CN112998648B - Imaging System - Google Patents
Imaging System Download PDFInfo
- Publication number
- CN112998648B CN112998648B CN202110142153.XA CN202110142153A CN112998648B CN 112998648 B CN112998648 B CN 112998648B CN 202110142153 A CN202110142153 A CN 202110142153A CN 112998648 B CN112998648 B CN 112998648B
- Authority
- CN
- China
- Prior art keywords
- acousto
- optic crystal
- laser
- ultrasonic
- light
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000003384 imaging method Methods 0.000 title claims abstract description 59
- 239000013078 crystal Substances 0.000 claims abstract description 105
- 238000012634 optical imaging Methods 0.000 claims abstract description 39
- 230000003287 optical effect Effects 0.000 claims abstract description 19
- 239000013307 optical fiber Substances 0.000 claims description 12
- 230000005540 biological transmission Effects 0.000 claims description 9
- LAJZODKXOMJMPK-UHFFFAOYSA-N tellurium dioxide Chemical compound O=[Te]=O LAJZODKXOMJMPK-UHFFFAOYSA-N 0.000 claims description 4
- 238000002604 ultrasonography Methods 0.000 claims description 4
- 230000005855 radiation Effects 0.000 abstract description 5
- 210000000056 organ Anatomy 0.000 description 11
- 238000001514 detection method Methods 0.000 description 10
- 230000010287 polarization Effects 0.000 description 7
- 230000008878 coupling Effects 0.000 description 5
- 238000010168 coupling process Methods 0.000 description 5
- 238000005859 coupling reaction Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 230000005284 excitation Effects 0.000 description 5
- 238000012360 testing method Methods 0.000 description 3
- 238000005481 NMR spectroscopy Methods 0.000 description 2
- 238000002591 computed tomography Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000002592 echocardiography Methods 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000001808 coupling effect Effects 0.000 description 1
- 239000008710 crystal-8 Substances 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 238000002059 diagnostic imaging Methods 0.000 description 1
- ZASWJUOMEGBQCQ-UHFFFAOYSA-L dibromolead Chemical compound Br[Pb]Br ZASWJUOMEGBQCQ-UHFFFAOYSA-L 0.000 description 1
- ZOMNIUBKTOKEHS-UHFFFAOYSA-L dimercury dichloride Chemical compound Cl[Hg][Hg]Cl ZOMNIUBKTOKEHS-UHFFFAOYSA-L 0.000 description 1
- XJUNRGGMKUAPAP-UHFFFAOYSA-N dioxido(dioxo)molybdenum;lead(2+) Chemical compound [Pb+2].[O-][Mo]([O-])(=O)=O XJUNRGGMKUAPAP-UHFFFAOYSA-N 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0033—Features or image-related aspects of imaging apparatus, e.g. for MRI, optical tomography or impedance tomography apparatus; Arrangements of imaging apparatus in a room
- A61B5/0035—Features or image-related aspects of imaging apparatus, e.g. for MRI, optical tomography or impedance tomography apparatus; Arrangements of imaging apparatus in a room adapted for acquisition of images from more than one imaging mode, e.g. combining MRI and optical tomography
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/44—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device
- A61B8/4416—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device related to combined acquisition of different diagnostic modalities, e.g. combination of ultrasound and X-ray acquisitions
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/52—Devices using data or image processing specially adapted for diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/5215—Devices using data or image processing specially adapted for diagnosis using ultrasonic, sonic or infrasonic waves involving processing of medical diagnostic data
- A61B8/5238—Devices using data or image processing specially adapted for diagnosis using ultrasonic, sonic or infrasonic waves involving processing of medical diagnostic data for combining image data of patient, e.g. merging several images from different acquisition modes into one image
- A61B8/5261—Devices using data or image processing specially adapted for diagnosis using ultrasonic, sonic or infrasonic waves involving processing of medical diagnostic data for combining image data of patient, e.g. merging several images from different acquisition modes into one image combining images from different diagnostic modalities, e.g. ultrasound and X-ray
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Molecular Biology (AREA)
- Heart & Thoracic Surgery (AREA)
- Biophysics (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Pathology (AREA)
- Veterinary Medicine (AREA)
- Biomedical Technology (AREA)
- Physics & Mathematics (AREA)
- Medical Informatics (AREA)
- Public Health (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Radiology & Medical Imaging (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
Abstract
The application relates to an imaging system which comprises an acousto-optic crystal, a laser emitting device, an ultrasonic emitting device and an optical imaging device, wherein the laser emitting device and the optical imaging device are respectively arranged on two opposite sides of the acousto-optic crystal, the ultrasonic emitting device and an object to be imaged are respectively arranged on two opposite sides of the acousto-optic crystal, the laser emitting device emits laser to the acousto-optic crystal, the ultrasonic emitting device emits ultrasonic to the acousto-optic crystal, the optical imaging device collects first diffraction light signals generated by Bragg diffraction of the ultrasonic wave and the laser injected into the acousto-optic crystal, collects second diffraction light signals generated by Bragg diffraction of the laser in the acousto-optic crystal and reflected ultrasonic wave and reflected by the object to be imaged, distance information is obtained according to time difference obtained by two times and preset ultrasonic propagation speed, and an optical image of the object to be imaged is obtained according to the imaged image and the distance information. The application can improve the resolution and has no radiation hazard.
