CN104865566A - Distance measurement method based on correlated imaging - Google Patents

Abstract

The invention relates to a distance measurement method based on correlated imaging. Based on a fundamental principle of the correlated imaging, measurement of a distance between a spatial light modulation phase plate and a target object is realized. In the correlated imaging, two paths of light intensities are needed to carry out correlation operation so as to carry out imaging. One path is detected by a single pixel detector through the target object and is a detection light path light intensity. The other path is directly detected by a detector possessing spatial resolution, is not through the target object and is a reference light path light intensity. Correlation operation imaging is performed on the two light intensities so that advantages of high anti-interference performance, stability, reliability and the like are possessed. A target of distance measurement is reached through imaging. The distance measurement is realized and simultaneously an object image is acquired and a lot of information of the object is acquired too, which is not possessed by a traditional distance measurement method.

Description

A kind of distance measurement method based on relevance imaging

Technical field

The present invention relates to a kind of detection technique, particularly a kind of distance measurement technique method based on relevance imaging.

Background technology

Current distance measurement technique generally can only the distance of measurement target object, and complex structure, function singleness, can not obtain the information such as the image of object.Patent " range observation " (number of patent application 201080011510.9) describes a kind of phase differential of transmitting and receiving pulse train that utilizes and realizes range observation, the method generates has transmitting of pulse train, this pulse signal has the pulse repetition rate of regulation, making to transmit, it is thin to have frequency in a frequency domain, the guiding that will transmit object under test, and the reflected signal accepted from target object reflection, then the spectral line dredging regulation according to frequency is determined to transmit and reflected signal phase differential, realizes range finding according to phase differential.This complicated structure, makes and Installation and Debugging require higher, complex operation.And can only measuring distance, the information such as the image of object can not be obtained, function singleness.

Relevance imaging is a kind of novel imaging technique being different from traditional imaging mode, it utilizes light field correlativity to carry out imaging, relevance imaging only needs the light of single pixel detector acquisition from object not having spatial resolving power, and the detector with spatial resolving power is used for probe source information, the picture of object can be obtained by association computing.Relevance imaging is that the entangled photon pairs changing generation under utilizing Spontaneous Parametric realizes at first, but people utilize counterfeit thermo-optical, thermal light source can realize relevance imaging equally afterwards, and most researchers pays close attention to the light source of imaging, the essence of imaging.But it is less for the application of relevance imaging.

Summary of the invention

The present invention be directed to present range test Problems existing, propose a kind of distance measurement method based on relevance imaging, according to relevance imaging ultimate principle, propose a kind of new method being different from traditional range observation, not only can measuring distance, the bulk informations such as the image of object can also be obtained.

Technical scheme of the present invention is: a kind of distance measurement method based on relevance imaging, specifically comprises the steps:

1) detection light path light intensity is obtained: build range measurement system light path, laser exports from laser generator, is input to collimating apparatus and corrects, be then irradiated to spatial light phase modulation panel and modulate, light modulated exports from spatial light phase modulation panel, through target object and double lens, light intensity coverlet pixel detector is collected, and sends into computing machine, simultaneous computer is assisted, export drive control signal, constantly change spatial light phase modulation panel phase place, many groups detect light path light intensity B _r;

2) analog references light path light intensity: theoretical according to Fresnel-Huygens, simulates the light intensity I in reference path corresponding to different propagation distance Z _r(x, y, Z);

3) computing imaging and range finding is associated: by step 1) and 2) gained B _rand I _r(x, y, Z) carries out related calculation, and obtains the Recovery image that a series of different reference distance Z is corresponding, and calculate the Y-PSNR of Recovery image, namely the reference distance of the maximum correspondence of Y-PSNR is measuring distance.

Described step 1) middle detection light path light intensity B _rfor:

B _r＝∫∫I _r(x,y,L)T(x,y)dxdy

Wherein, T (x, y) represents target object, I _r(x, y, L) represents that light goes out the light intensity of defeated rear propagation distance L from spatial light phase modulation panel, constantly changes phase-plate, iterative operation N time, can detect light path light intensity B in detection light path _r.

