JP2013102898A - Endoscopic diagnostic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endoscopic diagnostic apparatus capable of acquiring an image with an excellent diagnostic capability by measuring different fluorescence characteristics depending on an observed region of a subject and the state of lesion (the stage of progression, etc.) with measuring light in advance and by performing autogenous fluorescent observation based on optimum observation conditions.SOLUTION: The endoscopic diagnostic apparatus includes: a light source part 12 for emitting at least two kinds of excitation light with different center wavelengths; an imaging part for acquiring an autogenous fluorescent image; a contrast calculation means 69 for calculating a contrast based on the autogenous fluorescent image acquired in the pre-imaging by the imaging part; and an imaging condition determining means 71 for determining an imaging condition for main imaging based on the contrast. The imaging part executes the pre-imaging a plurality of times to acquire a plurality of autogenous fluorescent images. The contrast calculation means 69 calculates a plurality of contrasts acquired in the pre-imaging. The imaging condition determining means 71 determines kinds of excitation light and light emission ratios of the excitation light to be simultaneously emitted based on the contrast as imaging conditions for the main imaging.

Description

  The present invention relates to an endoscope diagnosis apparatus that captures autofluorescence emitted from an autofluorescent substance contained in an observation region of a subject (living body) and acquires an autofluorescence image.

  Conventionally, normal light (white light) emitted from the light source device is guided to the distal end of the endoscope and irradiated on the subject's observation area, and the reflected light is imaged to obtain a normal light image (white light image). In addition, an endoscope that performs normal light observation (white light observation) is used. On the other hand, in recent years, in addition to normal light observation, excitation light (special light) for autofluorescence observation is irradiated to the observation area of the subject, and autofluorescence emitted from the autofluorescent material is imaged to synthesize autofluorescence. An endoscope diagnostic apparatus that acquires an image (autofluorescence image, special light image) and performs autofluorescence observation (special light observation) is used.

  For example, Patent Document 1 discloses an endoscope diagnostic apparatus that performs fluorescence observation including autofluorescence observation, and can perform switching between normal light observation and fluorescence observation (special light observation). Is described.

  Further, Patent Document 2 describes an endoscope diagnostic apparatus that can perform autofluorescence observation and has a plurality of excitation light sources.

  Patent Document 3 discloses an endoscope diagnosis apparatus that can perform autofluorescence observation, and distinguishes between normal and abnormal tissues of a subject using autofluorescence. Have been described.

JP 2011-62408 A JP 2006-187598 A JP 2002-512067 A

  However, although Patent Documents 1 to 3 describe an endoscope diagnostic apparatus that can perform autofluorescence observation, the wavelength band of the excitation light source and the intensity ratio of the excitation light source are the subject (observation site) and It is fixed regardless of the observation conditions, and it depends on the observation site and the state of the lesion, that is, the thickness of the mucous membrane, blood volume, and the type and amount of autofluorescent substances differ. Fluorescence observation was not performed.

  The purpose of the present invention is to perform autofluorescence observation under the optimum observation conditions corresponding to the observation site and the state of the lesion, so pre-photographing (pre-photometry) is performed in advance to measure the optimum observation conditions, and the measured optimum Another object of the present invention is to provide an endoscope diagnostic apparatus characterized by performing autofluorescence observation based on various observation conditions.

  In order to solve the above-described problems, the present invention includes a light source unit that irradiates two or more types of excitation light having different center wavelengths, and the living tissue is irradiated with the excitation light from the light source unit. An imaging unit that captures autofluorescence emitted from the autofluorescent material to acquire an autofluorescence image, and a contrast calculation unit that calculates contrast of the autofluorescence image based on the autofluorescence image acquired by pre-imaging by the imaging unit And imaging condition determining means for determining imaging conditions for main imaging based on the calculated contrast of the autofluorescence image, and changing the type and the emission ratio of the excitation light simultaneously irradiated from the light source unit Excitation light is emitted, a plurality of pre-photographing is performed by the imaging unit to obtain a plurality of autofluorescence images, and the plurality of pre-photographing images obtained by the contrast calculation unit The contrast of the autofluorescence image is calculated, and the imaging condition determining means determines the type of excitation light to be irradiated simultaneously and the light emission ratio as the imaging conditions for the main photographing based on the calculated contrast of the plurality of autofluorescence images. An endoscope diagnosis apparatus for determining is provided.

The contrast calculation by the contrast calculation means is performed by creating a histogram from the pixel values of the autofluorescence image and calculating the following formula (1) from the high pixel value L _max and the low pixel value L _{min in the} histogram. It is preferable to calculate by doing.

The contrast calculation by the contrast calculation means is performed by creating a histogram from the pixel values of the autofluorescence image and calculating the following equation (2) from the high pixel value L _max and the low pixel value L _{min in the} histogram. It is preferable to calculate by doing.

The contrast calculation in the contrast calculation means is performed by creating a histogram from the pixel values of the autofluorescence image and calculating the following equation (3) from the high pixel value L _max and the low pixel value L _{min in the} histogram. It is preferable to be calculated.

The contrast calculation in the contrast calculation means is performed by creating a histogram from the pixel values of the autofluorescence image and calculating the following equation (4) from the high pixel value L _max and the low pixel value L _{min in the} histogram. It is preferable to be calculated.

The contrast calculation by the contrast calculation means is performed by creating a histogram from the pixel values of the autofluorescence image and calculating the following equation (5) from the high pixel value L _max and the low pixel value L _{min in the} histogram. It is preferable to be calculated.

The contrast calculation by the contrast calculation means is performed by creating a histogram from the pixel values of the autofluorescence image and calculating the following equation (6) from the high pixel value L _max and the low pixel value L _{min in the} histogram. It is preferable to be calculated.