Description
Technical Field
The application relates to the technical field of image inspection, in particular to an imaging system.
Background
Clinical medical imaging testing typically employs non-invasive imaging testing. Currently, commonly used non-invasive imaging tests are generally B-ultrasound, CT (Computed Tomography electron computed tomography), nuclear magnetic resonance, and the like.
CT, nuclear magnetic resonance and the like have radiation, while B ultrasonic has the advantages of nondestructive imaging detection and non-radiation imaging detection on human tissues and organs, however, the size of an ultrasonic transducer array element adopted by B ultrasonic imaging is generally millimeter-sized, and the large array element size directly limits the imaging resolution, so that the spatial resolution of ultrasonic imaging is not high.
Disclosure of Invention
In view of the foregoing, it is desirable to provide an imaging system that can improve resolution and is free of radiation hazards.
An imaging system comprises an acousto-optic crystal, a laser emission device, an ultrasonic emission device and an optical imaging device, wherein the laser emission device and the optical imaging device are respectively arranged at two opposite sides of the acousto-optic crystal, and the ultrasonic emission device and an object to be imaged are respectively arranged at two opposite sides of the acousto-optic crystal;
The laser emission device emits laser to the acousto-optic crystal, the ultrasonic emission device emits ultrasonic waves to the acousto-optic crystal, the optical imaging device collects first diffraction light signals generated by Bragg diffraction of the ultrasonic waves and the laser emitted into the acousto-optic crystal, and collects second diffraction light signals generated by Bragg diffraction of the ultrasonic waves reflected after the ultrasonic waves reach the target to be imaged and the laser in the acousto-optic crystal through the acousto-optic crystal, and obtains time differences of collecting the first diffraction light signals and the second diffraction light signals, distance information is obtained according to the time differences and preset ultrasonic propagation speed, and an optical image of the target to be imaged is obtained according to the imaged image and the distance information.
In the imaging system, a laser emission device and an ultrasonic emission device are adopted to emit laser and ultrasonic waves to an acousto-optic crystal respectively, an optical imaging device is used for collecting first diffraction light signals generated by Bragg diffraction of the laser and the ultrasonic waves, collecting second diffraction light signals generated by Bragg diffraction of the ultrasonic waves after the ultrasonic waves reach a target to be imaged and returning the target to be imaged, imaging the target, obtaining distance information according to time difference obtained by the two times of collection and preset ultrasonic propagation speed, obtaining an optical image according to the distance information and an imaged image, detecting the target to be imaged based on the ultrasonic waves by combining ultrasonic detection with the laser, and transmitting information of the target to be imaged, obtained by ultrasonic detection, to the diffraction light signals by Bragg diffraction.
In one embodiment, the acousto-optic crystal is an acousto-optic crystal made of tellurium dioxide.
In one embodiment, the angle between the laser and the propagation direction of the ultrasonic wave is equal to the Bragg diffraction angle.
In one embodiment, the imaging system further includes an optical fiber and a laser collimator, wherein the laser collimator is disposed between the laser emitting device and the acousto-optic crystal, and the laser emitting device is connected to the laser collimator through the optical fiber.
In one embodiment, the imaging system further includes a light homogenizer and a light transmission component with a window, the light homogenizer is disposed between the laser emitting device and the acousto-optic crystal, and the light transmission component is disposed between the light homogenizer and the acousto-optic crystal;
The laser emitted by the laser emitting device is integrated into a uniform beam with the size matched with the ultrasonic field formed by the ultrasonic waves through the light homogenizing device and the light transmitting component, and the uniform beam is incident to the acousto-optic crystal.
In one embodiment, the window is rectangular.
In one embodiment, the imaging system further includes a beam expanding unit, where the beam expanding unit is disposed between the laser emitting device and the light homogenizer.
In one embodiment, the beam expanding unit includes a first lens and a second lens with different focal lengths and diameters, and the first lens and the second lens are sequentially disposed between the laser emitting device and the light homogenizer.
In one embodiment, the imaging system further includes a first polarizer disposed between the laser emitting device and the acousto-optic crystal and a second polarizer disposed between the acousto-optic crystal and the optical imaging device.
In one embodiment, the imaging system further includes a focusing lens disposed between the acousto-optic crystal and the optical imaging device.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments or the conventional techniques of the present application, the drawings required for the descriptions of the embodiments or the conventional techniques will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.
FIG. 1 is a schematic diagram of an imaging system in one embodiment;
fig. 2 is a schematic diagram of an imaging system in another embodiment.
