CN107510430A - Endoscopic optical imaging method and system a kind of while that obtain otherwise visible light color image and blood-stream image - Google Patents

Abstract

The invention discloses an endoscope optical imaging method and system for synchronously acquiring visible light color images and blood flow images. The method comprises: simultaneously illuminating the biological tissue to be measured with the laser light and the visible light through the endoscope optical system, after passing through the endoscope optical system, using a spectroscopic component to separate the laser light and visible light backscattered by the biological tissue, and using two photoelectric imaging The devices are probed and imaged separately. Among them, the visible light backscattered by the biological tissue is collected by a color photoelectric imaging device to obtain a color image of the biological tissue; the laser speckle image backscattered by the biological tissue is collected by a monochromatic photoelectric imaging device and processed by the laser speckle blood flow imaging method Blood flow images in biological tissue. The invention obtains the color image of biological tissue and blood flow image simultaneously through the optical endoscope, realizes multi-functional optical endoscopic imaging, and overcomes the slow imaging speed and time asynchrony caused by the time-sharing switching of multiple light sources when using a single photoelectric imaging device and other shortcomings.

Description

An endoscopic optical imaging for simultaneous acquisition of visible light color images and blood flow images method and system

technical field

The invention belongs to the field of biomedical imaging, and in particular relates to an endoscopic optical imaging method and system capable of synchronously acquiring visible light color structural images and blood flow functional images of tissues such as a cavity in a human body.

Background technique

Endoscopic imaging is an important part of modern medical imaging, and it is essential for detecting lesions in human cavity and performing minimally invasive surgery. In recent years, in order to improve the effect of endoscopic imaging, especially to improve the detection success rate of small tumors, endoscopic imaging is no longer limited to simple structural imaging, OCT tomographic imaging, fluorescence imaging, spectral imaging, laser speckle blood flow, etc. Imaging and other functional imaging technologies are gradually applied to endoscopic imaging. Functional imaging such as fluorescence imaging, spectral imaging, and laser speckle blood flow imaging are all optical imaging methods. Incoherent or coherent light sources are used to irradiate biological tissues, the reflected light is collected, and the reflected light information is analyzed to obtain important physiological parameters of biological tissues. A conventional endoscope structure includes a white light source, an illumination assembly, an imaging assembly, and an image acquisition and display unit. In order to enable the endoscope to perform structural imaging and at the same time realize the above-mentioned functional imaging, endoscopic imaging is required to collect reflected light of biological tissues of different wavelengths. For example, fluorescence imaging requires monochromatic light source illumination for fluorescence excitation, and biological tissue reflection needs to be filtered out during imaging. The monochromatic excitation light source is used to collect the fluorescence emission light. How to improve the structure of conventional endoscopes to realize the collection of optical signals in different wavelength bands is the key difficulty in realizing synchronous imaging of endoscope structures and functions. At present, there are generally two solutions. One is to add a rotatable filter wheel in front of the original white light source of the endoscope, and install two or more filters of specific wavelength bands on the filter wheel and drive them electronically; Another method is to use multiple light sources with specific wavelengths for time-sharing lighting. For example, the invention patent of application number "CN201710312530.3" "multi-spectral fluorescence imaging system and imaging method based on rigid endoscope", the invention patent of application number "CN201710046429.8" "a multi-spectral endoscope imaging device" , the invention patent of application number "CN201710312538.X" "a fluorescent endoscopic imaging system" uses a filter wheel to select the light band, and the invention patent of application number "201610376586.0" "a multi-spectral endoscopic imaging system" "Acquisition method and system thereof" is a time-sharing lighting method using multiple monochromatic light sources.

