Fiber optic scanning imaging device and method

Abstract

The present invention discloses an optical fiber scanning imaging device and method, comprising: a Y-type optical fiber containing two completely independent optical fibers. The light emitted by a light source is input through one end of the Y-type optical fiber, and the corresponding other end of the optical fiber is fixed in a second piezoelectric ceramic tube, which drives the optical fiber to form a scanning motion under the action of the piezoelectric ceramic drive, and the light emitted by the light source and transmitted through the optical fiber is projected onto the target to be imaged, and the formed reflected light is collected by another independent optical fiber of the Y-type optical fiber. The other end of the optical fiber corresponding to the receiving optical fiber is driven by the same first piezoelectric ceramic tube for scanning, and the light plane output by the optical fiber scanning is imaged by a photoelectric detection unit, so as to obtain an image of the target to be imaged. The synchronous scanning of the transmitting optical fiber and the receiving optical fiber can automatically realize the synchronization of the object space and the image space, and improve the imaging speed. There is no need to synthesize three-color light, which reduces the complexity of the system. Through simple modification, it can be used for spontaneous fluorescence imaging.

Description

Technical Field

[0001] The present invention relates to the field of scanning imaging technology, and in particular to an optical fiber scanning imaging device and method, which can be used in an endoscope imaging system. Background Art

[0002] Traditional fiber endoscopes use fiber bundles to transmit images. Each fiber can only transmit one pixel, so the number of fiber bundles determines the resolution of the image. High-resolution images also represent larger endoscope diameters. Fiber scanning endoscopes use a single fiber scanning imaging method. With its ultra-small diameter advantage, it has become the next generation of endoscope technology. However, the existing fiber scanning technology uses a fixed receiving method at the receiving end and measures through a conventional photodiode (PD) or avalanche photodiode (APD). PD or APD only has time resolution but lacks spatial resolution. Therefore, complex software and hardware synchronization technology is required for the final data processing to form an image (publication number: CN104936504A

[0051] ), which is prone to image distortion and will result in a very low image frame rate, which may be less than 15 frames per second. At the same time, this method also has relatively high requirements for the motion control accuracy of fiber scanning, and requires the introduction of closed-loop feedback for control, and the system is relatively complex (publication number: US9872606B2). Secondly, if color light imaging is required, the emission light input end needs to synthesize three-color light, and the corresponding receiving end also needs to use a spectrometer and multiple photoelectric receiving elements (publication numbers: CN110794574A

[0043] , CN110850588A

[0045] ), making the system hardware and software processing extremely complex. Summary of the invention

[0003] The purpose of the present invention is to use a simple signal acquisition and processing system to directly image the output end surface of the light transmission unit through the area array imaging unit, thereby improving the imaging frame rate of the endoscope. For color imaging, ordinary white light can be used as input without the need for three-color light synthesis. When a monochromatic laser is used as the excitation light, the device can also be used for autofluorescence imaging.

