CN201837826U - All-directional stereoscopic vision system based on single camera - Google Patents

Abstract

The utility model discloses a novel all-directional stereoscopic vision system based on a single camera. The system comprises a transparent cylinder, two upper and lower reflecting mirror surfaces with specific shape, and a perspective camera, wherein an upper side mirror surface adopts a combination mirror surface composed of two of a hyperboloid, an ellipsoid, a paraboloid and a plane mirror; a lower side mirror surface adopts the hyperboloid or the paraboloid; the perspective camera is mounted on the lower side mirror surface, the principal optic axis is coaxial with main shafts of the two upper and lower reflecting mirror surfaces, and the lens is slightly smaller than a light-passing hole at the top part of the lower side mirror surface; a part of the combination mirror surface can independently form an image; and the other part forms a reentry system with the lower side mirror surface, two images of an object can be formed on one camera, and corresponding image points are positioned on the half line which adopts an image center as a center. The all-directional stereoscopic vision system based on the single camera has compact structure, and is portable, small and exquisite, three-dimensional viewing field with certain angles of horizontal 360 degrees, vertically upwards and downwards, so that stereoscopic vision information can be acquired by utilizing depth recovery arithmetics.

Description

One camera omnibearing stereo vision system

Technical field

The utility model belongs to the vision sensor of robot device, be used for ground robot, unmanned vehicle, the obtaining of panoramic vision information of weeder or other intelligence system automatically, and can go out three-dimensional range information by the depth recovery algorithm computation, a kind of omnibearing stereo vision system of compact conformation specifically.

Background technology

Vision system can obtain the image of surrounding environment fast by the imaging hardware device, by the surface characteristics of target in the software module analysis image, the depth data of calculating target, very big application potential is arranged.Therefore, at ground robot, unmanned vehicle, and in other intelligence systems, vision system has become the important means of tasks such as perception environment, auxiliary mark identification, path planning.Tradition perspective projection camera and comprehensive camera all are the vision systems that is used widely, and the latter gains great popularity because of bigger visual range.

Compare with large-scale unmanned plane with ground robot, small-sized/Micro Aerial Vehicle has that volume is little, light and flexible, can vertical takeoff and landing etc. advantage, can be application such as investigation under the complex environment, remote sensing ideal platform is provided, but its limited load capacity makes the configuration of sensor comparatively thorny.Small-sized/Micro Aerial Vehicle is the most important condition that sensors configured will be considered to the restriction of size and weight; In addition, the forward direction visual field on working direction, complete three-dimensional scene all needs to pay close attention to around the aircraft.As seen, small-sized/Micro Aerial Vehicle is higher to the requirement of environment sensing, but load capacity is poorer.Therefore, designed vision system not only wants volume little, in light weight, and will have satisfactory performance at aspects such as visual field and resolution.

The mirror surface that comprehensive camera can be added given shape by traditional perspective camera constitutes, and horizontal visual range is 360 degree, and vertical visual range can reach more than 90 degree.When the mirror surface shape is plane, ellipsoid, hyperboloid or when parabolic, camera has the single view attribute, i.e. the formation of picture point on the imaging plane is because camera has been caught the light on the specific direction.For example, in the light of numerous directive hyperboloidal mirrors, has only light, imaging on the camera through just being positioned at another focus place after the direct reflection along focus direction.Its advantage is in the imaging optical path calculation process, to need not to obtain the surface normal of light incident place minute surface, thereby guarantee that object point arrives speed and precision that picture point geometric projection is calculated, is convenient to the depth information of fast quick-recovery object.Constituting stereo visual system with comprehensive camera can adopt based on double camera and two kinds of basic comprising modes of one camera:

(1), constitutes by two identical comprehensive cameras based on the omnibearing stereo vision system of double camera with to constitute the mode of stereo visual system by two perspective cameras similar.This system has the big advantage of comprehensive viewing field of camera, but the comprehensive camera that is positioned at downside can constitute the visual field of upside camera and blocks.The more important thing is that there is certain limitation in this system aspect structural compactness and the weight, the more ground machine philtrum that is applied to;

(2) the omnibearing stereo vision system based on one camera then is the specific position relation of utilizing between two or more mirror surfaces, produces two pictures of Same Scene on a perspective camera.Specifically, a kind of structure is: adopt two hyperboloidal mirrors, and the focus of a catoptron and primary optical axis conllinear, and the focus of another catoptron and optical axis form an angle.Though this design has realized that one camera becomes space image, have that baseline is short, system's assembling difficulty, to the improvement of system architecture compactedness and drawback such as not obvious.Another kind of structure is made of two hyperboloidal mirror faces and a perspective camera as described in the patent 200510045648.1, two minute surface main shafts all with the primary optical axis conllinear of camera, has reduced the lateral dimension of system, effectively prolonged baseline, and the system of being convenient to assembles.But because the perspective camera is positioned at mirror surface downside a distance, the height of total system is still bigger, can bring adverse effect to small-sized/Micro Aerial Vehicle flight stability.