Neither of the above two methods can simultaneously acquire multiple bands of optical signals, resulting in structural images and functional images being acquired at different times, and unavoidable signal errors will occur during subsequent signal analysis or image fusion. In terms of structure, the filter wheel is a mechanical switch, which has the problems of significant delay, relatively limited mechanical life, and high mechanical noise. Time-sharing lighting of multiple light sources is not suitable for high stability of light source performance (such as power and coherence). application of gender requirements. In addition, different optical imaging has inconsistent requirements for image acquisition units. For example, fluorescence imaging generally requires a high-sensitivity EMCCD camera, laser speckle blood flow imaging generally uses a monochromatic imaging device, and structural imaging only requires ordinary image acquisition equipment. Therefore, In synchronous imaging, using the same camera often cannot meet the imaging requirements of both modes at the same time.

Blood flow is an important physiological parameter of living organisms, and it is a functional signal. Most lesion areas are accompanied by abnormal signs of increased or decreased blood flow, which can reflect information that cannot be expressed by structural/morphological signals. For example, tiny tumors in the human cavity are difficult to find or identify on structural imaging, but on blood flow images, suspected tumor tissues with abnormally high blood flow signals can be found effectively and quickly. The flow image can effectively define the tumor boundary. Laser speckle blood flow imaging technology or laser Doppler technology is an emerging means of detection and imaging of blood flow signals in recent years, both of which have the advantages of non-contact, non-invasive, and no need for contrast agents. In field blood flow imaging, the temporal resolution can reach tens of milliseconds, and the spatial resolution can reach microns. Because of its non-invasive and real-time performance, it has become popular in clinical testing in recent years. Using the endoscope system to realize the simultaneous acquisition and display of color structural images and laser speckle blood flow functional images has important clinical guiding significance for the rapid and effective qualitative and localization of lesions. In the invention patent "An Endoscopic Imaging System" with the application number "CN201610090949.4", the endoscopic imaging technology is combined with the laser speckle blood flow imaging technology, but there is also the problem that the structural image and the functional image cannot be acquired synchronously. The problem is that multiple light sources are time-sharing controlled, and a single imaging device is used, which makes it difficult to meet the different performance requirements of photoelectric imaging devices for different color structure images and blood flow image detection.

Contents of the invention

In order to solve the above problems, the present invention provides an endoscopic optical imaging method and system for simultaneously acquiring visible light color images and blood flow images.

The invention discloses an endoscopic optical imaging method for synchronously acquiring visible light color images and blood flow images.

The method process is:

The laser and visible light pass through the endoscope optical system to simultaneously illuminate the biological tissue to be tested. After passing through the endoscope optical system, the laser and visible light backscattered by the biological tissue are separated by using a spectroscopic component, and two photoelectric imaging devices are used to detect and image respectively. Among them, the visible light backscattered by the biological tissue is collected by a color photoelectric imaging device to obtain a color image of the biological tissue; the laser light scattered back by the biological tissue is collected by a monochromatic photoelectric imaging device, and the biological tissue is obtained by laser speckle blood flow imaging method Blood flow image.

The line width stability (ie, the fluctuation of the line width) of the laser is less than ±0.02nm.

The laser is in the near-infrared band.

The laser light is coupled to the endoscope optical system through a single-mode fiber bundle.

The invention discloses an endoscope optical imaging system for synchronously acquiring visible light color images and blood flow images.

The system includes a visible light source and a laser light source. The light emitted by the visible light source and the laser light source passes through the coupling unit and passes through the endoscope lighting assembly to illuminate the biological tissue to be tested. The visible light and laser light scattered back by the biological tissue pass through the endoscope imaging assembly. After being separated by the light-splitting component, they are respectively collected by a color photoelectric imaging device and a monochrome photoelectric imaging device through an optical adapter. The color photoelectric imaging device and the monochrome photoelectric imaging device are connected to an image processing unit, and the image processing unit is connected to an image display unit connect.

As shown in Figure 1, the lighting unit of the device of the present invention includes a wide-spectrum visible light source and a laser light source, and the coupling unit connects the visible light source and the laser light source to the lighting assembly of the endoscope optical system, and the endoscope optical system It includes an illumination component and an imaging component. The spectroscopic component is connected with the imaging component to separate the wide-spectrum visible light reflected by the biological tissue to be measured from the laser. The visible light is connected to the color photoelectric imaging device through the optical adapter, and the laser is connected to the monochromatic photoelectric imaging device through the optical adapter. The devices are connected, the image processing unit is connected with the color photoelectric imaging device and the monochromatic photoelectric imaging device, and the image display unit is connected with the image processing unit.

