Phase-shifted mirror based oil debris three-dimensional imaging system

Abstract

The application provides a lubricating oil abrasive particle three-dimensional imaging system based on a phase shift micromirror, which comprises a light source system, a first beam splitter, a second beam splitter, a sampling system, a phase modulation system and a detection system; parallel light beams emitted by the light source system are incident to the first beam splitter and are divided into reflected light beams and transmitted light beams; the reflected light beams are incident to the sampling system after being transmitted by the second beam splitter to obtain sample light beams with lubricating oil sample information and return to the second beam splitter by the original route; the transmitted light beams are incident to the phase modulation system to be phase modulated to obtain reference light beams which are incident to the second beam splitter; the reference light beams and the sample light beams interfere to form interference light beams which are incident to the detection system to obtain interference spectrum information of the interference light beams; amplitude and phase information of a cross-correlation term in an interference light intensity expression are extracted from the interference spectrum information to construct a complex function of the interference light beam signal, then Fourier transform is performed on the complex function, and finally a clear lubricating oil abrasive particle three-dimensional reconstruction image is obtained.

Description

Technical Field

[0001] This invention relates to the field of imaging instrument technology, and in particular to a three-dimensional imaging system for lubricating oil abrasive particles based on a phase-shifting micromirror. Background Technology

[0002] Aero engines are critical components of aircraft, with complex internal structures. Under high temperature and high load conditions, they are prone to component wear, seriously threatening operational safety. Of major aircraft accidents caused by mechanical reasons, approximately 40% are due to engine failure, with wear-related failures accounting for over 80%. Therefore, detecting the wear condition of aero engines is of great significance for accelerating their development, ensuring service safety, and preventing catastrophic accidents. Lubricating oil in aero engines is used to lubricate, cool, and clean bearings, gears, and other moving parts. When engine wear occurs, abrasive particles generated on the surfaces of components enter the lubricating oil system, resulting in oil containing abrasive particles of different shapes caused by various types of wear. A sudden increase in the abrasive particle generation rate indicates abnormal engine wear; the morphology and composition of the abrasive particles can identify the location of the wear; and the number, shape, and size of the abrasive particles can determine the type and degree of wear. Therefore, detecting the characteristic parameters such as the number, size, and shape of abrasive particles in the lubricating oil can effectively assess the wear condition of aero engine equipment.

[0003] Current abrasive particle detection methods employ optical, electromagnetic, and chemical methods to obtain various indicators of lubricating oil abrasive particles, thereby determining the wear condition of aero engines. Based on the detection method, these can be divided into offline and online detection. Offline detection typically involves collecting oil samples and then analyzing them using methods such as ferrography, scanning electron microscopy, or atomic emission spectroscopy. While this method offers high accuracy, it is resource-intensive and cannot provide timely information on engine wear conditions. Existing online detection methods primarily use detectors based on electromagnetic induction, which are mostly limited to detecting the size and quantity of lubricating oil particles, failing to acquire shape information. Currently, abrasive particle detection technology is increasingly improving in sensitivity and counting reliability. Abrasive particle information is evolving from simple raw signal feature extraction to image analysis and refined feature extraction and classification. Simultaneously, detection methods are shifting towards actively controlling lubricating oil and abrasive particles to improve detection efficiency and reliability. Summary of the Invention

[0004] In view of the above problems, the purpose of this invention is to propose a three-dimensional imaging system for lubricating oil abrasive particles based on a phase-shifting micromirror. This system extracts the three-dimensional information of the abrasive particles based on the principle of light interference, solving the problem that traditional detection methods struggle to achieve three-dimensional imaging of abrasive particles. It utilizes a Mach-Zehnder interference structure to obtain the interference spectra of the sample beam and the reference beam, and performs Fourier transform and other processing to achieve three-dimensional imaging of the abrasive particles. Simultaneously, the use of a phase-shifting micromirror structure enables multi-channel static phase modulation, solving problems such as mirror images and parasitic images in single-channel imaging. This system offers advantages such as fast imaging speed, high clarity, good stability, and a compact structure.

