JP2001161696A - Method and apparatus for acquiring fluorescent image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for acquiring a fluorescent image without producing a visually adverse effect even if a value with a large percentage of noise is included in the fluorescence intensity value of pixels obtained by imaging the fluorescence generated from an organism, etc., by the irradiation of excitation light. SOLUTION: In the fluorescent imaging apparatus, an image taking unit 300 extracts the fluorescence intensity of plural different wavelength regions from the fluorescence generated from a biological tissue 1 by the irradiation of excitation light Le to the biological tissue 1, and a discrimination operation unit 500 executes the operation based on the fluorescence intensity to obtain image data for displaying a fluorescent image of the biological tissue 1. Then, a judging unit 400 judges whether each pixel constituting the fluorescent image is suitable or unsuitable for operation. If the pixel is suitable for operation, the value of the pixel is obtained by the operation. If the pixel is unsuitable for operation, such a value as will not have a visually adverse effect when the fluorescent image is displayed as a visible image is allotted as the value of the pixel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for acquiring a fluorescence image for measuring fluorescence emitted from a sample such as a living body by irradiation of excitation light as an image.

[0002]

2. Description of the Related Art Conventionally, there has been known a diagnostic apparatus or the like which obtains the intensity of weak fluorescence or spectrum intensity generated from a living body or the like by irradiation of excitation light and obtains information to be used for diagnosis. These diagnostic devices detect fluorescence (auto-fluorescence) generated by irradiating living tissue with excitation light, or generate fluorescence by irradiating excitation light to living tissue that has previously absorbed a fluorescent diagnostic agent. There is a method of detecting (drug fluorescence) and the like. In many cases, the method is incorporated into an endoscope, a colpososcope, a surgical microscope, or the like inserted into a body cavity, and is used for diagnosis of tissue characteristics of a living body.

[0003] Initially, an attempt was made to focus on the intensity of fluorescence generated from a living tissue by irradiation with excitation light, but a change in the relative positional relationship (angle, distance) between the living tissue and a portion irradiated with the excitation light was examined. The intensity of the excitation light applied to the living tissue changes as a result, and the intensity of the fluorescence generated from the living tissue irradiated with the excitation light also changes. The intensity of the fluorescence generated from the tissue would change, and sufficient diagnostic ability could not be obtained only by the information on the intensity of the fluorescence. Therefore,
Many current diagnostic devices attempt identification based on the fact that the spectral intensity profile of the fluorescence emitted from a living tissue differs depending on the difference in tissue state.For example, a diseased tissue and a normal tissue emit the same from that tissue. Focusing on the fact that the ratio of the intensity in the green wavelength region of the fluorescence to the intensity in the red wavelength region is significantly different, the intensity in the green band wavelength region of the fluorescence emitted from the living tissue to be diagnosed is converted into the wavelength in the red band. Dividing by the intensity of the region, the value is compared with a value obtained by a method similar to the above from a living tissue previously determined to be normal tissue by another method, whereby the living tissue is a diseased tissue. Japanese Patent Application Laid-Open No. 6-54792 proposes a method of identifying whether the tissue is a normal tissue or not and displaying the image as an image.

[0004] Furthermore, the present applicant also discloses Japanese Patent Application Laid-open No. Hei 10-225.
No. 436, the intensity of the fluorescence in the green wavelength region generated from the living tissue due to the irradiation of the excitation light is divided by the intensity of the fluorescence in substantially the entire wavelength range of the spectrum of the fluorescence (hereinafter referred to as the entire wavelength region). Whether the tissue is a diseased tissue or a normal tissue by comparing the normalized value and a standardized value obtained from a living tissue previously determined to be normal tissue by another method in the same manner as above, A method of identifying and displaying as an image is proposed.

[0005]

However, the fluorescence intensity value of each pixel obtained by imaging weak fluorescence generated from a living tissue includes noise (fixed pattern noise / photon shot noise / dark shot noise) of the image sensor. /
Readout noise), electrical processing circuit noise, signal transmission system noise, and optical system noise (stray light such as light scattering due to dust attached to optical components). For a pixel in a very weak region, for example, even if the intensity of the fluorescence in the green wavelength region is divided by the intensity of the fluorescence in the entire wavelength region and standardized to obtain a value as information to be used for diagnosis, these values are extremely large. Since the intensity of the noise component is small compared to the intensity of the fluorescence that is the original measurement target included in these values, the information that correctly reflects the tissue properties of the living body even when an operation such as division is performed is However, when such information is displayed as a visible image as it is, there is a possibility that the visual image may be adversely affected when observing the visible image.

[0006] This type of problem is caused by the fluorescence (autofluorescence) generated when the living tissue is irradiated with excitation light and the fluorescence generated when the living tissue that has previously absorbed the fluorescent diagnostic agent is irradiated with the excitation light. (Drug fluorescence).

