CN103983980B - A kind of variable resolution laser three-dimensional imaging array design methodology - Google Patents

Abstract

The present invention relates to a kind of variable resolution laser three-dimensional imaging array design methodology, belong to laser three-D array image-forming technical field.The inventive method is by selecting multiple circular light electric explorer, form annular three-dimensional imaging array structure: each annular detector array comprises N number of detector, the detector of same annular detector array is identical, and the detector of each annular detector array is different; In same ring, adjacent two detectors are tangent, and the center of circle of N number of detector is positioned on same annulus; The detector one_to_one corresponding of adjacent two annular detector arrays is tangent.And the parameter detector computing formula of annular three-dimensional imaging array is proposed, the imaging array obtained can adopt space-variant system mode to sample to target, takes into account Large visual angle and high resolving power advantage.

Description

A Design Method of Variable Resolution Laser 3D Imaging Array

technical field

The invention relates to a design method of a laser three-dimensional imaging array with variable resolution, belonging to the technical field of laser three-dimensional array imaging.

Background technique

Compared with traditional two-dimensional image sensors, laser three-dimensional array imaging can not only provide target intensity images, but also provide target distance information, so the description of the target is richer and more accurate. At the same time, laser three-dimensional array imaging also has the advantages of strong anti-interference ability and high resolution, so it can be widely used in machine vision, image monitoring, intelligent navigation and other fields. At present, laser three-dimensional array imaging methods include scanning and non-scanning. Although the scanning method can be used for high-resolution imaging, the scanning mechanism restricts system integration and the imaging efficiency is low; area array imaging mainly relies on detectors with the same size to image the target. Although the imaging efficiency is high, the imaging resolution is a fixed value. Usually, not all images in the field of view are the region of interest. Therefore, constant resolution imaging will lead to data redundancy and fail to effectively utilize high-sensitivity detectors. Valid pixels of the array.

Contents of the invention

The purpose of the present invention is to solve the above-mentioned problems, and propose a variable resolution laser three-dimensional imaging array design method, which can optimize the structural layout and parameters of the detector according to typical design indicators, so as to complete the variable resolution laser 3D imaging.

A variable resolution laser three-dimensional imaging array design method is realized through the following technical solutions:

In step 1, a plurality of circular photodetectors are selected to form a ring-shaped three-dimensional imaging array, and the specific structure is:

The annular three-dimensional imaging array includes multiple concentric annular detector arrays, each annular detector array includes N detectors, the detectors of the same annular detector array are the same, and the detectors of each annular detector array are different. In the same ring, two adjacent detectors are tangent, and the centers of N detectors are located on the same ring. The detectors of two adjacent circular detector arrays are in one-to-one correspondence with each other.

Step 2, the detector parameters of the ring-shaped three-dimensional imaging array described in step 1 satisfy the following formula:

Among them, f is the focal length of the receiving optical system, r _max is the maximum radius of the annular three-dimensional imaging array structure, is the field angle of the annular 3D imaging array, D ₁ is the diameter of a single detector in the first ring of the annular 3D imaging array, R is the target distance, l is the resolution of the object space, M is the ring number of the annular 3D imaging array, and N is The number of detectors per ring, Represents the upward and downward rounding, r ₀ is the radius of the blind hole, q is the inter-ring growth coefficient, r ₁ is the radius of the ring where the first ring detector is located, D _i is the diameter of a single detector in the i-th ring, r _i is the radius of the ring where the i-th ring detector is located, P _r '(t) is the received power of a single detector in the first ring, E(t) is the pulse energy of the transmitting optical system, τ _r is the echo pulse width, ρ _r is the diffuse emission coefficient of the target, At is the irradiation area at the target, D _r is the aperture of the receiving system of the annular three-dimensional imaging array, _{η D} is the detection efficiency of the annular three-dimensional imaging array, T _a is the one-way atmospheric transmission coefficient, T _o is the optical system efficiency of echo reception.

The designed detector parameters are required to satisfy the boundary condition P _r '(t)≥P _rmin . Among them, P _rmin is the minimum detectable power of a single detector.

Beneficial effect

A variable-resolution laser three-dimensional imaging array design method proposed by the present invention can obtain a complete set of detector parameters through simple parameter input, reducing the design cycle; Large field of view and high resolution advantages.

Description of drawings

Fig. 1 is a detector array structural diagram of the present invention;

Fig. 2 is a detector structure parameter diagram of the present invention;

Fig. 3 is the parameter solution flowchart of the present invention;

Fig. 4 is the solution process figure of the embodiment of the present invention;

Fig. 5 is a structural diagram of a typical parameter detector array in a specific embodiment of the present invention.

detailed description

Specific embodiments of the present invention will be described below in conjunction with the accompanying drawings.

As shown in Figure 1, a variable resolution laser three-dimensional imaging array of the present invention is realized by designing a circularly arranged detector array, the structural parameters of the detector array are shown in Figure 2, and the parameters include: the diameter of the first ring detector D _1. The second ring detector diameter D ₂ , the i-th ring detector diameter D _i , the M-th ring detector diameter D _M , the blind hole radius r ₀ , the first ring detector radius r ₁ , the second ring detector The radius r ₂ , the i-th ring detector radius r _i , the M-th ring detector radius r _M , and the maximum structure radius r _max . The solution method is shown in Figure 3, and the specific parameter settings are shown in Figure 4, which are described as follows:

Step 1: Input typical design indicators.