Further, the low pixel value L _min is an average value of the low value 10% in the histogram after removing the high value 5% from the histogram, and the high pixel value L _max is the high value 5% from the histogram. It is preferable that the average value is a high value of 10% in the histogram after removal.

  The contrast calculation by the contrast calculation means is performed by creating a histogram from the pixel values of the autofluorescence image and removing an average value of 30% from the histogram after removing a high value of 10% from the histogram. It is preferable to be calculated as follows.

  Further, the contrast calculating means calculates a plurality of contrasts by changing a ratio of irradiation intensities of the plurality of excitation light sources, and the imaging condition determining means calculates these contrasts by a quadratic curve using a least square method. It is preferable to perform fitting and select the ratio of the irradiation intensity of the excitation light source that gives the maximum peak as the optimum imaging condition for autofluorescence observation of the target region of the subject.

  Moreover, it is preferable that the autofluorescence image used for the contrast calculation in the contrast calculation unit is an autofluorescence image output at a low resolution in the imaging unit.

  Moreover, it is preferable that the autofluorescence image used for the contrast calculation in the contrast calculation means is the autofluorescence image in which only the central region of the captured image is output in the imaging unit.

  Moreover, it is preferable that the said autofluorescence image is a synthesized image produced | generated by the image process part based on the image signal of the normal light imaged in the said imaging part, and the image signal of autofluorescence.

  In addition, the light source unit includes a first excitation light source and a second excitation light source, and a first imaging condition in which an irradiation intensity of the first excitation light source and the second excitation light source is 1: 0, Second imaging condition in which the irradiation intensity of the first excitation light source and the second excitation light source is 0.5: 0.5, and the irradiation intensity of the first excitation light source and the second excitation light source The image is picked up based on a third imaging condition in which the ratio is 0: 1, and the contrast calculation means includes a first contrast for the first imaging condition, a second contrast for the second imaging condition, and the third Calculating a third contrast with respect to the imaging condition, and the imaging condition determining means determines an imaging condition having the largest contrast among the first contrast, the second contrast, and the third contrast; Said determined Based on the image condition, it is preferable that autofluorescence is performed.

  The light source section preferably includes a first excitation light source having a center wavelength of 405 ± 10 nm and a second excitation light source having a center wavelength of 445 ± 10 nm.

  According to the present invention, different fluorescence characteristics depending on the observation region of the subject and the state of the lesion (such as progress) are measured by prior pre-photographing (pre-photometry), and autofluorescence observation is performed based on optimal observation conditions. Therefore, it is possible to obtain a captured image with better diagnostic ability.

1 is an external view showing an embodiment of an overall configuration of an endoscope diagnostic apparatus according to the present invention. It is a block diagram of this embodiment which shows the internal structure of the endoscope diagnostic apparatus shown in FIG. It is a conceptual diagram showing the front-end | tip part of the endoscope insertion part of the endoscope diagnostic apparatus shown in FIG. It is a conceptual diagram of the rotation filter provided in front of the image pick-up element of the endoscope diagnostic apparatus shown in FIG. It is explanatory drawing explaining an example of the contrast calculation in the contrast calculation means of the endoscope diagnostic apparatus shown in FIG. It is explanatory drawing explaining the other example of the contrast calculation in the contrast calculation means of the endoscope diagnostic apparatus shown in FIG.

  An endoscope diagnostic apparatus according to the present invention will be described in detail below based on a preferred embodiment shown in the accompanying drawings.

FIG. 1 is an external view of an embodiment showing an overall configuration of an endoscope diagnosis apparatus according to the present invention, and FIG. 2 is a block diagram of the embodiment showing an internal configuration thereof.
The endoscope diagnosis apparatus 10 shown in these drawings includes a light source device 12 that emits a plurality of excitation lights for normal light or autofluorescence observation, and guides light emitted from the light source device 12 to an observation area of a subject. An endoscope body 14 that irradiates and images reflected light or autofluorescence from a subject, a processor device 16 that performs image processing on an image captured by the endoscope body 14 and outputs an endoscope image, and a processor device 16 includes a display device 18 that displays an endoscopic image output from 16 and an input device 20 that receives an input operation.

  Here, the endoscope diagnosis apparatus 10 irradiates a subject with normal light (white light), images the reflected light, and displays (observes) a normal light image (white light image) (normal light observation mode (white). A self-illumination mode) and an excitation light (special light) for self-fluorescence observation, illuminate the subject, image the self-fluorescence excited by the excitation light, and display a self-fluorescence composite image (autofluorescence image) It is equipped with a fluorescence observation mode (special light observation mode), and when switching from the normal light observation mode to the autofluorescence observation mode, the optimum imaging conditions for the autofluorescence observation (combination of excitation light with different central wavelengths, excitation light Pre-photographing (pre-photometry) for determining the irradiation intensity and irradiation time is performed. Each mode is appropriately switched based on an instruction input from the selector switch 66 (described later) of the endoscope body 14 or the input device 20.

  Although details will be described later, the endoscope diagnosis apparatus 10 of the present invention includes a plurality of imaging conditions used for pre-imaging in a storage unit 72 (to be described later) of the processor device 14 in advance, and switches to the autofluorescence observation mode. Then, pre-photographing is performed based on the plurality of imaging conditions.

(Light source device)
The light source device 12 includes a light source control unit 22, two types of laser light sources LD 1 and LD 2 that emit laser beams having different center wavelengths, a combiner (multiplexer) 24, and a coupler (demultiplexer) 26. ing.

