CN112269161A

CN112269161A - Optical space positioning system and space positioning method thereof

Info

Publication number: CN112269161A
Application number: CN202010933075.0A
Authority: CN
Inventors: 杨建明; 屠晓伟; 杨庆华
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2020-09-08
Filing date: 2020-09-08
Publication date: 2021-01-26
Anticipated expiration: 2040-09-08
Also published as: CN112269161B

Abstract

The invention discloses an optical space positioning system and a space positioning method thereof. The system of the invention consists of at least three groups of detection units consisting of tyre tread lenses and linear array photosensitive elements. The tire tread lens converges light rays emitted by a point light source in the space into a linear shape, and the linear array light sensitive element is received by the linear array light sensitive element, and the linear array light sensitive element is positioned in the surrounding center of the tire tread lens; the detection units consisting of at least three tire tread lenses and linear array photosensitive elements are arranged in a non-parallel mode in space, and the position of the spatial point light source relative to the detector is calculated by obtaining the position coordinates of the intersection point of light emitted by the point light source in the space and the linear array photosensitive elements in each detection unit. The invention can realize the high-precision detection function of large-range spatial positions and has low cost. The invention belongs to the field of space positioning.

Description

Optical space positioning system and space positioning method thereof

Technical Field

The invention relates to a novel configuration space positioning system and a space positioning method thereof, belonging to the field of optical engineering and sensing.

Background

The positioning technology is mainly divided into indoor and outdoor in terms of application scenes, and currently, outdoor positioning mainly adopts satellite-dependent technologies such as GPS or Beidou. The positioning accuracy error of this technique is generally 3m or more, and most of the requirements can be satisfied, but for positioning requiring higher accuracy, it is necessary to rely on other techniques. In indoor location, because there is generally no GPS signal, mainly adopt techniques such as WIFI, bluetooth, Zigbee and UWB, but positioning accuracy hardly reaches millimeter level.

The ultra-high precision positioning technology mainly adopts a photoelectric detection mode, namely, the positioning technology is formed by combining at least three linear array CCD or CMOS photoelectric sensors and a cylindrical lens group, light spots in a space are converged into a line on the photoelectric sensor in each detection unit after passing through the cylindrical lens, and the position of the line is recorded by the photoelectric sensor. The three position information can be equivalent to three planes that intersect at a point in space, the position of which is the spot position. Thus, by obtaining the positions on the three photosensors, the positional information of the light spot in space can be calculated.

However, the conventional cylindrical lens group has a small field angle, generally the full field angle does not exceed 50 °, and the combination of a plurality of spherical lenses and cylindrical lenses is required to realize the function of converging into a line, which is heavy and high in cost. The invention adopts the toroidal lens, can realize the detection range of more than 120 degrees, and has light weight and low cost.

Disclosure of Invention

The invention aims to solve the problems of small detection range and heaviness of the existing photoelectric position detector, provides an optical space positioning system and a space positioning method thereof, can realize high-precision positioning in a detection range of more than 120 degrees, and solves the problems of small field angle and heaviness of the existing photoelectric position detection.

In order to achieve the purpose, the invention has the following conception:

the light-sensitive center of the linear array photosensitive element is positioned on the rotating central shaft of the toroid, each group of the toroidal lenses and the linear array photosensitive element form a detection unit, light rays emitted by a light spot in a space are converged on the linear array photosensitive element after penetrating through the toroidal lenses, the photosensitive point and a toroidal equivalent line form a conical surface, three conical surfaces can be formed through the three detection units, the conical surfaces can meet at a point in the space, and the point is the position of the detection light spot.

According to the inventive concept, the invention adopts the following technical scheme:

a space positioning system comprises a toroidal lens and linear array photosensitive elements, wherein the toroidal lens and the linear array photosensitive elements form a detection unit, at least three detection units are distributed at different positions in space, and the direction of the linear array photosensitive elements in at least one unit is not parallel to the direction of the linear array photosensitive elements in other units, so that a complete space positioning system is formed.

