CN104352216B - Endoscope irradiation spectrum selection device and hyperspectral endoscope imaging system - Google Patents

Abstract

The invention discloses a hyper-spectral endoscope imaging system, which comprises a light source, an irradiation spectrum selection device, an endoscope, an image processing unit and a display unit, wherein the irradiation spectrum selection device comprises a dispersion element, a convergent lens and a movable reflector, different wavelength light emitted by the dispersion element is projected to the movable reflector after passing through the convergent lens, and the wavelength light is respectively coupled to an incident surface of a light guide of an electronic endoscope through the movement of the movable reflector. The invention uses the principle of light dispersion, uses the wavelength selection device to simply and conveniently select the wavelength of the irradiated light, and obtains the irradiated spectrum of any spectral band in the spectral range from near infrared to visible light of the measured tissue in real time; the doctor can select the spectral image to be shot according to the condition of a patient and the optical characteristics of the pathological tissue, so that the integration of the atlas and the real-time spectral imaging of the in-vivo living tissue are realized.

Description

Endoscope irradiation spectrum selection device and hyperspectral endoscope imaging system

technical field

The present invention relates to a spectral imaging medical device based on an endoscope, in particular to a selection device for endoscope multi-spectral irradiation spectrum, and also relates to a hyperspectral endoscopic imaging system using the above selection device.

Background technique

Spectral imaging technology is a combination of spectral analysis and optical imaging technology, which can simultaneously obtain the morphological information of biological tissues and the complete spectral data of biological tissues in a certain wavelength range. Since biological tissues have unique reflectance spectra, autofluorescence spectra, and induced fluorescence spectra under different pathological conditions, spectral imaging of biological tissues and quantitative analysis can achieve early diagnosis of certain pathological changes. In particular, it is of great significance to the research on the pathogenesis, clinical diagnosis, disease detection and curative effect evaluation of tumors and other diseases.

At present, the spectral imaging of tissues in the medical field basically requires the collection and preparation of samples first, and then collects data with imaging spectral equipment. This method cannot perform in vivo spectral imaging on living tissues, which greatly limits the application of spectral imaging technology in the fields of early diagnosis of diseases and evaluation of treatment effects.

In recent years, relevant literature and patents have proposed a device combining multispectral imaging technology with an endoscope, which has realized in vivo spectral imaging of living tissues to a certain extent. For example, Olympus has proposed a narrowband spectral imaging (NarrowBandImaging) endoscope. This endoscope uses light of two wavelengths (blue light: 405nm-425nm/green light: 540-560nm) that is easily absorbed by hemoglobin to irradiate and image the capillaries on the surface of the mucous membrane and the fine structure of the mucous membrane. . When the tissue becomes cancerous, the blood vessels in the lesion will increase, and the structure formed by the capillary on the mucosal surface will change. Taking advantage of this, the narrow-band spectral imaging endoscope can provide powerful help for the early detection of cancer.

For another example, Olympus proposed an autofluorescence imaging (AutoFluorescence Imaging) endoscope, which utilizes the induced fluorescence characteristics of the tissue, and uses blue light (390nm-470nm) excitation light to irradiate the submucosa, so that the tissue produces a strong fluorescence. If the fluorescence encounters abnormal developmental lesions (such as abnormal collection of superficial blood vessels or thickened mucosa), the light decreases and the fluorescence becomes weaker. The endoscope system will convert these subtle changes into color information, so that the subtle differences between normal mucosa and lesions can be emphasized, and provide a basis for diagnosing pathological changes in tissues.

Chinese patent CN103340601A proposes an endoscope-based multi-spectral imaging system and method. The device proposed in this patent provides near-infrared and visible light sources, and uses multiple sets of filters to filter the light, so as to obtain images corresponding to the filters. Multispectral imagery.

The narrow-band spectral imaging endoscope and autofluorescence imaging endoscope proposed by Olympus mentioned above, and the patent CN103340601A proposed "endoscope-based multi-spectral imaging system" usually include a light source for providing near-infrared to visible light. Spectrum illumination light; filter combination, used to select a narrower spectrum of light in the illumination light and couple it to the endoscope to irradiate the tissue under examination; endoscope, to photograph the tissue under examination under the illumination of the specified spectrum band Spectral image; image processing unit, which fuses and processes the spectral images of the inspected tissue under various spectral illumination lights to obtain the spectral image of the tissue; and a display unit, which performs image display on the above-mentioned images; these devices can be used in To a certain extent, in vivo spectral imaging of tissues in vivo can be realized. But there are still its limitations.

The common point of the above-mentioned solutions is to use the light source filtered by the filter to illuminate the tissue, so as to obtain the illumination spectrum image corresponding to the filter. Or use a monochromatic laser as a light source to obtain a spectral image corresponding to the laser wavelength.