  In the present embodiment, the laser light sources LD1 and LD2 emit narrowband light in a predetermined wavelength range (for example, center wavelength ± 10 nm) having center wavelengths of 405 nm and 445 nm, respectively. The laser light source LD1 is a light source that irradiates excitation light for simultaneously emitting autofluorescence from a plurality of autofluorescent substances, for example, FAD (Flavin Adenin Dinucleotide), porphyrin (PAD), and the like included in the observation region of the subject. . The laser light source LD2 also functions as a light source for irradiating excitation light for simultaneously emitting autofluorescence from a plurality of autofluorescent materials or the like included in the observation area of the subject, as with the above-described LD1, and as will be described later. Also, it functions as a light source for generating excitation light for generating white light (pseudo white light) from the phosphor.

For example, FAD emits autofluorescence in a wavelength range of about 450 to 550 nm when irradiated with excitation light having a predetermined center wavelength included in a wavelength range of about 330 to 400 nm. Porphyrin emits autofluorescence of about 610 to 640 nm when irradiated with excitation light having a predetermined center wavelength included in a wavelength range of about 350 to 550 nm.
The amount of these autofluorescent substances contained in the observed area of the subject varies depending on the observation site, and also varies depending on whether the observed area is a lesion, the degree of progression of the lesion, and each individual. The contrast of the observed autofluorescence image differs depending on the center wavelength of the excitation light and the irradiation intensity.

Moreover, although porphyrin and FAD were mentioned as an autofluorescent substance, an autofluorescent substance is not necessarily limited to these.
For example, other autofluorescent materials include NADH and collagen, which emit autofluorescence upon receiving excitation light having a wavelength range of about 250 to 400 nm and about 200 to 400 nm, respectively.

The laser light sources LD1 and LD2 are individually subjected to on / off control, light intensity control based on irradiation intensity and irradiation time (that is, imaging conditions) by a light source control unit 22 controlled by a control unit 70 of the processor device 16 described later, In the case of pre-shooting, as described above, the control unit 70 reads out a plurality of imaging conditions stored in the storage unit 72 described later, and the light source control unit 22 controls the light amount based on the plurality of imaging conditions. Is made. In the case of autofluorescence observation after pre-photographing, among the plurality of imaging conditions used for pre-photographing, an imaging condition most suitable for autofluorescence observation is determined by the imaging condition determination means 71 described later, and the imaging conditions Based on the above, the light source control unit 22 controls the light amount. It is also possible to add a new imaging condition via the input device 20 described later.
As the laser light sources LD1 and LD2, broad type InGaN laser diodes can be used, and InGaNAs laser diodes, GaNAs laser diodes, and the like can also be used.

  The normal light source for generating normal light in the normal light observation mode is not limited to the combination of excitation light and phosphor, and any light source that emits white light may be used. For example, a xenon lamp, a halogen lamp, a white light An LED (light emitting diode) or the like can also be used. The excitation light source for generating the excitation light in the auto fluorescence observation mode (including pre-photographing) is not limited to the laser light source (semiconductor laser), and the autofluorescence substance can be excited to emit autofluorescence. Various light sources capable of emitting excitation light with sufficient intensity, for example, a combination of a white light source and a band limiting filter can be used.

  In addition, the wavelength of the excitation light in the normal light observation mode (center wavelength, narrow-band light wavelength range) is not particularly limited, and all excitation light having a wavelength capable of generating pseudo white light from the phosphor can be used. It is. The wavelength of the excitation light in the autofluorescence observation mode is not particularly limited, and all excitation lights having wavelengths that can simultaneously excite a plurality of autofluorescent substances to emit autofluorescence can be used. Light having a wavelength of 405 ± 10 nm or light having a central wavelength of 445 nm ± 10 nm can be preferably used.

  Further, the present invention is not limited to irradiating a subject with excitation light of one kind of central wavelength and simultaneously emitting autofluorescence from a plurality of autofluorescent materials, but for simultaneously emitting a plurality of autofluorescence from the light source device 12. A configuration may be employed in which a plurality of excitation lights having different center wavelengths are simultaneously irradiated. In the present embodiment, the normal light source and the excitation light source are configured as a common light source, but the normal light source and the excitation light source may be provided separately.

In the normal light observation mode, the light source control unit 22 turns off the laser light source LD1, turns on the laser light source LD2, controls the combiner 24 and the coupler 26, and the narrow band light from the laser light source LD2 is phosphor 54A described later. And 54B, which will be described later, are controlled to be irradiated from optical fibers 48A and 48B.
The light source control unit 22 turns on the laser light sources LD1 and LD2 based on the irradiation intensity and the irradiation time determined in advance in the autofluorescence observation mode (including pre-photographing), and combines the combiner 24 and the coupler. 26 is controlled so that the narrow-band light emitted from these laser light sources LD1 and LD2 is combined and emitted from optical fibers 46A and 46B described later.
In the case of pre-photographing, since a plurality of imaging conditions are set in advance, the light source control unit 22 sequentially performs pre-photographing (autofluorescence imaging) based on the plurality of imaging conditions. The image data of the autofluorescence obtained by the pre-photographing is combined with the normal light image captured in the normal light observation mode in the image processing unit 68 to be described later to be an autofluorescence image. The contrast of the fluorescence image (composite image with the normal light image) is calculated.
Based on the calculated contrast, an imaging condition determining unit 71 (to be described later) of the control unit 70 determines an imaging condition optimal for autofluorescence observation, and the light source control unit 22 performs light amount control based on the determined imaging condition. Done.

  Laser light emitted from each of the laser light sources LD1 and LD2 is input to the corresponding optical fiber via a condenser lens (not shown), combined by a combiner 24, and demultiplexed into four systems of light by a coupler 26. Is transmitted to the connector portion 32A. The combiner 24 and the coupler 26 are configured by a half mirror, a reflection mirror, or the like. Further, the combiner 24 and the coupler 26 are controlled by the light source controller 22, and the laser light emitted from each of the laser light sources LD1 and LD2 is controlled to be emitted from a desired optical fiber. However, the present invention is not limited thereto, and the laser light from each of the laser light sources LD1 and LD2 may be sent directly to the connector portion 32A without using the combiner 24 and the coupler 26.