The laser light source 2 includes a semiconductor laser, a drive current controller, a constant temperature cavity and a constant temperature controller. The wavelength of the semiconductor laser is in the near-infrared band and is connected to the drive current controller. The semiconductor laser is installed in the constant temperature cavity. The constant temperature cavity is connected with a constant temperature controller, and the constant temperature controller controls the temperature fluctuation of the semiconductor laser to be less than ±0.01°C.

The coupling unit 3 includes a laser light source connection adapter, a visible light source connection adapter, a single-mode fiber bundle, a multi-mode fiber bundle, an endoscope optical system lighting component connection adapter, and the single-mode fiber bundle is connected to the laser light source connection adapter. The multi-mode fiber bundle is connected to the visible light source adapter, and the endoscope optical system lighting component connection adapter is connected to the single-mode fiber bundle and the multi-mode fiber bundle.

The monochromatic photoelectric imaging device 10 is an area array digital CCD camera/video camera, or an area array digital CMOS camera/camera, and its analog-to-digital conversion bit number is not less than 12 bits.

The spectroscopic component 6 is composed of a dichroic mirror or a spectroscopic prism, a first filter and a second filter. The first filter filters out laser light, and the second filter filters out wide-spectrum visible light.

The present invention uses two photoelectric imaging devices to acquire color structure images and blood flow images of biological tissues at the same time, which overcomes the slow imaging speed and time asynchrony caused by the use of a single photoelectric imaging device requiring a filter wheel or time-sharing switching of multiple light sources. shortcoming. The use of the light splitter in conjunction with two photoelectric imaging devices makes it unnecessary to light up the laser light in time, ensuring the long-term stability of the performance of the laser light source after the warm-up time. In addition, the laser light source uses constant temperature and constant current dual drive control to ensure the high stability and coherence of the output laser; the optical coupling unit uses a single-mode fiber to transmit the laser, which effectively prevents the disturbance of the illumination laser when the fiber is bent or moves; the laser is monochromatic The light source uses monochromatic photoelectric imaging devices to collect laser signals reflected by biological tissues, avoiding the loss of sampling pixels caused by the use of color imaging devices; the above is an important measure to ensure the use of endoscopic optical systems to obtain high-quality blood flow images.

Description of drawings

FIG. 1 is a schematic block diagram of the principle of an endoscopic optical imaging system for synchronously acquiring visible light color images and blood flow images according to the present invention.

Fig. 2 is a schematic structural view of the endoscope optical imaging system of the present invention.

1. Visible light source, 2-laser light source, 3-coupling unit, 4-illumination component, 5-imaging component, 6-light splitting component, 7-optical adapter, 8-color photoelectric imaging device, 9-biological tissue to be tested, 10-monochrome photoelectric imaging device, 11-image processing unit, 12-image display unit. 31-Visible light source connection adapter, 32-Laser light source connection adapter, 33-Multi-mode fiber bundle, 34-Single-mode fiber bundle, 35-Lighting component connection adapter. 61-dichroic mirror, 62-bandpass filter, 63-narrowband filter.

detailed description

In the following description, numerous specific details are given in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without one or more of these details. In order to avoid confusion with the present invention, some technical features known in the art are not described.

In the following description, detailed steps and detailed structure are proposed in order to explain the technical solution of the present invention. However, the invention may have other embodiments than these detailed descriptions.

The invention provides an endoscopic optical imaging method capable of simultaneously collecting and displaying color structure images and blood flow function images of human cavity tissue.

The process of the method is as follows: the laser light and the visible light pass through the endoscope optical system to simultaneously illuminate the biological tissue to be tested, and after passing through the endoscopic optical system, use a spectroscopic component to separate the laser light and visible light backscattered by the biological tissue, and use two photoelectric The imaging devices detect and image separately; among them, the visible light backscattered by the biological tissue is collected by a color photoelectric imaging device to obtain a color image of the biological tissue; the laser light scattered back by the biological tissue is collected by a monochromatic photoelectric imaging device and imaged by laser speckle blood flow Methods The blood flow images of biological tissues were processed.

