CN105068083A - Vertical super-resolution imaging method for single-pixel laser radar - Google Patents

Abstract

The invention discloses a vertical super-resolution imaging method for single-pixel laser radar. An apparatus includes a pulse laser, a light beam uniform beam expander, a light modulator, an optical reception system, a single-pixel detection and data acquisition unit, and a time-delay pulse generation controller. The apparatus is simple and practical, and is simple in design. The system cost can be effectively controlled without changes or increases of system hardware. Vertical super-resolution image information of a target is obtained through a signal processing method, and vertical super-resolution imaging is conducted for a single-pixel laser imaging radar system. The method has great application prospects in the field of target detection, identification, tracking and the like.

Description

A kind of method realizing the imaging of single pixel laser radar longitudinal super resolution rate

Technical field

The present invention relates to single pixel laser imaging radar field, specifically a kind of method realizing the imaging of single pixel laser imaging radar longitudinal super resolution rate.

Background technology

At present, people obtain target object image information to detect, and often adopt area array CCD detector.And low at some wave band area array CCD detective quantum efficiency, and involve great expense.While area array CCD imaging system development, a kind of based on single pixel detector and the imaging system of no-raster device receives the concern of people, be referred to as single pixel laser imaging radar herein.This system can overcome the deficiency of ccd detector, has the advantage of cost and high imaging quality at some imaging band.When utilizing this system to carry out three-dimensional imaging, do not consider laser pulse pulsewidth, the longitudinal frame of target object image is subject to the restriction of single pixel detector and acquisition system response frequency.And target object high precision longitudinal frame image contains abundant information, there is very large application demand in fields such as target detection, identification and trackings.In order to obtain the longitudinal image of target object high resolving power, the normal method adopted is the acquisition system using high performance single pixel detector and high sampling rate.But do like this and can increase system cost, and the signal to noise ratio (S/N ratio) of detectable signal can reduce and causes image quality to decline, and this restrict the application of this imaging system.Therefore needing to design a kind of method overcomes sampling rate restriction when not changing system hardware level, obtaining target object and surmounting system longitudinal frame image.

Summary of the invention

The object of this invention is to provide a kind of method realizing the imaging of single pixel laser radar longitudinal super resolution rate, to overcome the restriction of existing single pixel laser imaging radar system sampling rate.

In order to achieve the above object, the technical solution adopted in the present invention is:

A kind of method realizing the imaging of single pixel laser radar longitudinal super resolution rate, the feature of single pixel imaging radar system is: comprise delay pulse generator controller, pulsed laser, single pixel detection and data acquisition unit, there is the optical receiving system of focussing force, the control end access delay pulsing controller of described pulsed laser, the emitting light path of pulsed laser is disposed with homogenizer beam expander, photomodulator, described single pixel detection and the photodetection face of data acquisition unit are placed on the focus place of optical receiving system, single pixel detection enters delay pulse generator controller with the sequential control termination of data acquisition unit,

Delay pulse generator controller gating pulse laser instrument emission pulse laser, the pulse laser launched of pulsed laser through homogenizer beam expander carry out uniform intensity and expand laggard enter in light path, light beam has specific two Distribution value after light modulator modulates afterwards, finally irradiates target object; The reflected light of target object, after optical receiving system focuses on, is detected by single pixel and obtains target object light intensity reflection echo signal with data acquisition unit.

A kind of described method realizing the imaging of single pixel laser radar longitudinal super resolution rate, is characterized in that: pulsed laser can be launched the light beam of narrow pulse width and have synchronizing signal output function.

A kind of described method realizing the imaging of single pixel laser radar longitudinal super resolution rate, is characterized in that: photomodulator has external trigger and the controlled function of modulation signal.

A kind of described method realizing the imaging of single pixel laser radar longitudinal super resolution rate, is characterized in that: single pixel detection has less Time delay with data acquisition unit and shakes.

A kind of described method realizing the imaging of single pixel laser radar longitudinal super resolution rate, is characterized in that: delay pulse generator controller can send the controlled and split-second precision delayed pulse trigger pip of pulsewidth.