[0005] To achieve the above objectives, the present invention adopts the following specific technical solution:

[0006] This invention provides a three-dimensional imaging system for lubricating oil abrasive particles based on a phase-shifting micromirror, comprising a light source system, a first beam splitter, a second beam splitter, a sampling system, a phase modulation system, and a detection system;

[0007] The parallel beam emitted by the light source system is incident on the first beam splitter and split into a reflected beam and a transmitted beam;

[0008] The reflected beam is transmitted through the second beam splitter and then incident on the sampling system; the transmitted beam is incident on the phase modulation system.

[0009] The sampling system includes: a scanning mirror, an objective lens, and an oil abrasive detection area;

[0010] The sampling system is used to collect three-dimensional information of the lubricating oil sample on the oil abrasive detection area, which is used to hold the lubricating oil sample extracted from the aero-engine.

[0011] The scanning mirror is rectangular and rotates around the axis of symmetry of its reflecting surface. The center of the scanning mirror coincides with the image-side focal point of the objective lens.

[0012] The phase modulation system includes: a plane mirror and a phase-shifting micromirror;

[0013] in,

[0014] After the reflected beam is incident on the sampling system, it is reflected by the scanning mirror and refracted by the objective lens and then converges into the oil abrasive particle detection area. The reflected beam illuminates the flowing lubricating oil abrasive particles in the oil abrasive particle detection area and interacts with the abrasive particles in the lubricating oil sample to generate a sample beam carrying the information of the lubricating oil sample, which returns to the second beam splitter along the original path.

[0015] After the transmitted beam is incident on the phase modulation system, it is reflected by the plane mirror and the phase-shifting micromirror and then incident on the second beam splitter as a reference beam.

[0016] The reference beam and the sample beam interfere at the exit position of the second beam splitter, forming an interference beam which is then incident on the detection system to obtain the interference spectrum information of the interference beam;

[0017] The amplitude and phase information of the cross-correlation terms in the interference intensity expression are extracted from the interference spectrum information to construct a complex function of the interference beam signal. Then, a Fourier transform is performed on the complex function to finally obtain a clear three-dimensional reconstructed image of lubricating oil abrasive particles.

[0018] Preferably, the first beam splitter and the second beam splitter are placed at 45° to the optical axis, and the beam splitting ratio is 1:1.

[0019] Preferably, the light source system includes: a broadband light source and a light source collimating lens; the broadband light source is a near-infrared point light source, and the broadband low-coherence beam emitted by the broadband light source becomes a parallel beam after being collimated by the light source collimating lens.

[0020] Preferably, the plane mirror is placed at an angle of 45° along the optical axis.

[0021] Preferably, the phase-shifting micromirror is fabricated using the MOEMS process and consists of steps. The surface of each step is coated with a reflective film. Each step corresponds to a phase modulation channel, and the light beam in each phase modulation channel travels through different optical paths under the modulation effect of the phase-shifting micromirror.

[0022] Preferably, the scanning mirror is rectangular and rotates around its axis of symmetry. The center of the rectangle coincides with the image-side focal point of the objective lens, which is used to achieve scanning imaging at different positions in the oil abrasive particle detection area.

[0023] The scanning direction of the scanning mirror is perpendicular to the flow direction of the lubricating oil sample.

[0024] Preferably, the detection system includes: a dispersive grating, an imaging mirror, and an area array detector;

[0025] The imaging mirror is a cylindrical mirror;

[0026] The interference beam is incident on the dispersion grating and then dispersed. After being refracted by the imaging mirror, it converges to the area array detector to obtain interference spectral information of different channels and different spectral bands.

[0027] Preferably, for any phase modulation channel, the beam subjected to static phase modulation is:

[0028] Let the reference beam signal be:

[0029] I R(k) =S R(k) ei2kr

[0030] Among them, S R(k) Let e ​​be the spectral power distribution function of the reference beam. i2kr is the phase, 2r is the optical path length of the reference beam, and k is the wave number;

[0031] Let the sample beam signal be:

[0032]

[0033] Among them, S S(k，z) Let be the spectral power density function of the reflected light from different depth layers of the lubricating oil sample, n be the refractive index of the lubricating oil sample, and r+nz be the optical path length of the reflected light at depth z in the lubricating oil sample.