(Endoscope body)
Subsequently, the endoscope main body 14 has four lines (four lights) of light (normal light or autofluorescence observation (including pre-photographing)) from the tip of the endoscope insertion portion 28 inserted into the subject. This is an electronic endoscope having an illumination optical system that emits (excitation light) and an imaging optical system of one system (single eye) that captures an endoscopic image of the observation region. The endoscope main body 14 includes an endoscope insertion section 28, an operation section 30 that performs an operation for bending and observing the distal end of the endoscope insertion section 28, and the endoscope main body 14 as a light source device 12 and a processor. Connector portions 32A and 32B that are detachably connected to the device 16 are provided.

  The endoscope insertion portion 28 includes a flexible soft portion 34, a bending portion 36, and a distal end portion (hereinafter also referred to as an endoscope distal end portion) 38.

  The bending portion 36 is provided between the flexible portion 34 and the distal end portion 38 and is configured to be bent by a rotation operation of the angle knob 40 disposed in the operation portion 30. The bending portion 36 can be bent in an arbitrary direction and an arbitrary angle depending on a portion of the subject in which the endoscope main body 14 is used, and the endoscope distal end portion 38 can be directed to a desired observation portion. it can.

  Although not shown, various channels such as a forceps channel for inserting a tissue collection treatment instrument and the like and a channel for air supply / water supply are provided inside the operation unit 30 and the endoscope insertion unit 28. It has been.

  As shown in FIG. 3, two systems of illumination windows 42 </ b> A and 42 </ b> B that irradiate light to the observation region, and reflected light or autofluorescence 1 from the observation region are imaged on the distal end surface of the endoscope distal end portion 38. In addition to the system observation window 44, a forceps port 45 and the like are arranged.

  Two systems of optical fibers 46A and 48A are housed behind the illumination window 42A. The optical fibers 46A and 48A are laid from the light source device 12 to the scope distal end portion 38 via the connector portion 32A. An optical system such as a lens 50A is attached to the tip of the optical fiber 46A (on the illumination window 42A side). On the other hand, a phosphor 54A is disposed at the tip of the optical fiber 48A, and an optical system such as a lens 52A is attached to the tip of the phosphor 54A.

  Similarly, in the back of the illumination window 42B, there are two systems, an optical fiber 46B having an optical system such as a lens 50B at the tip, and an optical fiber 48B having an optical system such as a phosphor 54B and a lens 52B at the tip. An optical fiber is housed.

The phosphors 54A and 54B absorb a part of blue laser light (for example, center wavelength 445 ± 10 nm) from the laser light source LD2 and excite and emit green to yellow light (for example, YAG-based fluorescent material). Or a fluorescent material such as BAM (BaMgAl ₁₀ O ₁₇ ). When excitation light for normal light observation is irradiated onto the phosphors 54A and 54B, green to yellow excitation emission light (fluorescence) emitted from the phosphors 54A and 54B and the phosphors 54A and 54B are transmitted without being absorbed. Combined with the blue laser light, white light (pseudo white light) is generated.

  The illumination optical systems on the illumination window 42A side and the illumination window 42B side have the same configuration and operation, and illumination unevenness can be prevented by irradiating the illumination light from the illumination windows 42A and 42B simultaneously. Different illumination lights can be irradiated from the illumination windows 42A and 42B. An equivalent function can be realized even in an illumination optical system that emits four systems of illumination light.

  On the other hand, an optical system such as a lens 56 is attached to the back of the observation window 44, and a rotary filter 74 is provided to the back of the lens 56. The light transmitted through the rotary filter 74 is attached to an image sensor 58 such as a CCD (Carge1 Coupled Device) image line or a CMOS (Charge Metal-Oxide Semiconductor) image sensor that acquires image information of an observation area provided at the tip of the filter. It has been. Since the image sensor 58 is used for each frame by dividing time, it is used for both normal light observation and autofluorescence observation (including pre-photographing). In the present invention, the imaging unit includes an observation window 44, a lens 56, a rotary filter 74, an imaging element 58, a scope cable 62 described later, an A / D converter 64 described later, an image processing unit 68 described later, and the like. The

Further, as shown in FIG. 4, the rotary filter 74 is installed in the normal light observation mode, and transmits the reflected light from the subject tissue as it is, and the autofluorescence observation mode (including pre-photographing mode). And an excitation light blocking unit 78 that cuts excitation light that is reflected light from the subject tissue. The rotary filter 74 is used by switching between the transmission unit 76 and the excitation light blocking unit 78 in accordance with an imaging mode switching instruction from the input device 20 or the changeover switch 66 described later. In the autofluorescence observation mode, the normal light observation is performed. And autofluorescence observation are alternately performed, they are rotated by a rotating means (not shown) according to the period of normal light observation and autofluorescence observation.
The excitation light blocking unit 78 is a band pass filter that transmits light in a wavelength band from 450 nm to 640 nm, for example.

  The imaging element 58 receives normal light (reflected light) and autofluorescence on a light receiving surface (imaging surface), photoelectrically converts the received light, and outputs an imaging signal (analog signal). A plurality of sets of pixels are arranged on a matrix, with a set of three colors of G and B pixels. On the light receiving surface of the image sensor 58, the reflected light in the wavelength range of 370 to 720 nm of the visible light from the observation region is divided into three wavelength regions corresponding to the R pixel, G pixel, and B pixel, respectively. R, G, and B color filters (not shown) having spectral transmission characteristics that transmit light are provided.

