CN106405566A - High-measurement-precision laser radar distance measurement method - Google Patents

Abstract

The invention discloses a high-measurement-precision laser radar distance measurement method, and relates to the technical field of laser distance measurement. The method comprises the following steps that the actual distance d0 of a target object corresponding to a first photoelectric imager imaging position X0 and the actual distance d1 of the target object corresponding to a second photoelectric imager imaging position X1 are acquired by using a standard measurement instrument, (X0, d0) and (X1, d1) act as calibration point pair data, and X is the actual laser position value; and the actual distance d corresponding to the unknown actual laser position X is acquired through an approximation method. According to the method, a reasonable calibration point matrix is arranged so that the influence of laser lens distortion and the influence of certain devices can be avoided, distance measurement is performed by only depending on the calibration data and distance measurement is more accurate.

Description

The high laser radar range method of certainty of measurement

Technical field

The present invention relates to laser ranging technique field, more particularly, to one kind can accurately calculate the actual measurement of laser radar The method of distance.

Background technology

Triangle telemetry is that light source, tested object plane, 3 points of optical receiver system collectively form a triangle light path, by laser The light that device sends, incides on testee surface after plus lens focuses on, and optical receiver system receives and is derived from incidence point The scattered light at place, and be imaged on photoelectric position detector sensitive area, measured by displacement on imaging surface for the luminous point A kind of measuring method of tested object plane displacement.Single-point type laser triangulation can be divided into direct-injection type and two kinds of knots of oblique fire formula Structure, how light source and optical receiver system are arranged mainly flexibly is selected by the requirement of test target, measuring system construction etc..

Using oblique fire formula laser triangulation method, principle is as shown in Figure 1.The parallel rayies of laser instrument transmitting, through overconvergence Form light beam, this beam orthogonal is mapped to testee surface after lens focuss.The relative movement of target face to be measured or its surface Change all can lead to the received vertical lens of scattered light that incident luminous point moves forward and backward Laser Measurement along incident light axis to be irradiated to light If incident luminous point defines displacement x in photoelectronic imaging device on electric position detector, then target face to be measured axially relative Displacement is d.According to triangle telemetry position relationship we can calculate the value of d according to following formula:

In formula:

S- incidence luminous point and receiving lens enter the distance of luminous point;

F- receiving lens enter luminous point to the vertical dimension of imaging surface;

β-incident laser optical axis and the angle of receiving lens optical axis.

Explanation：Principle above is the standard principle of laser triangulation, and the parameter of needs has f（Lens focus）, s（Mirror Head photocentre is to the distance of laser center）, β（Laser rays and photocentre away from angle）；And the numerical value of s, β can not obtain in these parameters To being accurately worth very much, along with optical lens have distortion, therefore, it is can not to be effectively tested device to arrive using above-mentioned scheme The distance of object.

Content of the invention

The technical problem to be solved is a kind of laser radar range method providing certainty of measurement high, by institute The distance stating method calculating is more accurate.

For solving above-mentioned technical problem, the technical solution used in the present invention is：A kind of high laser radar of certainty of measurement Distance-finding method is it is characterised in that methods described comprises the steps：

Obtain the first photoelectronic imaging device image space X using SMI₀Corresponding target object actual range be d0 with And the second photoelectronic imaging device image space X₁Corresponding target object actual range is d1, will（X₀, d0）With（X₁, d1）As mark To data, X is actual laser positions value to fixed point；

Unknown actual laser position X corresponding target object actual range d is obtained by approximatioss：

The weights of d0 are, the weights of d1 are.

Further technical scheme is：Between 2 points that unknown point X must fall in nominal data；Unknown point X from X₀、X₁In that put nearer, weights are bigger.

Further technical scheme is：Demarcation is processed using 5 field smoothing techniques with image, and processing method is as follows：

.

Further technical scheme is：Pixel in demarcation image is finely divided, and increases the explanation degree of image, is swashing In ligh-ranging module, each pixel is changed into 10 pixels,

The parameter of location of pixels 0 has X0（Positional value）, Val0 (positional value), the parameter of location of pixels 1 has X1（Positional value）、Val1 （Positional value）, threshold value is valThreshold, then difference formula is as follows：

Right boundary is asked for by calculus of finite differences and asks for crest location, that is, crest location is the center of right boundary.

Have the beneficial effects that using produced by technique scheme：This method avoid the shadow of laser instrument lens distortion Ring, and the impact of some devices, rely solely on nominal data and found range, range measurement is more accurate.

Additionally, processing to image by using 5 field smoothing techniques, eliminate the excessive and how little pixel of brightness Point, image is smoothened, is conducive to the extraction of image object point；Because laser eyepiece point assumes symmetry（Normal distribution）, ripple There is very big noise it is impossible to effectively obtain crest value in peak position, therefore ask for right boundary by calculus of finite differences and ask for ripple Peak position, that is, crest location is the center of right boundary.

Brief description

The present invention is further detailed explanation with reference to the accompanying drawings and detailed description.

Fig. 1 is laser instrument principle of triangulation figure；

Fig. 2 is that laser instrument approaches telemetry schematic diagram；

Fig. 3 is that pixel target optimizes structure chart；

Fig. 4 is the principle assumption diagram of two points of look-up tables；

Wherein：1st, laser instrument；2nd, photoelectronic imaging device；3rd, location of pixels 0；4th, location of pixels 1；5th, starting point；6th, end point； 7th, target object.