Detailed Description
In order that the application may be readily understood, a more complete description of the application will be rendered by reference to the appended drawings. Embodiments of the application are illustrated in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It will be understood that the terms first, second, etc. as used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be connected to the other element through intervening elements. Further, "connection" in the following embodiments should be understood as "electrical connection", "communication connection", and the like if there is transmission of electrical signals or data between objects to be connected.
As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof.
In one embodiment, referring to FIG. 1, an imaging system is provided, which includes an acousto-optic crystal 110, a laser emitting device 120, an ultrasonic emitting device 130, and an optical imaging device 140, wherein the laser emitting device 120 and the optical imaging device 140 are respectively disposed on opposite sides of the acousto-optic crystal 110, and the ultrasonic emitting device 130 and an object 200 to be imaged are respectively disposed on opposite sides of the acousto-optic crystal 110. For example, taking the acousto-optic crystal 110 as a stereoscopic hexahedron, including an upper face, a lower face, a front face, a rear face, a left face and a right face, the laser emitting device 120 is disposed on the left side of the acousto-optic crystal 110, the optical imaging device 140 is disposed on the right side of the acousto-optic crystal 110, the ultrasonic emitting device 130 is disposed on the rear side of the acousto-optic crystal 110, and the object 200 to be imaged is disposed on the front side of the acousto-optic crystal 110.
The laser emitting device 120 is a device capable of emitting laser, the ultrasonic emitting device 130 is a device capable of emitting ultrasonic, the acousto-optic crystal 110 is an acousto-optic coupling medium, when the ultrasonic passes through the acousto-optic coupling medium, elastic deformation is caused, dielectric coefficient and refractive index of the acousto-optic coupling medium are periodically changed and are equivalent to forming a phase grating, at the moment, when the laser enters the acousto-optic coupling medium at a certain angle with the ultrasonic propagation direction, and the ultrasonic frequency is higher, the coherence length is longer, bragg diffraction is generated in the acousto-optic coupling medium by the laser, and a +1 or-1 diffraction optical signal is generated, so that amplitude and phase information carried by the ultrasonic wave is transmitted to the diffraction optical signal.
The optical imaging device 140 is a device that can detect an optical signal and image it. The laser emitting device 120 emits laser to the acousto-optic crystal 110, the ultrasonic emitting device 130 emits ultrasonic to the acousto-optic crystal 110, the optical imaging device 140 collects first diffraction light signals generated by Bragg diffraction of the ultrasonic waves and the laser light which are emitted into the acousto-optic crystal 110, and collects second diffraction light signals generated by Bragg diffraction of the ultrasonic waves and the laser light in the acousto-optic crystal which are reflected after reaching the object to be imaged through the acousto-optic crystal 110, images are formed, time differences of the first diffraction light signals and the second diffraction light signals are collected are obtained, distance information is obtained according to the time differences and preset ultrasonic propagation speed, and an optical image of the object to be imaged is obtained according to the imaged image and the distance information. That is, after the laser emitting device 120 emits laser to the acousto-optic crystal 110 and the ultrasonic emitting device 130 emits ultrasonic to the acousto-optic crystal 110, the laser and the ultrasonic generate Bragg diffraction light signals in the acousto-optic crystal 110 as first diffraction light signals, the ultrasonic reaches the target 200 to be imaged after passing through the acousto-optic crystal 110 and then is reflected, bragg diffraction light signals are generated again with the laser in the acousto-optic crystal 110 as second diffraction light signals, the optical imaging device 140 acquires the first diffraction light signals and the second diffraction light signals, images according to the second diffraction light signals, and acquires the time difference of the two acquisition diffraction light signals. Specifically, the optical imaging device 140 collects the twice diffracted light signals in one pulse ultrasound period.
When the ultrasonic waves are incident to the object 200 to be imaged, for example, the object 200 to be imaged can be human tissues and organs, after the ultrasonic waves reach the object 200 to be imaged, the ultrasonic waves are reflected by the surface of the object 200 to be imaged, the reflection degrees caused by different acoustic impedances are different, part of the ultrasonic waves enter the interior of the object 200 to be imaged while the reflection is generated, the density structures of different objects are different, the attenuation caused by the different structures is different, meanwhile, when the acoustic impedances are continuously transmitted forwards, the ultrasonic waves are reflected at two different acoustic impedance interfaces, the ultrasonic waves are attenuated, and the amplitude changes of the ultrasonic echoes caused by the reflection carry the information of the shape and the structure of the object 200 to be imaged, and the corresponding transmission time of the ultrasonic echoes carries the distance information of the object. The intensity of the ultrasonic echo is adjusted by the object 200 to be imaged, the intensity distribution of the ultrasonic echo is directly related to the structure of the object to be imaged, and meanwhile, in Bragg diffraction, the relation between the ultrasonic intensity and the diffraction efficiency satisfies the following formula:
Where M is the quality factor of the acousto-optic crystal 110, n is the refractive index of the acousto-optic crystal 110, ρ is the density of the acousto-optic crystal 110, P is the elasto-optic coefficient of the acousto-optic crystal 110, V S is the propagation speed of the ultrasonic wave in the acousto-optic crystal 110, I 0 is the ultrasonic intensity, P s is the elasto-optic coefficient of the acousto-optic crystal 110, H, L is the height and length of the acousto-optic crystal 110, respectively, λ 0 is the wavelength of the laser light, and η is the diffraction efficiency.