Further, at the time of pre-photographing in the autofluorescence observation mode, the image sensor 58 may perform binning processing to reduce the number of pixels and output the image data of the autofluorescence image. You may output only the imaging data of the autofluorescence image acquired in the part.
The pre-photographing is merely for the purpose of determining the imaging conditions, not for obtaining an autofluorescence image or the like, and if the data capacity of the imaging data to be output is reduced, an image to be described later This is because the contrast calculation unit 69 of the processing unit 68 can also calculate the contrast quickly.

  Note that it is not essential to simultaneously capture R, G, and B images using a color image sensor as the image sensor 58, and a monochrome image sensor and R, G, and B colors may be used. In combination with a color filter, R, G, and B color images may be taken in a frame sequential manner.

  The light guided from the light source device 12 by the optical fibers 46A and 46B and 48A and 48B is irradiated from the endoscope distal end portion 38 toward the observation area of the subject. Then, the reflected light from the observation region irradiated with light or the autofluorescence emitted from the autofluorescent material in the observation region is imaged on the light receiving surface of the image sensor 58 by the lens 56, and is imaged by the image sensor 58. Photoelectrically converted and imaged. The imaging element 58 outputs an imaging signal (analog signal) of the observed area of the imaged subject.

  In the normal light observation mode, excitation light for normal light observation emitted from the laser light source LD2 is guided by the optical fibers 48A and 48B and applied to the phosphors 54A and 54B, and white light emitted from the phosphors 54A and 54B. Light is emitted from the illumination windows 42A and 42B to the observation area of the subject. Then, the reflected light from the observation area of the subject irradiated with white light is collected by the lens 56 and dispersed by a color filter (not shown), and normal light is imaged by the image sensor 58.

  On the other hand, in the autofluorescence observation mode (including pre-photographing), the excitation light for autofluorescence observation emitted from the laser light sources LD1 and LD2 is guided by the optical fibers 46A and 46B based on the set imaging conditions. Then, the light is irradiated from the endoscope distal end portion 38 toward the observation area of the subject. Then, the combined light of autofluorescence simultaneously emitted from a plurality of autofluorescent materials included in the observation region of the subject irradiated with the excitation light is collected by the lens 56 and is excited by the excitation light blocking unit 78 with the excitation light component (center wavelength). 405 ± 10 nm, reflected light of 445 ± 10 nm) is cut, and autofluorescence is imaged by the image sensor 58.

At the time of pre-photographing, autofluorescence is imaged as described above based on all the imaging conditions stored in advance in the storage unit 72, and the contrast calculation means 69 of the image processing unit 68 described later determines the contrast of the autofluorescence image. Based on the calculated contrast, an imaging condition determining unit 71 (to be described later) of the control unit 70 determines an imaging condition optimal for autofluorescence observation of the target region of the subject.
Then, after the pre-photographing is completed, the laser light sources LD1 and LD2 are controlled by the light source control unit 22 based on the determined optimal imaging condition, and optimal autofluorescence observation is performed.

  The excitation light for autofluorescence observation in this embodiment is a combination of the laser light (LD1) with the center wavelength of 405 ± 10 nm and the laser light (LD2) with the center wavelength of 445 ± 10 nm as described above. The synthesized light in the wavelength range of about 460 to 640 nm is received through the excitation light blocking filter 78 and imaged. Therefore, the autofluorescence image mainly contains autofluorescence components of FAD and porphyrin.

  In addition, an image signal (analog signal) of an image (normal light image, autofluorescence image) output from the image sensor 58 is input to the A / D converter 64 through the scope cable 62. The A / D converter 64 converts an image signal (analog signal) from the image sensor 58 into an image signal (digital signal). The converted image signal is input to the image processing unit 68 of the processor device 16 via the connector unit 32B.

(Processor unit)
Subsequently, the processor device 16 includes an image processing unit 68, a control unit 70, and a storage unit 72. The image processing unit 68 includes a contrast calculation unit 69, and the control unit 70 includes an imaging condition determination unit 71. . The display device 18 and the input device 20 are connected to the control unit 70. As described above, the input device 20 switches the imaging mode (normal light observation mode and autofluorescence observation mode) as well as the input device 20 as described above. It is also possible to additionally set a new imaging condition via.
The processor device 16 controls the light source control unit 22 of the light source device 12 based on an instruction input from the changeover switch 66 of the endoscope main body 14 or the input device 20, and an image signal input from the endoscope main body 14. Are processed, a display image is generated, stored in the storage unit 72, and output to the display device 18.

In both the normal light observation mode and the autofluorescence observation mode, the image processing unit 68 performs the A / D converter 64 of the endoscope main body 14 according to the image type of the normal light image and the autofluorescence image. The image signal (image data) supplied from is subjected to predetermined image processing suitable for each of the normal light image and the autofluorescence image, and the normal light image signal (normal light image) and the autofluorescence image signal (autofluorescence) Image).
The autofluorescence image signal (autofluorescence image) is a composite image generated by synthesizing the above-described normal light image signal and autofluorescence image signal supplied from the endoscope body by the image processing unit 68. It is a signal (composite image).

  The image signal processed by the image processing unit 68 is sent to the control unit 70. In the control unit 70, the normal light image or the autofluorescence image is displayed on the display device 18 based on the normal light image signal and the autofluorescence image signal according to the observation mode. Further, under the control of the control unit 70, the normal light image signal and the autofluorescence image signal are stored in the storage unit 72 including a memory or a storage device, for example, in units of one (one frame) image as necessary. Is done.

  Further, the image processing unit 68 includes a contrast calculating unit 69. When the endoscope diagnosis apparatus 10 is switched to the autofluorescence observation mode and performs pre-imaging, the image processor 68 is based on the autofluorescence image signal acquired by pre-imaging. Then, the contrast of the autofluorescence image is calculated.