Summary of the invention

The purpose of this utility model is to provide a kind of structure one camera omnibearing stereo vision system of compactness more.

The technical solution that realizes the utility model purpose is: a kind of one camera omnibearing stereo vision system, comprise a transparent cylinder, two mirror surfaces and a perspective camera, described mirror surface comprises upside minute surface and downside minute surface, the upside minute surface is installed on the upper end of transparent cylinder, and the downside minute surface is installed on the lower end of transparent cylinder; The upside minute surface is the combination minute surface of the two formation in hyperboloid, ellipsoid, parabola, the level crossing, and the downside minute surface is hyperboloid or parabola; Downside minute surface top is provided with light hole; The upside minute surface is identical with the external diameter of downside minute surface, and the external diameter of upside minute surface and downside minute surface is as the diameter of system, and this diameter is less than the internal diameter of transparent cylinder; Described perspective camera is installed on downside minute surface inside, and the camera lens external diameter of perspective camera is had an X-rayed camera primary optical axis and two mirror surface main shaft conllinear less than the light hole diameter.

The utility model compared with prior art, its remarkable advantage: (1) compact conformation, owing to adopt camera to be positioned at the composite design of minute surface inside and three eyeglasses, when guaranteeing the stereo imaging system performance, effectively reduce the height of system, having in the strict robot system that limits at the volume and weight to vision system has good prospects for application; (2) bigger field angle, can form level 360 degree, vertically upward, the three-dimensional visual field of each certain angle downwards, be used for depth calculation; Simultaneously, can't be used for the image-region of depth calculation, also can be according to the correlation theory of exercise recovery, for the robot navigation provides information; (3) depth calculation fast, accurately, structure of the present invention has guaranteed that stereo visual system has rational base length, simultaneously, the conllinear feature of stereogram is convenient to the search of matched pixel, and then helps improving the speed of depth calculation.The present invention is from the application demand of small-sized/Micro Aerial Vehicle, but can be widely used in other intelligence systems that need obtain scene Stereo Vision on a large scale.

Description of drawings

Fig. 1 is the structural representation of the utility model one camera omnibearing stereo vision system.

Fig. 2 is the system architecture synoptic diagram of the utility model embodiment 1.

Fig. 3 is the system architecture synoptic diagram of the utility model embodiment 2.

Fig. 4 is the system architecture synoptic diagram of the utility model embodiment 3.

Fig. 5 is the analogous diagram of image that the utility model embodiment 1 becomes.

Fig. 6 is system architecture and the imaging optical path synoptic diagram of the utility model embodiment 1

Embodiment

Below in conjunction with accompanying drawing the utility model is described in further detail.

The utility model one camera omnibearing stereo vision system, comprise a transparent cylinder 4, two mirror surfaces and perspective cameras 3, described mirror surface comprises upside minute surface 1 and downside minute surface 2, upside minute surface 1 is installed on the upper end of transparent cylinder 4, and downside minute surface 2 is installed on the lower end of transparent cylinder 4; Upside minute surface 1 is the combination minute surface of the two formation in hyperboloid, ellipsoid, parabola, the level crossing, and downside minute surface 2 is hyperboloid or parabola; Downside minute surface 2 tops are provided with light hole; Upside minute surface 1 is identical with the external diameter of downside minute surface 2, and the external diameter of upside minute surface 1 and downside minute surface 2 is as the diameter of system, and this diameter is slightly less than the internal diameter of transparent cylinder 4; Described perspective camera 3 is installed on downside minute surface 2 inside by holding screw 5, and the camera lens external diameter of perspective camera 3 is slightly less than the light hole diameter, perspective camera 3 primary optical axis and two mirror surface main shaft conllinear.

The utility model one camera omnibearing stereo vision system, a slice minute surface is as independent imaging minute surface 1a in the upside minute surface 1, another sheet minute surface is as turning back minute surface 1b, turning back, minute surface 1b and downside minute surface 2 are common to constitute the system imaging of turning back, on the imaging plane of perspective camera 3, two image positions of object are in being on the ray in the center of circle with the picture centre; When the minute surface 1b that turns back was level crossing, ellipsoid or hyperboloid, imaging minute surface 1a all can be hyperboloid or ellipsoid separately, and downside minute surface 2 is a hyperboloid; When the minute surface 1b that turns back was parabola, imaging minute surface 1a can be hyperboloid or ellipsoid separately, and downside minute surface 2 is parabolic.