[0034] The interference spectrum signal I(k) generated after the interference of the reference beam and the sample beam is:

[0035]

[0036] The actual area array detector detects the real part I′(k) of the interference spectrum signal I(k), and the expression for the actual interference spectrum signal I′(k) is:

[0037]

[0038] By performing a Fourier transform on the intermediate terms of the actual interference spectral signal I′(k), the depth information of the lubricating oil sample in that channel can be obtained using FFT{I (k)},Right now:

[0039]

[0040] The acquisition of depth information of lubricating oil samples by a single channel is subject to interference from DC terms and cross-correlation terms of reflections from each depth layer. In addition, since the area array detector can only acquire the real part of the interference spectrum signal and cannot acquire the imaginary part, it also leads to conjugate image interference.

[0041] The interference signal I(k) with wavelength λ simplifies to:

[0042]

[0043] Wherein, I0 represents the DC term and the self-coherent term;

[0044] A and φ are the amplitude and phase of the interference signal, respectively;

[0045] The signal obtained on the array detector is the real part I′ of the interference signal with wavelength λ.

[0046]

[0047] Preferably, when the number of steps of the phase-shifting micromirror is n: the spatial arrangement of the steps can generate a phase shift of π / 2 in each phase modulation channel, and the interference spectrum signal of n channels at the test point is obtained through a single imaging: the amplitude A and phase of the interference signal are solved. A complex function of the interference signal is constructed, and a Fourier transform is performed on the complex function of the interference signal to obtain the depth information of the lubricating oil abrasive particles.

[0048] Compared with existing technologies, this invention extracts the three-dimensional information of abrasive particles based on the principle of light interference, solving the problem that traditional detection methods are difficult to achieve three-dimensional imaging of abrasive particles. It utilizes a Mach-Zehnder interference structure to obtain the interference spectra of the sample beam and the reference beam, and performs Fourier transform and other processing to achieve three-dimensional imaging of the abrasive particles. Simultaneously, it employs a phase-shifting micromirror structure to achieve multi-channel static phase modulation, solving problems such as mirror images and parasitic images in single-channel imaging. This results in advantages such as fast imaging speed, high clarity, good stability, and compact structure. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the structure of a three-dimensional imaging system for lubricating oil abrasive particles based on a phase-shifting micromirror, provided according to an embodiment of the present invention.

[0050] Figure 2 This is a schematic diagram of the optical path of a dispersive grating provided according to an embodiment of the present invention.

[0051] Figure 3 This is a schematic diagram of the spectral information distribution of each channel of the area array detector provided in an embodiment of the present invention.

[0052] Figure 4 This is a schematic diagram of the optical path for scanning imaging using a scanning mirror and a tilting mirror, provided according to an embodiment of the present invention.

[0053] The reference numerals in the figures include: broadband light source 1, light source collimating mirror 2, first beam splitter 3, plane mirror 4, phase-shifting micromirror 5, second beam splitter 6, scanning mirror 7, objective lens 8, oil abrasive detection area 9, dispersive grating 10, imaging mirror 11, and area array detector 12. Detailed Implementation

[0054] In the following description, embodiments of the invention will be described with reference to the accompanying drawings. In the description below, the same modules are denoted by the same reference numerals. Where the same reference numerals are used, their names and functions are also the same. Therefore, their detailed description will not be repeated.

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0056] Figure 1 A three-dimensional imaging system for lubricating oil abrasive particles based on a phase-shifting micromirror, according to an embodiment of the present invention, is shown.

[0057] like Figure 1 As shown, the three-dimensional imaging system for lubricating oil abrasive particles based on a phase-shifting micromirror provided in this embodiment of the invention adopts a Mach-Zehnder interferometer structure and includes a light source system, a first beam splitter 3, a second beam splitter 6, a sampling system, a phase modulation system, and a detection system. The first beam splitter 3 and the second beam splitter 6 are placed at 45° to the optical axis, and their beam splitting ratios are both 1:1.

[0058] The light source system includes: a broadband light source 1 and a light source collimating lens 2; the broadband light source 1 can be a near-infrared point light source with strong penetration capability of lubricating oil, and the broadband low-coherence beam emitted by the broadband light source 1 becomes a parallel beam after being collimated by the light source collimating lens 2.

[0059] The parallel beam emitted by the light source system is incident on the first beam splitter 3 and split into a reflected beam and a transmitted beam.

[0060] The reflected beam is transmitted through the second beam splitter 6 and then enters the sampling system; the transmitted beam enters the phase modulation system.