すると、自家蛍光画像のコントラストが求められる。 As shown in FIG. 5, the contrast calculation unit 69 calculates the contrast by creating a histogram corresponding to the pixel value and the number of pixels from the autofluorescence image signal (autofluorescence image data). 5% is cut off, and from the remaining image data (histogram in the dotted frame in FIG. 5), the average value of the upper 10% pixel values (average value of luminance values) L _max and the average value of the lower 10% pixel values (Average value of luminance values) L _min is calculated.
After calculating L _max and L _min , Micson contrast formula (1) is calculated based on these values.

Then, the contrast of an autofluorescence image is calculated | required.

  The contrast of the image signal processed by the image processing unit 68 and the autofluorescence image calculated by the contrast calculation unit 69 is stored in the storage unit 72 through the control unit 70 together with the imaging condition of the autofluorescence image.

As shown in FIG. 6, the contrast calculation unit 69 calculates the contrast by creating a histogram corresponding to the pixel value and the number of pixels from the autofluorescence image data as shown in FIG. The average of the upper 30% pixel values may be taken from the image data (histogram in the dotted frame in FIG. 6) to obtain the contrast of the autofluorescence image.
As described above, the calculated contrast of the autofluorescence image is stored in the storage unit 72 through the control unit 70 together with the autofluorescence image data, the imaging condition of the autofluorescence image, and the like.

としてもよく、また、（１）式の各Ｌに対して対数（常用対数、自然対数どちらでも可）をとって、

としてもよく、また、同様に、（２）式の各Ｌに対して対数（常用対数、自然対数どちらでも可）をとって、

としてもよい。 Note that the contrast calculation in the contrast calculation means 69 is performed by taking a simple difference between L _max and L _{min in} addition to the above-described equation (1).

Also, taking a logarithm (either common logarithm or natural logarithm is acceptable) for each L in the equation (1),

Similarly, taking a logarithm (either common logarithm or natural logarithm is acceptable) for each L in equation (2),

It is good.

としてもよい。
上述の他にも、Ｌ_ｍａｘとＬ_ｍｉｎとの単純な比率（Ｌ_ｍａｘ／Ｌ_ｍｉｎ）を

としてもよく、また、Ｌ_ｍａｘを、そのまま用いて、

としてもよい。
また、前述の画素値と画素の数に対応するヒストグラムの全面積、つまり、自家蛍光画像の全画素数と、自家蛍光画像の全画素値の積算値とを用いて、画素値の平均値を算出し、その平均値を自家蛍光画像のコントラストとしてもよい。 Further, each L in the equation (1) is set to a power of x (x is an arbitrary number),

It is good.
In addition to the above, a simple ratio (L _max / L _min ) between L _max and L _min

It is also possible to use L _max as it is,

It is good.
Further, using the total area of the histogram corresponding to the above-described pixel value and the number of pixels, that is, the total number of pixels of the autofluorescence image and the integrated value of all the pixel values of the autofluorescence image, the average value of the pixel values is calculated. The average value may be calculated as the contrast of the autofluorescence image.

In addition, the autofluorescence image used for the above-described contrast calculation is subjected to processing such as binning (or, if there is a low-resolution image sensor in addition to a high-resolution image sensor, A captured low-resolution autofluorescence image may be used, or an autofluorescence image obtained by extracting only the central region of the captured autofluorescence image may be used. Since the number of pixels used to calculate contrast is reduced, processing can be performed quickly.
The contrast calculation method in the contrast calculation unit 69 can be switched through the input device 20.

  The contrast calculation based on the autofluorescence image data is performed based on the captured autofluorescence image, that is, the number of pre-stored imaging conditions, and is stored in the storage unit 72 together with the autofluorescence image data.

The control unit 70 is based on an instruction from the changeover switch 66 of the endoscope body 14 or the input device 20, for example, an instruction such as an observation mode (normal light observation mode and autofluorescence observation mode (including pre-imaging)). The operations of the image processing unit 68 and the light source control unit 22 of the light source device 12 are controlled.
In addition, the control unit 70 stores the display image that has been subjected to image processing by the image processing unit 68 and can be displayed in the storage unit 72, and displays the display image on the display device 18 as required by an instruction from the input device 20 or the like. .

The control unit 70 performs pre-photographing (autofluorescence image capturing) based on a plurality of image capturing conditions stored in advance in the storage unit 72 during pre-photographing, and the image processing unit 68 and the contrast calculating unit 69 perform the pre-photographing. The storage unit 72 stores the autofluorescence image corresponding to the calculated imaging condition and its contrast, and the imaging condition determining unit 71 determines the imaging condition with the highest contrast.
The control unit 70 controls the light source control unit 22 based on the determined imaging condition, so that autofluorescence observation can be performed under an imaging condition optimal for observation of the observation area of the subject.

In addition, the contrast calculating unit 69 calculates a plurality of contrasts by changing the intensity ratio of the excitation light (ratio of irradiation intensity between LD1 and LD2; the total is 1.0), and the imaging condition determining unit 71 The contrast may be fitted with a quadratic curve using the least square method, and the intensity ratio of the excitation light that gives the maximum peak may be determined as an optimal imaging condition for autofluorescence observation of the target region of the subject. .
The above is the configuration of the endoscope diagnostic apparatus 10 of the present invention.

  Next, the operation of the endoscope diagnosis apparatus 10 of the present invention will be described for each observation mode.

