CN110021041A - Unmanned scene progressive mesh structural remodeling method based on binocular camera - Google Patents

Unmanned scene progressive mesh structural remodeling method based on binocular camera Download PDF

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CN110021041A
CN110021041A CN201910156872.XA CN201910156872A CN110021041A CN 110021041 A CN110021041 A CN 110021041A CN 201910156872 A CN201910156872 A CN 201910156872A CN 110021041 A CN110021041 A CN 110021041A
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scene
grid
visual signature
camera
image
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CN110021041B (en
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朱建科
李昱辰
章国锋
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Zhejiang University ZJU
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    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00Image analysis
    • G06T7/50Depth or shape recovery
    • G06T7/55Depth or shape recovery from multiple images
    • G06T7/579Depth or shape recovery from multiple images from motion
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00Indexing scheme for image analysis or image enhancement
    • G06T2207/10Image acquisition modality
    • G06T2207/10016Video; Image sequence
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00Indexing scheme for image analysis or image enhancement
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    • G06T2207/20228Disparity calculation for image-based rendering

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Abstract

The unmanned scene progressive mesh structural remodeling method based on binocular camera that the invention discloses a kind of.Its disparity map is calculated after pre-processing to the binocular video frame of input, and corresponding depth map is calculated based on this, and initial scene gridding structure is then constructed by triangulation and grid subdivision stage;Network smoothing processing is carried out after eliminating grid sting phenomenon;The motion information between present frame and previous frame is calculated using the location information that satellite navigation acquires, it resolves to obtain the new patch grids that global scene gridding structure is added in conjunction with the scene grid structural remodeling result of present frame, completes the work of scene grid structures to form eventually by part again triangulation methodology.The present invention innovatively utilizes the vision difference between two field pictures to find new vision region, and global scene reconstructed results are updated incrementally with gridding structure type, to obtain better performances and under multiclass environment with the method for reconstructing three-dimensional scene of higher robustness.

Description

Unmanned scene progressive mesh structural remodeling method based on binocular camera
Technical field
The invention belongs to 3 D scene rebuilding technical fields, and in particular to a kind of unmanned scene based on binocular camera Progressive mesh structural remodeling method
Background technique
Modern Shi Jin, automatic driving vehicle, the unmanned carrier such as automatic flight unmanned plane has obtained significant progress, right For these unmanned carriers, self-navigation and path planning in traveling or flight course are very crucial technology rings Section.For nearly all self-navigation and Path Planning Technique, various types of scene structure maps are all essential , traditional scene rebuilding generally uses the offline scenario structural remodeling scheme based on all kinds of high-precision hardware, such as: automatic Driving field, researcher often pass through one and are equipped with a kind of high-precision RTK (carrier wave phase for positioning when high-precision real Position differential technique) the manned vehicle of equipment and multi-thread beam laser radar carries out the acquisition and reconstruction of scene structure data.This There are two drawbacks for kind acquisition method: 1) scene structure constructed by is made of dense laser point cloud, is substantially scatterplot structure, And the scene structure in real scene is made of continuous line or face, scatterplot structure can lose important scene continuous structure letter Breath;2) hardware cost needed for this scene structure reconstruction model is very high, is not particularly suited for all research institutions and development teams.
For the drawbacks described above that the offline scenario structural remodeling scheme based on all kinds of high-precision hardware is included, and with The development of SLAM (synchronous to position and build figure) technology, has had some advanced SLAM technologies that can directly estimate by state now The mode of meter constructs dense scene map, but this kind of technology still remains and some is difficult to the drawbacks of being solved perfectly at present: 1) institute The scene structure of building is made of the dense point cloud with colouring information, is substantially scatterplot structure, and the field in real scene Scape structure is made of continuous line or face, and scatterplot structure can lose important scene continuous structure information;2) more due to scene Various in sample and scene to be difficult to expect emergency case, even state-of-the-art SLAM technology also can not be in all types of rings Outstanding state is kept to resolve effect in border, so the dense scene map for fully relying on the building of SLAM technology tends not to reach Satisfactory precision.
To sum up, problem to be solved of the present invention is:
1. the discontinuous problem of scene structure reconstructed results: dense map constructed by many classical scenario structural remodeling schemes It is a kind of spot style " pseudo- dense " map, this map obviously can not directly support the self-navigation of all kinds of unmanned carriers With the tasks such as path planning;
2. the excessively high problem of scene structure reconstructed cost: in the scene based on high-precision RTK equipment Yu multi-thread beam laser radar In structural remodeling scheme, research and development team generally requires the very expensive hardware device of procurement price, such as high-precision satellite Navigation equipment and 64 line laser radars etc., for most of research and development team, this hardware cost will be will cause significantly Financial burden, for company, this hardware device scheme problem excessively high due to own cost, it is clear that be unable to meet volume Production demand.