As can be seen from the equation, the intensity of the ultrasound is optically related to the height and length of the acousto-optic crystal 110. The higher the Bragg diffraction efficiency is, the stronger the corresponding diffraction light signal intensity is, namely the larger the acoustic impedance of a certain area is, the amplitude of an ultrasonic echo is in direct proportion to the acoustic impedance, namely the higher the ultrasonic intensity corresponding to the ultrasonic echo is, the higher the corresponding diffraction light signal is, the stronger the corresponding diffraction light signal is, the transmission of ultrasonic wave carrying information is completed through the relation between the ultrasonic intensity and the diffraction efficiency, the morphology and structure information of an object 200 to be imaged are transmitted to the diffraction light signal through the ultrasonic echo carrying the difference of the Bragg diffraction efficiency, and the high-resolution optical image can be obtained through collecting the diffraction light signal and carrying imaging combination distance information. Specifically, the optical imaging device 140 may obtain a gray value from the diffracted light signal, and generate an optical image by associating the gray value with the distance information.
Taking a target 200 to be imaged as human tissues and organs as an example, carrying out ultrasonic scanning on the human tissues and organs, reflecting ultrasonic waves by the human tissues and organs, modulating wave fronts of the ultrasonic waves by the human tissues and organs so as to carry the morphology and structure information of the human tissues and organs, forming an ultrasonic grating in the acousto-optic crystal 110 when the ultrasonic waves reflected by the human tissues and organs return to pass through the acousto-optic crystal 110, generating +1 or-1 diffraction optical signals by Bragg diffraction under proper conditions when laser passes through the acousto-optic crystal 110 with ultrasonic fields, transmitting the morphology and structure information of the human tissues and organs carried by the wave fronts of the ultrasonic waves into +1 or-1 diffraction optical signals, and acquiring wave front image information reflected by the human tissues and organs by collecting the image formed by the diffraction optical signals so as to obtain the image of the human tissues and organs.
Specifically, the optical imaging apparatus 140 may record the time of receiving the first diffracted light signal and the time of receiving the second diffracted light signal, and calculate the time difference between the recorded two times. It will be appreciated that the optical imaging apparatus 140 may also obtain the time difference by other means, such as starting the timing when the first diffracted light signal is received and stopping the timing when the second diffracted light signal is received. The distance information refers to the distance to the object 200 to be imaged, and the optical imaging device 140 may calculate the distance information by using a preset calculation model.
Taking the time of recording two acquisitions as an example, receiving the first diffraction light signal and recording the time to obtain a first moment, receiving the second diffraction light signal and recording the time to obtain a second moment, and calculating to obtain distance information according to the first moment, the second moment and the ultrasonic propagation speed, wherein the calculation formula is as follows:
S=1/2V*(T2-T1)
Wherein S is distance information, V is an ultrasonic propagation speed, T 2 is a second time, and T 1 is a first time.
On one hand, considering that the size of the array element in an imaging system can directly influence the transverse resolution of imaging, the array element size of an ultrasonic transducer used in traditional ultrasonic imaging is far larger than that of an optical imaging device 140, and the corresponding transverse resolution of ultrasonic imaging is low. On the other hand, the distance information of the object 200 to be imaged is obtained according to the flight time of ultrasonic waves in the conventional ultrasonic imaging, the distance information precisely corresponds to the axial resolution, the distance information of the object 200 to be imaged can be precisely obtained according to the time difference (flight time) between the reference light and the signal light in consideration of the fact that the limit value of the axial resolution of the ultrasonic imaging is lambda/2, which not only causes a certain error in the distance information in the detection process but also affects the axial resolution of the space in the ultrasonic imaging, and therefore, the axial resolution of the imaging can be improved by taking a diffraction light signal obtained by first Bragg diffraction of ultrasonic waves and laser light as reference light and taking diffraction light obtained by second Bragg diffraction of ultrasonic waves reflected by the object 200 to be imaged as signal light.
In the imaging system, the laser emission device 120 and the ultrasonic emission device 130 are adopted to emit laser and ultrasonic to the acousto-optic crystal 110 respectively, the optical imaging device 140 is used for collecting first diffraction light signals generated by Bragg diffraction of the laser and the ultrasonic, collecting second diffraction light signals generated by Bragg diffraction of the ultrasonic after the ultrasonic reaches the object 200 to be imaged and returning, obtaining distance information according to time difference of the two collection and preset ultrasonic propagation speed, obtaining an optical image according to the distance information and an imaged image, and by combining ultrasonic detection with the laser, the object 200 to be imaged is detected based on the ultrasonic detection, no radiation hazard is caused, and the information of the object 200 to be imaged, obtained by ultrasonic detection, is transmitted to the diffraction light signals by Bragg diffraction, and the optical imaging device 140 is used for optical imaging, so that the array element size of the optical imaging is small, and the imaging resolution is high.