[0004] The technical solution adopted by the present invention is: an optical fiber scanning imaging device, comprising: a data processing unit 1, a piezoelectric ceramic drive 2, a transmission line 3, a photoelectric detection unit 4, a first piezoelectric ceramic tube 5, a light source 6, an optical fiber 7, a fixed base 8, a Y-type optical fiber 9, a cable 10, a protective sleeve 11, a receiving optical fiber 12, a second piezoelectric ceramic tube 13, a transmitting optical fiber 14, an objective lens 15 and a target to be imaged 16, wherein the Y-type optical fiber 9 contains two completely independent optical fibers, the light emitted by the light source 6 is input through one end of the Y-type optical fiber 9, and the corresponding other end of the optical fiber is fixed in the second piezoelectric ceramic tube 13, which drives the transmitting optical fiber 14 to form a scanning motion under the action of the piezoelectric ceramic drive 2, and the light emitted by the light source 6 and transmitted through the optical fiber is projected onto The reflected light formed on the target 16 to be imaged is collected by another independent receiving optical fiber 12 of the Y-type optical fiber 9, and the other end optical fiber 7 corresponding to the receiving optical fiber 12 is driven by the same first piezoelectric ceramic tube 5 to be scanned, and the light plane of the scanning output of the optical fiber 7 is imaged by the photoelectric detection unit 4, so as to obtain the image of the target 16 to be imaged, wherein the target 16 to be imaged is the object that the device needs to directly measure, and the objective lens 15 can focus the laser coupled from the other end of the transmitting optical fiber 14 located in the Y-type optical fiber 9 onto the target 16 to be imaged. The spatial distance between the objective lens 15 and the target 16 to be imaged depends on the focal length of the selected objective lens 15. The transmitting optical fiber 14 passes through the second piezoelectric ceramic tube 13, and its right end is suspended for about several millimeters. The two ends of the transmitting optical fiber 14 and the second piezoelectric ceramic tube 13 that are in contact can be bonded and fixed by optical glue or ultraviolet glue. The same bonding method can be used between the optical fiber 7 and the first piezoelectric ceramic tube 5. The transmitting optical fiber 14 is used to transmit light. A part of the light emitted by it to the target 16 to be imaged is reflected back to the receiving optical fiber 12. The receiving optical fiber 12 can collect the reflected light and transmit it to the other end of the corresponding optical fiber 7. The piezoelectric ceramic driver 2 can output two sinusoidal modulated voltages with a fixed phase difference of a fixed angle. The first piezoelectric ceramic tube 5 and the second piezoelectric ceramic tube 13 are the same ceramic tubes with four partitioned polarizations. One end of them is fixed on the fixed base 8, and the other end is in a free suspended state. The two currents output by the piezoelectric ceramic driver 2 The pressure is connected to the two piezoelectric ceramic tubes in the same way through the cable 10, which can drive the suspended end of the piezoelectric ceramic tube to make a spiral or row and column scanning regular movement. The piezoelectric ceramic tube drives the optical fiber 7 and the end of the transmitting optical fiber 14 to move. The protective sleeve 11 is used to encapsulate the second piezoelectric ceramic 13 and the receiving optical fiber 12 to protect them from damage by liquid in the environment. The light source 6 can output white light or monochromatic laser, and its output light is transmitted to the target 16 to be imaged through the optical fiber to play a lighting role. The Y-type optical fiber 9 serves as a carrier of the internal optical fiber and plays a protective role. The photoelectric detection unit 4 images the optical fiber scanning plane 17 driven by the first piezoelectric ceramic, and transmits it to the data processing unit 1 through the transmission line 3. The latter can process the collected data.Thus, a color image, a fluorescent image, or a superimposed image of the two is obtained and presented to the user.

[0005] Furthermore, the data processing unit 1 may be a computer; the piezoelectric ceramic driver 2 may be a signal generator; the transmission line 3 may be a network cable; and the photoelectric detection unit 4 may be a CMOS camera.

[0006] An optical fiber scanning imaging method, comprising:

[0007] Step (1), the first piezoelectric ceramic tube 5 and the second piezoelectric ceramic tube 13 form the same scanning track under the control of the same piezoelectric ceramic driver 2, and the end point tracks of the two optical fibers form a one-to-one correspondence in space;

[0008] Step (2), the photoelectric detection unit 4 images the scanning trajectory of the optical fiber 7. Since the two optical fiber scanning trajectories correspond one to one in space, the photoelectric detection unit 4 completes the point-by-point scanning imaging of the imaging target 16. The photoelectric detection unit 4 is a CMOS camera. By selecting the appropriate piezoelectric ceramic scanning frequency of the first piezoelectric ceramic tube 5 and the second piezoelectric ceramic tube 13 and the exposure time of the CMOS camera, the imaging of the entire target can be completed in one frame of image acquisition of the CMOS camera.

[0009] In step (3), the image captured by the camera can be transmitted to the data processing unit 1 for further software processing, noise removal, and superposition of the fluorescence image and the color image.

[0010] Furthermore, the scanning frequency of the ceramic tube is 100kHz, and the area to be imaged needs to be scanned 500 times, so the time to complete the scanning of the entire target area is 5ms. The exposure time of the camera is set to 5ms, and the system can achieve an imaging speed of 200 frames / second.