Described step 2) simulate the light intensity I that in reference path, different propagation distance Z place is corresponding _r(x, y, Z) is:

I _r(x,y,Z)＝|E _r(x,y,Z)| ²，

$E_r(x,y,Z)=E_r(x,y,0)\⊗h_Z(x,y),$

Wherein, h _z(x, y) represents the Fresnel propagation function of propagation distance Z in reference path, symbol represent convolutional calculation, E _r(x, y, 0) is for being irradiated to the Electric Field Distribution of the incident light before spatial light phase modulation panel, E _r(x, y, Z) exports from spatial light phase modulation panel, the Electric Field Distribution of the light after propagation distance Z.

Described step 3) in the pixel value O (x, y) of Recovery image:

$O(x,y)=\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}[B_r-\stackrel{\‾}{B}]\·I_r(x,y,Z),$

Wherein, represent N number of light intensity average that N operation sheet pixel detector detects, change Z value value size, utilize computer mould to draw up a series of reference path light intensity, a series of Recovery image can be obtained.

Beneficial effect of the present invention is: the advantages such as the distance measurement method that the present invention is based on relevance imaging, has strong interference immunity, reliable and stable; Reached the target of measuring distance by imaging, realizing measuring distance simultaneously, also obtain subject image, obtain the information that object is a large amount of, this is not available for traditional distance-finding method.

Accompanying drawing explanation

Fig. 1 is the Range Measurement System structural drawing that the present invention is based on relevance imaging;

Fig. 2 is a series of Recovery image figure that the present invention utilizes different propagation distance Z in computer simulation reference path to obtain;

Fig. 3 is the Y-PSNR trend map that the present invention calculates Recovery image.

Embodiment

Based on relevance imaging ultimate principle, implementation space light phase modulation panel is to the measurement of the spacing of target object.Relevance imaging needs two-way light intensity to carry out related calculation imaging, and target object coverlet pixel detector of leading up to detects, and is namely detect light path light intensity; Another road is not by target object, and directly being detected by the detector with spatial resolution, is namely reference path light intensity, and carry out related calculation both imaging.

The present invention utilizes to build light path to obtain and detects light path light intensity; Reference path light intensity is then theoretical according to Fresnel-Huygens, utilize the reference path light intensity of computer simulation different propagation distance, detection light path light intensity and reference path light intensity are carried out related calculation, obtain the Recovery image of a series of target object, namely reference distance corresponding to the optimum place of picture quality be testing distance.

As shown in Figure 1 based on the Range Measurement System structural drawing of relevance imaging, system comprises laser generator 1, collimating apparatus 2, spatial light phase modulation panel 3, target object 4, double lens 5, single pixel detector 6 and computing machine 7.Distance between measurement space light phase modulation panel 3 to target object 4.This programme mainly comprises three steps:

1, the 1 range measurement system figure built with reference to the accompanying drawings, laser exports from laser generator 1, is input to collimating apparatus 2 and corrects, then be irradiated to spatial light phase modulation panel 3 to modulate, light modulated exports from phase-plate 3, and through target object 4 and double lens 5, light intensity coverlet pixel detector 6 is collected.Assisted by computing machine 7, export drive control signal, constantly change spatial light phase modulation panel phase place, can obtain detecting light path light intensity vector B _r, general multiplicity N gets 16000,

Detect light path light intensity B _ravailable formula (1) represents:

B _r＝∫∫I _r(x,y,L)T(x,y)dxdy (1)

Wherein, T (x, y) represents target object, I _r(x, y, L) represents that light exports from spatial light phase modulation panel, and the light intensity after propagation distance L, constantly changes phase-plate, iterative operation N time, can detect light path light intensity B in detection light path _r;

2, area of computer aided is utilized, theoretical according to Fresnel-Huygens, simulate in reference path by formula (2) and formula (3), the light intensity I after different propagation distance Z _r(x, y, Z), utilizes a series of Recovery image figure that different propagation distance Z in computer simulation reference path obtains as shown in Figure 2, specific as follows:

Formula (2) can obtain reference path glazing exports the light after rear propagation distance Z Electric Field Distribution E from spatial light phase modulation panel _r(x, y, Z)