[0061] The phase modulation system includes a plane mirror 4 and a phase-shifting micromirror 5. The plane mirror 4 is tilted along the optical axis at an angle of 45°. The phase-shifting micromirror 5 is fabricated using the MOEMS process and consists of multiple steps. The surface of each step is coated with a reflective film, and each step corresponds to a phase modulation channel. The beam in each phase modulation channel travels through different optical paths under the modulation effect of the phase-shifting micromirror. The phase-shifting micromirror 5 used in this invention achieves multi-channel static modulation of the beam phase through the spatial arrangement of different positions on each step, without adding any additional movable structures, thus ensuring the stability of the system. Furthermore, this invention can achieve phase modulation of multiple channels at the same measurement point simultaneously, significantly improving the imaging efficiency of the system.

[0062] The transmitted beam is transmitted through the first beam splitter 3 and then incident on the plane mirror 4. After being reflected by the plane mirror 4, the transmitted beam is incident on the phase-shifting micromirror 5. After being reflected again by the phase-shifting micromirror 5, it is used as a reference beam and incident on the second beam splitter 6.

[0063] The sampling system includes a scanning mirror 7 and an objective lens 8. The scanning mirror 7 is rotated to scan the oil abrasive detection area 9, with the scanning direction of the scanning mirror 7 perpendicular to the flow direction of the lubricating oil sample. The scanning mirror 7 is rectangular and rotates around its axis of symmetry. The center of the rectangle coincides with the image-side focal point of the objective lens 8, enabling scanning imaging of different positions in the oil abrasive detection area 9.

[0064] The reflected beam is transmitted through the second beam splitter 6 and incident on the scanning mirror 7. After being reflected by the scanning mirror 7 and refracted by the objective lens 8, it irradiates the oil abrasive detection area 9, generating a scattered echo with the information of the abrasive particles of the lubricating oil to be tested, which is the sample beam. The sample beam returns to the second beam splitter 6 along the original path.

[0065] The reference beam and the sample beam interfere at the exit position of the second beam splitter 6, resulting in an interference beam that is incident on the detection system.

[0066] The detection system includes: a dispersive grating 10, an imaging mirror 11, and an area array detector 12. The imaging mirror 11 is a cylindrical mirror.

[0067] Figure 2 The optical path of a dispersive grating provided according to an embodiment of the present invention is shown.

[0068] like Figure 2 As shown, the interference beam is incident on the dispersive grating 10 and dispersed. After being refracted by the imaging mirror 11, it converges to the area array detector 12 to obtain interference spectral information of different channels and different spectral bands. The interference spectral information is processed by algorithms such as Fourier transform, and then a clear three-dimensional image of lubricating oil abrasive particles is obtained through three-dimensional reconstruction.

[0069] Figure 3 The spectral information distribution of each channel of the area array detector provided according to an embodiment of the present invention is shown.

[0070] like Figure 3 As shown, the array detector 12 receives interference information from five channels of the test point in the direction of parallel grating fringes. The grayscale output of each row of pixels in each channel of the array detector 12 is the same. The average grayscale value of the above pixels can be used as the initial data for three-dimensional reconstruction to reduce the influence of random errors.

[0071] The array detector 12 in the vertical grating stripe direction receives the spectral information of the five channels of the point to be measured.

[0072] Figure 4 The optical path for scanning imaging using a scanning mirror and a pendulum mirror according to an embodiment of the present invention is shown.

[0073] like Figure 4As shown, by scanning with the scanning mirror 7, depth information at different locations of the lubricating oil abrasive particles is obtained and three-dimensional reconstruction is performed, thus obtaining the three-dimensional structural information of all abrasive particles on the oil abrasive particle detection area 9. The amplitude and phase information of the cross-correlation term in the interference intensity expression can be extracted from the interference spectrum. Then, a Fourier transform is performed on the reconstructed complex function to obtain the three-dimensional reconstructed structure of the lubricating oil abrasive particles after eliminating parasitic terms and mirror images.

[0074] The above calculation process includes:

[0075] For a beam that has undergone static phase modulation in a phase modulation channel of the three-dimensional detection system provided by this invention, its interference spectrum is obtained after the interference of the reference beam and the sample beam. Let the reference beam signal be:

[0076] I R(k) =S R(k) e i2kr

[0077] Among them, S R(k) Let e ​​be the spectral power distribution function of the reference beam. i2kr is the phase, 2r is the optical path length of the reference light, and k is the wave number.