3. scene structure reconstructed results precision deficiency problem: many classical scenario structural remodeling schemes are based especially on each The scene structure reconstruction model of type games information solving technique, the scene structure result constructed are often not achieved satisfactory Precision, it is because the algorithm of single type often can not be in love in institute after all that the reason of causing such case, which has a lot, Satisfactory processing result can be obtained under condition, the solution institute that this is also primarily based upon algorithm types technology is intrinsic extensively One of disadvantage.
Summary of the invention
In order to solve the problems in background technique, present invention combination stereovision technique, Triangulation Technique, grid subdivision Technology and lattice optimization techniques etc., the increment type scene of high stability can be kept under outdoor free environments by having developed a whole set of Gridding structural remodeling method, and by the way that experimental results demonstrate the validity of the system.
The technical solution adopted by the present invention includes the following steps:
1) the single frames binocular video frame in the scene acquired by vehicle-mounted binocular camera is inputted, to the single frames binocular vision of input Frequency frame carries out scene grid structural remodeling, therefrom obtains network structure feature.
The present invention is applied to unmanned or other indoor or outdoors scenes with clear visual texture feature, nobody drives It sails scene and specifically includes the common road scene such as urban road, country road, highway.
The step 1) specifically:
1.1) visual signature in the two images in the single frames binocular video frame acquired by binocular camera is extracted respectively Point;Herein can be there are many visual signature point Choice, such as FAST characteristic point, ORB characteristic point, BRIEF characteristic point etc., Can be according to varying environment feature, situations such as different system frame per second requirements, different hardware equipment, is chosen.In different type environment In, the best feature vertex type of effect is likely to be different;FAST characteristic point, ORB characteristic point or the BRIEF acquired Characteristic point is visual signature point.
1.2) visual signature point matching stage: the point of visual signature obtained in step 1.1) is matched based on violence (Brute-Force Matcher) method is matched to obtain visual signature point pair, calculates the parallax of every a pair of of visual signature point Value;
1.3) camera coordinates the visual signature point depth estimation stage: are established using left mesh camera initial position as coordinate origin System, exists according to the visual signature point of the left mesh image of parallax value computation vision characteristic point centering of visual signature point pair in step 1.2) Three-dimensional position in camera coordinates system, specific calculating process are as follows:
1.3.1 the depth value of each visual signature point) is calculated, to obtain the sparse depth figure of left mesh image:
Wherein, d is parallax value, and b is binocular camera baseline length, and f is camera focus, and z is depth value;
1.3.2 three-dimensional position of the visual signature point of left mesh image in camera coordinates system) is calculated:
Pw=zK-1Puv
Wherein, K is the Intrinsic Matrix of binocular camera, PuvThe homogeneous seat fastened for visual signature point in image pixel coordinates Mark, image pixel coordinates system are using the image upper left corner as the two-dimensional coordinate system of origin, PwIt is visual signature point in camera coordinates system In coordinate, u is visual signature point corresponding position in transverse coordinate axis in image pixel coordinates system, and v is visual signature point The corresponding position in longitudinal coordinate axle in image coordinate system, X are visual signature point corresponding position in x-axis in camera coordinates system It sets, Y is that corresponding position, Z are visual signature point z-axis in camera coordinates system to visual signature point in y-axis in camera coordinates system Upper corresponding position;
1.4) the triangulation stage: carrying out subdivision to visual signature point set inside using Delaunay Triangulation method, Triangle gridding structure is obtained, wherein the visual signature point set is the set of visual signature point on left mesh image;
1.5) the grid subdivision stage: according to step 1.4) triangle gridding structure generated and the depth of each grid vertex Angle value carries out depth interpolation to the triangle gridding structure of present frame, describes sub- iteration by Census and finds integrated triangular net lattice knot Visual signature point in structure on the left mesh image of depth error maximum preceding 5% as visual signature point to be updated, and according to Hamming distance matches visual signature point to be updated again, visual signature point set is added in visual signature point to be updated, again Delaunay Triangulation is carried out inside visual signature point set, thus the scene grid structure after being segmented.