In one embodiment, the acousto-optic crystal 110 is an acousto-optic crystal made of tellurium dioxide. The quality of the acousto-optic crystal made of tellurium dioxide is high, and the Bragg diffraction efficiency can be improved and the stability of acousto-optic interaction can be improved by using the acousto-optic crystal with a higher quality factor. It will be appreciated that in other embodiments, the acousto-optic crystal 110 may be made of other materials having higher quality factors, such as lithium niobate, lead molybdate, lead bromide, mercurous chloride, and the like.
In one embodiment, the laser emitting device 120 is an infrared laser. The infrared laser is a device for emitting infrared laser, and the infrared laser beam has small divergence angle, high brightness and good use effect.
In one embodiment, the ultrasonic wave emitting device 130 may include an excitation signal controller connected to an ultrasonic transducer disposed on a side of the acousto-optic crystal 110 opposite to the object 200 to be imaged, and an ultrasonic transducer.
The excitation signal controller sends a pulse signal to the ultrasonic transducer, which receives the pulse signal and emits ultrasonic waves to the acousto-optic crystal 110. Specifically, the excitation signal controller may complete control of the high-voltage excitation signal, i.e., the pulse signal, according to the set control parameters. The ultrasonic transducer is controlled to emit ultrasonic waves by adopting the excitation signal controller, so that the structure is simple.
Specifically, the ultrasonic transducer can adopt a transducer probe capable of transmitting ultrasonic waves with the frequency of 2MHz-15MHz under the action of pulse signals, and the probe has a better sound absorption substrate so as to reduce the cycle number in a pulse envelope.
In one embodiment, the optical imaging Device 140 includes a CCD (Charge-coupled Device) disposed on a side of the acousto-optic crystal 110 opposite the laser emitting Device 120. The CCD is adopted for optical imaging, so that the imaging effect is good and the resolution ratio is high.
In one embodiment, the angle between the propagation direction of the laser light and the ultrasonic wave is equal to the Bragg diffraction angle. Wherein the Bragg diffraction angle is a predetermined angle. An ultrasonic transducer is used for transmitting a beam of pulse ultrasonic waves, the ultrasonic waves are directly coupled into the acousto-optic crystal 110, so that the refractive index of the acousto-optic crystal 110 is periodically distributed to generate a phase grating, at the moment, the included angle between the incident laser and the propagation direction of the ultrasonic waves meets the Bragg diffraction angle, and the Bragg diffraction angle formula is as follows:
where λ 0 is the wavelength of the laser light, f s is the ultrasonic frequency, n is the refractive index of the acousto-optic crystal 110, and V s is the propagation speed of the ultrasonic wave in the acousto-optic crystal 110.
When the Bragg diffraction angle is satisfied, the ultrasonic frequency is high, and the coherence length of ultrasonic waves and laser light is long, the coupling effect of the ultrasonic waves and the laser light beam in the acousto-optic crystal 110 satisfies the Bragg diffraction condition, and the Bragg diffraction only generates +1 or-1 diffraction optical signals.
In one embodiment, referring to fig. 2, the imaging system further includes an optical fiber 151 and a laser collimator 152, the laser collimator 152 is disposed between the laser emitting device 120 and the acousto-optic crystal 110, and the laser emitting device 120 is connected to the laser collimator 152 through the optical fiber 151. The optical fiber 151 conducts laser, so that the incident angle of the laser can be conveniently adjusted, and the laser collimator 152 is used for collimating the laser emitted by the optical fiber 151 into parallel light.
In one embodiment, the imaging system further includes a light homogenizer disposed between the laser emitting device 120 and the acousto-optic crystal 110, and a light transmission component with a window disposed between the light homogenizer and the acousto-optic crystal 110. The laser emitted by the laser emitting device 120 is shaped into a uniform beam with the size matched with the ultrasonic field formed by ultrasonic waves through the light homogenizer and the light transmission component, and the uniform beam is incident on the acousto-optic crystal.
The light homogenizer is used for ensuring that the light intensity distribution of the laser beam incident into the acousto-optic crystal 110 is uniform, and the laser beam passes through the light homogenizer so that the light intensity distribution of the cross section of the laser beam becomes uniform. The size of the laser beam with uniform light field intensity passes through the window, specifically, the size of the window is adjustable, and the shape and the size of the laser beam are adjusted by adjusting the size of the window, so that the size of the beam can be adjusted according to the requirement, and the size of the incident laser beam is specifically adjusted to be matched with the ultrasonic beam. If the laser beam is too large, the redundant part can act as background noise to influence the imaging of the diffraction optical signal, and if the laser beam is too small, part of the ultrasonic echo does not participate in Bragg diffraction, so that information is lost. Therefore, the size of the laser beam is adjusted, so that the incident laser is matched with the ultrasonic sound beam, and the imaging precision is improved.