[0078] Let the signal of the sample beam reflected back from the lubricating oil sample be:

[0079]

[0080] Among them, S S(k，z) Let be the spectral power density function of reflected light from different depth layers of the lubricating oil sample, n be the refractive index of the sample, and r+nz be the optical path length of reflected light at depth z in the sample.

[0081] The interference spectrum signal I(k) generated after the reference beam and sample beam interfere with each other is:

[0082]

[0083] The actual area array detector detects the real part I′(k) of the interference spectrum signal I(k), and the expression for the actual interference spectrum signal I′(k) is:

[0084]

[0085] The above formula consists of three terms: the first term is the DC component, the second term is the sum of multiple cosine functions, which contains the depth structure information of the lubricating oil sample, and the third term is the mutual interference between different reflective layers of the lubricating oil sample.

[0086] By performing a Fourier transform on the second term of the actual interference spectral signal I′(k), the depth information of the lubricating oil sample in that channel can be obtained using FFT{I (k)},Right now:

[0087]

[0088] The acquisition of depth information of lubricating oil samples by a single channel is subject to interference from DC terms and cross-correlation terms of reflections from each depth layer. In addition, since the area array detector can only acquire the real part of the interference spectrum signal and cannot acquire the imaginary part, it also leads to conjugate image interference.

[0089] The interference signal I(k) with wavelength λ can be simplified as follows:

[0090]

[0091] in,

[0092] I0 represents the DC term and the self-coherent term, while A and φ represent the amplitude and phase of the interference signal. Only by finding these two terms can the complex function of the interference signal be reconstructed, thereby eliminating interference such as mirror images and parasitic images.

[0093] The real part I′ of the interference signal with wavelength λ obtained on the area array detector is:

[0094]

[0095] Through the modulation effect of the phase-shifting micromirror of this invention, taking a five-step scale as an example, the spatial arrangement of the steps can cause each modulation channel to generate a phase shift of π / 2. At this time, the interference spectral signals of the five channels of the test point can be obtained in a single imaging:

[0096]

[0097] The amplitude A and phase of the cross-correlation term in the expression for interference light intensity can be directly obtained from the above equation.

[0098]

[0099]

[0100] The phase-shifting micromirror used in this invention achieves multi-channel static modulation of the beam phase through the spatial arrangement of stepped reflective surfaces, without adding any additional movable structures, thus ensuring the stability of the system. Furthermore, the phase-shifting micromirror in this invention can achieve phase modulation of multiple channels simultaneously, significantly improving the imaging efficiency of the system.

[0101] Although embodiments of the present invention have been shown and described above, it is understood that these embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention. The specific embodiments described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A three-dimensional imaging system for lubricating oil abrasive particles based on a phase-shifting micromirror, characterized in that, It includes a light source system, a first beam splitter, a second beam splitter, a sampling system, a phase modulation system, and a detection system; The parallel beam emitted by the light source system is incident on the first beam splitter and split into a reflected beam and a transmitted beam; The reflected beam is transmitted through the second beam splitter and then incident on the sampling system; the transmitted beam is incident on the phase modulation system. The sampling system includes: a scanning mirror, an objective lens, and an oil abrasive detection area; The sampling system is used to collect three-dimensional information of the lubricating oil sample on the oil abrasive detection area, which is used to hold the lubricating oil sample extracted from the aero-engine. The scanning mirror is rectangular and rotates around the axis of symmetry of its reflecting surface. The center of the scanning mirror coincides with the image-side focal point of the objective lens. The phase modulation system includes: a plane mirror and a phase-shifting micromirror; in, After the reflected beam is incident on the sampling system, it is reflected by the scanning mirror and refracted by the objective lens and then converges into the oil abrasive particle detection area. The reflected beam illuminates the flowing lubricating oil abrasive particles in the oil abrasive particle detection area and interacts with the abrasive particles in the lubricating oil sample to generate a sample beam carrying the information of the lubricating oil sample, which returns to the second beam splitter along the original path. After the transmitted beam is incident on the phase modulation system, it is reflected by the plane mirror and the phase-shifting micromirror and then incident on the second beam splitter as a reference beam. The reference beam and the sample beam interfere at the exit position of the second beam splitter, forming an interference beam which is then incident on the detection system to obtain the interference spectrum information of the interference beam; The amplitude and phase information of the cross-correlation terms in the interference intensity expression are extracted from the interference spectrum information to construct a complex function of the interference beam signal. Then, a Fourier transform is performed on the complex function to finally obtain a clear three-dimensional reconstructed image of lubricating oil abrasive particles.