2) it is found in scene grid structure using network structure feature and the position of grid " sting " phenomenon occurs, and eliminated Grid " sting " phenomenon recycles approximate Laplce's smoothing method to promote the smoothness of overall scenario network structure.
" sting " phenomenon refers to the several nets of single or only a few in the local location appearance of scene gridding structure Lattice vertex depth compares the excessive phenomenon of difference for trellis depth around, and this phenomenon is to lead to overall scenario gridding knot One of the main reason of structure estimation inaccuracy.
The step 2) specifically:
2.1) grid " sting " removes the stage: each grid vertex in scene grid structure is handled to traversal formula, when The depth of grid vertex be more than or less than all of its neighbor grid vertex depth, and with the mean depth on all of its neighbor vertex it Between absolute value of the difference when being greater than threshold value, with the depth of the mean depth on all of its neighbor vertex substitution grid vertex;
2.2) network smoothing stage: with a kind of approximate Laplce's smoothing method to the net in scene grid structure Lattice vertex is smoothed one by one, and the calculation of approximate Laplce's smoothing method is as follows:
Wherein, ZcFor the depth value of grid vertex to be processed, ZcIt is averaged for all of its neighbor vertex of grid vertex to be processed Depth value, α are the damping parameter manually set, PwFor position of the grid vertex to be processed in camera coordinates system, PoIt is to be processed Position of the grid vertex after optimization in camera coordinates system.
3) using the location information of Vehicular satellite navigation equipment acquisition scene, by location information resolving previous frame and currently Motion information between frame carries out new vision region detection to obtain the transformation matrix that description interframe continuously moves later;Newly Visual zone detection are as follows: virtual image is constructed according to the scene grid structure of transformation matrix and previous frame, utilizes virtual image The new vision region of previous frame compared with the vision difference between present frame determines present frame.
The detection method in new vision region is to detect in present frame in a manner of based on virtual image in the step 3) New vision region, it is specific as follows:
It constructs and obtains after each pixel of left mesh image in previous frame single frames binocular video frame is handled as follows Virtual image:
PpFor the homogeneous coordinates that the pixel coordinate of left mesh image of the pixel in previous frame single frames binocular video frame is fastened, zpDepth value for pixel at the previous frame moment, PcFor left mesh image of the pixel in present frame single frames binocular video frame The homogeneous coordinates that pixel coordinate is fastened, zcDepth value for pixel at the present frame moment, T are the corresponding fortune of inter motion information Dynamic matrix, K are the Intrinsic Matrix of binocular camera;
Image repair is carried out to virtual image using Navier-Stokes equation, then compares the virtual image after repairing Vision difference in the left mesh image of present frame on each tri patch region, obtains vision difference value, the tool of vision difference value Body calculation is as follows:
Wherein, n is sum of all pixels in tri patch region, gpiFor gray value of the ith pixel position in virtual image, gciFor in the gray value of the left mesh image of present frame, d is vision difference value;
It finally chooses vision difference value and is higher than composition face of the tri patch of average visual difference value as new vision region Piece completes the detection in new vision region;The average visual difference value is the virtual image and the left mesh image of present frame after repairing In the average value of all vision difference values that obtains more afterwards of vision difference on each tri patch region.
4) it relative to the cumulative motion information of the camera position of initial frame and has been constructed using the camera position of present frame Scene dough sheet in overall scenario gridding structure determines local scene to be updated in conjunction with the new vision region in step 3) Gridding locations of structures.
The scene grid that the overall scenario gridding structure constructed constructs for all frames before present frame Structure;The scene grid structure that overall scenario gridding structure constructs for all frames before present frame and present frame.
The step 4) is specific as follows: using following calculation method by three in the overall scenario gridding structure constructed Edged surface piece projects on present frame:
Wherein, PwFor position of the vertex in the world coordinate system using first frame as origin of tri patch, z is depth, T For present frame camera position relative to initial frame camera position cumulative motion information, K be binocular camera intrinsic parameter square Battle array, PuvThe homogeneous coordinates fastened for the vertex of the tri patch projected on present frame in pixel coordinate;
In the overall scenario gridding structure constructed, by or part weight Chong Die with the new vision region in present frame It is folded, and tri patch position of the space length between new vision region corresponding to present frame within 5 meters is considered as Local scene gridding locations of structures to be updated.
5) scene grid structure increment formula joining method: by new vision region and local scene gridding knot to be updated After structure position is associated, the splicing of overall scenario gridding structure is carried out by Delaunay Triangulation method.