The utility model one camera omnibearing stereo vision system, when the described minute surface 1b that turns back was level crossing, perspective camera 3 photocentres overlapped with the over focus of independent imaging minute surface 1a, and level crossing equates with the over focus distance of photocentre and downside minute surface 2; When the minute surface 1b that turns back was ellipsoid or hyperboloid, perspective camera 3 photocentres were with the over focus of imaging minute surface 1a and 3 of the over focuses of the minute surface 1b that turns back overlap separately; When the minute surface 1b that turns back was parabola, perspective camera 3 photocentres overlapped with the focus of the minute surface 1b that turns back and 3 of the over focuses of independent imaging minute surface 1a.

The structure of system as shown in Figure 1.Design omnibearing stereo vision system needs the relative position parameter between definite mirror shape and minute surface and camera, specifically describes as follows:

(1) mirror shape: the minute surface with the level crossing of analytical expression and the ellipsoid in the surface of revolution, hyperboloid and parabolic shape all satisfies the single view constraint of common comprehensive camera, is the mirror surface of using always.In order further to constitute the stereo visual system of compact conformation, the upside minute surface is made up of two parts: the independent imaging minute surface and the minute surface of turning back.The former receive incident ray and the reflection after directly imaging on camera; The latter and downside minute surface constitute the system of turning back, incident ray through two secondary reflections after, on camera, become another picture.The shape of minute surface of turning back can be hyperboloid, ellipsoid, parabola or plane, and the imaging minute surface can be hyperboloid, ellipsoid or parabola separately; The downside minute surface can be hyperboloid or parabola.Specifically, when the minute surface of turning back was level crossing, ellipsoid or hyperboloid, the imaging minute surface all can be hyperboloid or ellipsoid separately, and the downside minute surface is a hyperboloid; When the minute surface of turning back was parabola, the imaging minute surface can be hyperboloid or ellipsoid separately, and the downside minute surface is parabolic.

(2) relation of the position between each ingredient: under the constraint of single view attribute, the relative position relation of the combination minute surface of upside and downside minute surface, camera photocentre need satisfy following condition: when the minute surface of turning back in the upside minute surface is level crossing, and the over focus F ' of camera photocentre O and independent imaging minute surface _aOverlap, and the over focus F ' of level crossing and photocentre and downside minute surface ₂Distance equates, as Fig. 3; When the minute surface of turning back is ellipsoid or hyperboloid, the over focus F ' of camera photocentre O and independent imaging minute surface _aOver focus F ' with the minute surface of turning back _b3 coincidences are as Fig. 4; When the minute surface of turning back is parabola, camera photocentre O and the focal point F of the minute surface of turning back and the over focus F ' of independent imaging minute surface _a3 coincidences.

The vision system of selecting mirror shape and parameter thereof to set up according to mentioned above principle, can utilize a camera to obtain two width of cloth images of scene, the analogous diagram of its imaging as shown in Figure 5, a spheroid has respectively become two pictures with a chessboard in the three dimensions, lays respectively in two concentric circless.Imaging system in this example, upside minute surface are that combination, the downside minute surface of hyperboloid and level crossing is hyperboloid.The outer ring of image is the imaging results of independent imaging minute surface, and inner ring is the imaging results of the system of turning back.According to imaging optical path,, can go out the degree of depth of specific object point by image calculation as Fig. 6.Among Fig. 6, the Ray Of Light warp of object point P after independent imaging direct reflection, imaging point p1 on the imaging plane of camera; Another bundle light forms another picture point p2 through the system of turning back simultaneously.And two image positions are in being on the ray in the center of circle with the picture centre.Therefore, can on this ray, carry out signature search, obtain the pairing matched pixel p2 of pixel p1.After this, be true origin with independent imaging minute surface focus, to be parallel to the level of imaging plane and vertical direction be x axle and y axle, be the coordinate system F of z axle perpendicular to imaging plane and the direction that makes progress _aAmong the XYZ, the three-dimensional coordinate of object point P (X, Y Z) can calculate acquisition by following formula:

The pixel coordinate that makes p1 is (u ₁, v ₁), the pixel coordinate of p2 is (u ₂, v ₂), imaging process then shown in Figure 6 can be described with following formula:

${\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">u</figure-callout>}}_1=\frac{f_0\&CenterDot;\mathrm{<figure-callout\; id="1"\; label="X\; k"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">X</figure-callout>}}{\sqrt{k_{}}}+u_0,---\left(1\right)$

${\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">v</figure-callout>}}_1=\frac{f_0\&CenterDot;\mathrm{<figure-callout\; id="1"\; label="Y\; k"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">Y</figure-callout>}}{\sqrt{k_{}}}+v_0,---\left(2\right)$

${\mathrm{<figure-callout\; id="2"\; label="u"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">u</figure-callout>}}_2=\frac{f_0\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="X\; k"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">X</figure-callout>}}{\sqrt{k_{}}}+u_0,---\left(3\right)$

${\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">v</figure-callout>}}_2=\frac{f_0\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="Y\; k"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">Y</figure-callout>}}{\sqrt{k_{}}}+v_0,---\left(4\right)$

Wherein, f ₀Be camera focus, (u ₀, v ₀) be the pixel coordinate at camera photocentre place, c ₁, k ₁With c ₂, k ₂Be respectively bi-curved parameter up and down, d is the distance of camera photocentre to downside hyperboloid over focus, and the parameter of these imaging systems can be determined by calibration process;

Three unknown number X that contain in four equations of formula (1)-(4), Y, Z is so can obtain unique solution.

At coordinate system F _aUnder the XYZ, separately the imaging minute surface be hyperboloid, ellipsoid and paraboloidal mathematic(al) representation respectively suc as formula shown in (5)-(7):

${(Z-\frac{c_a}{2})}^2-({\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">X</figure-callout>}}^2+Y^2)(\frac{k_a}{2}-1)=\frac{c_a^2}{4}\left(\frac{k_a-2}{k_a}\right),k_a>2,c_a>0---\left(5\right)$

${(Z-\frac{c_a}{2})}^2+({\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">X</figure-callout>}}^2+Y^2)(1+\frac{c_a^2}{2k_a})=\left(\frac{{2k}_a+c_a^2}{4}\right),k_a>0,c_a\&GreaterEqual;0---\left(6\right)$

$Z=l-\frac{(X^2+Y^2)}{4l}---\left(7\right)$

C wherein _aBe focal length, k _aBe the coefficient relevant with the mirror surface centrifugal rate, l is the distance of parabolic summit to focus.When turn back minute surface and downside minute surface were above-mentioned three kinds of shapes, its expression formula and (5)-(7) form class seemingly only had certain translation at the z direction of principal axis, and the size of translational movement is subjected to the restriction of factors such as single view attribute and vision system height, radius.In addition, when the minute surface of turning back was level crossing, its expression formula was:

$Z=\frac{d}{2}---\left(8\right)$

Wherein, d is the distance of camera photocentre to downside minute surface over focus.

Because in the native system, the upside minute surface is that two kinds of difform minute surfaces are put together, by above-mentioned equation as can be known, the hyperboloid that is adopted, ellipsoid and parabola are surface of revolution.Level crossing is the circular flat of go-no-go.The junction diameter of two minute surfaces is identical, and the size of diameter is determined by the particular location of combination.

Embodiment 1

According to the basic structure of Fig. 1,1a and 2 is hyperboloid in this embodiment, and the two is staggered relatively, link to each other with base plate with top board respectively, and 1b is the circular flat mirror, and its radius depends on the position that combines with 1a.1a and central shafts 1,2 identical with 2 bore overlap.3 are the perspective camera, and its circuit board is fixed in the inside of minute surface 2 by screw 5, and the camera primary optical axis overlaps with the main shaft of all minute surfaces.4 is the transparent cylinder that glass, crystal, acrylic (acrylic) or other macromolecule transparent materials are made, and internal diameter is more bigger than the bore of 1a and 2, so that install.

In vertical direction, the relative position relation of above-mentioned each parts need meet following principle: the photocentre of camera 3 overlaps with the over focus of independent imaging minute surface, and simultaneously, the minute surface of turning back equates with the distance of downside minute surface over focus and photocentre.Therefore, parameter undetermined comprises c in the total system ₁, k ₁, c ₂, k ₂, d, w, wherein c ₁, k ₁, c ₂, k ₂Be the form parameter (seeing formula 1) of hyperboloidal mirror about the control, parameter d has determined the level crossing position and then has determined the diameter of level crossing that w is the radius of whole vision system.These six systematic parameters had both determined the apparent size of system, as radius and height, had determined the imaging performance of system again, as field angle.