This way of spectral imagery has great limitations. The number of filters in a set of equipment determines the spectral composition of the multispectral image of tissue that can be collected. An example is Olympus' narrowband spectral imaging endoscopy device. The device has two groups of five filters in total: R (600nm~700nm), G (500nm~600nm), B (400nm~500nm) filter group and Ga (540nm~560nm), Ba (405nm~415nm) filter group, the device can only obtain two spectral images of tissue.

To sum up, the current technical solutions can only obtain very few specific spectral images of tissues due to the dependence on filters or monochromatic lasers.

Contents of the invention

In view of the disadvantages of the above solutions, the purpose of the present invention is to provide a device for selecting the irradiation spectrum of an endoscope, which can simply and conveniently acquire any spectrum from near-infrared to visible light for spectral imaging of endoscopes.

Another object of the present invention is to provide a hyperspectral endoscopic imaging system using the above selection device, which can obtain spectral images of any spectral segment within the spectral range from near-infrared to visible light of the measured tissue.

The first object of the present invention is achieved by the following technical measures: a selection device for endoscope irradiation spectrum, comprising:

The dispersion element is used to disperse the visible light beam incident on the dispersion element according to different wavelengths, so that the angle or position of the outgoing light is distributed according to the wavelength of the incident light;

A converging lens, the focal point of which is located at the incident point of the visible light beam and the dispersion element;

The movable mirror is controlled by the drive circuit for one-dimensional movement;

The light guide of the electronic endoscope is used to couple the irradiation spectrum of different bands;

Lights of different wavelengths emitted by the dispersing element are projected onto the movable reflector after passing through the converging lens, and the light of each wavelength is respectively coupled to the incident surface of the light guide of the electronic endoscope through the movement of the movable reflector.

Preferably, the dispersion element is a reflective grating.

Another object of the present invention is achieved by the following technical measures: a hyperspectral endoscopic imaging system, comprising: a light source for providing illumination light from the near-infrared to the full spectrum of visible light; In the illumination light, any light of a specified spectrum is selected and coupled to the endoscope to irradiate the tissue to be inspected; the endoscope captures the spectral image of the tissue to be inspected under the illumination of the specified spectrum; the image processing unit converts the tissue to be inspected Image fusion and processing of spectral images under various spectral bands of illumination light to obtain spectral images of tissues; and a display unit for image display of the above images;

It is characterized in that the selection device of the irradiation spectrum comprises:

The dispersion element is used to disperse the visible light beam incident on the dispersion element according to different wavelengths, so that the angle or position of the outgoing light is distributed according to the wavelength of the incident light;

A converging lens, the focal point of which is located at the incident point of the visible light beam and the dispersion element;

The movable mirror is controlled by the drive circuit for one-dimensional movement;

The light guide of the electronic endoscope is used to couple the irradiation spectrum of different bands;

Lights of different wavelengths emitted by the dispersing element are projected onto the movable reflector through the converging lens, and the light of each wavelength is respectively coupled to the incident surface of the light guide of the electronic endoscope through the movement of the movable reflector.

Preferably, the dispersion element is a reflective grating.

Preferably, the light source includes: a xenon lamp and a collimating lens, and the illumination light emitted by the xenon lamp is collimated by the collimating lens into parallel light output and projected onto the dispersion element.

Further, the light source also includes an iris diaphragm for changing the size of the clear aperture, and the parallel light collimated by the collimator lens is output and projected onto the dispersion element after passing through the iris diaphragm.

Further, the image processing unit is provided with a control module, which is used to respectively trigger and control the driving of the movable mirror, the shooting of the endoscope, the image processing and the adjustment of the diaphragm aperture.

The present invention utilizes the dispersion principle of light and uses a wavelength selection device to simply and conveniently select the wavelength of the irradiated light, and obtain in real time the irradiated spectrum of any spectrum from the near-infrared to the visible spectrum of the tissue to be measured; Optical characteristics of diseased tissue, select the spectral image that needs to be taken, realize the integration of maps and real-time spectral imaging of living tissues in vivo; realize early diagnosis of certain pathological changes. In particular, it is of great significance to the research on the pathogenesis, clinical diagnosis, disease detection and curative effect evaluation of tumors and other diseases.

Description of drawings

Fig. 1 system principle composition block diagram of the present invention;

Fig. 2 is a schematic diagram of selecting different wavelengths in the wavelength selection device of the present invention.

detailed description

Figure 1 is an example of the present invention. As shown in FIG. 1 , the hyperspectral endoscopic imaging system of this embodiment includes: a light source device 1 , a wavelength selection device 2 , an electronic endoscope 3 , an image processor 4 , and a display 5 .

