CN-116893427-B - Object inclination angle measurement method based on ellipticity continuous change optical vortex

Abstract

The invention relates to an object inclination angle measuring method based on optical vortex with continuously-changed ellipticity, which firstly clarifies a rotating Doppler frequency shift mechanism of vortex rotation with different ellipticity, then adopts a complex amplitude modulation method to adjust the intensity and the phase of a light beam to prepare a group of vortex light beams with continuously-changed ellipticity, sequentially irradiates the vortex light beams onto a rotating object, receives echo signals, and then combines a time-frequency analysis method to obtain a rotating Doppler time spectrum. According to theoretical analysis, when the vortex light ellipticity and the object inclination angle meet the corresponding relation, the spectrum broadening is minimum, and the signal amplitude is maximum. Thus, from the time-frequency spectrum variation, the optimal ellipticity of the light beam and the inclination angle of the object can be determined. The method has the advantages that the required detection system is simple, the operation is convenient, and the inclination angle of the object can be accurately measured, so that the method has great application potential in telemetry.

Inventors

• REN YUAN
• LIU ZHENGLIANG
• ZHU XIANGYANG
• FAN YAOHUI
• WEN XINYI
• CHEN XIAOCEN
• Tu Dianya
• LIU TONG
• TANG RUOYU
• DING YOU

Assignees

• 中国人民解放军战略支援部队航天工程大学

Dates

Publication Date

20260505

Application Date

20230714

Claims (1)

1. 1. An object inclination angle measurement method based on optical vortex with continuous change of ellipticity is characterized in that firstly, the ellipticity of the optical vortex is controlled, a group of optical vortex holograms with regular change of ellipticity is obtained through coordinate conversion and expansion proportion, the optical vortex holograms are sequentially and continuously loaded on a spatial light modulator, a group of vortex light beams with continuous change of ellipticity is prepared by using linear polarized light irradiation, a rotating target is sequentially scanned and irradiated by using the prepared vortex light beam group, the frequency of an elliptical vortex light beam is modulated by the rotating target to generate rotating Doppler frequency shift, an echo time domain signal is obtained by adopting a photoelectric detector to receive the echo time domain signal, a rotating Doppler time spectrum is obtained after the echo time domain signal is processed by a time-frequency analysis means, the object inclination angle is obtained by combining the corresponding relation between the inclination angle and the moment in the time-varying frequency spectrum, wherein a geometrical model of the object inclination angle detected by the elliptical vortex light beam under the inclination condition is set, the relation among the ellipticity of the vortex light beam and the rotating Doppler frequency shift is set, namely: Wherein the method comprises the steps of Representing the rotational doppler shift frequency, Represents the ellipticity of the sample, The number of topological charges is represented, Represents the rotation speed of the motor, Representing the azimuth angle of the beam, Representing the angular velocity vector of a rotating object At the position of Projection of a surface An included angle of the axes, an expression between the corresponding time and the object inclination angle in the time spectrum of the echo signal is established , Is the corresponding time when the rotational doppler spectrum is narrowest, Is the initial time of one cycle and, Is a hologram switching interval, and Is the ellipticity interval of the probe beam, Representing the inclination angle, and obtaining the inclination angle of the object through the time corresponding to the frequency in the time spectrum.

Description

Object inclination angle measurement method based on ellipticity continuous change optical vortex Technical Field The invention relates to the technical field of light field regulation and optical detection, in particular to an object inclination angle measurement method based on ellipticity continuous change optical vortex Background Allen 1992 proposed for the first time that in addition to spin angular momentum, the vortex beam had another momentum dimension, orbital angular momentum, and demonstrated that the orbital angular momentum of each photon in the vortex light field wasWhereinFor the number of topological charges,Is about the planck constant. The vortex beam carrying the orbital angular momentum is focused by a large number of researchers, and the vortex beam has great application potential from tiny particle manipulation, rotation detection, celestial body measurement and the like. In which the frequency of the light beam is shifted due to its particular phase distribution, which is very sensitive to angular velocities or accelerations perpendicular to the direction of propagation of the light beam, known as the rotational doppler effect. Since the rotational doppler effect was proposed, a great deal of research has been conducted around it, including from non-coaxial rotational doppler effects to the detection of geometric features of rotating objects, and so on. Meanwhile, the optical vortex plays an important role in micro-displacement measurement and compound motion decoupling. Nevertheless, no more information about the relative pose of the object can be extracted from the rotational doppler shift. In the conventional radar detection, the existence of a target and the overall azimuth of the target can be identified only according to the linear Doppler shift of the object, the specific characteristics and the gesture of the target cannot be clearly identified, while the conventional optical imaging can clearly identify the pose of the target, but has a limited acting distance and is greatly influenced by weather, so that a telemetry means capable of clearly describing the gesture of the object is needed. Disclosure of Invention In view of the above, the invention provides an object inclination angle measurement method based on ellipticity continuous variation optical vortex, which can realize remote accurate measurement of inclination angle of a rotating object. In order to achieve the above purpose, the technical scheme of the invention is as follows: An object inclination angle measuring method based on ellipticity continuous change optical vortex firstly establishes a geometric model of an elliptical vortex beam detection inclined object, reveals a rotating Doppler frequency shift mechanism related to the object inclination angle and ellipticity of the vortex beam under the inclination condition, then adjusts the beam phase according to a complex amplitude modulation method to obtain a group of elliptical optical vortex holograms with continuously changed ellipticity, sequentially loads the elliptical optical vortex holograms on a spatial light modulator, irradiates the device with linearly polarized light beams to obtain the optical vortex with continuously changed ellipticity, receives echo time domain signals after interaction with the object, obtains a rotating Doppler time spectrum after time-frequency conversion, obtains vortex light ellipticity corresponding to the narrowest frequency shift according to the time spectrum of the signals and combines with a rotating Doppler frequency shift expression of the elliptical vortex rotation, and calculates the object inclination angle according to the corresponding relation between the inclination angle and the ellipticity of the optical vortex at the moment. The ellipticity of the optical vortex is controlled by a coordinate conversion method, a group of optical vortex holograms with fixed ellipticity intervals and regular changes are obtained, the optical vortex holograms are sequentially and continuously loaded on a spatial light modulator, and linearly polarized light irradiates the device to prepare a group of vortex light beams with different ellipticities. Firstly, establishing a geometric model of an elliptical vortex beam detection inclined object, and secondly, disclosing a rotating Doppler frequency shift mechanism related to the inclination angle of the object and the ellipticity of the vortex beam under the inclined condition, namely: Wherein the method comprises the steps of Representing the rotational doppler shift frequency,Represents the ellipticity of the sample,The number of topological charges is represented,Represents the rotation speed of the motor,Represents the angle of inclination and,Representing the azimuth angle of the beam,Representing the angular velocity vector of a rotating objectAt the position ofProjection of a surfaceThe included angle of the axes continuously scans the rotating object by using an optical