[0011] The principle of the present invention is as follows: As described in the background description, the current technology uses ordinary photodetectors as signal receiving units, which lack the spatial resolution of the image plane. In order to obtain a two-dimensional image, it is necessary to synchronize the collected signal and the scanning position, and perform more complex data processing. The present invention innovatively uses two identical piezoelectric ceramic tubes at the transmitting scanning end and the receiving scanning end, and uses the same scanning control signal. The receiving end uses a detection device with spatial resolution, typically CMOS, CCD, photodiode array, etc., which can automatically synchronize the scanning position and the signal collection position. The image acquisition speed depends only on the photoelectric receiving device, such as the frame rate of the CMOS camera, and the scanning speed of the piezoelectric ceramic tube, and the CMOS camera and piezoelectric ceramics can reach extremely high frequencies, so it can be foreseen that the frame rate of the entire system will be greatly improved. Further, the current color CMOS or CCD camera has the function of automatically collecting three colors, so the present invention is different from the previous technology and can automatically realize color imaging.

[0012] Compared with the prior art, this invention has the following major technical advantages:

[0013] First, synchronous scanning of the transmitting fiber and the receiving fiber can automatically achieve synchronization between the object space and the image space without the need for additional software programming for data processing, thereby increasing the imaging speed of the system.

[0014] Second, since it is only necessary to ensure that the transmitting optical fiber and the receiving optical fiber have the same scanning mode, there is no need to form the spiral line scanning required in the patent (publication number: US9872606B2) or the row and column scanning mode shown in the patent (publication number: CN110850588A paragraph

[0045] ).

[0015] Third, the detection unit in the implementation case, such as a CMOS camera, has an automatic color function, and the RGB three-color light does not need to be collected separately. The emission light source can use ordinary white light, and there is no need to synthesize the three-color light, which reduces the complexity of the system.

[0016] Fourth, the system can be used to implement the autofluorescence imaging in Case 2 through simple modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a fiber optic scanning imaging device of the present invention;

[0018] Figure 2 A schematic diagram of a synchronous scanning track of the first piezoelectric ceramic and the second piezoelectric ceramic in the present invention;

[0019] Figure 3 A second schematic diagram of synchronous scanning tracks of the first piezoelectric ceramic and the second piezoelectric ceramic in the present invention;

[0020] The meanings of the reference numerals in the figure are:

[0021] 1: Data processing unit, typically a computer; 2: Piezoelectric ceramic drive, typically a signal generator;

[0022] 3: Transmission line, typically a network cable; 4: Photoelectric detection unit, typically a CMOS camera;

[0023] 5: first piezoelectric ceramic tube; 6: light source;

[0024] 7: optical fiber; 8: fixed base;

[0025] 9: Y-type optical fiber; 10: cable;

[0026] 11: Protective sleeve; 12: Receiving optical fiber;

[0027] 13: second piezoelectric ceramic tube; 14: transmitting optical fiber;

[0028] 15: objective lens; 16: target to be imaged;

[0029] 17: The first piezoelectric ceramic drives the optical fiber scanning plane; 18: The second piezoelectric ceramic drives the optical fiber scanning plane. DETAILED DESCRIPTION

[0030] The present invention is further described below with reference to the accompanying drawings and specific embodiments.

[0031] like Figure 1 As shown, the present invention provides an optical fiber scanning imaging device, comprising the following units:

[0032] Data processing unit 1, typically a computer; piezoelectric ceramic driver 2, typically a signal generator; transmission line 3, typically a network cable; photoelectric detection unit 4, typically a CMOS camera; first piezoelectric ceramic tube 5; light source 6; optical fiber 7; fixed base 8; Y-type optical fiber 9; cable 10; protective sleeve 11; receiving optical fiber 12; second piezoelectric ceramic tube 13; transmitting optical fiber 14; objective lens 15; target to be imaged 16.

[0033] The Y-type optical fiber 9 used in the present invention contains two completely independent optical fibers. The light emitted by the light source 6 is input through one end of the Y-type optical fiber 9, and the corresponding other end of the optical fiber is fixed in the second piezoelectric ceramic tube 13, which drives the transmitting optical fiber 14 to form a scanning motion under the action of the piezoelectric ceramic drive 2. Correspondingly, the light emitted by the light source 6 through the optical fiber is projected onto the target 16 to be imaged, and the reflected light formed is collected by another independent receiving optical fiber 12 of the Y-type optical fiber 9. The other end optical fiber 7 corresponding to the receiving optical fiber 12 is driven by the same first piezoelectric ceramic tube 5 for scanning, and the light plane scanned and output by the optical fiber 7 is imaged by the photoelectric detection unit 4, thereby obtaining an image of the target 16 to be imaged. Figure 2 and Figure 3 This is a schematic diagram of the synchronous scanning trajectory of the first piezoelectric ceramic and the second piezoelectric ceramic in the present invention. The scanning trajectory is not limited to that shown in the figure and can be any graph.