Wherein, the light source device 1 is used for providing illumination light. The illuminating light provided by the illuminating device 1 has a continuous distribution of light radiation intensity as the frequency changes within the near-infrared to visible spectrum. In this embodiment, the light source device 1 includes: a xenon lamp 7, which functions to emit illuminating light; a collimating lens 8, which collimates the illuminating light emitted by the xenon lamp 7 into parallel light; Under the control of the circuit, the size of the light aperture is changed, so as to realize the control of the output illumination light intensity.

The function of the wavelength selection device 2 is to select the light in a specified spectral range from the illumination light, and converge the light in the spectral range to the incident surface of the light guide 12 of the electronic endoscope 3 . The wavelength selection device 2 includes: a dispersion element 9 , a converging lens 10 , a movable mirror 11 and a light guide 12 . The role of the dispersion element 9 is to disperse the light beam incident on the scattering element 9 according to the wavelength, so that the angle or position of the outgoing light is distributed according to the wavelength of the incident light; in this embodiment, the GR50-0603 reflection grating produced by Thorlabs can be used as a dispersive element. The front focal point of the converging lens 10 is located at the incident point of the illumination light and the dispersion element; the movable mirror 11 is located between the converging lens 10 and the light guide 12; the moving position of the movable reflector 11 is between the converging lens 10 and the light guide 12 The positional relationship of the light satisfying the specified spectral range is converged by the converging lens 10 , reflected by the movable mirror 11 , and the light is focused on the end face of the light guide 12 . In this embodiment, the movable mirror performs one-dimensional translational movement; the driving circuit of the movable mirror can be realized by a single-chip microcomputer.

FIG. 2 is a schematic diagram of the principle of selecting a specified wavelength by the wavelength selection device 3 . According to the grating formula, for a reflective grating with a pitch of d, the incident light is incident at an incident angle α relative to the normal of the grating surface, and the relationship between the outgoing angle θ of the m-level outgoing light relative to the normal of the grating surface and the wavelength λ of the incident light is as follows:

d(sin(θ)-sin(α))=mλ

In the illumination light, the light rays with wavelength λ ₁ and wavelength λ ₂ will exit at different angles after passing through the reflective grating. Since the focal point of the converging lens ₁₀ is located at the incident point of the illumination light and the reflective grating, light rays with a wavelength of λ1 and a wavelength of _λ2 are focused in different positions after passing through the converging lens. If the focal length of the converging lens is f, the distance Δl between the converging point of the light rays with wavelength λ ₁ and wavelength λ ₂ passing through the converging lens is:

Δl=f(tanθ ₁ -tanθ ₂ )

As shown in FIG. 2 , the diameter of the incident surface of the light guide 12 is a. In _one state, the light with wavelength λ1 is reflected by the movable mirror 11 and converges to the center of the light guide 12 . If the distance Δ1 between the light of wavelength _λ2 and the converging point of wavelength λ1 after passing through the converging lens is greater than ₁ /2a, the light of wavelength λ2 cannot enter the light guide ₁₂ . In another state, if the movable reflector moves to the right by a distance Δl, the light with a wavelength of _λ2 converges to the center of the light guide ₁₂ , while the light with a wavelength of λ1 cannot enter the light guide 12. In this way, desired wavelengths can be selected to be coupled into the light guide 12 by controlling the position of the movable mirror.

When it is necessary to take spectral images of λ ₁ , λ ₂ .... λ _n , a reflective grating including light in different wavelength bands of dispersion λ ₁ , λ ₂ .... λ _n can be selected, and the mirror needs to move n positions in one-dimensional translation These different wavelengths and position points need to be adjusted in advance and stored and recorded in the control module and the mirror driving circuit.

The above-mentioned dispersive element can also adopt transmission grating, dispersive prism, spectrophotometer, spectrometer, acousto-optic deflector or liquid crystal tunable filter, etc., and the principles of these elements are similar to the above-mentioned reflective grating. The movable mirror can also control its rotation to adjust the reflection angle, and couple the different wavelengths output by the dispersion element into the light guide.

The function of the electronic endoscope 3 is to insert into the body cavity and take image information of tissues in the cavity, which is stored by the image processor 4 .

The role of the image processor 4 is to store the electronic images on the imaging element and synthesize the images of the tissues under a series of spectral irradiations to obtain spectral images of the tissues with high spectral resolution.

The image processing unit is provided with a control module, which is used to respectively trigger and control the driving of the movable mirror, the shooting of the endoscope, the image processing and the adjustment of the diaphragm aperture.