Scene grid structure increment formula joining method in the step 5) specifically: by the new vision region of present frame In all tri patch carry out connected region search, all connected regions are sorted out, by each connected region and to be updated The position that projects on the left mesh image of present frame of local scene gridding locations of structures concentrate after carry out Delaunay tri- again Angle subdivision updates overall scenario gridding structure with this.
6) iteration step 1-5, until vehicle-mounted binocular camera obtain all single frames binocular video frames all everywhere Reason, it is final to obtain the overall scenario gridding structural remodeling result that can satisfy unpiloted use demand.
The beneficial effects of the present invention are:
One, the present invention innovatively has found new vision region using the vision difference between two field pictures, and with gridding knot Configuration formula incrementally updates global scene reconstructed results, to obtain better performances and have higher robust under multiclass environment The method for reconstructing three-dimensional scene of property.
Two, the present invention significantly optimizes following three classes defect possessed by classical scenario structural remodeling scheme:
1. the discontinuous problem of scene structure reconstructed results: scene structure constructed by the present invention is gridding structure, this Gridding structure be it is stringent continuous, there is no any structural hole theory, can satisfy all kinds of unmanned carriers carry out it is automatic For the demand of scene structure map when the tasks such as navigation, path planning.
2. the excessively high problem of scene structure reconstructed cost: the present invention does not depend on expensive multi-thread beam laser radar completely and sets It is standby, hardware cost needed for significantly reducing scene structure reconstructing system.
3. scene structure reconstructed results precision deficiency problem: the present invention solves scene structure reconstructed results essence from two angles It spends insufficient problem: 1) improving the precision that scene depth resolves by Mesh Subdivision Technique and lattice optimization techniques;2) pass through satellite Navigation equipment obtains inter motion information more more accurate than the inter motion information obtained by motion information solving technique.
Detailed description of the invention
Fig. 1 is general frame figure of the invention;
Fig. 2 illustrates contextual data acquisition module;
Fig. 3 illustrates single frames scene grid structure and resolves module;
Fig. 4 is mapping graph of the single frames network on single-frame images;
Fig. 5 illustrates single frames scene grid structure optimization module;
Fig. 6 illustrates the scene grid structure optimization effect reflected with depth map;(a) optimization to be reflected with depth map Preceding scene gridding structure;It (b) is the scene grid structure after the optimization that is reflected with depth map;
Fig. 7 illustrates scene grid structure increment formula update module;
Fig. 8 illustrates the virtual image of generation;It (a) is the virtual image before image repair processing;(b) at image repair Virtual image after reason;
Fig. 9 illustrates new vision area detection result;
Figure 10 illustrates the local corresponding diagram in new vision region;(a) (c) is depth value inaccuracy or vision in previous frame The incomplete part of information;(b) (d) is new vision area detection result;
Figure 11 illustrates scene grid structural remodeling result;It (a) is grid configuration;(b) form is rendered for RGB.
Specific embodiment
As shown in Figure 1, the invention mainly comprises following four technology modules, each technology modules are made with reference to the accompanying drawing It is further described:
One, contextual data acquisition module (as shown in Figure 2)
First stage, the video frame acquisition phase based on binocular camera:
It is continuous needing to construct using equipment such as vehicle-mounted binocular camera, UAV system binocular camera or hand-held binocular cameras Mobile exploration is carried out in the scene of gridding structure, acquires the continuous binocular video frame of scene, it is worth mentioning at this point that, it is used here Binocular camera be by strictly demarcating, for binocular camera equipment preferable for quality, the step should be It completes in assembling stage, for general for quality or self assembly binocular camera equipment, needs by additional stringent Staking-out work since this work is not core of the invention content, therefore is not unfolded to be described in detail.At this stage, it needs to guarantee Binocular camera keeps horizontal in collection process, and keeps frame rate stable, just can guarantee acquired scene visual information in this way Availability.
Second stage, the motion information acquisition stage based on satellite navigation:
Using all kinds of satellite navigations, synchronous recording world coordinates during recording scene continuous binocular video frame Location information in system, and resolved from location information and obtain inter motion information.It should be noted that since frame number is different or Some other error for being difficult to completely eliminate, the position that the scene visual information and satellite navigation that binocular camera is recorded are recorded Information can not accomplish proper fully synchronized, and the solution taken of the present invention is here: assuming that mobile vehicle exists The movement of (< 0.1s) is uniform motion in the very short time, is then believed according to corresponding scene visual information time stamp with position The difference ceased between timestamp carries out at the uniform velocity position compensation.It is demonstrated experimentally that this solution is effective.