Specifically, as shown in FIG. 2, the imaging system includes a light homogenizer and a light transmissive assembly with a window, the light homogenizer and the light transmissive assembly being combined into a single unit 170. The homogenizer may be disposed after the laser collimator 152 and before the acousto-optic crystal 110.
In one embodiment, the window is rectangular. Because there is an interaction length in the acousto-optic effect, and the ultrasonic field and the laser beam are perpendicular, if the ultrasonic field is a circular light spot, the ultrasonic field is uneven through the diameter and the edge of the circular light beam, especially when the circular light spot is subjected to Gaussian distribution, the edge intensity is lower, and the diffraction efficiency is positively related to the light field intensity. By adopting a rectangular window, the laser emitted by the laser emitting device 120 is changed into a rectangular beam, so that the light field intensity of the edge can be ensured to increase the diffraction efficiency, and meanwhile, the rectangular beam can be better matched with the ultrasonic sound beam.
In one embodiment, the imaging system further includes a beam expanding unit disposed between the laser emitting device 120 and the light homogenizer. The beam expanding unit expands the diameter of the laser beam, specifically, the beam expanding unit expands the diameter of the laser beam to be consistent with the aperture of the light uniformizing device, so that the light uniformizing effect is improved.
In one embodiment, as shown in fig. 2, the beam expanding unit includes a first lens 161 and a second lens 162 having different focal lengths and diameters, and the first lens 161 and the second lens 162 are sequentially disposed between the laser emitting device 110 and the light homogenizer. The beam expanding unit is formed by adopting two lenses with different focal lengths and diameters, the first lens 161 diffuses laser, and the second lens collimates the diffused laser, so that the purpose of expanding the laser beam is achieved, and the emergent laser spot is amplified by a proper multiple.
Specifically, as shown in fig. 2, the first lens 161 and the second lens 162 are sequentially disposed between the laser collimator 152 and the light homogenizer, and after the laser emitted by the laser emitting device 120 reaches the laser collimator 152 through the optical fiber 151, the laser passes through the windows of the first lens 161, the second lens 162, the light homogenizer and the light transmitting component in sequence.
In one embodiment, referring to fig. 2, the imaging system further includes a first polarizer 181 and a second polarizer 182, wherein the first polarizer 181 is disposed between the laser emitting device 120 and the acousto-optic crystal 110, and the second polarizer 182 is disposed between the acousto-optic crystal 110 and the optical imaging device 140.
The beam emitted by the acousto-optic crystal 110 actually has not only +1-level or-1-level diffraction light signals, but also unmodulated zero-level diffraction light, wherein the zero-level diffraction light is used as main noise for imaging, and can not be filtered through a filter because the wavelength of the zero-level diffraction light is almost consistent with that of the diffraction light signals, meanwhile, the Bragg diffraction angle is smaller because the included angle between the +1-level or-1-level diffraction light signals and the zero-level diffraction light is 2 times of Bragg diffraction angle, and meanwhile, the beam has a certain divergence angle, so that the angle of the laser beam emitted by the acousto-optic crystal 110 is smaller, the +1-level or-1-level diffraction light signals and the zero-level diffraction light are mixed together, are difficult to separate at a short distance through a traditional diaphragm, and the zero-level diffraction light can easily enter the CCD as noise, so that the imaging quality of the +1-level or-1-level diffraction light signals is reduced. When the diffraction efficiency is low, the intensity of zero-order diffracted light as noise may even exceed the intensity of +1 or-1 order diffracted light signal, so that an optical image of the object 200 to be imaged cannot be obtained.
By adding a first polarizer 181 before laser enters the acousto-optic crystal 110, polarizing the incident laser beam by the first polarizer 181, so that the laser entering the acousto-optic crystal 110 is linearly polarized, adding a second polarizer 182 before the diffraction light signal is collected into the optical imaging device 140, the second polarizer 182 is used for polarizing the polarized incident light, the polarization direction of the second polarizer 182 is required to be perpendicular to the polarization direction of the first polarizer 181, +1-order or-1-order diffraction light is subjected to Bragg diffraction, the polarization direction is changed to a certain extent, and therefore the second polarizer 182 can be used, and zero-order diffraction light can not pass through the second polarizer 182 due to no modulation, and the polarization direction of the second polarizer 182 is perpendicular to the first polarizer 181, so that the filtering effect of the zero-order diffraction light is achieved, the +1-order or-1-order diffraction light enters the optical imaging device 140, the zero-order diffraction light is filtered, and the signal to noise ratio of Bragg diffraction imaging is improved, so that the imaging quality is improved.
Specifically, as shown in fig. 2, the first polarizer 181 is disposed between the integrator 170 and the acousto-optic crystal 110, and the laser beam is shaped into a rectangular beam by the integrator and the window, and then enters the acousto-optic crystal 110 through the first polarizer 181.