The specific coordinated control process is as follows: the doctor sets the required spectral images of λ ₁ , λ ₂ .... λ _n according to the patient's condition and the optical characteristics of the tissue. The control module sends a control signal to the drive circuit, so that the movable mirror 11 moves to position _A , so that the light of wavelength λ1 is coupled into the light guide 12, and irradiates the measured light through the light guide 12 and the electronic endoscope 4 organizationally. The electronic endoscope 4 collects the reflected light or induced fluorescence on the tissue under test, images it on the image plane of the imaging element, and stores it as _a λ1 image by the image processor 5. The control module sends a control signal to the drive circuit, so that the movable mirror 11 moves to position B, so that the light of wavelength λ2 is coupled into the light guide ₁₂ , and irradiates the measured light through the light guide 12 and the electronic endoscope 3 organizationally. The electronic endoscope 3 collects the reflected light or induced fluorescence on the tissue under test, images it on the image plane of the imaging element, and stores it as a λ2 image by the image processor ₄ . In this way, a set of λ ₁ , λ ₂ . . . λ _n spectral images of the measured tissue is obtained. The image processor synthesizes the group of images to obtain the synthesized spectral images of the measured tissue in the λ ₁ , λ ₂ . . . λ _n spectrum. And displayed by display 5.

The present invention is not limited to the above-mentioned specific embodiments. According to the above-mentioned content, according to the common technical knowledge and conventional means in this field, without departing from the above-mentioned basic technical idea of the present invention, the present invention can also make other equivalents in various forms. Amendments, substitutions or alterations all fall within the protection scope of the present invention.

Claims (7)

1. a selecting arrangement for endoscope's illumination spectra, is characterized in that comprising:

Dispersion element, carries out dispersion for the visible light beam that will incide on dispersion element by the difference of wavelength, the angle of emergent light or position is distributed according to lambda1-wavelength;

Collecting lens, the focus of collecting lens is positioned at the incidence point of visible light beam and dispersion element;

Movable reflecting mirror, is controlled down to carry out motion in one dimension by drive circuit;

The light guide therefor of endoscope, for the illumination spectra of the input different-waveband that is coupled;

Each different wavelengths of light of dispersion element outgoing projects movable reflecting mirror after collecting lens, by the movement of movable reflecting mirror, each wavelength light is coupled to respectively the incident end face of the light guide therefor of endoscope.

2. the selecting arrangement of a kind of endoscope according to claim 1 illumination spectra, is characterized in that: described dispersion element is reflecting grating.

3. a ultraphotic spectrum endoscopic imaging system, comprising: light source, for providing the illumination light of full spectral coverage in near-infrared to visible ray; The selecting arrangement of illumination spectra, specifies arbitrarily the coupling light of spectral coverage to irradiate tested tissue to endoscope for selecting in illumination light; Endoscope, takes and is testedly organized in the spectrum picture of specifying under spectral coverage illumination; Graphics processing unit, carries out image co-registration and process by the tested spectrum picture be organized under various spectral coverage illumination light, obtains the spectrum picture of tissue; And display unit, image display is carried out to the tissue spectrum image that above-mentioned graphics processing unit obtains;

It is characterized in that the selecting arrangement of described illumination spectra comprises:

Dispersion element, carries out dispersion for the visible light beam that will incide on dispersion element by the difference of wavelength, the angle of emergent light or position is distributed according to lambda1-wavelength;

Collecting lens, the focus of collecting lens is positioned at the incidence point of visible light beam and dispersion element;

Movable reflecting mirror, is controlled down to carry out motion in one dimension by drive circuit;

The light guide therefor of endoscope, for the illumination spectra of the input different-waveband that is coupled;

Each different wavelengths of light of dispersion element outgoing projects movable reflecting mirror after collecting lens, by the movement of movable reflecting mirror, each wavelength light is coupled to respectively the plane of incidence of the light guide therefor of endoscope.

4. a kind of ultraphotic spectrum endoscopic imaging system according to claim 3, is characterized in that: described dispersion element is reflecting grating.

5. a kind of ultraphotic spectrum endoscopic imaging system according to claim 3, it is characterized in that: described light source comprises: xenon lamp and collimating lens, the illumination light that described xenon lamp sends is collimated into directional light output through collimating lens and projects on described dispersion element.

6. a kind of ultraphotic spectrum endoscopic imaging system according to claim 5, it is characterized in that: described light source also comprises the iris for changing clear aperature size, the directional light that described collimating lens is collimated into exports and projects on described dispersion element after iris.

7. a kind of ultraphotic spectrum endoscopic imaging system according to claim 6, it is characterized in that: in described graphics processing unit, be provided with control module, regulate for the shooting of the driving of respectively movable reflecting mirror described in trigging control, endoscope, image procossing and the aperture of the diaphragm.