(Normal light observation mode)
In the normal light observation mode, under the control of the light source control unit 22, the laser light source LD1 is turned off and the laser light source LD2 is turned on. Laser light having a central wavelength of 445 ± 10 nm emitted from the laser light source LD2 is applied to the phosphors 54A and 54B, and white light is emitted from the phosphors 54A and 54B. The white light emitted from the phosphors 54A and 54B is irradiated onto the subject, and the reflected light is received by the image sensor 58, and a normal light image including R, G, and B channel image signals is acquired. The normal light image is displayed in color based on the R, G, and B channel image signals.

(Autofluorescence observation mode)
In the case of pre-photographing in the autofluorescence observation mode, for example, if three imaging conditions are stored in advance in the storage unit 72 and pre-photographing is performed based on the three imaging conditions (for example, first imaging condition: LD1). 405 nm (emission intensity of excitation light 1.0), second imaging condition: LD1, 405 nm (0.5) + LD2, 445 nm (0.5), and third imaging condition: LD2, 445 (1.0)) The first imaging condition, the second imaging condition, and the third imaging are controlled by controlling the light emission, irradiation intensity, and irradiation time of the laser light sources LD1 and LD2 through the light source control unit 22 in units of 3 frames as the number of imaging conditions. Imaging is performed in the order of the conditions.

  In the above-described example, in the pre-shooting, all the shooting conditions from the first shooting condition to the third shooting condition are picked up at once. For example, the normal light observation and the pre-shooting are alternately switched for each frame. First frame: normal light observation, second frame: imaging under the first imaging condition, third frame: normal light observation, fourth frame: imaging under the second imaging condition, fifth frame: normal light observation, Imaging may be performed in the order of the sixth frame: imaging under the third imaging condition.

Then, in the image processing unit 68, the normal light image signal (normal light image data) stored in the storage unit 72 and the FAD or porphyrin autofluorescence image signal (image data) are combined, and a combined image ( That is, the autofluorescence image is displayed on the display device 18.
For example, here, by assigning the auto-fluorescent image signal to the G channel of the composite image and the R and B channels of the normal light image to the R channel and B channel of the composite image, respectively, the composite image is simulated. Displayed in color.

  It should be noted that when displaying a composite image (autofluorescent image) in pseudo color, it is arbitrary which image signal of which image is assigned to which color channel of the composite image. Further, it is not essential to display the synthesized image in pseudo color.

  As described above, the image processing unit 68 performs image processing on the autofluorescent image corresponding to the imaging condition, calculates the contrast of the autofluorescent image in the contrast calculating unit 69, and passes the first imaging condition through the control unit 72. The autofluorescence image corresponding to the third imaging condition and its contrast are stored in the storage unit 72.

When the contrast of the autofluorescence image corresponding to the first imaging condition to the third imaging condition is stored in the storage unit 72, the control unit 70 obtains the contrast from the storage unit 72, and the imaging condition determination unit 71 The imaging condition with the highest contrast is determined as the imaging condition optimal for autofluorescence observation.
In the case of Table 1 below, since the contrast of the first imaging condition is the highest, the first imaging condition is determined as the optimal imaging condition for autofluorescence observation.

  The control unit 70 controls the irradiation intensity and irradiation time of the laser light sources LD1 and LD2 through the light source control unit 22 based on the determined imaging condition (first imaging condition in the example of Table 1), and performs autofluorescence observation. .

  In the autofluorescence observation after the pre-photographing is performed, for example, imaging is repeatedly performed in units of two frames. Of the two frames, the first frame is the same observation mode as the normal light observation mode, and the second frame is an observation mode unique to the autofluorescence observation mode.

  First, in the normal light observation mode of the first frame, as described above, the subject is irradiated with white light, and a normal light image including R, G, and B channel image signals is captured. Then, the normal light image signal is stored in the storage unit 72 under the control of the control unit 70.

  Subsequently, in the auto-fluorescence observation mode of the second frame, the laser light source LD1 and the laser light source LD1 are controlled based on the imaging condition (for example, the first imaging condition in Table 1) having the highest contrast during the pre-imaging by the control of the light source control unit 22. The light emission, irradiation intensity, and irradiation time of the LD 2 are controlled. When laser light (excitation light) emitted from the laser light sources LD1 and LD2 is irradiated to the observation region of the subject, autofluorescence is simultaneously emitted from FAD and porphyrin included in the observation region. Then, the combined light of both autofluorescences is received by the image sensor 58 and the autofluorescence is imaged.

  Autofluorescence imaging data (analog data) is converted into image data (digital data) by an A / D converter 58, input to an image processing unit 68, image processed by an image processing unit 68, and a normal light image. And converted into a display image, and output to the display device 18 and the storage unit 72 through the control unit 70. Since the image was captured under the optimal imaging condition determined based on the pre-photographing, the autofluorescence image displayed on the display device 18 is an autofluorescence image with high contrast and easy to observe.

  As mentioned above, although the endoscope diagnostic apparatus 10 of this invention was demonstrated in detail, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, various improvement and change are performed. May be.