Two, single frames scene grid structure resolves module (as shown in Figure 3)
First stage, visual signature point extract the stage:
In three-dimensional reconstruction field, the basis that scene structure is rebuild is the resolving of scene depth, in the present invention, scene Depth is obtained by Stereo Vision, stringent this requires having between the two images in single frames binocular video frame This point may be implemented there are many technical solution, in the present invention, since structure is by grid in accurately pixel matching relationship Form presented, it is desirable that grid vertex can more efficiently embody the significant structure feature of scene, therefore use Visual signature point, which is extracted, realizes that the accurate pixel between two images matches with matched mode.Herein can there are many view Feel characteristic point Choice, such as FAST characteristic point, ORB characteristic point, BRIEF characteristic point etc., can according to varying environment feature, Situations such as different system frame per second requirements, different hardware equipment, is flexibly chosen, it is demonstrated experimentally that effect is most in different type environment Good feature vertex type is likely to be different.
Second stage, visual signature point matching stage:
Since the basic thought of the scene depth estimation in the present invention is stereoscopic vision thought, so having extracted single frames After visual signature point in binocular video frame in two images, it is also necessary to be carried out to the visual signature point in two images accurate Matching.This process can be realized that rebuilding not due to scene structure of the invention is on-line reorganization by kinds of schemes, and It is by reconstructing completion offline, so do not have strict requirements for the real-time of matching scheme, therefore present invention employs sudden and violent Power matches the mode of (Brute-Force Matcher), according to selected visual signature vertex type, directly calculating two images Between each visual signature point between Euclidean distance or Hamming distance, then carry out two images between visual signature point With work, it is demonstrated experimentally that this matching strategy is effective.
Phase III, the visual signature point depth estimation stage:
After completing the visual signature point between the two images in single frames binocular video frame and precisely matching, so that it may According to pixel difference in horizontal direction between matching visual signature point pair, the parallax of corresponding position is obtained.In the present invention, with binocular Magazine left camera be scene structure perception basis, therefore pass through this phase process, available left mesh image it is sparse Disparity map, the position with parallax value information are exactly the position of visual signature point on left mesh image.When having known parallax value and double After mesh camera parameter, according to binocular camera modular concept, so that it may obtain the accurate depth value of corresponding points, calculation is as follows:
Wherein, d is parallax value, and b is binocular camera baseline length, and f is camera focus, and z is depth results;
So far, the sparse depth figure of left mesh image has just been obtained.
After the sparse depth figure for having obtained left mesh image, also need to know the pixel with depth value in three dimensions Exact position, can be calculated here by pinhole camera modular concept, calculation is as follows:
Pw=zK-1Puv
Wherein, K is the Intrinsic Matrix of binocular camera, PuvThe homogeneous seat fastened for visual signature point in image pixel coordinates Mark, PwFor the coordinate of visual signature point in three dimensions.
So far, the exact position of each visual signature point in three dimensions in left mesh image has just been obtained.
Fourth stage, the triangulation stage:
What the present invention to be rebuild is the scene grid structure for having Complete Continuity, only sparse scene characteristic point Accurate three-dimensional is insufficient for this point if position.Herein, have been obtained that represent scene in left mesh image significant The position of the visual signature point of feature in three dimensions, need by a kind of triangulation scheme by these scatterplots by point with Continuous grid is connected and composed between point.Delaunay Triangulation scheme is used in the present invention to be realized, this is chosen The main reason for kind triangulation scheme is that Delaunay Triangulation scheme maximizes minimum angle, be may be constructed closest to rule The triangulation network then changed, this is very helpful for real embodiment scene structure.