The present invention has been made in view of the above circumstances, and includes a large ratio of noise in the fluorescence intensity value of each pixel obtained by imaging fluorescence generated from a living body or the like by irradiation of excitation light. It is an object of the present invention to provide a fluorescence image acquisition method and apparatus capable of acquiring a fluorescence image that does not visually affect even if a value exists.

[0008]

According to the fluorescence image acquiring method of the present invention, a fluorescence intensity of at least one wavelength region is obtained from fluorescence emitted from a sample such as a living body by irradiating the sample with excitation light. A fluorescent image acquiring method for acquiring image data representing a fluorescent image of the sample by performing an operation based on the intensity, wherein for each pixel constituting the fluorescent image, whether the pixel is an operation-appropriate pixel or an operation inappropriate based on the fluorescence intensity It is determined whether the pixel is a pixel, and the above calculation is performed for a pixel suitable for calculation to obtain a pixel value, and for a pixel not suitable for calculation, a value that does not visually adversely affect the fluorescent image portion corresponding to the pixel suitable for calculation. It is characterized in that it is assigned as a pixel value.

In the determination, for each pixel constituting the fluorescence image, a comparison is made between the fluorescence intensity at each pixel and the noise value at each pixel generated by the fluorescence intensity measurement means for obtaining the fluorescence intensity measured and stored in advance. Can be performed.

[0010] When performing image processing of the image data representing the acquired fluorescent image, only the calculation-appropriate pixels can be subjected to image processing.

[0011] The sample may be a living body, and the fluorescence may be autofluorescence emitted from inside the living body.

As the light source of the excitation light, a GaN-based semiconductor laser can be used.

[0013] A fluorescence image acquiring apparatus according to the present invention comprises an excitation light irradiating means for irradiating a sample such as a living body with excitation light, and at least one wavelength from fluorescence emitted from the sample irradiated with the excitation light by the excitation light irradiating means. A fluorescence intensity measurement unit for obtaining the fluorescence intensity of the region, and a fluorescence image acquisition device including a calculation processing unit for performing an operation based on the fluorescence intensity to obtain image data representing a fluorescence image of the sample, wherein the fluorescence image For each of the constituent pixels, a determination means is provided for determining whether the pixel is a calculation-appropriate pixel or a calculation-inappropriate pixel based on the fluorescence intensity. It is characterized in that the configuration is such that a value that does not visually affect the fluorescent image portion corresponding to the calculation-appropriate pixel is assigned as the pixel value for the calculation-unsuitable pixel. To.

The discriminating means calculates, for each pixel constituting the fluorescent image, the fluorescence intensity at each pixel and the noise value at each pixel generated by the fluorescence intensity measuring means itself for obtaining the fluorescence intensity measured and stored in advance. It can be determined by comparing.

[0015] The image processing apparatus may further include image processing means for performing image processing on the image data representing the acquired fluorescence image, and the image processing means may perform image processing only on image data of pixels suitable for calculation.

[0016] The sample may be a living body, and the fluorescence may be autofluorescence emitted from inside the living body.

The light source of the excitation light may be a GaN-based semiconductor laser.

[0018] The fluorescence image acquiring apparatus may be an endoscope.

The "noise in each pixel generated by the fluorescence intensity measuring means itself" refers to all or one of the noises generated from the reception of the fluorescence by the means to the completion of obtaining the fluorescence intensity in each wavelength region. Part or noise including them, and typical noise components include, for example, a circuit of an image sensor, a circuit for handling an electrical signal converted by the image sensor, a signal transmission circuit for transmitting the signal, and imaging of fluorescence. And the like generated in an optical system for performing the operation.

The “calculation” is a calculation performed based on the fluorescence intensity in one wavelength region obtained from the fluorescence emitted from a sample such as a living body by irradiating the sample with excitation light. Means a calculation for assigning a value reflecting the fluorescence intensity and a calculation performed between the reference intensity and the fluorescence intensity determined from the reflected light reflected from the sample by irradiating the sample with near-infrared light, and In the case where the calculation is performed based on the fluorescence intensities in two or more wavelength regions obtained from the fluorescence emitted from the sample by irradiating the sample such as a living body with excitation light, the fluorescence intensity between the obtained fluorescence intensities is calculated. This means the calculation and the calculation performed including the fluorescence intensity and the reference intensity.

The unsuitable pixel is a pixel in which the amount of fluorescence received by a certain pixel is extremely weak, and the amount of noise contained in the value of this pixel is relatively large compared to the amount of received fluorescence. Means a pixel for which it is considered that a result that correctly reflects the tissue property of the living body cannot be obtained even if the calculation of is performed.

In contrast to the above-mentioned calculation inappropriate pixel, the calculation-appropriate pixel has a large amount of fluorescent light received by a certain pixel, and the amount of noise included in the value of this pixel is smaller than the amount of fluorescent light received. It means a pixel that is relatively small and is considered to provide a result that correctly reflects the tissue properties of the living body by performing an operation on the pixel.

It is to be noted that the above-mentioned calculation-suitable pixels and calculation-unsuitable pixels do not necessarily have the calculation-suitable pixels and the calculation-unsuitable pixels in advance. It is determined for each pixel based on the obtained amount of fluorescent light.