$E_r(x,y,Z)=E_r(x,y,0)\⊗h_Z(x,y)---\left(2\right)$

Wherein, h _z(x, y) represents the Fresnel propagation function of propagation distance Z in reference path, symbol represent convolutional calculation, thus the Electric Field Distribution E of the light after reference path propagation distance Z can be obtained _r(x, y, Z), E _r(x, y, 0) is for being irradiated to the Electric Field Distribution of the incident light before phase-plate.Reference path light intensity I _r(x, y, Z) can be calculated by formula (3):

I _r(x,y,Z)＝|E _r(x,y,Z)| ²(3)

3, the B that two steps above obtain is utilized _rand I _r, according to formula (4), by B _rand I _rcarry out related calculation, obtain the Recovery image that a series of different reference distance Z is corresponding, calculate the Y-PSNR (PSNR) of Recovery image, namely the reference distance of Y-PSNR (PSNR) maximum correspondence is measuring distance,

The pixel value O (x, y) of Recovery image:

$O(x,y)=\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}[B_r-\stackrel{\‾}{B}]\·I_r(x,y,Z)---\left(4\right)$

Wherein, represent N number of light intensity average that N operation sheet pixel detector detects, change Z value value size, computer mould is utilized to draw up a series of reference path light intensity, a series of Recovery image can be obtained by formula (4), wherein namely the reference path distance at Recovery image optimal quality place is measuring distance, the quality of Recovery image is weighed with Y-PSNR (PSNR), the maximum corresponding reference distance of Recovery image Y-PSNR (PSNR) is namely testing distance, as shown in Figure 3.

Claims (4)

1. based on a distance measurement method for relevance imaging, it is characterized in that, specifically comprise the steps:

1) detection light path light intensity is obtained: build range measurement system light path, laser exports from laser generator, is input to collimating apparatus and corrects, be then irradiated to spatial light phase modulation panel and modulate, light modulated exports from spatial light phase modulation panel, through target object and double lens, light intensity coverlet pixel detector is collected, and sends into computing machine, simultaneous computer is assisted, export drive control signal, constantly change spatial light phase modulation panel phase place, many groups detect light path light intensity B _r;

2) analog references light path light intensity: theoretical according to Fresnel-Huygens, simulates the light intensity I in reference path corresponding to different propagation distance Z _r(x, y, Z);

3) computing imaging and range finding is associated: by step 1) and 2) gained B _rand I _r(x, y, Z) carries out related calculation, and obtains the Recovery image that a series of different reference distance Z is corresponding, and calculate the Y-PSNR of Recovery image, namely the reference distance of the maximum correspondence of Y-PSNR is measuring distance.

2. according to claim 1 based on the distance measurement method of relevance imaging, it is characterized in that, described step 1) middle detection light path light intensity B _rfor:

B _r＝∫∫I _r(x,y,L)T(x,y)dxdy

Wherein, T (x, y) represents target object, I _r(x, y, L) represents that light goes out the light intensity of defeated rear propagation distance L from spatial light phase modulation panel, constantly changes phase-plate, iterative operation N time, can detect light path light intensity B in detection light path _r.

3. according to claim 1 based on the distance measurement method of relevance imaging, it is characterized in that, described step 2) simulate the light intensity I that in reference path, different propagation distance Z place is corresponding _r(x, y, Z) is:

I _r(x,y,Z)＝|E _r(x,y,Z)| ²，

$E_r(x,y,Z)=E_r(x,y,0)\⊗h_Z(x,y),$

Wherein, h _z(x, y) represents the Fresnel propagation function of propagation distance Z in reference path, symbol represent convolutional calculation, E _r(x, y, 0) is for being irradiated to the Electric Field Distribution of the incident light before spatial light phase modulation panel, E _r(x, y, Z) exports from spatial light phase modulation panel, the Electric Field Distribution of the light after propagation distance Z.

4. according to claim 1 based on the distance measurement method of relevance imaging, it is characterized in that, described step 3) in the pixel value O (x, y) of Recovery image:

$O(x,y)=\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}[B_r-\stackrel{\‾}{B}]\·I_r(x,y,Z),$

Wherein, represent N number of light intensity average that N operation sheet pixel detector detects, change Z value value size, utilize computer mould to draw up a series of reference path light intensity, a series of Recovery image can be obtained.