DESCRIPTION OF SYMBOLS 10 Endoscope diagnostic apparatus 12 Light source apparatus 14 Endoscope main body 16 Processor apparatus 18 Display apparatus 20 Input apparatus 22 Light source control part 24 Combiner (multiplexer)
26 Coupler
28 Endoscope insertion part 30 Operation part 32A, 32B Connector part 34 Soft part 36 Bending part 38 End part (Endoscope end part)
40 Angle knob 42A, 42B Illumination window 44 Observation window 45 Forceps port 46A, 46B, 48A, 48B Optical fiber 50A, 50B, 52A, 52B, 56 Lens 54A, 54B Phosphor 58 Image sensor 62 Scope cable 64 A / D converter 66 changeover switch 68 image processing unit 69 contrast calculation unit 70 control unit 71 imaging condition determination unit 72 storage unit 74 rotating filter 76 transmission unit 78 excitation light blocking unit LD1, LD2 laser light source

Claims (15)

A light source unit that emits two or more types of excitation light having different center wavelengths;
An imaging unit that captures autofluorescence emitted from an autofluorescent material contained in the living tissue by irradiating the living tissue with excitation light from the light source unit, and acquires an autofluorescence image;
Contrast calculation means for calculating the contrast of the autofluorescence image based on the autofluorescence image acquired by pre-shooting by the imaging unit;
An imaging condition determining means for determining an imaging condition for main imaging based on the calculated contrast of the autofluorescence image,
The contrast calculation unit is configured to irradiate the excitation light by changing the type and the emission ratio of the excitation light simultaneously emitted from the light source unit, perform a plurality of pre-photographs by the imaging unit, and obtain a plurality of autofluorescence images. The contrast of a plurality of autofluorescence images acquired in pre-imaging is calculated, and the imaging condition determining means sets the imaging conditions for the main imaging based on the calculated contrasts of the plurality of autofluorescence images. An endoscope diagnosis apparatus that determines the type of excitation light to be emitted and the emission ratio thereof. The calculation of the contrast in the contrast calculation means is to create a histogram from the pixel values of the autofluorescence image and calculate the following equation (1) from the high pixel value L _max and the low pixel value L _{min in the} histogram. The endoscope diagnosis apparatus according to claim 1, wherein the endoscope diagnosis apparatus is calculated by:

The calculation of the contrast in the contrast calculation means is to create a histogram from the pixel values of the autofluorescence image and calculate the following equation (2) from the high pixel value L _max and the low pixel value L _{min in the} histogram. The endoscope diagnosis apparatus according to claim 1, wherein the endoscope diagnosis apparatus is calculated by:

The calculation of the contrast in the contrast calculation means is to create a histogram from the pixel values of the autofluorescence image and calculate the following expression (3) from the high pixel value L _max and the low pixel value L _{min in the} histogram. The endoscope diagnosis apparatus according to claim 1, wherein the endoscope diagnosis apparatus is calculated by:

The calculation of the contrast in the contrast calculation means is to create a histogram from the pixel values of the autofluorescence image and calculate the following equation (4) from the high pixel value L _max and the low pixel value L _{min in the} histogram. The endoscope diagnosis apparatus according to claim 1, wherein the endoscope diagnosis apparatus is calculated by:

The calculation of the contrast in the contrast calculation means is to create a histogram from the pixel values of the autofluorescence image and calculate the following equation (5) from the high pixel value L _max and the low pixel value L _{min in the} histogram. The endoscope diagnosis apparatus according to claim 1, wherein the endoscope diagnosis apparatus is calculated by:

The calculation of the contrast in the contrast calculation means is to create a histogram from the pixel values of the autofluorescence image and calculate the following equation (6) from the high pixel value L _max and the low pixel value L _{min in the} histogram. The endoscope diagnosis apparatus according to claim 1, wherein the endoscope diagnosis apparatus is calculated by:

The low pixel value L _min is an average value of the low value 10% in the histogram after removing the high value 5% from the histogram, and the high pixel value L _max is the high value 5% excluded from the histogram. The endoscope diagnosis apparatus according to any one of claims 2 to 7, wherein the endoscope diagnosis apparatus has an average value of 10%, which is a high value in a later histogram.   The calculation of the contrast in the contrast calculation means creates a histogram from the pixel values of the autofluorescence image, and uses the average value of 30% of the high value of the histogram after removing the high value of 10% from the histogram as the contrast. The endoscope diagnosis apparatus according to claim 1, wherein the endoscope diagnosis apparatus is calculated as described above.   The contrast calculating means calculates a plurality of contrasts by changing a ratio of irradiation intensities of the plurality of excitation light sources, and the imaging condition determining means fits these contrasts with a quadratic curve using a least square method. 10. The endoscopy according to claim 1, wherein a ratio of the irradiation intensity of the excitation light source that gives the maximum peak is selected as an optimal imaging condition for autofluorescence observation of the target region of the subject. Mirror diagnostic device.   The endoscopy according to any one of claims 1 to 10, wherein the autofluorescence image used for calculating the contrast in the contrast calculation means is an autofluorescence image output at a low resolution in the imaging unit. Mirror diagnostic device.   The autofluorescence image used for calculating the contrast in the contrast calculation means is the autofluorescence image in which only the central region of the captured image is output in the imaging unit. The endoscope diagnosis apparatus according to any one of the above.   The self-fluorescent image is a composite image generated by an image processing unit based on an image signal of normal light and an image signal of autofluorescence captured by the imaging unit. The endoscopic diagnostic apparatus according to any one of the above. The light source unit includes a first excitation light source and a second excitation light source,
A first imaging condition in which an irradiation intensity of the first excitation light source and the second excitation light source is 1: 0;
A second imaging condition in which an irradiation intensity of the first excitation light source and the second excitation light source is 0.5: 0.5; and an irradiation intensity of the first excitation light source and the second excitation light source Image based on the third imaging condition of 0: 1
The contrast calculation means calculates a first contrast for the first imaging condition, a second contrast for the second imaging condition, and a third contrast for the third imaging condition;
The imaging condition determining means determines an imaging condition having the highest contrast among the first contrast, the second contrast, and the third contrast, and based on the determined imaging condition, autofluorescence observation The endoscope diagnosis apparatus according to claim 1, wherein the endoscope diagnosis apparatus is performed.   The said light source part is provided with the 1st excitation light source of center wavelength 405 +/- 10nm, and the 2nd excitation light source of center wavelength 445 +/- 10nm, The inside in any one of Claims 1-14 characterized by the above-mentioned. Endoscopic diagnostic device.

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