The auto-fluorescence emitted from the living body may be called “in vivo auto-fluorescence”.

[0025]

According to the fluorescent image acquiring method and apparatus of the present invention, it is determined whether each pixel constituting the fluorescent image is a pixel suitable for calculation or a pixel inappropriate for calculation. The value of the pixel is obtained by performing the calculation based on the above. Regarding the unsuitable pixel, the unsuitable pixel does not visually affect the area of the suitable pixel when the fluorescent image is intentionally displayed as a visible image. Since the value is assigned as the value of the inappropriate pixel, it is possible to achieve excellent observation suitability that is not adversely affected visually by the inappropriate pixel when the image data including the inappropriate pixel is displayed as a visible image. Fluorescent images can be obtained.

In addition, since the calculation is not performed on the unsuitable calculation pixel, the time required for the calculation for obtaining the image data representing the fluorescent image can be reduced.

Further, the above-mentioned determination is made by determining, for each pixel constituting the fluorescence image, the fluorescence intensity at each pixel and the value of the noise at each pixel generated by the fluorescence intensity measuring means itself for obtaining the fluorescence intensity measured and stored in advance. Is compared, the calculation-appropriate pixel and the calculation-inappropriate pixel can be determined more rationally.

Further, when performing image processing on the acquired image data representing the fluorescent image, if only the pixels suitable for calculation are subjected to image processing, the pixels suitable for calculation are displayed when the image data is displayed as a visible image. Region can be prevented from being visually adversely affected, and the time required for the process of acquiring a fluorescent image can be reduced.

If a GaN-based semiconductor laser is used as the light source of the excitation light, the size of the device can be reduced and the cost of the device can be reduced.

Further, if the specimen is a living body and the fluorescence intensity is obtained from the autofluorescence emitted from the living body, the inside of the living body can be diagnosed.

Further, if the fluorescent image acquiring device is an endoscope, it is possible to more easily diagnose the inside of a living body.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a fluorescent endoscope in which a fluorescent image acquiring device is applied to an endoscope as a first embodiment of the present invention.

As shown in FIG. 1, a fluorescent endoscope 600 includes a light source unit 100 having a light source for excitation light and white light.
A normal image (hereinafter, referred to as a normal image) obtained by irradiating the living tissue 1 with the white light Wh guided from the light source unit 100 is captured, and the excitation light Le guided from the light source unit 100 is captured by the living tissue 1. An endoscope tip unit 200 that propagates an image of autofluorescence (hereinafter, referred to as a fluorescence image) obtained by irradiating the endoscope with the optical fiber 26,
The normal image picked up by the endoscope head unit 200 is stored as normal image data, and the fluorescence image transmitted from the endoscope head unit 200 by the optical fiber 26 is divided into three wavelength regions and received. An image capturing unit 300 that stores three types of fluorescence intensity values (fluorescence intensity values for each pixel constituting a fluorescence image) respectively corresponding to the wavelength regions.
And input the fluorescence intensity value stored in the image capturing unit 300 to determine whether each pixel constituting the fluorescent image is a pixel suitable for calculation or a pixel inappropriate for calculation, and calculates the pixel position of the pixel inappropriate for calculation. The determination unit 400 stores the data as inappropriate pixel position data, and refers to the calculation inappropriate pixel position data stored in the determination unit 400 and refers to the normal tissue and the diseased tissue based on the three types of fluorescence intensity values stored in the image capture unit 300. Performs an identification operation to identify
And an identification operation unit 500 for storing the identification result as identification image data.

The normal image data output from the image capturing unit 300 and the identification image data output from the identification operation unit 500 are combined with the video signal processing circuit 60.
Are converted into video signals and output to external normal image TV monitor 80 and fluorescent image TV monitor 81 for display. The control of the entire apparatus is performed by the control unit 70.

The white light source 12 of the light source unit 100 includes a white light source 1 controlled by the control unit 70.
0 is connected, the white light source 12 generates pulsed white light Wh with a period of 1/60 second, and the white light Wh is collected by the white light collecting lens 14 and connected to the light source unit 100. Light guide 25-1 formed of a multi-component glass fiber.

On the other hand, the excitation light source 1 of the light source unit 100
The laser light source 3 is pulse-driven by the LD power supply 11 controlled by the control unit 70,
Pulsed excitation light Le with a wavelength of 410 nm with a period of / 60 seconds
Is generated at a timing that does not overlap with the pulsed white light Wh. The excitation light Le is condensed by the excitation light condensing lens 15 and is formed of a silica glass fiber connected to the light source unit 100.
2 is incident.

The white light guide 25-1 and the excitation light guide 25-2 are bundled.
The light guide 25 is integrated in a cable shape.

