard insertion portion 30 via the condenser lens 42, the dichroic mirror 43, and the optical cable LC, and is irradiated from the irradiation lens 30d of the hard insertion portion 30. Irradiate the observation part. On the other hand, the special light L2 emitted from the LD light source 44 of the light source device 2 is incident on the hard insertion portion 30 via the condenser lens 46, the mirror 47, the dichroic mirror 43, and the optical cable LC, and the irradiation lens of the hard insertion portion 30 is obtained. The portion to be observed is irradiated with normal light from 30d.

  Then, a normal image based on the reflected light reflected from the observed portion by the irradiation of the normal light L1 is captured, and a fluorescent image based on the fluorescence emitted from the observed portion by the irradiation of the special light L2 is captured. It should be noted that ICG is administered to the observed part in advance, and fluorescence emitted from the ICG is imaged.

  More specifically, when the normal image is captured, the normal image L3 based on the reflected light reflected from the observed portion by the irradiation of the normal light L1 is incident from the tip 30Y of the insertion member 30b, and the inside of the insertion member 30b. Are guided by the imaging lens 30e and the lens group and emitted toward the imaging unit 20.

  The normal image L3 incident on the imaging unit 20 is reflected by the dichroic prism 21 in the direction perpendicular to the imaging element 26, and is imaged on the imaging surface of the imaging element 26 by the second imaging optical system 25. 26 sequentially captures images at predetermined intervals. In the present embodiment, it is assumed that a normal image is captured at a frame rate of 30 fps.

  The normal image signal sequentially output from the image sensor 26 is subjected to CDS / AGC (correlated double sampling / automatic gain control) processing and A / D conversion processing in the imaging control unit 27, and then the image is transmitted through the cable 5. The data is sequentially output to the processing device 3.

  On the other hand, when the fluorescent image is picked up, a fluorescent image L4 based on the fluorescence emitted from the observed portion by the irradiation of the special light enters from the tip 30Y of the insertion member 30b, and the imaging lens 30e and the lens in the insertion member 30b. The light is guided by the group and emitted toward the imaging unit 20.

  The fluorescent image L4 incident on the imaging unit 20 passes through the dichroic prism 21 and the special light cut filter 22, and then is imaged on the imaging surface of the high-sensitivity imaging device 24 by the first imaging optical system 23, and has high sensitivity. Images are taken at a predetermined interval by the image sensor 24. In the present embodiment, it is assumed that the fluorescence image is captured at a frame rate of 5 to 10 fps.

  The fluorescent image signals sequentially output from the high-sensitivity image sensor 24 are subjected to CDS / AGC (correlated double sampling / automatic gain control) processing and A / D conversion processing in the imaging control unit 27, and then passed through the cable 5. Are sequentially output to the image processing apparatus 3.

  The normal image signal input to the image processing device 3 is temporarily stored in the normal image input controller 31 and then stored in the memory 34. Then, the normal image signal for each frame read from the memory 34 is subjected to gradation correction processing and sharpness correction processing in the image processing unit 33 and then sequentially output to the video output unit 35.

  Then, the video output unit 35 performs a predetermined process on the input normal image signal to generate a display control signal, and sequentially outputs the display control signal for each frame to the monitor 4. The monitor 4 displays a normal image based on the input display control signal.

  On the other hand, the fluorescence image signal input to the image processing device 3 is temporarily stored in the fluorescence image input controller 32 and then stored in the memory 34. The fluorescent image signals for each frame read from the memory 34 are subjected to predetermined image processing in the image processing unit 33 and then sequentially output to the video output unit 35.

  The video output unit 35 performs a predetermined process on the input fluorescent image signal to generate a display control signal, and sequentially outputs the display control signal for each frame to the monitor 4. The monitor 4 displays a fluorescent image based on the input display control signal.

  In the present embodiment, the normal image and the fluorescence image are displayed at the same time. FIG. 7 shows an example of a normal image and a fluorescence image displayed on the monitor 4.