One realizes single pixel laser radar longitudinal super resolution rate formation method, it is characterized in that: generation has the light pulse of identical two Distribution value to irradiate target object, in each gatherer process, delay pulse generator controller applies the pulse triggering signal of different delayed time successively to single pixel detection and data acquisition unit, and ensure enough large pulsewidth and can receive whole object returns signal, the signal now gathered can think the low resolution echoed signal determined by acquisition system resolution;

By the time delay low resolution echo signal data group gathered, the method that exploitation right heavy phase adds to obtain high-resolution echoed signal distance weighting information and, and the weight information of this high-resolution echoed signal and provide necessary condition for carrying out the imaging of longitudinal super resolution rate;

The modulation of light beam random binary and the collection of reflected signal are carried out in circulation, obtain organize two-value modulation intelligence, non-delayed echoed signal and and high-resolution echoed signal weight information and;

Utilize three groups of information of preserving, adopt compressed sensing algorithm can obtain reflectivity information and the super-resolution distance-reflectivity information of object;

Super-resolution distance-reflectivity information is finally adopted to obtain target object longitudinal super resolution rate image divided by reflectivity information.

Advantage of the present invention is: the present invention can on the basis of original longitudinal low resolution list pixel laser imaging radar system, do not change or increase system hardware, realize the imaging of longitudinal super resolution rate by the time delay of control system application time, be with a wide range of applications in high-resolution imaging field.

Accompanying drawing explanation

Fig. 1 is structural representation of the present invention.

Fig. 2 is that m the Time-delayed trigger with identical two Distribution value pulse laser echoed signals gathers schematic diagram.

Embodiment

As shown in Figure 1, realize a method for single pixel laser radar longitudinal super resolution rate imaging, its device comprises pulsed laser 1, homogenizer beam expander 2, photomodulator 3, optical receiving system 4, the detection of single pixel and data acquisition unit 5, delay pulse generator controller 6;

Pulsed laser 1 sends pulse laser, have larger cross-sectional distribution, and light distribution is even after homogenizer beam expander 2 is modulated;

Light beam irradiation after homogenizer beam expander 2 is on photomodulator 3, and the light beam after modulation has random binary distribution, and then modulated beam of light irradiates target object;

Target object reflected light focuses on the photodetection face of the detection of single pixel and data acquisition unit 5 through optical receiving system 4 and obtains reflection echo signal;

Delay pulse generator controller 6 controls delay pulse trigger pip to control the work schedule relation of laser instrument 1 and the detection of single pixel and data acquisition unit 5;

A kind of method realizing the imaging of single pixel laser radar longitudinal super resolution rate, produce multiple light pulse with identical two Distribution value to irradiate target object, different time time delay collection is carried out to the target object echoed signal of this multiple pulse laser, completes the collection of one group low resolve echoes signal data;

By the time delay low resolution echo signal data group gathered, the method that exploitation right heavy phase adds to obtain high-resolution echoed signal distance weighting information and, and the weight information of this high-resolution echoed signal and provide necessary condition for carrying out the imaging of longitudinal super resolution rate;

The modulation of light beam random binary and the collection of reflected signal are carried out in circulation, obtain the high-resolution echoed signal under different two-value modulation signal, preserve respectively organize two-value modulation intelligence, non-delayed echoed signal and and high-resolution echoed signal weight information and;

Utilize three groups of information of preserving, adopt compressed sensing algorithm can obtain reflectivity information and the super-resolution distance-reflectivity information of object;

Super-resolution distance-reflectivity information is finally adopted to obtain target object longitudinal super resolution rate image divided by reflectivity information.

It is the gordian technique that native system is implemented that time delays triggers, and Fig. 2 gives m the Time-delayed trigger with identical two Distribution value pulse laser echoed signals and gathers schematic diagram.Suppose in a certain modulating pulse situation, the echoed signal form that detection acquisition system obtains is I _m(i _m1, i _m2..., i _mn), do not consider the restriction of laser pulse pulsewidth, then the distance, delta z between the corresponding each little section of object is:

$\mathrm{\Δ}z=\frac{c\mathrm{\Δ}\mathrm{\τ}}{2}.---\left(1\right)$

Wherein, c is the light velocity, and Δ τ is the time response of acquisition system.Each echoed signal can think by several less section distance, delta z ' echoed signal and form, namely

$\begin{array}{c}{i}_{m1}=i_{m1}^1+i_{m1}^2+...+i_{m1}^k,\\ i_{m2}=i_{m2}^1+i_{m2}^2+...+i_{m2}^k,\\ ...\\ i_{mn}=i_{mn}^1+i_{mn}^2+...+i_{mn}^k.\end{array}---\left(2\right)$

Wherein, Δ z=k Δ z '.Obtain the echoed signal of less section, just can utilize these information to realize the imaging surmounting system longitudinal frame.