The light guide 25 is inserted into the endoscope distal end unit 200, and is disposed so that the living tissue 1 is irradiated with the excitation light Le or the white light Wh through the illumination lens 21. . The image of the living tissue 1 illuminated by the irradiation of the white light Wh is formed on the light receiving surface of the normal observation CCD imaging device 23 by the normal observation objective lens 22, and is converted into an electric signal by the imaging device 23. C
The data is transmitted to the image capturing unit 300 via the CD cable 27. On the other hand, the image of the fluorescence Ke generated from the living tissue 1 when irradiated with the excitation light Le is reflected by the fluorescence observation objective lens 2.
0 forms an image on the end face Ki of the fluorescent image fiber 26, and the image propagates through the fluorescent image fiber 26 and is guided to the other end face Ko of the fluorescent image fiber 26 connected to the image capturing unit 300. .

The image capturing unit 300 converts the electrical image signal transmitted by the CCD cable 27 into an A / D signal.
An A / D converter for normal observation 30 for conversion and a normal image memory 31 for storing an A / D converted image are provided for processing of a normal image. On the other hand, for processing fluorescent images,
An excitation light cut filter 32 for blocking a wavelength of 410 nm or less, and a fluorescent light condenser for forming a fluorescent image guided to the end face Ko of the fluorescent image fiber 26 on the light receiving surface of the high-sensitivity image sensor 34 for fluorescent observation. An optical system including a lens 33; a fluorescence observation A / D converter 35 for A / D converting an electric image signal received and converted by the fluorescence observation high-sensitivity imaging device 34; Image h1 memory 36-1 and fluorescence image h2 memory 36-2 for storing the images (values corresponding to the fluorescence intensities of the respective pixels constituting the image).
And a fluorescent image memory 36 including a fluorescent image h3 memory 36-3.

A wavelength region h1 (a wavelength region near 480 nm) and a wavelength region h2 as shown in FIG. 2 are provided between the high-sensitivity image sensor for fluorescence observation 34 and the condenser lens 33 for fluorescence.
(A wavelength region in the vicinity of 630 nm) and three types of filters H1 (filters that transmit light in the wavelength region h1) and filters H2 (shown in FIG. 3) having characteristics of transmitting the wavelength region h3 (all wavelength regions), respectively. A color separation filter 3 including a filter that transmits light in the wavelength region h2 and a filter H3 (a transparent filter that transmits light in the wavelength region h3).
7 is a high-sensitivity image sensor for fluorescence observation 3
It is arranged to rotate in synchronization with an imaging cycle of 1/60 second of 4. End face Ko of fluorescence image fiber 26
The fluorescence image of the wavelength region h1 by the color separation filter 37,
The images are separated into three wavelength regions of h2 and h3 and are picked up by the high-sensitivity image pickup device for fluorescence observation 34, and these picked-up images are A / D converted and correspond to the respective fluorescence intensities that have been A / D converted. The values (hereinafter referred to as fluorescent intensity values) are stored in the fluorescent image h1 memory 36-1, the fluorescent image h2 memory 36-2, and the fluorescent image h3 memory 36-3 for each wavelength region.
Is stored.

The discrimination unit 400 compares each of the three types of fluorescence intensity values stored in the fluorescence image memory 36 with the noise image data stored in the noise level memory 41 in advance, thereby determining each pixel of the fluorescence image. Is provided as a calculation inappropriate pixel and a calculation inappropriate pixel, and the position of each pixel determined to be a calculation inappropriate pixel is stored as a calculation inappropriate pixel position data as a calculation inappropriate pixel position data.
Is stored.

The identification calculation unit 500 receives the three types of fluorescence intensity values stored in the fluorescence image memory 36 and performs an operation between the fluorescence intensity values with reference to the inappropriate pixel position data. The result of the operation performed by the identification operation section 51 is stored in the identification image memory 52 as identification image data.

Next, the operation of the above embodiment will be described.

First, the pulsed white light Wh emitted from the white light source 12 is guided to the endoscope tip unit 200 via the white light condenser lens 14 and the white light guide 25-1, and is illuminated. Living tissue 1 via lens 21
Is irradiated. The image of the living tissue 1 illuminated by the white light Wh is formed on the light receiving surface of the normal observation CCD imaging device 23 by the normal observation objective lens 22. The image signal imaged by the image sensor 23 and converted into an electrical signal is further converted into a digital value by an A / D converter 30 for normal observation, and is converted as image data into a normal image memory 3.
1 is stored.

When the irradiation of the white light Wh is completed, the pulse-like excitation light Le emitted from the excitation light source 13 is next emitted.
Are the excitation light condenser lens 15 and the excitation light light guide 2.
The light is guided to the endoscope distal end unit 200 via 5-2 and is irradiated toward the living tissue 1 through the illumination lens 21.