In one embodiment, as shown in fig. 2, the imaging system further includes a focusing lens 190, where the focusing lens 190 is disposed between the acousto-optic crystal 110 and the optical imaging device 140. The focusing lens 190 collects the diffracted light signals and focuses the diffracted light signals into the optical imaging apparatus 140. Specifically, the focusing lens 190 is disposed between the second polarizer 182 and the optical imaging device 140.
Taking an infrared laser as an example, the use of the imaging system is described in detail with reference to fig. 2, after the infrared laser light source comes out from the infrared laser, the infrared laser light source sequentially passes through the optical fiber 151, the laser collimator 152, the first lens 161, the second lens 162, the light homogenizer, the rectangular window and the first polarizer 181, so as to ensure that the laser beam is uniformly incident into the acousto-optic crystal 110 in a rectangular shape and with a certain polarization direction. The operation comprises the following steps:
s1, laser emitted by an infrared laser is changed into a parallel laser beam through an optical fiber 151 through an optical fiber collimator 152, the laser beam is expanded through a first lens 161 and a second lens 162 in sequence, then the laser beam is changed into a rectangular laser beam with adjustable size through a light homogenizer and a rectangular window, the light intensity distribution of the cross section of the laser beam is uniform, and the rectangular beam is changed into a laser beam with a certain polarization direction through a first polarizer 181 and is incident into an acousto-optic crystal 110.
And S2, the laser emitted from the acousto-optic crystal 110 passes through the second polaroid 182, enters the CCD through the focusing lens 190 to image, and adjusts the second polaroid 182 so that the laser intensity received by the CCD is at the lowest when no ultrasonic wave passes through the acousto-optic crystal 110.
And S3, starting an ultrasonic transducer to emit pulse ultrasonic waves, adjusting the directions of the laser beam and the ultrasonic beam, and ensuring that the included angle between the laser beam and the ultrasonic beam meets Bragg diffraction conditions.
S4, ultrasonic waves emitted by an ultrasonic transducer are transmitted to a target 200 to be imaged, bragg diffraction is generated between the ultrasonic waves and a rectangular light beam in an acousto-optic crystal 8, due to the Bragg diffraction, the emergent laser has zero-order and +1-order or-1-order diffraction light signals, the included angle of the two beams of light is 2 times of Bragg angle, and the second polaroid 182 is finely adjusted to enable the light intensity of the +1-order or-1-order diffraction light signals to be maximum, meanwhile, the minimum zero-order diffraction light intensity is guaranteed, and the +1-order or-1-order diffraction light signals and the acquisition time T1 are recorded through a CCD.
The Bragg-diffracted optical signal passes through the second polarizer 182 having a polarization direction perpendicular to that of the first polarizer 181, and the laser light which is not diffracted cannot be filtered by passing through the second polarizer 182, and the Bragg-diffracted optical signal passes through the second polarizer 182 and enters the CCD.
S5, when the ultrasonic wave reaches the target 200 to be imaged, the reflected ultrasonic wave passes through the acousto-optic crystal 110 again, bragg diffraction is carried out on the ultrasonic wave, a diffraction light signal is collected by the CCD, and the collection time T2 is recorded.
And S6, obtaining an image of the surface morphology and the structure of the target 200 to be imaged through CCD imaging, and obtaining axial distance information of the target 200 to be imaged according to the recorded time T1 and time T2 and the ultrasonic propagation speed.
The Bragg diffraction of infrared laser and ultrasonic waves is used as a basic principle to carry out high-resolution optical imaging on an object to be imaged, the method plays a positive role in the field of medical image detection, the traditional ultrasonic imaging detection at present is replaced by high-resolution imaging, the imaging resolution is greatly improved, and the problems of misdiagnosis, missed diagnosis and the like caused by insufficient B ultrasonic imaging resolution are reduced.
In the description of the present specification, reference to the terms "some embodiments," "other embodiments," "desired embodiments," and the like, means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.
Claims (5)
1. The imaging system is characterized by comprising an acousto-optic crystal, a laser emission device, an ultrasonic emission device and an optical imaging device, wherein the laser emission device and the optical imaging device are respectively arranged at two opposite sides of the acousto-optic crystal, and the ultrasonic emission device and an object to be imaged are respectively arranged at two opposite sides of the acousto-optic crystal;
The laser emission device emits laser to the acousto-optic crystal, the ultrasonic emission device emits ultrasonic waves to the acousto-optic crystal, the optical imaging device collects first diffraction light signals generated by Bragg diffraction of the ultrasonic waves and the laser waves emitted into the acousto-optic crystal, and collects second diffraction light signals generated by Bragg diffraction of the ultrasonic waves reflected by the acousto-optic crystal after reaching the target to be imaged and the laser waves in the acousto-optic crystal, and obtains time differences of collecting the first diffraction light signals and the second diffraction light signals, distance information is obtained according to the time differences and preset ultrasonic propagation speed, and an optical image of the target to be imaged is obtained according to the imaged image and the distance information;
the imaging system further comprises a light homogenizer, a light transmission component with a window, a beam expanding unit, a first polaroid and a second polaroid, wherein the window is rectangular, the light homogenizer is arranged between the laser emission device and the acousto-optic crystal, and the light transmission component is arranged between the light homogenizer and the acousto-optic crystal;
The beam expanding unit comprises a first lens and a second lens with different focal lengths and diameters, and the first lens and the second lens are sequentially arranged between the laser emission device and the light homogenizer;
The first polaroid is arranged between the laser emitting device and the acousto-optic crystal, and the second polaroid is arranged between the acousto-optic crystal and the optical imaging device.