  Here, as shown in FIG. 7, the fluorescent image includes the mark fluorescent image of the mark M provided at the tip of the forceps 6, that is, the mark fluorescent image signal representing the mark fluorescent image in the fluorescent image signal. It is included. In the rigid endoscope system of the present embodiment, distance information between the tip of the hard insertion portion 30 and the observed portion is acquired based on the mark fluorescence image signal included in the fluorescence image signal.

  Specifically, as shown in the flowchart of FIG. 8, the distance information acquisition unit 39 acquires a fluorescence image signal (S10), and the acquired fluorescence image signal is the cosine fourth power of the lens of the first imaging system. Correction processing is performed to remove the influence caused by the law and the influence caused by the illuminance distribution of the excitation light irradiated to the observed part (S12).

  Specifically, as the correction process, the fluorescence image signal Q (x, y) of each pixel is multiplied by the correction coefficient k (x, y) to obtain Q ′ (x, y) for each pixel. To do.

  The correction coefficient k (x, y) is obtained by irradiating the complete diffusion plate or the like with the excitation light emitted from the LD light source 44 at a predetermined irradiation distance, and obtaining the excitation light image signal by imaging the reflected light. The excitation light image signal is obtained by calculating k (x, y) = QL (0, 0) / QL (x, y). Note that QL (x, y) in the above equation is the value of each pixel of the excitation light image signal, and QL (0, 0) is the value of the maximum luminance value of the excitation light image signal. In the present embodiment, it is assumed that the optical axis of the excitation light and the optical axis of the first imaging system are substantially coaxial, and the maximum luminance value QL (0, 0) is the value of the center pixel.

  Here, as shown in FIG. 9, the fluorescence caused by the cosine fourth law of the lens of the first imaging system when the distance between the tip of the hard insertion portion 30 and the observed portion is L1 and L2. FIG. 10 shows intensity changes C1 and C2 of the image signal, and intensity changes D1 and D2 of the fluorescence image signal due to the illuminance distribution of the excitation light irradiated to the observed part. Note that the origin 0 in FIG. 10 is the position of the central pixel, and the horizontal axis indicates position information in the radial direction.

  As shown in FIG. 10, the distribution shape of the product of the distribution C1 and the distribution D2 and the distribution shape of the product of the distribution C2 and the distribution D2 have a similar relationship regardless of the distance. Therefore, k (x, y) calculated by the above equation, that is, the ratio between the maximum luminance value and the value of the predetermined pixel becomes a constant value without depending on the distance.

  Then, the distance information acquisition unit 39 extracts the mark fluorescence image signal from the corrected fluorescence image signal Q ′ (x, y) calculated as described above (S14). The extraction of the mark fluorescence image signal may be performed based on, for example, pattern recognition or the intensity of the fluorescence image signal.

In the distance information acquisition unit 39, as shown in FIG. 11, the distance information between the tip of the hard insertion unit 30 and the observed portion is associated with the corrected fluorescence image signal Q ′ (x, y). A table is set in advance, and the distance information acquisition unit 39 acquires distance information L _x based on the mark fluorescence image signal extracted as described above (S16).

Then, the distance information is distance information L _x acquired by the acquisition unit 39 is output to the CPU 38, the CPU 38, the intensity of the excitation light corresponding to the input distance information L _x is obtained. It is assumed that a lookup table in which the distance information L _x and the intensity of excitation light are associated with each other is set in the CPU 38 in advance. The intensity of the excitation light is such that more than necessary excitation light is irradiated to the observed part so that the observed part is not damaged and sufficient fluorescence intensity is obtained from the observed part. Is set to That is, the intensity of the excitation light increases as the distance information increases, and the intensity of the excitation light decreases as the distance information decreases. Further, as long as the observed portion is not damaged, the operator may arbitrarily adjust the intensity of the excitation light.

  The CPU 38 outputs a control signal to the LD driver 45 based on the intensity of the excitation light acquired as described above, and the LD driver 45 outputs the excitation light output from the LD light source 44 based on the input control signal. Is controlled (S18).

  In the description of the above embodiment, only one cylindrical mark M is provided on the forceps 6. However, the present invention is not limited to this, and a plurality of line-shaped marks M1 are provided on the forceps 6 as shown in FIG. , M2 may be provided.