The auto-fluorescence Ke emitted from the living tissue 1 by the irradiation of the excitation light Le forms an image on the end face Ki of the fluorescence image fiber 26 by the fluorescence observation objective lens 20 and propagates to the other end face Ko. The fluorescence image transmitted to the end face Ko is subjected to the auto-fluorescence Ke by the excitation light cut filter 32.
The excitation light Le mixed into the color separation filter 37 is removed.
High-sensitivity imaging device 34 for fluorescence observation through filter H1
And an image is formed on the light receiving surface. The fluorescent image picked up by the fluorescent observation high-sensitivity imaging device 34 is converted into a signal charge, and converted into a digital value (fluorescent intensity value of each pixel) by the fluorescent observation A / D converter 35, and is stored in the fluorescent image h1 memory. 36-1.

In the next cycle in which the pulsed excitation light Le is irradiated, a fluorescent image is captured through the filter H2 of the color separation filter 37, and the fluorescent intensity value of each pixel is stored in the fluorescent image h2 memory 36-2. In the next cycle of excitation light irradiation, a fluorescence image is captured through the filter H3, and the fluorescence intensity value of each pixel is stored in the fluorescence image h3 memory 36-3.
The fluorescent images transmitted through 1, h2, and h3 are sequentially captured as a set of three images, and the fluorescent intensity values of the pixels of these three images are stored as fluorescent intensity values Dh1, Dh2, and Dh3 as the fluorescent image h1 memory 36-1. , Fluorescent image h2 memory 36-
2 and the fluorescent image h3 are stored in the memory 36-3.

Next, the fluorescence intensity values of one set of the three images are input to the discrimination calculation section 40 and compared with the noise image data stored in the noise level memory 41. The pixel position is stored in a calculation inappropriate pixel position memory.

Here, the details of a specific example of a method for determining a pixel suitable for calculation and a pixel inappropriate for calculation will be described. The noise image data Dn stored in the noise level memory 41 is, as shown in FIG. 4, the position (x,
This is a matrix-like value obtained in advance by measurement or the like corresponding to y). The value of the noise image data Dn (x, y) is
For example, in a dark place where light does not reach at all, the high-sensitivity imaging device 3 for fluorescence observation is not irradiated with the white light Wh and the excitation light Le.
4, the value of each pixel of the image data that has been converted into a digital value by A / D conversion can be treated as a value of noise generated from an image sensor, an electric processing circuit, a signal transmission system, and the like. The value is the noise image data Dn
It can be obtained by storing as the value of (x, y).

The pixel suitable for calculation or the pixel unsuitable for calculation is determined by, for example, setting the pixel of interest to be the pixel at the position (X1, Y1) and the same pixel position (X1, Y1) transmitted through the three filters H1, H2 and H3, respectively. ), The values of the three fluorescence intensity values Dh1, Dh2, and Dh3 are all smaller than the coefficient times (α times) the value of the noise image data Dn (X1, Y1) corresponding to the position (X1, Y1). If so, the pixel is stored as a computationally unsuitable pixel. That is, Dh1 (X1, Y1) <α × Dn (X1, Y1) and Dh2 (X1, Y1) <α × Dn (X1, Y1) and Dh3 (X1, Y1) <α × Dn (X1, Y1) When the determination condition is satisfied, the pixel at the position (X1, Y1) is determined to be inappropriate for calculation, and the pixel that does not satisfy the determination condition is determined to be a calculation-appropriate pixel. The determination is performed for all the pixels, and among the pixels determined to be the calculation inappropriate pixels, the pixel positions are stored in the calculation inappropriate pixel position memory 42 as the calculation inappropriate pixel position data GF.

Next, the identification operation unit 51 performs an operation among the fluorescence intensity values Dh1, Dh2 and Dh3. Specifically, the fluorescence component near 480 nm and 630 nm
A fluorescence difference component obtained by subtraction from a nearby fluorescence component (the difference between the fluorescence intensity value Dh1 transmitted through the wavelength region h1 and detected and the fluorescence intensity value Dh2 transmitted through the wavelength region h2).
Is divided by the total fluorescence component (the fluorescence intensity value Dh3 transmitted through the entire wavelength region that is the wavelength region h3) to obtain the identification image data Sh. That is, Sh (x, y) = ｛Dh2 (x, y) −Dh1 (x,
y)｝ / Dh3 (x, y) = Dh2 (x, y) / Dh3 (x, y) −Dh1 (x,
y) / Dh3 (x, y) Here, comparing the intensity distribution Sp of the spectrum of the autofluorescence emitted from the normal tissue of the living body with the intensity distribution Bp of the spectrum of the autofluorescence emitted from the diseased tissue, FIG.
As shown in (a), the intensity of the normal tissue is higher, and these spectra are expressed by the ratio of the integrated value of the fluorescent intensity in a specific wavelength region to the integrated value of the fluorescent intensity over the entire wavelength region. By comparing the relative intensity ratio profile Skp of the normal tissue obtained by determining the relative intensity ratio with the relative intensity ratio profile Bkp of the diseased tissue (that is, the value obtained by integrating the intensity of the fluorescence over the entire wavelength region of each spectrum) Is converted to have the same value, for example, by converting it to 1), and as shown in FIG. 5B, in the wavelength region of 550 nm or less (especially near 480 nm), the fluorescent component of In the wavelength region of 600 nm or more (especially in the vicinity of 630 nm), the fluorescence component of the normal tissue is larger than the fluorescence component of the diseased tissue. Smaller.