Preferably, the toroidal lens has two optical surfaces, each of which has a center of rotation as a center of the line photosensitive element, and a combination of the two optical surfaces can focus a light beam onto the line photosensitive element, which is composed of micron-sized photosensitive pixels arranged in a straight line. CCD or CMOS is preferably adopted, and photosensitive pixels are preferably arranged in a column; or the photosensitive pixels are preferably a plurality of columns of at least two columns, and when constituted by a plurality of columns, data of the middle part of the columns is taken as a calculation element.

Preferably, the toroidal lens is composed of one lens, or two toroidal lenses in combination, or more than two toroidal lenses, wherein each toroidal lens takes the photosensitive center of the linear array photosensitive element as the rotation center, and the configuration has the advantage of maintaining the rotational symmetry of the system, so that all directions perpendicular to the rotation axis are kept consistent, thereby realizing the increase of the detection range without increasing the size of the light spot converged on the photosensitive element.

Preferably, on the cross section of the toroidal rotating shaft, the combination of the optical surfaces of the toroidal lens can focus a light beam onto the linear array photosensitive element, so that the photosensitive element detects light energy, wherein the light beam is emitted by a detected light spot, the distance range of the detected light spot from the toroidal lens is different along with the difference of the optical surface type, preferably 1 meter to infinity or 10 cm to 100 cm, and in a specified detection range, the toroidal lens needs to converge the light emitted by the light spot to a micron-sized size, so as to achieve the purpose of accurate positioning.

The optical space positioning system can not only realize optical space positioning by detecting in a small range of angles smaller than 120 degrees. It is particularly preferred that the optical spatial localization system of the present invention is adapted to perform localization operations within a detection range up to or exceeding 120 °. Therefore, the optical space positioning system has wider adaptability in detection range angles, has diversified detection ranges, and has unique advantages of positioning operation in a detection range exceeding 120 degrees.

A method for realizing space positioning by using the space positioning system of the invention realizes positioning by the following method:

step one, enabling the toroidal lens to be equivalent to a section of equivalent circular arc, obtaining the position of a pixel point of the linear array photosensitive element illuminated by light, and enabling the pixel point and the equivalent circular arc to form a conical surface;

step two, at least three conical surfaces intersect at one point in space; and calculating the position of the point by solving a conical surface equation set, namely the position of the detected point.

The necessary condition that the three conical surfaces need to intersect at one point is that the directions of the linear array photosensitive elements cannot be completely parallel, and when more than three detection units are arranged, combination can be increased to obtain more measurement data so as to improve the detection precision.

Compared with the prior art, the invention has the following obvious prominent substantive characteristics and remarkable technical progress:

1. the invention keeps rotational symmetry through the combination of the toroidal lens and the linear array photosensitive element, and can realize accurate position detection of spatial position in a range of more than 120 degrees;

2. the number of lenses used by each group of photosensitive members is greatly reduced, such as from the previous 6-7 lenses to only one lens, so that the complexity and the cost of the system are reduced, and the weight of the system is also reduced.

Drawings

Fig. 1a is a schematic diagram of a cross-sectional light ray passing through a rotating center of a toroid when a single toroidal lens is adopted as a detection unit, and fig. 1b is a top view of a light path of the detection unit.

Fig. 2a is a schematic diagram of a cross-sectional light ray passing through a rotating center of a toroid when two toroidal lenses are used as the detection unit in fig. 2, and fig. 2b is a top view of a light path of the detection unit.

Fig. 3 is a schematic diagram of a toroidal lens and a pixel in a detection unit forming a cone.

Fig. 4a is a schematic diagram of three cones locating a point, and fig. 4b is a schematic diagram of four cones meeting at a point.

Fig. 5 shows an arrangement of three detecting units centered on the same line.

Fig. 6 shows an arrangement of three detecting units in an isosceles triangle.

Fig. 7 shows a square arrangement of four detection units.

Wherein: 1. the lens comprises 1-1-1 parts of a toroidal lens, 1-1-2 parts of a front surface of the toroidal lens, 1-1-3 parts of a rear surface of the toroidal lens, 1-1-4 parts of a non-optical surface of the toroidal lens, an equivalent circle of the toroidal lens, 1-2 parts of a first toroidal lens, 1-2-1 parts of a front surface of the first toroidal lens, 1-2-2 parts of a rear surface of the first toroidal lens, 1-3 parts of a second toroidal lens, 1-3-1 parts of a front surface of the second toroidal lens, 1-3-2 parts of a rear surface of the second toroidal lens, 2 parts of a linear array photosensitive element.