[0034] Implementation case 1: Color endoscopic imaging.

[0035] The present invention can be used for color fiber optic endoscope imaging, such as Figure 1 The light source 6 shown in the figure is a white light source, and its output light is coupled to one end of the Y-type optical fiber 9 for input. The Y-type optical fiber used is typically a dual-core multimode optical fiber with a diameter of 50um-200um. The input light is emitted through the transmitting optical fiber 14 and reflected on the target 16 to be imaged. The reflected light is imaged on the photoelectric detection unit 4 through the collecting optical fiber 7. In order to form a color image, the photoelectric detection unit 4 uses a high-speed color array CMOS camera. The transmitting optical fiber 14 and the collecting optical fiber 7 are driven by the first piezoelectric ceramic tube 5 and the second piezoelectric ceramic tube 13 with the same parameters to cause resonant motion. In order to reduce the diameter of the optical fiber probe, the first piezoelectric ceramic tube 5 and the second piezoelectric ceramic tube 13 are made of piezoelectric ceramic tubes made of PZT5A1 from Morgan Ceramics Company of Germany. The inner diameter of the ceramic tube is 0.3mm and the outer diameter is 0.5mm. After being packaged by the protective sleeve 11, typically, the diameter of the optical fiber endoscope probe can be less than 1mm. The first piezoelectric ceramic tube 5 and the second piezoelectric ceramic tube 13 are characterized in that metal electrodes need to be plated on their inner and outer surfaces, and the inner surface electrode is used as a reference ground, and the outer surface electrode needs to be segmented and polarized, and a typical enameled wire with a diameter of about 0.1 mm needs to be welded on the segmented electrodes. The enameled wire needs to be connected to the piezoelectric ceramic driver 2. In this application, the driving current required for the piezoelectric ceramic tube is relatively small, and a signal generator can be directly used as a substitute. Typically, the SDG5082 signal generator of SIGLENT is used. Similar products with signal generator functions are all acceptable, not limited to this model.

[0036] Implementation case 2: Fluorescence endoscopic imaging.

[0037] The present invention can also be used for fluorescence endoscopy imaging, which is similar to the system in the first embodiment, except that Figure 1 The light source 6 shown in the figure is a monochromatic laser light source, a typical wavelength is a near-infrared laser of 785nm. The Y-type optical fiber 9 used is a low-hydroxyl low spontaneous fluorescence optical fiber, or a hollow core optical fiber. The photoelectric detection unit 4 uses a high-speed fluorescence imaging CMOS camera, which can be typically used for a near-infrared imaging camera near a wavelength of 825nm.