Accordingly, from the relative intensity ratio Gk (Dh2 (x, y) / Dh3 (x, y)) in the wavelength region near 480 nm to the relative intensity ratio Rk (Dh1 in the wavelength region near 630 nm).
If the value of the identification image data Sh (x, y) obtained by subtracting (x, y) / Dh3 (x, y) becomes a large value, it is identified as a normal tissue (see FIG. 6A). Is small, the tissue is identified as a diseased tissue (see FIG. 6- (b)).

The above calculation is performed with reference to the calculation inappropriate pixel position data GF, and the above calculation for determining the identification image data Sh is not performed for the calculation inappropriate pixel. On the other hand, the above calculation is performed on the pixels suitable for calculation, and the value of the identification image data Sh (x, y) obtained for each pixel position is stored in the identification image memory 52. As described above, the amount of noise included in the value of the pixel that is present in the region where the amount of fluorescence received by the high-sensitivity imaging element for fluorescence observation 34 is extremely weak is relatively larger than the amount of received fluorescence light, Pixels having a value that does not provide a result that correctly reflects the tissue properties of the living body even after the calculation are excluded from the calculation as inappropriate pixels.

The operation for discriminating between the normal tissue and the diseased tissue is not performed on the inappropriate pixel, and the value of the image data corresponding to the position of the inappropriate pixel is determined by the identification operation unit 5.
For example, a value that is displayed dark on the fluorescent image TV monitor 81 is assigned by 1, and finally the fluorescent image TV monitor 8 is assigned.
The image displayed in No. 1 is, as shown in FIG.
s is displayed brightly, normal tissue Ss is displayed darkly, and the position Ef corresponding to the unsuitable pixel for calculation is displayed darkly so as not to visually affect. Further, the value assigned to the image data corresponding to the position of the inappropriate pixel is not limited to the above example, but may be 0.
Alternatively, the same value as the normal tissue or the same brightness and color as the background of the screen of the TV monitor can be assigned.

Next, the identification image data Sh (x, y) stored in the identification image memory 52 is subjected to image processing (edge enhancement, smoothing, various filtering, histogram correction, etc.) by the image processing section 53, and the video is processed. The information is output to the signal circuit 60, converted into a video signal, and displayed on the fluorescent image TV monitor 81 as information to be used for diagnosis. The image processing unit 53 receives information on the position of the unsuitable pixel from the unsuitable pixel position memory 42, and outputs the information to the image processing unit 5.
In the image processing performed by the image processing unit 3, the processing such as the operation is not performed on the unsuitable pixels, and the value assigned by the identification operation unit 51 is directly output to the video signal circuit 60 via the image processing unit 53 and the fluorescent image T
It is displayed by the V monitor 81.

On the other hand, the image data of the normal image stored in the normal image memory 31 is converted into a video signal by the video signal processing circuit 60, and is converted into a normal observation image.
Output to the monitor 80.

The calculation for determining the identification image data Sh performed by the identification calculation unit 51 is not limited to the calculation method of dividing the intensity of the fluorescence difference component by the intensity of all the fluorescence components, and the intensity of the fluorescence component near 480 nm is calculated at 630 nm. It can also be performed by a different calculation method such as dividing by the intensity of a nearby fluorescent component.

Further, in the above embodiment, the image acquisition method relating to the fluorescence intensity value obtained by imaging the autofluorescence has been described. However, the medicine generated by irradiating the living tissue, which has absorbed the fluorescent diagnostic agent in advance, with the excitation light. The same method can be applied to fluorescence.

The method and apparatus for acquiring a fluorescent image according to the present invention described in the above embodiment can be applied to a device other than an endoscope, for example, a colposcope, a surgical microscope, and the like.

Further, the range of the wavelength region through which the fluorescent image is transmitted, the number of regions to be set, and the like are not limited to the settings in the above embodiment.

Since the value of noise included in each pixel of the fluorescent image differs depending on conditions such as temperature, the noise image data Dn (x, y) for each temperature condition is stored in the noise level memory 41 as a table. Alternatively, a method of selecting noise image data that meets conditions from this table for each measurement can be adopted.

The value of the noise image data Dn (x, y) may be determined by measuring and storing noise for each pixel, storing the average value of the noise as a representative value, or detecting the fluorescence to be detected. It is also possible to adopt a method of measuring and storing noise including noise due to the adhesion of dust or the like to the optical system for making the light incident.