Detailed Description

The present invention will be described in further detail with reference to preferred embodiments in conjunction with the accompanying drawings. The specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention.

The first embodiment is as follows:

referring to fig. 1, an optical spatial positioning system includes a toroidal lens 1 and linear array photosensitive elements 2, where the toroidal lens 1 and the linear array photosensitive elements 2 form a detection unit, and at least three detection units are distributed at different positions in a space, and a direction of the linear array photosensitive element 2 in at least one unit is not parallel to a direction of the linear array photosensitive elements 2 in other units, so as to form a complete spatial positioning system.

The optical space positioning system of the embodiment can perform positioning operation in a detection range including a small range of angles and is also suitable for a large range of angles. Therefore, the optical space positioning system of the embodiment has wider adaptability in the detection range angle. Meanwhile, the optical space positioning system can particularly realize high-precision positioning in a larger detection range, and solves the problems of small field angle and heaviness of the conventional photoelectric position detection.

Example two:

this embodiment is substantially the same as the first embodiment, and is characterized in that:

in this embodiment, the toroidal lens has two optical surfaces, each of which uses the center of the linear array photosensitive element 2 as a rotation center, and the combination of the two optical surfaces can focus a light beam onto the linear array photosensitive element 2, and the linear array photosensitive element 2 is formed by arranging micron-sized photosensitive pixels in a straight line.

In the present embodiment, the toroidal lens 1 is composed of one lens, or two toroidal lenses 1-2 and 1-3, or more than two toroidal lenses, wherein each toroidal lens has a center of rotation of the line photosensitive element 2.

In this embodiment, the combination of the optical surfaces of the toroidal lens 1 is capable of focusing a light beam onto the line photosensitive element 2.

The optical space positioning system of the present embodiment is not only capable of detecting angles in a small range, but is particularly suitable for performing positioning operations in a small range of angles smaller than 120 ° or in a detection range up to or exceeding 120 °. Therefore, the optical space positioning system of the embodiment has wider adaptability in the detection range angle, and has unique advantages particularly in the detection range of reaching or exceeding 120 degrees for positioning operation.

In the embodiment, the combination of the toroidal lens and the linear array photosensitive element maintains rotational symmetry, and especially, the accurate position detection of a wider space position can be realized; the number of lenses used in each set of photosensitive members is greatly reduced, for example, from the previous 6-7 lenses to only one lens, so that the complexity and cost of the system are reduced, and the weight of the system is also reduced.

Example three:

this embodiment is substantially the same as the above embodiment, and is characterized in that:

a space positioning method using the optical space positioning system comprises the following operation steps:

step one, equating the toroidal lens 1 to a section of circular arc to obtain the position of a pixel point of the linear array photosensitive element 2 illuminated by light, wherein the point and the circular arc form a conical surface;

The embodiment can realize the high-precision detection function of the large-range spatial position, and is low in cost.

Example four:

as shown in fig. 1, which is a schematic diagram of an optical path using a toroidal lens 1 in combination with a line photosensitive element 2, the toroidal surface is a curved surface formed by a curve defined in the yz plane through rotation about a central axis parallel to the y axis, also called a tire tread, and the equation of the curve in the yz plane can be expressed as:

where c is the curvature, k is the conic coefficient, m is a natural number, α_nAre the coefficients of each time. The distance between the curve vertex and the rotating shaft is the rotating radius, and in the invention, the rotating center is the photosensitive center of the linear array photosensitive element 2. As shown in fig. 1a, in the yz plane, after passing through the toroidal lens or the lens group, the light can converge on the linear array photosensitive element 2, so as to be detected by the linear array photosensitive element 2. The material of the toroidal lens 1 may be optical resin or optical glass.