  And, for example, between the corrected fluorescent image signal Q ′ (x, y), the first mark fluorescent image signal corresponding to the mark M1, the second mark fluorescent image signal corresponding to the mark M2, and the mark M1 and the mark M2 The unmarked fluorescent image signal corresponding to the portion NM not coated with the fluorescent material is extracted, and the unmarked fluorescent image signal is obtained from the average value or the maximum value of the first mark fluorescent image signal and the second mark fluorescent image signal. And the distance information may be acquired based on the subtracted third mark fluorescence image signal and the look-up table shown in FIG.

  The reason for subtracting the markless fluorescence image signal as described above is that the fluorescence image signals corresponding to the marks M1 and M2 include a signal based on the background fluorescence emitted from the periphery of the mark. This is because the influence of this background fluorescence is reduced, and more accurate distance information is acquired.

  Moreover, in the said embodiment, although the line formed on the circumference of the forceps 6 was used as a mark, it is not restricted to this, For example, you may make it use a rectangular pattern.

  In the above-described embodiment, the mark is provided on the forceps. However, the present invention is not limited to this, and the mark may be provided on a treatment instrument used in other surgery, or a sheet provided with the mark may be observed. You may make it stick in the vicinity of a part.

  Moreover, in the said embodiment, although the intensity of excitation light was controlled based on distance information, you may make it control the intensity | strength of normal light based on distance information.

  In the above embodiment, a xenon lamp is used as a normal light source. However, the present invention is not limited to this, and a high-intensity white light source using a GaN-based semiconductor laser (trade name: Micro White, Nichia Corporation) May be used. This high-intensity white light source guides light emitted from a semiconductor laser having a wavelength of 445 nm to an optical fiber using an optical lens, and has a total luminous flux of 501 nm from the other end face of the optical fiber coated with a phosphor material. It emits white light.

  Moreover, although the said embodiment applies the imaging device of this invention to a rigid endoscope system, you may apply not only to this but the other endoscope system which has a flexible endoscope apparatus, for example. .

DESCRIPTION OF SYMBOLS 1 Rigid endoscope system 2 Light source device 3 Image processing apparatus 4 Monitor 6 Forceps 10 Rigid mirror imaging apparatus 20 Imaging unit 30 Hard insertion part 39 Distance information acquisition part

Claims (6)

An endoscope insertion part that is inserted into a body cavity and emits excitation light to the observation part, and receives fluorescence emitted from the observation part by irradiation of excitation light by the endoscope insertion part and receives the observation light In a fluorescence endoscope apparatus including an imaging unit that captures a fluorescence image of a part,
The imaging unit captures a fluorescent label installed in the vicinity of the observed portion;
A fluorescence endoscope comprising a distance information acquisition unit that acquires distance information between the distal end of the endoscope insertion unit and the observed portion based on a signal intensity of a fluorescent marker imaged by the imaging unit Mirror device.   The distance information acquisition unit is preset with correction data resulting from the cosine fourth law of the optical system of the imaging unit, and corrects the signal intensity of the fluorescent marker using the correction data. The fluorescence endoscope apparatus according to claim 1, wherein the distance information is acquired based on the corrected signal intensity.   The distance information acquisition unit is preset with correction data resulting from the illuminance distribution of the excitation light irradiated on the fluorescent label, and corrects the signal intensity of the fluorescent label using the correction data. The fluorescence endoscope apparatus according to claim 1, wherein the distance information is acquired based on the corrected signal intensity subjected to. A plurality of the fluorescent labels are arranged at predetermined intervals,
4. The fluorescent information according to claim 1, wherein the distance information acquisition unit acquires the distance information based on a signal intensity of the fluorescent label and a signal intensity of the interval. Endoscopic device.   The fluorescence endoscope apparatus according to any one of claims 1 to 4, wherein the fluorescent label is provided on a treatment instrument installed in the vicinity of the observed portion.   The fluorescence endoscope according to any one of claims 1 to 5, further comprising an irradiation intensity control unit that controls an irradiation intensity of the excitation light based on distance information acquired by the distance information acquisition unit. Mirror device.