Further, the determination of the pixel suitable for calculation or the pixel unsuitable for calculation is made by determining the fluorescence intensity values Dh1 (x, y), Dh at the same pixel position (x, y) in the three wavelength regions h1, h2 and h3.
When all the values of 2 (x, y) and Dh3 (x, y) are smaller than the coefficient times (α times) the value of the noise image data Dn (x, y) at the pixel position (x, y), the position ( The fluorescent intensity values Dh1 (x, y) at the same pixel position (x, y) in the three wavelength regions h1, h2, and h3 are not limited to the discrimination method in which the pixel corresponding to (x, y) is stored as a calculation inappropriate pixel. Dh
At least one of the values of 2 (x, y) and Dh3 (x, y) is a coefficient multiple (α times) of the value of the pixel position (x, y) noise image data Dn (x, y). When the value becomes smaller, the pixel at the position (x, y) is determined to be an inappropriate pixel for calculation, or three wavelength regions h1 and h2.
Pixel positions (x, y) that have passed through and h3 respectively
Of the fluorescence intensity values Dh1 (x, y), Dh2 (x, y), and Dh3 (x, y) are noise image data Dn (x, y) at the pixel position (x, y).
When the value of the value of y) is smaller than the coefficient times (α times), the pixel at the position (x, y) may be determined to be an unsuitable operation pixel by a determination method or the like.

The coefficient α may be determined as a fixed value, or may be in a form that can be appropriately changed by a measurer at the time of measurement. The coefficient α can be changed by an equation or the like.

When the amount of fluorescent light generated from the living tissue is small and the value of each pixel of the fluorescent image is expected to be small in advance, the value received by the high-sensitivity image pickup device for fluorescent observation is determined by a technique such as binning. , And a plurality of pixels are treated as one pixel (for example, 2 × 2 pixels are treated as one pixel or 4 × 4 pixels are treated as one pixel, etc.), and if the same processing as described above is performed, the image resolution becomes Although the amount of the received fluorescent light is deteriorated but can be increased apparently, a part of the pixels which have been determined to be the calculation inappropriate pixels can be handled as the calculation suitable pixels.

Further, the block diagram of the processing of the image data shown in FIG. 1 is not limited to this mode, and the configuration of the discrimination unit 400 or the identification operation unit 500 can be different.

The image of the normal image and the image of the fluorescent image are
It can also be displayed on one TV monitor.

The wavelength of the excitation light Le is not limited to the wavelength region near 410 nm, but may be selected to be a wavelength region in which fluorescence can be efficiently generated from living tissue.

As shown in FIG. 8A, the light source is connected to one light source 91 connected to a power supply 90 that generates light in a wavelength range including the wavelength range of the excitation light Le and the wavelength range of the white light Wh. 8B in which a semicircular bandpass filter transmitting the wavelength region of the excitation light Le and a semicircular bandpass filter transmitting the wavelength region of the white light Wh are replaced.
The disk-shaped split filter 97 shown in FIG.
1 is provided on the optical path for emitting light from
The excitation light Le and the white light Wh can be generated alternately by rotating the filter 97 in synchronization with the light receiving timing of the image sensor by the motor 95 controlled by the motor 95. Here, the excitation light Le transmitted through the two-part filter 97 transmits through the first cube beam splitter 92 having the dichroic surface Fd that reflects the white light Wh and transmits the excitation light Le, and is collected by the condenser lens 15. The light is emitted and enters the excitation light guide 25-2 (see FIG. 1). On the other hand, the white light Wh transmitted through the two-part filter 97
Is reflected by the first cube beam splitter 92 having the dichroic surface Fd that reflects the white light Wh and transmits the excitation light Le, is further reflected by the second cube beam splitter 93, and is collected by the condenser lens 14. Incident on the white light guide 25-1 (see FIG. 1).

In the above embodiment, the normal observation CCD image pickup device 23 is installed at the end of the endoscope. However, by using an image fiber, the image pickup device 23 is installed in the image capturing unit 300. May be installed. Further, the image fiber for the normal image and the image fiber for the fluorescent image can be used in common with the image pickup device. However, in this case, a means such as an optical filter for separating and acquiring a fluorescent image transmitted through a desired wavelength region and a normal image is provided on the front surface of the image sensor.

Further, it is also possible to arrange the high-sensitivity image sensor for fluorescence observation 34 in the endoscope tip unit 200 and to share the CCD image sensor 23 for normal observation and the high-sensitivity image sensor 34 for fluorescence observation. it can. However, in this case, a mosaic filter or the like having the same function as the color separation filter 37 is provided on the front surface of the imaging device of the endoscope distal end unit 200.

Further, by using a GaN-based semiconductor laser as the light source of the excitation light, the size of the device can be reduced and the cost of the device can be reduced.

As described above, according to the fluorescence image acquisition method and apparatus of the present invention, a large proportion of noise is included in the fluorescence intensity value of each pixel obtained by imaging fluorescence generated from a living body or the like by irradiation of excitation light. It is possible to acquire a fluorescence image so that even if there is a value included in the image, it does not adversely affect the image, and by excluding a value containing a large proportion of this noise from the calculation target, Data processing time can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram in which a fluorescence image acquisition device of the present invention is applied to a fluorescence endoscope.