Typical design indicators include object space resolution l, target distance R, field of view Structure maximum radius r _max .

Step 2: Set the initial parameters.

The initial parameter is arbitrarily set as blind hole radius r ₀ , r ₀ <r _max .

Step 3: Set boundary conditions.

The boundary condition is the minimum detectable power P _rmin of the detector.

Step 4: Form the target parameters.

The target parameters include the number M of rings of the detector array, and each ring includes the number N of detectors.

Step five: process optimization.

Process optimization is the process of obtaining the target parameters, and the specific steps are as follows:

Step 5.1, find the focal length f of the receiving optical system

In the known parameters r _max , On the basis of using the following formula to obtain

Step 5.2, calculate the detector diameter D ₁ of the first ring detector

Substituting the result in step 5.1 into the following formula, D ₁ can be obtained

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; l</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}$

In step 5.3, calculate the number N of detectors in each ring. Considering the actual situation, it should be rounded up:

Step 5.4, calculate the inter-ring growth coefficient q

In step 5.5, calculate the ring number M of the detector array. Considering the actual situation, it should be rounded down:

Step 5.6, calculate the power of the detector in the innermost ring

Step 6: Determine whether the target parameters meet the design indicators

Compare the obtained P'r(t) with the minimum detectable power P _rmin , if the boundary condition P _r '(t)≥P _rmin is met, then enter the seventh step, if the boundary condition is not satisfied, change the radius of the blind hole r ₀ re-enter step 5.3 until the boundary conditions are satisfied.

Step 7: Output structure parameters.

The parameters obtained through the above steps are substituted into the following formula to obtain the diameter D _i of the i-th ring detector and the radius r _i of the ring where the i-th ring detector is located:

${\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}$

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; q</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; q</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\end{array}\right.<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; m</span>}$

The final output structure parameters include: focal length f of the receiving system, number of rings M, number of detectors included in each ring N, inter-ring growth factor q, blind hole radius r ₀ , detector diameter D _i of the i-th ring, detection of the i-th ring From the radius r _i of the ring where the detector is located, the structural parameters of the entire detector array are obtained.

In this embodiment, the initial input parameters are set as follows:

R=200m, l = 10 mm, r _max = 100 mm, r ₀ = 0.5 mm, λ = 905 nm, E _t = 100 mJ, D _r = 50 mm, T _o = 0.9, T _a = 0.7, ρ _r = 0.6, P _rmin = 3nW.

After the above solution, the parameters of the detector array are as follows:

f=336mm, M=29, N=40, q=1.17, r ₀ =1 mm, r ₁ =1.1 mm, r _i =1.1×1.2 ^i-1 (i=2,3,...,30), D ₁ =0.17 mm, D _i =0.17×1.27 ⁱ⁻¹ (i=2, 3, . . . , 30).

The detector array structure generated by this structure is shown in Fig. 5 .

The above are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (2)

1. A variable resolution laser three-dimensional imaging array design method is characterized in that: a plurality of circular photodetectors are selected to form an annular three-dimensional imaging array, and the specific structure is: The annular three-dimensional imaging array includes a plurality of concentric annular detector arrays, each annular detector array includes N detectors, the detectors of the same annular detector array are the same, and the detectors of each annular detector array are different; the same ring Among them, two adjacent detectors are tangent, and the centers of N detectors are located on the same ring; the detectors of two adjacent annular detector arrays are tangent to one another; The detector parameters of the annular three-dimensional imaging array satisfy the following formula: Among them, f is the focal length of the receiving optical system, r _max is the maximum radius of the annular three-dimensional imaging array structure, is the field angle of the annular 3D imaging array, D ₁ is the diameter of a single detector in the first ring of the annular 3D imaging array, R is the target distance, l is the resolution of the object space, M is the ring number of the annular 3D imaging array, and N is The number of detectors per ring, Represents the upward and downward rounding, r ₀ is the radius of the blind hole, q is the inter-ring growth coefficient, r ₁ is the radius of the ring where the first ring detector is located, D _i is the diameter of a single detector in the i-th ring, r _i is the radius of the ring where the i-th ring detector is located, P _r '(t) is the received power of a single detector in the first ring, E(t) is the pulse energy of the transmitting optical system, τ _r is the echo pulse width, ρ _r is the diffuse emission coefficient of the target, At is the irradiation area at the target, D _r is the aperture of the receiving system of the annular three-dimensional imaging array, _{η D} is the detection efficiency of the annular three-dimensional imaging array, T _a is the one-way atmospheric transmission coefficient, T _o is the optical system efficiency of echo reception. 2. a kind of variable resolution laser three-dimensional imaging array design method according to claim 1, is characterized in that: the detector parameter that design obtains is required to satisfy boundary condition P _r '(t) ≥ P _rmin ; Wherein, P _rmin is The minimum detectable power of a single detector.