Embodiment shown in Figure 2 has following systematic parameter: c ₁=11.96, k ₁=5.71, c ₂=23.88, k ₂=9.76, d=22.58, w=1.8.Under camera coordinates system, the equation of two hyperboloidal mirrors and a level crossing is shown in formula (9)-(11):

${(Z-\frac{{\mathrm{<figure-callout\; id="1"\; label="c"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">c</figure-callout>}}_1}{2})}^2-({\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">X</figure-callout>}}^2+Y^2)(\frac{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}{2}-1)=\frac{{\mathrm{<figure-callout\; id="1"\; label="c"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">c</figure-callout>}}_1^2}{4}\left(\frac{k_1-2}{k_1}\right)---\left(9\right)$

${[Z-(d-{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">c</figure-callout>}}_2/2)]}^2-({\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">X</figure-callout>}}^2+Y^2)(\frac{{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">k</figure-callout>}}_2}{2}-1)=\frac{{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="HSA00000305983100011.png,HSA00000305983100021.png"\; state="\{\{state\}\}">c</figure-callout>}}_2^2}{4}\left(\frac{k_2-2}{k_2}\right)---\left(10\right)$

$Z=\frac{d}{2}---\left(11\right)$

The said system parameter is that (w≤1.8cm, h≤15cm) and field angle (α 〉=14 °, β 〉=20 °, γ 〉=10 °) are the result that mathematical model that objective function is set up is tried to achieve for constraint condition, with maximum base length with the system appearance size.The height of final system is 15cm, and radius is 1.8cm, and the field angle that makes progress is 14 °, and downward field angle is 13.3 °, and base length is 13.15cm.

Embodiment 2

As shown in Figure 3, as different from Example 1, the upside minute surface of this example adopts the combination of ellipsoid and level crossing.

Embodiment 3

As shown in Figure 4, as different from Example 1, the upside minute surface of this example adopts ellipsoid and bi-curved combination.

Claims (4)

1. one camera omnibearing stereo vision system, it is characterized in that: comprise a transparent cylinder [4], two mirror surfaces and a perspective camera [3], described mirror surface comprises upside minute surface [1] and downside minute surface [2], upside minute surface [1] is installed on the upper end of transparent cylinder [4], and downside minute surface [2] is installed on the lower end of transparent cylinder [4]; Upside minute surface [1] is the combination minute surface of the two formation in hyperboloid, ellipsoid, parabola, the level crossing, and downside minute surface [2] is hyperboloid or parabola; Downside minute surface [2] top is provided with light hole; Upside minute surface [1] is identical with the external diameter of downside minute surface [2], and the external diameter of upside minute surface [1] and downside minute surface [2] is as the diameter of system, and this diameter is less than the internal diameter of transparent cylinder; Described perspective camera [3] is installed on downside minute surface [2] inside, and the camera lens external diameter of perspective camera [3] is had an X-rayed camera [3] primary optical axis and two mirror surface main shaft conllinear less than the light hole diameter.

2. one camera omnibearing stereo vision system according to claim 1, it is characterized in that: a slice minute surface is as independent imaging minute surface [1a] in the upside minute surface [1], another sheet minute surface is as turning back minute surface [1b], the minute surface [1b] of turning back constitutes the system imaging of turning back jointly with downside minute surface [2], on the imaging plane of perspective camera [3], two image positions of object are in being on the ray in the center of circle with the picture centre; When the minute surface of turning back [1b] was level crossing, ellipsoid or hyperboloid, imaging minute surface [1a] all can be hyperboloid or ellipsoid separately, and downside minute surface [2] is a hyperboloid; When the minute surface of turning back [1b] was parabola, imaging minute surface [1a] can be hyperboloid or ellipsoid separately, and downside minute surface [2] is parabolic.

3. one camera omnibearing stereo vision system according to claim 1, it is characterized in that: when the described minute surface of turning back [1b] is level crossing, perspective camera [3] photocentre overlaps with the over focus of independent imaging minute surface [1a], and level crossing equates with the over focus distance of photocentre and downside minute surface [2]; When the minute surface of turning back [1b] was ellipsoid or hyperboloid, the over focus of perspective camera [3] photocentre and independent imaging minute surface [1a] and 3 of the over focuses of the minute surface [1b] of turning back overlapped; When the minute surface of turning back [1b] was parabola, perspective camera [3] photocentre overlapped with the focus of the minute surface of turning back [1b] and 3 of the over focuses of independent imaging minute surface [1a].

4. one camera omnibearing stereo vision system according to claim 1 is characterized in that: the material of transparent cylinder [4] is glass, crystal or acrylic.

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