2. The imaging system of claim 1, wherein the acousto-optic crystal is an acousto-optic crystal made of tellurium dioxide.
3. The imaging system of claim 1, wherein the laser light is at an angle to the direction of propagation of the ultrasound wave equal to a Bragg diffraction angle.
4. The imaging system of claim 1, further comprising an optical fiber and a laser collimator disposed between the laser emitting device and the acousto-optic crystal, and the laser emitting device is connected to the laser collimator through the optical fiber.
5. The imaging system of claim 1, further comprising a focusing lens disposed between the acousto-optic crystal and the optical imaging device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110142153.XA CN112998648B (en) | 2021-02-02 | 2021-02-02 | Imaging System |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110142153.XA CN112998648B (en) | 2021-02-02 | 2021-02-02 | Imaging System |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112998648A CN112998648A (en) | 2021-06-22 |
| CN112998648B true CN112998648B (en) | 2024-11-29 |
Family
ID=76385338
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110142153.XA Active CN112998648B (en) | 2021-02-02 | 2021-02-02 | Imaging System |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112998648B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN215383964U (en) * | 2021-02-02 | 2022-01-04 | 深圳市威富视界有限公司 | Imaging system |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103635784A (en) * | 2012-05-15 | 2014-03-12 | 松下电器产业株式会社 | Photoacoustic vibration meter |
| WO2014174800A1 (en) * | 2013-04-22 | 2014-10-30 | パナソニックＩｐマネジメント株式会社 | Acousto-optical imaging device |
| CN110530257A (en) * | 2019-09-26 | 2019-12-03 | 深圳市威富视界有限公司 | Femto-second laser distribution interferometer system |
| CN111958108A (en) * | 2020-07-20 | 2020-11-20 | 华中科技大学 | Acousto-optic double-focus lens for laser processing and laser processing system |
-
2021
- 2021-02-02 CN CN202110142153.XA patent/CN112998648B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN215383964U (en) * | 2021-02-02 | 2022-01-04 | 深圳市威富视界有限公司 | Imaging system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112998648A (en) | 2021-06-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107238575B (en) | Photoacoustic microscopic system based on perfect vortex optical excitation SPR | |
| JP5235586B2 (en) | Biological information processing apparatus and biological information processing method | |
| US5615675A (en) | Method and system for 3-D acoustic microscopy using short pulse excitation and 3-D acoustic microscope for use therein | |
| US8879352B2 (en) | Ultrasonic/photoacoustic imaging devices and methods | |
| JP6049293B2 (en) | Acoustic wave acquisition device | |
| Nuster et al. | Hybrid photoacoustic and ultrasound section imaging with optical ultrasound detection | |
| CN115112770B (en) | Photoacoustic imaging device and method | |
| CN106236145B (en) | A device and method for ultrasonic detection and photoacoustic imaging based on total reflection | |
| WO2013183247A1 (en) | Acoustooptic imaging device | |
| Alles et al. | Adaptive light modulation for improved resolution and efficiency in all-optical pulse-echo ultrasound | |
| US9566006B2 (en) | Object information acquisition apparatus | |
| CN106970157A (en) | The Optical devices and method of transparent fluid and transparent solid internal acoustic field are observed simultaneously | |
| TWI459015B (en) | An image generation system | |
| CN215383964U (en) | Imaging system | |
| US7652773B2 (en) | Enhanced detection of acousto-photonic emissions in optically turbid media using a photo-refractive crystal-based detection system | |
| CN103313649A (en) | Measuring apparatus | |
| CN112998648B (en) | Imaging System | |
| CN110133879B (en) | Device and method for improving ultrasonic modulation light imaging depth | |
| RU2486501C2 (en) | Laser optical-acoustic tomography method and apparatus for realising said method (versions) | |
| Thompson et al. | Laser-induced synthetic aperture ultrasound imaging | |
| US20170065252A1 (en) | Object information acquiring apparatus | |
| CN111938579A (en) | A multi-pulse photoacoustic microscopy imaging method and device for improving photoacoustic image quality based on fiber delay | |
| WO2019044594A1 (en) | Photoacoustic image generation device and image acquisition method | |
| Ashkenazi et al. | High frequency ultrasound imaging using Fabry-Perot optical etalon | |
| JP5575293B2 (en) | Subject information acquisition apparatus and subject information acquisition method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |