阅读说明：本技术 一种用于高分辨率测量的激光测距装置及方法 (Laser ranging device and method for high-resolution measurement ) 是由 许新科 孔明 徐靖翔 赵军 王道档 刘璐 郭天太 刘维 于 2020-05-21 设计创作，主要内容包括：本发明提供一种用于高分辨率测量的激光测距装置。可调谐激光器发出的激光信号经过分束器后被分为两路进入主光路和辅助光路,主光路中的信号通过变焦透镜照射目标后原路返回至光路,信号经过耦合器耦合后被探测器采集。进入辅助光路中的信号同样被探测器采集,两部分的信号存在光程差因此会产生干涉,数据采集卡将探测器中的信号以正弦形式输出。通过ESPRIT算法对该信号数据进行计算,实现被测目标的高分辨率测量。本发明解决现有激光测距时难以实现的高分辨率测量的问题。有益效果：利用ESPRIT算法对目标信号的数据进行计算,提高了该装置测量的分辨率。(The invention provides a laser ranging device for high-resolution measurement. Laser signals emitted by the tunable laser are divided into two paths after passing through the beam splitter and enter the main light path and the auxiliary light path, signals in the main light path are irradiated on a target through the zoom lens and then return to the light path, and the signals are coupled by the coupler and then collected by the detector. The signals entering the auxiliary optical path are also collected by the detector, the signals of the two parts have optical path difference so as to generate interference, and the data acquisition card outputs the signals in the detector in a sine form. And calculating the signal data through an ESPRIT algorithm to realize high-resolution measurement of the measured target. The invention solves the problem of high-resolution measurement which is difficult to realize in the existing laser ranging. Has the advantages that: the data of the target signal is calculated by utilizing an ESPRIT algorithm, so that the measurement resolution of the device is improved.)

1. A laser ranging device for high resolution measurements, characterized by: the device comprises a tunable laser (1), a first beam splitter (2), a main optical path, an auxiliary optical path, a data acquisition card (13) and a computer (14), wherein the main optical path comprises a second beam splitter (3), a circulator (4), a zoom lens (5), a first delay single-mode optical fiber (6), a first coupler (7) and a first detector (8), the auxiliary optical path comprises a third beam splitter (9), a second delay single-mode optical fiber (10), a second coupler (11) and a second detector II (12), optical signals are transmitted between the main optical path and each optical device of the auxiliary optical path through optical fibers, output signals of the tunable laser (1) pass through the first beam splitter (2), at least 90% of signals enter the main optical path, and after passing through the second beam splitter (3) in the main optical path, one path of the signals passes through the circulator (4) and the zoom lens (5) and irradiates an external target, then the reflected signal returns along the same path, the returned reflected signal is coupled with the other path of signal branched by the second beam splitter in the first coupler (7), and the reflected signal is converted into an electric signal to be output after being detected by the first detector (8) and is output by the data acquisition card (13); the signal entering the auxiliary optical path is divided into two paths by the third beam splitter (9), one path passes through the second delay single-mode fiber (10), the other path acts on a local oscillator, then the two paths of light are coupled by the second coupler (11), the two paths of light are converted into electric signals after being detected by the second detector (12) and output and are recorded by the data acquisition card (13), the data acquisition card (13) transmits acquired data to the computer (14), and the computer (14) processes at least the signal acquired by the data acquisition card (13) and coming from the first detector (8) by utilizing an ESPRIT algorithm to obtain at least amplitude and frequency information of the signal.

2. The laser distance measuring device for high resolution measurement according to claim 1, wherein the tunable laser (1) stably outputs a laser signal at a frequency of 1KHz during measurement.

3. The laser rangefinder for high resolution measurements according to claim 1, characterized in that the zoom lens (5) is arranged on a rotating device, the orientation of the zoom lens (5) being adjusted according to the position of the external target, such that the zoom lens (5) faces the external target.

4. The laser distance measuring device for high resolution measurement according to claim 1, wherein the first beam splitter (2) is 99: 1 beam splitter, wherein 99% of the signal enters the main optical path after passing through the first beam splitter (2).

5. The laser distance measuring device for high resolution measurement according to claim 1, wherein the second beam splitter (3) is 99: 1, the third beam splitter (9) being a 50: 50 beam splitter.

6. The laser ranging device as claimed in any one of claims 1 to 5, wherein: the optical path adjusting device comprises a first delay single-mode fiber (6) in a main optical path and a second delay single-mode fiber (10) in an auxiliary optical path, wherein the first delay single-mode fiber and the second delay single-mode fiber have the capacity of adjusting the optical path, two paths of light coupled in a first coupler (7) and a second coupler (11) respectively generate an interference phenomenon under the influence of different optical paths, and a first detector (8) and a second detector (12) convert detected interference signals into sinusoidal signals to be output and recorded by a data acquisition card (13).

7. A ranging method using the laser ranging apparatus as claimed in any one of claims 1 to 6, wherein: the method comprises the following steps:

s1, periodically collecting the target voltage signal of the main light path and the resampling voltage signal in the auxiliary light path,

s2, resampling the target voltage signal by the resampled voltage signal to obtain a series of combined signals of a sinusoidal signal and white noise, wherein the amplitude of the combined signals changes according to an exponential law;

and S3, processing the combined signal by an ESPRIT algorithm to obtain the amplitude and phase information of each signal component.

Technical Field

The invention relates to the field of optical measurement, in particular to a laser ranging device and method for high-resolution measurement.