2. The three-dimensional imaging system for lubricating oil abrasive particles based on phase-shifting micromirrors according to claim 1, characterized in that, The first and second beam splitters are placed at 45° to the optical axis, with a beam splitting ratio of 1:

1.

3. The three-dimensional imaging system for lubricating oil abrasive particles based on a phase-shifting micromirror according to claim 2, characterized in that, The light source system includes: a broadband light source and a collimating lens; the broadband light source is a near-infrared point light source, and the broadband low-coherence beam emitted by the broadband light source becomes a parallel beam after being collimated by the collimating lens.

4. The three-dimensional imaging system for lubricating oil abrasive particles based on a phase-shifting micromirror according to claim 3, characterized in that, The plane mirror is placed at an angle of 45° along the optical axis.

5. The three-dimensional imaging system for lubricating oil abrasive particles based on a phase-shifting micromirror according to claim 4, characterized in that, The phase-shifting micromirror is fabricated using the MOEMS process and consists of steps. Each step is coated with a reflective film, and each step corresponds to a phase modulation channel. The light beam in each phase modulation channel travels through different optical paths under the modulation effect of the phase-shifting micromirror.

6. The three-dimensional imaging system for lubricating oil abrasive particles based on phase-shifting micromirrors according to claim 5, characterized in that, The scanning mirror is rectangular and rotates around its axis of symmetry. The center of the rectangle coincides with the image-side focal point of the objective lens, which is used to achieve scanning imaging at different positions in the oil abrasive particle detection area. The scanning direction of the scanning mirror is perpendicular to the flow direction of the lubricating oil sample.

7. The three-dimensional imaging system for lubricating oil abrasive particles based on a phase-shifting micromirror according to claim 6, characterized in that, The detection system includes: a dispersive grating, an imaging mirror, and an area array detector; The imaging mirror is a cylindrical mirror; The interference beam is incident on the dispersion grating and then dispersed. After being refracted by the imaging mirror, it converges to the area array detector to obtain interference spectral information of different channels and different spectral bands.

8. The three-dimensional imaging system for lubricating oil abrasive particles based on a phase-shifting micromirror according to claim 7, characterized in that, For any phase-modulated beam in any phase-modulated channel: Let the reference beam signal be: in, Let be the spectral power distribution function of the reference beam. For phase, The optical path length of the reference beam. Wave number; Let the sample beam signal be: in, Let be the spectral power density function of reflected light from different depth layers of the lubricating oil sample. The refractive index of the lubricating oil sample is... The depth of the lubricating oil sample is The optical path length of the reflected light; The interference spectrum signal generated after the reference beam and the sample beam interfere. for: The area array detector actually detects an interferometric spectral signal. real part The actual interference spectral signal The expression is: For actual interferometric spectral signals By performing a Fourier transform on the intermediate term in the equation, the depth information of the lubricating oil sample in that channel can be obtained. ,Right now: The acquisition of depth information of lubricating oil samples by a single channel is subject to interference from DC terms and cross-correlation terms of reflections from each depth layer. In addition, since the area array detector can only acquire the real part of the interference spectrum signal and cannot acquire the imaginary part, it also leads to conjugate image interference. Then the wavelength is Interference signal Simplified to: in, These are DC terms and self-coherent terms; and These represent the amplitude and phase of the interference signal, respectively. The wavelength obtained on the array detector is... The real part of the interference signal : 。 9. The three-dimensional imaging system for lubricating oil abrasive particles based on a phase-shifting micromirror according to claim 8, characterized in that, When the number of steps in the phase-shifting micromirror is n: the spatial arrangement of the steps can enable each phase modulation channel to generate The phase shift is obtained by acquiring the interference spectral signals of n channels at the test point through a single imaging process: the amplitude of the interference signal is then calculated. and phase A complex function of the interference signal is constructed, and a Fourier transform is performed on the complex function of the interference signal to obtain the depth information of the lubricating oil abrasive particles.

Images