Referring to Fig. 1 and Fig. 2, the present invention discloses an endoscopic optical imaging system for synchronously acquiring visible light color images and blood flow images.

The system includes a visible light source 1 and a laser light source 2. The light emitted by the visible light source and the laser light source passes through the coupling unit 3 and passes through the lighting assembly to illuminate the biological tissue 13 to be tested. Afterwards, collect by color photoelectric imaging device 8, monochromatic photoelectric imaging device 10 respectively through optical adapter, described color photoelectric imaging device, monochromatic photoelectric imaging device are connected with image processing unit 11, described image processing unit and image display unit 12 connect.

In a preferred but non-limiting embodiment of the present invention, the visible light wide-spectrum light source 1 can be selected from the original white light source of the endoscope, but is not limited to this light source, LED white light source, halogen lamp, etc. can also be selected to provide wide Additional light sources for spectral lighting.

The laser light source 2 of the present invention not only provides a constant current drive to ensure the stability of the laser output power, but also provides a constant temperature drive to ensure high coherence of the output laser. The laser light source is preferably but not limited to a laser diode (LD). Place the LD in an approximately closed constant temperature cavity, and the constant temperature drive will ensure that the temperature fluctuation in the constant temperature cavity is less than ±0.01°C, and the central wavelength of the outgoing laser will not be reduced due to the shift of the LD's working temperature after the heating temperature rises. . In order to distinguish the laser from the visible light band, its center wavelength is near-infrared band, preferably but not limited to 785nm.

The coupling unit 3 includes a visible light source connection adapter 31 connected to a visible light wide-spectrum light source, a laser light source connection adapter 32 connected to a laser light source, an illumination assembly connection adapter 35 connected to an endoscope illumination assembly, and a visible light wide-spectrum transmission adapter 35. The multi-mode optical fiber bundle 33 of the spectrum light source is connected to the visible light source connection adapter 31 , and the single-mode optical fiber bundle 34 of the conductive laser light source is connected to the laser light source connection adapter 32 . Laser speckle blood flow imaging takes advantage of the coherent properties of laser light. If a conventional multimode optical fiber is used to conduct the laser beam, when the optical fiber moves or is complete, the transmitted laser light will also affect the speckle pattern due to the change of the optical path, and the image acquisition unit will The false blood flow change signal generated by the change of the optical fiber instead of the blood flow change is collected, so when combining the laser speckle blood flow imaging technology with the endoscopic imaging system, the optical fiber 34 for conducting the laser light should specifically select a single-mode optical fiber bundle.

In the spectroscopic component 6 of the present invention, it is preferable but not limited to use a dichroic mirror 61 , which transmits a visible light band of 400-700 nm and reflects a near-infrared band above 700 nm. You can also choose beam splitting prism, dichroic prism, beam splitting flat plate, polarization beam splitting device, etc. A bandpass filter 62, preferably but not limited to 400-700nm, is used to filter out laser light by passing the visible light spectrum. It is preferably but not limited to a narrow-band filter 63 with a central wavelength of 785 nm, which is used to only pass the laser light and filter out the spectrum other than the central wavelength of the laser light.

The monochromatic photoelectric imaging device 10 of the present invention is preferably not limited to a 12-bit area array CCD camera with analog-to-digital conversion, so as to collect laser speckle images formed by reflecting laser light from biological tissues, and the analog-to-digital conversion is not less than 12-bit area array digital CCD camera/video camera, or area array digital CMOS camera/video camera.

The color photoelectric imaging device 8 of the present invention is preferably but not limited to a digital camera with the same area array size as the monochrome photoelectric imaging device 10, so as to realize the direct fusion of the color structural image and the blood flow function image without image cropping , zoom operation. You can also choose video camera/3CCD camera, etc.