FIG. 2 is a diagram showing transmission characteristics of each filter constituting a color separation filter 37;

FIG. 3 is a diagram showing a structure of a color separation filter 37;

FIG. 4 shows pixel positions (x, y) of noise image data Dn.
Figure showing

FIG. 5 (a) is a diagram showing a distribution of spectral intensities of fluorescence emitted from a normal tissue and a diseased tissue. FIG. 5 (b) is a diagram showing a relative intensity ratio profile of fluorescence emitted from a normal tissue and a diseased tissue.

FIG. 6 (a) 480n of fluorescence emitted from normal tissue
Diagram showing relative intensity ratios near m and 630 nm (b) Diagram showing relative intensity ratios of fluorescence emitted from diseased tissue near 480 nm and 630 nm

FIG. 7 is a view showing an image finally displayed on a fluorescent image TV monitor 81;

FIG. 8 is a diagram showing a configuration when two light sources are replaced by one light source 91;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Living tissue 12 White light source 13 Excitation light source 23 CCD image sensor for normal observation 25 Light guide 34 High-sensitivity image sensor for fluorescence observation 60 Video signal processing circuit 70 Control unit 100 Light source unit 200 Endoscope tip unit 300 Image capture Unit 400 Discrimination unit 500 Discrimination calculation unit 600 Fluorescence endoscope Wh White light Le Excitation light

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuo Hakamada 798, Miyadai, Kaisei-cho, Ashigara-gun, Kanagawa Prefecture F-Film Co., Ltd. F-term (reference) 2G043 AA03 BA16 CA05 DA02 EA01 FA05 GA04 GB18 GB19 HA01 HA05 HA09 JA02 JA03 KA02 KA05 KA09 LA03 NA01 NA06 4C061 AA00 BB00 CC06 DD03 HH54 JJ11 JJ17 LL02 NN01 QQ04 SS09 SS11

Claims (11)

[Claims] 1. A fluorescent image of the sample obtained by irradiating a sample such as a living body with excitation light to obtain fluorescence intensity in at least one wavelength region from fluorescence emitted from the sample, and performing an operation based on the fluorescence intensity. A fluorescent image acquisition method for acquiring image data representing the image data, wherein for each of the pixels constituting the fluorescent image, it is determined whether the pixel is an operation-appropriate pixel or an operation-improper pixel based on the fluorescence intensity. For the above, the value of the pixel is obtained by performing the above calculation, and for the inappropriate pixel, a value that does not visually affect the fluorescent image portion corresponding to the calculation suitable pixel is assigned as the value of the pixel. Fluorescent image acquisition method. 2. The method according to claim 1, further comprising determining, for each of the pixels constituting the fluorescence image, the fluorescence intensity at each pixel and the noise at each pixel generated by the fluorescence intensity measurement means for obtaining the fluorescence intensity measured and stored in advance. 2. The fluorescence image acquiring method according to claim 1, wherein the method is performed by comparing the values of the fluorescence image with the fluorescence image. 3. The fluorescence image acquisition according to claim 1, wherein when performing image processing of the image data representing the acquired fluorescence image, only the calculation-appropriate pixels are subjected to image processing. Method. 4. The fluorescence image acquiring method according to claim 1, wherein the sample is a living body, and the fluorescence is auto-fluorescence emitted from the inside of the living body. 5. The fluorescence image acquiring method according to claim 1, wherein a GaN-based semiconductor laser is used as a light source of the excitation light. 6. An excitation light irradiating means for irradiating a sample such as a living body with excitation light, and a fluorescence intensity of at least one wavelength region from fluorescence emitted from the sample irradiated with the excitation light by the excitation light irradiating means. A fluorescence image measurement device comprising: a fluorescence intensity measurement means to be obtained; and a calculation processing means for performing an operation based on the fluorescence intensity to obtain image data representing a fluorescence image of the sample. A determination unit that determines whether the pixel is an operation-appropriate pixel or an operation-inappropriate pixel based on the fluorescence intensity; and the operation processing unit performs the operation on the operation-appropriate pixel and calculates the value of the pixel. Get
A fluorescence image acquiring apparatus, wherein a value that does not visually affect the fluorescence image portion corresponding to the calculation-appropriate pixel is assigned to the inappropriate pixel as a value of the pixel. 7. The method according to claim 1, wherein the determination unit determines, for each pixel constituting the fluorescence image, the fluorescence intensity of each pixel, and a noise value of each pixel generated from the fluorescence intensity measurement unit itself measured and stored in advance. 7. The fluorescence image acquisition device according to claim 6, wherein the determination is made by comparing 8. An image processing means for performing image processing of the image data representing the acquired fluorescent image, wherein the image processing means performs image processing only on the image data of the calculation-appropriate pixel. The fluorescence image acquisition device according to claim 6 or 7, wherein: 9. The fluorescence image acquiring apparatus according to claim 6, wherein the sample is a living body, and the fluorescence is autofluorescence emitted from inside the living body. 10. The fluorescence image acquiring apparatus according to claim 6, wherein the excitation light source is a GaN-based semiconductor laser. 11. The fluorescence image acquisition device according to claim 6, wherein the fluorescence image acquisition device is an endoscope.