As an example, the following table lists the optical parameters of the system:

surface type	Radius of curvature (mm)	Thickness (mm)	Material	Radius of rotation (mm)
					Standard of merit	Infinity(s)	1500-infinity	Air (a)	-
Toroidal surface 1	-6	6.5	E48R	20
					Toroidal surface 2	-6.9	12.8	Air (a)	13.5
Standard of merit	Infinity(s)	0.7	BK7	-
					Standard of merit	Infinity(s)	-	-	-

The aspheric terms of the anterior surface 1-1-1 of the toroidal lens are: 0.073923902 y 2.

The aspheric terms of the rear surface 1-1-2 of the toroidal lens are:

-0.0077479252*y^2-2.4806961e-05*y^4+6.2830988e-06*y^6-8.4687312e-07*y^8+3.9098359e-08*y^10-7.3240518e-10*y^12。

as shown in fig. 1b, in the xz plane, the toroidal lens 1 has rotational symmetry with the center of the linear array photosensitive element 2 as the rotation axis, so that in this plane, each direction has the same optical property, and the detection range is increased by only increasing the rotation radian, so that the detection range with a large angle is easily realized.

To achieve higher resolution or increase throughput in the y-plane, more lenses may be used, as shown in fig. 2 for two toroidal lenses: the optical structure of the first toroidal lens 1-2 and the second toroidal lens 1-3. All the toroidal surfaces use the center of the linear array photosensitive element 2 as a rotating shaft, and when more than two toroidal surfaces are used, the center of the linear array photosensitive element 2 is required to be used as the rotating shaft so as to ensure the rotational symmetry of the system. As an example, the following table lists the optical parameters of the system:

surface type	Radius of curvature (mm)	Thickness (mm)	Material	Radius of rotation (mm)
					Standard of merit	Infinity(s)	1000-infinity	Air (a)	-
Toroidal surface 1	427.8	3.9	E48R	30
					Toroidal surface 2	-16	2.2	Air (a)	26.1
Toroidal surface 3	-12	8	E48R	23.9
					Toroidal surface 4	-9.3	15.2	Air (a)	15.9
Standard of merit	Infinity(s)	0.7	BK7	-
					Standard of merit	Infinity(s)	-	-	-

The aspheric terms of the first toroidal lens' front surface 1-2-1 are:

-0.023348487*y^2-4.9381754e-06*y^4+7.4131268e-07*y^6。

the aspheric terms of the first toroidal lens back surface 1-2-2 are:

0.0036150698*y^2+0.00026440428*y^4+1.7471189e-05*y^6-6.7314577e-07*y^8+2.7362814e-08*y^10-4.46693e-10*y^12。

the aspheric terms of the second toroidal lens' front surface 1-3-1 are:

0.037157699*y^2-2.4968672e-05*y^4+2.527433e-06*y^6-4.9260223e-08*y^8+4.9728081e-10*y^10-1.7638499e-12*y^12。

the aspheric terms of the rear surface 1-3-2 of the second toroidal lens are:

-0.0052346321*y^2+2.2422086e-05*y^4+4.9222241e-07*y^6-1.1964612e-08*y^8+1.7415734e-10*y^10-8.9830853e-13*y^12。

in the positioning process, as shown in fig. 3, the toroidal lens 1 can be optically equivalent to an arc with an optical focal length as a radius, after light rays emitted by a light spot in a space pass through the toroidal lens 1, a light sensing point H is generated on the linear array light sensing element 2, the light sensing point and the arc form a conical surface, and the space light spot P is located on the conical surface. In order to calculate the position of the spot P, at least three cones that intersect each other must be used, as shown in fig. 4a, and in order to achieve a higher accuracy of positioning, more than three detection units may be used, as shown in fig. 4b, which is a schematic diagram of four cones intersecting at a point.

In the yz plane, the toroidal lens has certain distortion, and the actual calculation seed and the corresponding theoretical position of the photosite H need to be obtained by performing inverse distortion correction according to distortion data.