The image processing unit 11 uses the laser speckle blood flow analysis method to reconstruct the laser speckle image acquired from the monochrome photoelectric imaging device 10 into a biological tissue blood flow image, and reconstructs the biological tissue blood flow image acquired from the color photoelectric imaging device 8 The color image is fused with the blood flow image.

The image display unit 12 can respectively display the color image of the biological tissue, the blood flow image of the biological tissue, and the fused image of the color image of the biological tissue and the blood flow image.

The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; Under the circumstances of the technical solution of the invention, many possible changes and modifications can be made to the technical solution of the present invention by using the methods and technical contents disclosed above, or be modified into equivalent embodiments with equivalent changes, which does not affect the essence of the present invention . Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention, which do not deviate from the technical solution of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims (10)

1. a kind of synchronous endoscopic optical imaging method for obtaining otherwise visible light color image and blood-stream image, it is characterised in that will Laser and visible ray illuminate biological tissues under test simultaneously by endoscope optical system, after endoscope optical system, use Light splitting part separates the laser through biological tissue's back scattering and visible ray, is separately detected into two photoelectronic imaging devices Picture；Wherein, the visible ray of biological tissue's back scattering is gathered by color photoelectric image device, obtains biological tissue's coloured image； The laser of biological tissue's back scattering is gathered by monochromatic photoelectronic imaging device, is handled and is given birth to through laser speckle blood current imaging method Thing tissue blood flow image.

2. endoscopic optical imaging method according to claim 1, it is characterised in that the wavelength of the laser is near-infrared Wave band.

3. endoscopic optical imaging method according to claim 1, it is characterised in that the line width stability of the laser is small In ± 0.02nm.

4. endoscopic optical imaging method according to claim 1, it is characterised in that the laser with single-mode fiber beam from Laser transmission is coupled to endoscope optical system.

5. endoscopic optical imaging method according to claim 1, it is characterised in that the monochromatic photoelectronic imaging device is Face battle array Digital CCD Camera/video camera, or face battle array digital CMOS camera/camcorder, its analog-to-digital conversion digit are not less than 12.

6. a kind of synchronous endoscopic optical imaging system for obtaining otherwise visible light color image and blood-stream image, it is characterised in that should System includes visible light source and LASER Light Source, and the light that the visible light source and LASER Light Source are sent passes through photograph after coupling unit Bright module light biological tissues under test, be split after the imaged component of visible ray and laser of biological tissue's back scattering part point From by optics adapter respectively by color photoelectric image device, the collection of monochromatic photoelectronic imaging device, the color photoelectric imaging Device, monochromatic photoelectronic imaging device are connected with graphics processing unit, and described image processing unit is connected with image-display units.

7. endoscopic optical imaging system according to claim 6, it is characterised in that the monochromatic photoelectronic imaging device is Face battle array Digital CCD Camera/video camera, or face battle array digital CMOS camera/camcorder, its analog-to-digital conversion digit are not less than 12.

8. endoscopic optical imaging system according to claim 6, it is characterised in that the LASER Light Source includes semiconductor Laser, drive current controller, constant temperature chamber and radiator valve, the semiconductor laser wavelength are near infrared band, with Drive current controller is connected, and the semiconductor laser installing is connected in constant temperature intracavitary, the constant temperature chamber with radiator valve.

9. endoscopic optical imaging system according to claim 6, it is characterised in that the coupling unit includes laser light Source connection adapter, visible light source connection adapter, single-mode fiber beam, multimode fiber-optic bundle, light fixture connection adapter, institute State single-mode fiber beam and be connected adapter with LASER Light Source and be connected, the multimode fiber-optic bundle is connected with visible light source adapter, institute Light fixture connection adapter is stated with single-mode fiber beam, multimode fiber-optic bundle to be connected.

10. endoscopic optical imaging system according to claim 6, it is characterised in that the light splitting part is by one two To Look mirror or Amici prism, the first filter, the second filter composition, first filter filters out laser, second filter Light device filters out wide spectrum visible ray.