The imaging of single pixel laser imaging radar system longitudinal super resolution rate is realized in order to analyze, the time delay sequential relationship of this system is analyzed, first the laser pulse without modulation intelligence is directly launched, obtain echoed signal, according to occurring that the position of signal is as the reference moment, then same modulation intelligence is applied to multiple laser pulse, applying different delay acquisition many groups echoed signals with reference to the moment.

Suppose that time delay, the distance of Δ τ ' correspondence was Δ z ', by formula (2), can to obtain corresponding time delay under a certain specific modulation information be the echoed signal of Δ τ ' is:

$\begin{array}{c}{i}_{m1}=i_{m1}^2+...+i_{m1}^k+i_{m2}^1,\\ i_{m2}=i_{m2}^2+...+i_{m2}^k+i_{m3}^1,\\ ...\\ i_{mn}=i_{mn}^2+...+i_{mn}^k.\end{array}---\left(3\right)$

K laser pulse is carried out to the modulation of identical modulation intelligence, the detection collection that time delay spacing is Δ τ ' is carried out to each echo-pulse, then the k obtained an echoed signal I ₁(i ₁₁, i ₁₂..., i _1n), I ₂(i ₂₁, i ₂₂..., i _2n) ..., I _k(i _k1, i _k2..., i _kn) can be expressed as:

$\begin{array}{c}{i}_{11}=i_{11}^1+i_{11}^2+...+i_{11}^k,\\ i_{12}=i_{12}^1+i_{12}^2+...+i_{12}^k,\\ ...\\ i_{1n}=i_{1n}^1+i_{1n}^2+...+i_{1n}^k.\end{array}\begin{array}{c}{i}_{21}=i_{11}^2+...+i_{11}^k+i_{12}^1,\\ i_{22}=i_{12}^2+...+i_{12}^k+i_{13}^1,\\ ...\\ i_{2n}=i_{1n}^2+...+i_{1n}^k.\end{array}....\begin{array}{c}{i}_{k1}=i_{11}^k+i_{12}^1+...+i_{12}^{k-1},\\ i_{k2}=i_{12}^k+i_{13}^1+...+i_{13}^{k-1},\\ ...\\ i_{kn}=i_{1n}^k.\end{array}---\left(4\right)$

Take advantage of corresponding time weighting to the respective items of k the echoed signal obtained, can obtain representation is:

$\begin{array}{c}{\mathrm{\αi}}_{11}=\mathrm{\α}(i_{11}^1+i_{11}^2+...+i_{11}^k),\\ 2{\mathrm{\αi}}_{12}=\mathrm{\α}(i_{12}^1+i_{12}^2+...+i_{12}^k),\\ ...\\ {\mathrm{n\αi}}_{1n}=n\mathrm{\α}(i_{1n}^1+i_{1n}^2+...+i_{1n}^k).\end{array}\begin{array}{c}{\mathrm{\αi}}_{21}=\mathrm{\α}(i_{11}^2+...+i_{11}^k+i_{12}^1),\\ 2{\mathrm{\αi}}_{22}=2\mathrm{\α}(i_{12}^2+...+i_{12}^k+i_{13}^1),\\ ...\\ {\mathrm{n\αi}}_{2n}=n\mathrm{\α}(i_{1n}^2+...+i_{1n}^k).\end{array}.\begin{array}{c}{\mathrm{\αi}}_{k1}=\mathrm{\α}(i_{11}^k+i_{12}^1+...+i_{12}^{k-1}),\\ 2{\mathrm{\αi}}_{k2}=2\mathrm{\α}(i_{12}^k+i_{13}^1+...+i_{13}^{k-1}),\\ ...\\ {\mathrm{n\αi}}_{kn}={\mathrm{n\αi}}_{1n}^k.\end{array}---\left(5\right)$

Wherein, the parameter that parameter alpha is relevant with temporal resolution.Carry out accumulation operations to above formula can obtain:

$IQ={\mathrm{\αi}}_{11}^1+2{\mathrm{\αi}}_{11}^2...+{\mathrm{kn\α}}_{1n}^k,---\left(9\right)$

Can finding out that high resolving power echoed signal has all carried out corresponding time weighting process by above formula, providing effective information for carrying out object longitudinal super resolution rate information recovery.This is the result obtained under a certain modulation intelligence, and the result changed under modulation intelligence acquisition t group different modulating information is:

IQ＝[IQ ₁,IQ ₂,...,IQ _t]。(10)

According to known modulation intelligence B=[B ₁, B ₂..., B _t], can obtain equation is:

IQ ^T＝B ^TO _DR，(11)

Utilize compressed sensing algorithm to calculate above formula, object information O can be obtained _dRbut what obtain due to system is the total echoed signal of object, so O _dRbe the mixed information containing Distance geometry object reflectance, need to remove reflectivity information for this reason inside the mixed information obtained, obtain longitudinal super resolution rate information.O _dRcan be equivalent to:

O _dR=O _d* O _r, (12) wherein, O _rfor the reflectivity information of object, O _dfor the longitudinal super resolution rate information of object.Simple image division arithmetic can be adopted to obtain the longitudinal super resolution rate information of object for this reason:

O _d=(O _dR/ O _r) mask (O _r), (13) wherein, mask in order to avoid except zero situation limit, it is the two values matrix of [0,1], works as O _rbe 1 during element non-zero, otherwise be 0.And the reflectivity information of object can utilize non-delayed echoed signal, utilize conventional method to obtain.

Obviously, those skilled in the art can by changing longitudinal super resolution rate list pixel laser imaging radar involved in the present invention and modification and do not depart from the spirit and scope of the present invention.Like this, if these amendments and variation belong within the scope of the claims in the present invention and equivalent technologies thereof, then the present invention is also intended to comprise these amendment and modification.

Claims (6)

1. one kind realizes the method for single pixel laser radar longitudinal super resolution rate imaging, it is characterized in that: comprise delay pulse generator controller, pulsed laser, single pixel detection and data acquisition unit, there is the optical receiving system of focussing force, the control end access delay pulsing controller of described pulsed laser, the emitting light path of pulsed laser is disposed with homogenizer beam expander, photomodulator, described single pixel detection and the photodetection face in data acquisition unit are placed on the focus place of optical receiving system, single pixel detection enters delay pulse generator controller with the sequential control termination of data acquisition unit,

Delay pulse generator controller gating pulse laser instrument emission pulse laser, the pulse laser launched of pulsed laser through homogenizer beam expander carry out uniform intensity and expand laggard enter in light path, light beam has specific two Distribution value after light modulator modulates afterwards, finally irradiates target object; The reflected light of target object, after optical receiving system focuses on, is detected by single pixel and obtains target object light intensity reflection echo signal with data acquisition unit.

2. a kind of method realizing the imaging of single pixel laser radar longitudinal super resolution rate according to claim 1, is characterized in that: pulsed laser can be launched the light beam of narrow pulse width and have synchronizing signal output function.

3. a kind of method realizing the imaging of single pixel laser radar longitudinal super resolution rate according to claim 1, is characterized in that: photomodulator has external trigger and the controlled function of modulation signal.

4. a kind of method realizing the imaging of single pixel laser radar longitudinal super resolution rate according to claim 1, is characterized in that: single pixel detection has less Time delay with data acquisition unit and shakes.

5. a kind of method realizing the imaging of single pixel laser radar longitudinal super resolution rate according to claim 1, is characterized in that: delay pulse generator controller can send the controlled and split-second precision delayed pulse trigger pip of pulsewidth.

6. one kind based on realization according to claim 1 single pixel laser radar longitudinal super resolution rate formation method, it is characterized in that: produce multiple light pulse with identical two Distribution value to irradiate target object, in each gatherer process, delay pulse generator controller applies the pulse triggering signal of different delayed time successively to single pixel detection and data acquisition unit, and ensure enough large pulsewidth and can receive whole object returns signal, the signal now gathered can think the low resolution echoed signal determined by acquisition system resolution;

By the time delay low resolution echo signal data group gathered, the method that exploitation right heavy phase adds to obtain high-resolution echoed signal distance weighting information and, and the weight information of this high-resolution echoed signal and provide necessary condition for carrying out the imaging of longitudinal super resolution rate;

The modulation of light beam random binary and the collection of reflected signal are carried out in circulation, obtain organize two-value modulation intelligence, non-delayed echoed signal and and high-resolution echoed signal weight information and;

Utilize three groups of information of preserving, adopt compressed sensing algorithm can obtain reflectivity information and the super-resolution distance-reflectivity information of object;

Super-resolution distance-reflectivity information is finally adopted to obtain target object longitudinal super resolution rate image divided by reflectivity information.