In order to realize intersection of at least three conical surfaces, a detection unit composed of a toroidal lens 1 and linear array photosensitive elements 2 needs to be placed in a non-parallel manner with at least one other at different positions in space, as shown in fig. 5, the three detection units have centers on a straight line, the center distance is w, the middle one is perpendicular to the direction of two photosensitive elements at the edge, the center of the middle detection unit is taken as a coordinate origin, and the positions of light spots in space are x, y and z. The theoretical spatial positioning algorithm formula of the placing mode is as follows:

wherein h is₁,h₂And h₃The theoretical position of the light spot irradiated on the three photosensitive elements after the inverse distortion correction is shown, and R is the radius of the equivalent circular arc.

In order to obtain more measurement data and simplify the calculation formula, the arrangement shown in fig. 7 may be adopted, with the centers of the four detection units as the origin of coordinates, and the calculation formula of the coordinates x, y, and z of the spatial light spot is:

wherein h is₁,h₂，h₃And h₄The theoretical position of the light spot irradiated on the four photosensitive elements after the inverse distortion correction is carried out, R is the radius of the equivalent circular arc, and w is the distance between the center point and the center of each photosensitive element of the detection unit.

In practice, there are many placement combinations, such as the angles of the detection units are not vertically distributed, and the distances between the detection units are not equal. For other placing modes, calculation formulas can be obtained correspondingly, and are not listed one by one here.

In summary, the above embodiments disclose a new configuration spatial positioning system and a spatial positioning method thereof. The system of the embodiment comprises at least three groups of detection units consisting of the tire tread lenses and the linear array photosensitive elements. The tire tread lens converges light rays emitted by a point light source in the space into a linear shape, and the linear array light sensitive element is received by the linear array light sensitive element, and the linear array light sensitive element is positioned in the surrounding center of the tire tread lens; the detection units consisting of at least three tire tread lenses and linear array photosensitive elements are arranged in a non-parallel mode in space, and the position of the spatial point light source relative to the detector is calculated by obtaining the position coordinates of the intersection point of light emitted by the point light source in the space and the linear array photosensitive elements in each detection unit. The embodiment can realize the high-precision detection function of a large-range space position, and is low in cost. The invention belongs to the field of space positioning.

The embodiments of the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the embodiments, and various changes and modifications can be made according to the purpose of the invention, and any changes, modifications, substitutions, combinations or simplifications made according to the spirit and principle of the technical solution of the present invention shall be equivalent substitutions, as long as the purpose of the present invention is met, and the present invention shall fall within the protection scope of the present invention without departing from the technical principle and inventive concept of the present invention.

Claims

1. An optical spatial positioning system comprising a toroidal lens (1) and a linear array photosensitive element (2), characterized in that: the toroidal lens (1) and the linear array photosensitive elements (2) form a detection unit, at least three detection units are distributed at different positions in space, and the direction of the linear array photosensitive elements (2) in at least one unit is not parallel to the direction of the linear array photosensitive elements (2) in other units, so that a complete space positioning system is formed.

2. The optical spatial location system of claim 1, wherein: the toroidal lens is provided with two optical surfaces, each surface takes the center of the linear array photosensitive element (2) as a rotating center, the combination of the two optical surfaces can focus light beams on the linear array photosensitive element (2), and the linear array photosensitive element (2) is formed by arraying micron-sized photosensitive pixels into a straight line.

3. The optical spatial location system of claim 1, wherein: the toroidal lens (1) is composed of one lens, or two toroidal lenses (1-2 and 1-3) in combination, or more than two toroidal lenses, wherein each toroidal lens takes the center of the linear array photosensitive element (2) as a rotation center.

4. The optical spatial location system of claim 1, wherein: the combination of the optical surfaces of the toroidal lens (1) enables focusing of the light beam on the line photosensitive element (2) in a section passing through the axis of rotation of the toroidal lens.

5. The optical spatial location system of claim 1, wherein: the method is suitable for positioning operation in a small range of angles less than 120 degrees or in a detection range reaching or exceeding 120 degrees.

6. A method for performing spatial localization using the optical spatial localization system of claim 1, comprising the steps of:

step one, equating the toroidal lens (1) to a section of circular arc to obtain the position of a pixel point of the linear array photosensitive element (2) which is illuminated by light, wherein the point and the circular arc form a conical surface;