Specific embodiment

With reference to the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete Ground description is it is clear that described embodiment is only a part of embodiment of the present invention, rather than whole embodiments.It is based on Embodiment in the present invention, it is every other that those of ordinary skill in the art are obtained under the premise of not making creative work Embodiment, broadly falls into the scope of protection of the invention.

Elaborate a lot of details in the following description in order to fully understand the present invention, but the present invention is acceptable To be implemented different from alternate manner described here using other, those skilled in the art can be without prejudice to intension of the present invention In the case of do similar popularization, therefore the present invention is not limited by following public specific embodiment.

As shown in Fig. 2 the embodiment of the invention discloses a kind of high laser radar range method of certainty of measurement, specifically including Following steps：

Laser Measurement reflects through object, in the image space X of photoelectronic imaging device.By the point pair demarcated（X, d）, by forcing Nearly method principle, obtains the actual range d of object.

Approach X0 corresponding target object actual range d0 in telemetry schematic diagram, x1 corresponding target object actual range For d1,（X0, d0）With（X1, d1）For fixed point to data, X is actual laser position value, we can according to approximatioss Lai Obtain the value of d：

Approximatioss principle is that distance is nearer, and weights are bigger, and the weights of d0 are, the weights of d1 are.

Explanation：Above-mentioned method, referred to as approximatioss are it is simply that use SMI（As grating scale）, obtain one group Impact point under known distanceRespectively in correspondence image, referred to as nominal data（,）.Logical Cross above-mentioned formula acquisition unknown point X apart from d, as follows：

1) unknown point X must fall the interval of 2 points in nominal data, such as A, B；

2) unknown point X is put close to more from that in A, B, and weights are bigger；（Unknown point X to A, B apart from weights, distance nearer, Weights are bigger）

3) utilize distance、, and 2）Weights in step、, obtain calculate unknown point X apart from d；

The method passes through that setting is rational to demarcate dot matrix, it is to avoid the impact of lens distortion, and the impact of some devices, only Nominal data is relied on to be found range.

Image optimization:

Image aspect has done 5 field smoothing techniques, and its method is as follows：

After said method, image eliminates miscellaneous point, as follows：

1) eliminate the excessive pixel of brightness；

2) eliminate the too small pixel of brightness；

Therefore, image is smoothened, is conducive to the extraction of image object point；

Pixel target optimizes:

Calculus of finite differences, it is simply that being finely divided each pixel, increased the explanation degree of image, in laser ranging module, we are right Similar carried out 10 deciles, that is, be equivalent to and each pixel changed into 10 pixels.The schematic diagram of calculus of finite differences such as Fig. 3：

The parameter of location of pixels 0 has X0（Positional value）, Val0 (positional value), the parameter of location of pixels 1 has X1（Positional value）、Val1 （Positional value）, threshold value is valThreshold, then difference formula is as follows：

Because laser eyepiece point assumes symmetry（Normal distribution）, the very big noise of crest location presence is it is impossible to effectively obtain Crest value, therefore asks for right boundary by calculus of finite differences and asks for crest location, and that is, crest location is the center of right boundary；

Nominal data carries out ascending order arrangement, and two way classification can rapidly search and obtain the distance of target；

After the peak obtaining laser, just pixel value need to be converted to distance value, due to adopting approximatioss, mutually use therewith The corresponding two points of look-up tables of nominal data, greatly accelerate the time of process.

The principle of two way classification is as shown in Figure 4：

By two way classification, in the distance conversion in laser ranging（Pixel value is converted to distance value）, the handling process of two way classification As follows：

1) obtain the middle sequence number of traversal, 5 is begin position, and 6 is end position；

2) when desired value is less than mid value,, repeat step 1,2；

3) when desired value is more than mid value,, repeat step 1,2,3；

When target meets mid value, two way classification terminates.

Claims (4)

1. a kind of high laser radar range method of certainty of measurement is it is characterised in that methods described comprises the steps：

Obtain the first photoelectronic imaging device image space X using SMI₀Corresponding target object actual range be d0 and Second photoelectronic imaging device image space X₁Corresponding target object actual range is d1, will（X₀, d0）With（X₁, d1）As demarcation To data, X is actual laser positions value to point；

Unknown actual laser position X corresponding target object actual range d is obtained by approximatioss：

The weights of d0 are, the weights of d1 are.

2. the high laser radar range method of certainty of measurement as claimed in claim 1 it is characterised in that：Unknown point X must fall Between 2 points in nominal data；Unknown point X is from X₀、X₁In that put nearer, weights are bigger.

3. the high laser radar range method of certainty of measurement as claimed in claim 1 is it is characterised in that demarcation image adopts 5 field smoothing techniques are processed, and processing method is as follows：

.

4. the high laser radar range method of certainty of measurement as claimed in claim 1 is it is characterised in that in demarcation image Pixel is finely divided, and increases the explanation degree of image, in laser ranging module, each pixel is changed into 10 pixels,

The parameter of location of pixels 0 has X0（Positional value）, Val0 (positional value), the parameter of location of pixels 1 has X1（Positional value）、Val1 （Positional value）, threshold value is valThreshold, then difference formula is as follows：

Right boundary is asked for by calculus of finite differences and asks for crest location, that is, crest location is the center of right boundary.