Background

With the development of modern precision measurement technology, laser ranging technology is increasingly widely applied in various fields of precision measurement, industrial design and manufacture, such as space positioning, dimension measurement, remote sensing mapping, mold design, manufacture and detection and the like. With the continuous development and progress of precision machining and manufacturing technology, the requirement for the resolution of laser measurement technology is also continuously increased. The laser ranging technology is based on a frequency modulation continuous wave laser detection technology, and as a novel coherent detection technology, linear frequency modulation signals are adopted to modulate laser, and stable beat frequency is formed by comparing a transmitting signal with echo signals reflected by a target point to perform spectrum analysis so as to obtain the distance. Generally, fourier transform is adopted to perform specific analysis on a frequency spectrum, and the resolution of the method is related to the bandwidth of a frequency modulation band, but the current tuning semiconductor laser is usually small in bandwidth of the frequency modulation band, so that the measurement resolution is difficult to further improve. In order to improve the measurement resolution without increasing the bandwidth of the frequency modulation, a high-resolution spectrum estimation algorithm is used for processing the beat frequency signal, and the resolution of the ranging system is improved.

Disclosure of Invention

In view of this, an object of the present invention is to provide a laser ranging apparatus for high resolution measurement, which can improve the measurement accuracy and measurement resolution in the existing laser ranging technology, and a design method of a main optical path and an auxiliary optical path is adopted in an optical path of the apparatus to correct the frequency modulation nonlinearity of a laser, and meanwhile, a feasible method is provided for improving the resolution during laser ranging measurement by further processing a target signal in combination with an ESPRIT algorithm.

The invention provides a laser distance measuring device for high-resolution measurement, which comprises a tunable laser (1), a first beam splitter (2), a main optical path, an auxiliary optical path, a data acquisition card (13) and a computer (14), wherein the main optical path comprises a second beam splitter (3), a circulator (4), a zoom lens (5), a first delay single-mode optical fiber (6), a first coupler (7) and a first detector (8), the auxiliary optical path comprises a third beam splitter (9), a second delay single-mode optical fiber (10), a second coupler (11) and a second detector II (12), optical signals are transmitted between optical devices of the main optical path and the auxiliary optical path through optical fibers, an output signal of the tunable laser (1) passes through the first beam splitter (2), and at least 90% of the signals enter the main optical path, after passing through a second beam splitter (3) in a main optical path, one path of signal passes through the circulator (4) and the zoom lens (5) and then irradiates to an external target, then a reflected signal returns along the same path, the returned reflected signal is coupled with the other path of signal split by the second beam splitter in a first coupler (7), and the reflected signal is converted into an electric signal to be output after being detected by a first detector (8) and then is converted into the electric signal to be output by a data acquisition card (13); the signal entering the auxiliary optical path is divided into two paths by the third beam splitter (9), one path passes through the second delay single-mode fiber (10), the other path acts on a local oscillator, then the two paths of light are coupled by the second coupler (11), the two paths of light are converted into electric signals after being detected by the second detector (12) and output and are recorded by the data acquisition card (13), the data acquisition card (13) transmits acquired data to the computer (14), and the computer (14) processes at least the signal acquired by the data acquisition card (13) and coming from the first detector (8) by utilizing an ESPRIT algorithm to obtain at least amplitude and frequency information of the signal.

Preferably, the tunable laser (1) stably outputs a laser signal at a frequency of 1KHz during measurement.

Preferably, the zoom lens (5) is arranged on a rotating device, and the direction of the zoom lens (5) is adjusted according to the position of the external target, so that the zoom lens (5) faces the external target.

Preferably, the first beam splitter (2) is 99: 1 beam splitter, wherein 99% of the signal enters the main optical path after passing through the first beam splitter (2).

Preferably, the second beam splitter (3) is 99: 1, the third beam splitter (9) being a 50: 50 beam splitter.

Preferably, the first delayed single-mode fiber (6) in the main optical path and the second delayed single-mode fiber (10) in the auxiliary optical path have an optical path adjusting capability, two paths of light respectively coupled in the first coupler (7) and the second coupler (11) generate an interference phenomenon under the influence of different optical paths, and the first detector (8) and the second detector (12) convert detected interference signals into sinusoidal signals to be output and recorded by the data acquisition card (13).

According to the purpose of the invention, the invention also provides a distance measuring method using the laser distance measuring device, which comprises the following steps:

s1, periodically collecting the target voltage signal of the main light path and the resampling voltage signal in the auxiliary light path,

s2, resampling the target voltage signal by the resampled voltage signal to obtain a series of combined signals of a sinusoidal signal and white noise, wherein the amplitude of the combined signals changes according to an exponential law;

and S3, processing the combined signal by an ESPRIT algorithm to obtain the amplitude and phase information of each signal component.

Compared with the prior art, the invention has the beneficial effects that: and the ESPRIT algorithm is utilized to calculate the target data, so that the resolution of the laser ranging device is greatly improved.

Drawings

FIG. 1 is a schematic view of the apparatus of the present invention;

FIG. 2 is a graph of a signal formed by superimposing sinusoidal-form signals having frequencies of 100.05Hz, 120.50Hz, and 120.60Hz with a random noise signal;

FIG. 3 is a graph of the spectrum of the signal after Fourier transformation;

FIG. 4 is a stem graph of the signal after calculation by the ESPRIT algorithm;

FIG. 5 is a further enlarged stem view of FIG. 4;

in the figure: 1-a tunable laser; 2-a first beam splitter; 3-a second beam splitter; 4-a circulator; 5-a zoom lens; 6-a first delay single mode fiber; 7-a first coupler i; 8-a first detector I; 9-a third beam splitter; 10-a second delayed single mode fiber; 11-a second coupler; 12-a third detector; 13-a data acquisition card; 14-computer.

Detailed Description

The invention will now be described in more detail by way of example with reference to the accompanying drawings.