Claims

1. A fiber scanning imaging device, characterized in that: include: A data processing unit (1), a piezoelectric ceramic drive (2), a transmission line (3), a photoelectric detection unit (4), a first piezoelectric ceramic tube (5), a light source (6), an optical fiber (7), a fixed base (8), a Y-type optical fiber (9), a cable (10), a protective sleeve (11), a receiving optical fiber (12), a second piezoelectric ceramic tube (13), a transmitting optical fiber (14), an objective lens (15) and a target to be imaged (16), wherein the Y-type optical fiber (9) contains two completely independent optical fibers, and the light emitted by the light source (6) is input through one end of the Y-type optical fiber (9), and the corresponding optical fiber at the other end is fixed in the second piezoelectric ceramic tube (13), which, under the action of the piezoelectric ceramic drive (2), drives the transmitting optical fiber (14) to form a scanning Scanning movement, light emitted by the light source (6) and transmitted through the optical fiber is projected onto the target (16) to be imaged, and the resulting reflected light is collected by another independent receiving optical fiber (12) of the Y-type optical fiber (9), and the other end optical fiber (7) corresponding to the receiving optical fiber (12) is driven by the same first piezoelectric ceramic tube (5) to scan, and the light plane scanned and output by the optical fiber (7) is imaged by the photoelectric detection unit (4), thereby obtaining an image of the target (16) to be imaged, wherein the target (16) to be imaged is an object that needs to be directly measured by the device, and the objective lens (15) can focus the laser light coupled from the other end of the transmitting optical fiber (14) located in the Y-type optical fiber (9) onto the target (16) to be imaged, and the objective lens (15) and the target (16) to be imaged are connected to the optical fiber (7) and the optical fiber (7) is ... The spatial distance of the image target (16) depends on the focal length of the selected objective lens (15). The transmitting optical fiber (14) passes through the second piezoelectric ceramic tube (13), and its right end is suspended for several millimeters. The two ends of the transmitting optical fiber (14) and the second piezoelectric ceramic tube (13) that are in contact are bonded and fixed by optical glue or ultraviolet glue. The optical fiber (7) and the first piezoelectric ceramic tube (5) are bonded in the same way. The transmitting optical fiber (14) is used to transmit light. A part of the light emitted by it to the imaged target (16) is reflected back to the receiving optical fiber (12). The receiving optical fiber (12) can collect the reflected light and transmit it to the other end of the corresponding optical fiber (7). The piezoelectric ceramic driver (2) can output two sinusoidal modulation voltages. , the phase difference is fixed at an angle, the first piezoelectric ceramic tube (5) and the second piezoelectric ceramic tube (13) are identical ceramic tubes with four partitioned polarizations, one end of which is fixed on a fixed base (8) and the other end is in a free suspended state, the two voltages output by the piezoelectric ceramic driver (2) are respectively connected to the two piezoelectric ceramic tubes through a cable (10) in the same manner, and the suspended end of the piezoelectric ceramic tube can be driven to perform a spiral or row and column scanning regular motion, the piezoelectric ceramic tube drives the end of the optical fiber (7) and the transmitting optical fiber (14) to move, the protective sleeve (11) is used to encapsulate the second piezoelectric ceramic tube (13) and the receiving optical fiber (12) to protect them from being damaged by liquid in the environment, the light source (6) can output white light or monochromatic laser,The light outputted by the optical fiber is transmitted to the target to be imaged (16) through the optical fiber to play an illumination role. The Y-shaped optical fiber (9) serves as a carrier of the internal optical fiber and plays a protective role. The photoelectric detection unit (4) images the optical fiber scanning plane (17) driven by the first piezoelectric ceramic and transmits the image to the data processing unit (1) through the transmission line (3). The data processing unit (1) can process the collected data to obtain a color image, a fluorescent image or a superimposed image of the two, and present it to the user.

2. The optical fiber scanning imaging device according to claim 1, characterized in that: The data processing unit (1) is selected as a computer; the piezoelectric ceramic driver (2) is selected as a signal generator; the transmission line (3) is selected as a network cable; and the photoelectric detection unit (4) is selected as a CMOS camera.

3. A fiber scanning imaging method, using the fiber scanning imaging device according to claim 1, characterized in that: include: In step (1), the first piezoelectric ceramic tube (5) and the second piezoelectric ceramic tube (13) form the same scanning trajectory under the control of the same piezoelectric ceramic driver (2), and the endpoint trajectories of the two optical fibers form a one-to-one correspondence in space; In step (2), the photoelectric detection unit (4) images the scanning trajectory of the optical fiber (7). Since the scanning trajectories of the two optical fibers correspond one to one in space, the photoelectric detection unit (4) completes point-by-point scanning imaging of the target to be imaged (16). The photoelectric detection unit (4) is a CMOS camera. By selecting appropriate piezoelectric ceramic scanning frequencies of the first piezoelectric ceramic tube (5) and the second piezoelectric ceramic tube (13) and exposure time of the CMOS camera, the imaging of the entire target can be completed in one frame of image acquisition of the CMOS camera. In step (3), the image captured by the camera can be transmitted to the data processing unit (1) for further software processing, noise removal, and superposition of the fluorescence image and the color image.

4. The optical fiber scanning imaging method according to claim 3, characterized in that: The scanning frequency of the ceramic tube can be adjusted according to the imaging speed requirements of the system. When the scanning frequency of the ceramic tube is 100kHz and the imaging area needs to be scanned 500 times, the scanning time for the entire target area is 5ms. The exposure time of the camera is set to 5ms, and the system can achieve an imaging speed of 200 frames / second.

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