5th stage, the grid subdivision stage:
The scene grid structure obtained by Delaunay Triangulation is the initial scene grid structure of comparison, essence Degree is not enough to that reality is supported to use, needs to make grid reach higher by the further subdivided meshes of grid subdivision scheme Precision.It determines the grid vertex that existing grid is newly added, is the chief motivation of mesh refinement scheme.In the third rank of this module Duan Zhong has obtained the sparse disparities figure of left mesh image, and in the fourth stage of this certain block, it is corresponding initial to have obtained left mesh image Scene grid structure, it is basic based on these data, so that it may which that the thick of left mesh image is obtained by triangle interior interpolation method Close disparity map, according to the dense disparity map of left mesh image, so that it may which any location of pixels in left mesh image is corresponded into right mesh In image, by Census description (a kind of description calculating side based on neighborhood of pixel points statistics for measuring pairing pixel Formula) between Hamming distance, judge the error degree of corresponding parallax.After obtaining the dense error degree figure of left mesh image, Image uniform is divided into several parts, several highest location of pixels of error degree is taken to add in each part as new Enter the position of the grid vertex of initial displaying grid, but these put the exact position in corresponding three-dimensional space not yet, For these points, since whole system is to be to maintain binocular phase based on binocular camera system, and when recording scene visual information Machine level, so only needing to describe the correspondence in the son search highest right mesh image of matching degree according to Census on a horizontal Then position calculates parallax, so that it may obtain the depth value of these points, can be obtained according to depth value and camera Intrinsic Matrix To these exact positions of point in three dimensions.It, will be original after the new grid vertex position that grid is added has been determined Delaunay Triangulation result empties, and re-starting Delaunay Triangulation further according to all grid vertexes can be obtained carefully Scene grid structure after point.According to available accuracy needs, successive ignition, which carries out above-mentioned grid subdivision process, be can be obtained completely The scene grid structural remodeling result as shown in Figure 4 of sufficient required precision.
Three, single frames scene grid structure optimization module (as shown in Figure 5)
First stage, grid sting remove the stage:
After having obtained single frames scene grid structural remodeling result, due in the grid subdivision stage, only iteratively Grid vertex is added into network, not according to stringent logic Delete Mesh vertex, so scene grid structure Error is still remained, most notable one error is exactly " sting " error.This error takes the form of in the certain of grid There is the very high triangle gridding vertex of the projecting degree of only a few in part suddenly, and this vertex constitutes the view similar to " sting " Feel effect, this arises primarily at matching error during resolving depth based on stereoscopic vision, obtains according to matching result To parallax it is excessive or too small be likely to cause " sting " phenomenon.In the present invention, the project plan comparison for removing grid sting is straight It connects, judges whether a grid vertex is the key that cause " sting " phenomenon vertex, mainly calculates the depth of the grid vertex Absolute value of the difference between the mean depth on all of its neighbor vertex, and compare depth and all of its neighbor vertex of the grid vertex Depth, when the depth absolute value of the difference is greater than some threshold value for setting based on practical experience, and the depth of the grid vertex More than or less than all of its neighbor vertex depth when, being considered as the point is the key that cause " sting " phenomenon vertex, and with the point All of its neighbor vertex mean depth replace the point original depth, thus can solve single " sting " phenomenon.Experiment It proves, after the process is acted on entire net region, so that it may solve all " stings " in scene grid structure Phenomenon.
Second stage, network smoothing stage:
In traditional network Smooth scheme, through being put down frequently with Laplce's Smooth scheme to network Sliding, this mode can significantly improve the smoothness of network, while can also change the position of several grid vertexes inside grid It sets.But in the present invention, the grid vertex in order not to be changed position changes in the position that image pixel coordinates are fastened Becoming, a kind of approximation Laplce's Smooth scheme is used, and this Smooth scheme is still to be handled by grid vertex, It is handled by following formula:
Wherein, ZcFor the depth value of grid vertex to be processed, ZnIt is averaged for all of its neighbor vertex of grid vertex to be processed Depth value, α are the damping parameter manually set, PwFor the position of grid vertex to be processed in three dimensions, PoFor net to be processed Position of the lattice vertex after optimization in three dimensions.
It is demonstrated experimentally that after the process is acted on entire net region, so that it may significantly improve scene grid knot The smoothness of structure is allowed to more close to real scene structure, be illustrated in figure 6 excellent with the scene grid structure of depth map reflection Change effect, Fig. 6 (a) and Fig. 6 (b) are respectively the scene grid structure before and after the optimization reflected with depth map.
Four, scene grid structure increment formula update module (as shown in Figure 7)
First stage, scene grid topology update detection-phase:
After by first time single frames scene grid structure optimization resume module, single frames scene grid has just been obtained All three-dimensional triangulation dough sheets for including in reconstructed results as a result, and be uniformly stored in scene grid structural library by structural remodeling. But this is only the scene grid structural remodeling of single frames as a result, being unsatisfactory for reality use needs, in the present invention, with one The form of kind increment type expands the gridding structure of scene, first after new frame binocular image input system, system meeting frame by frame The corresponding scene grid structure of new binocular image frame is constructed according to above three module, then judges the left side in new binocular image Which region belongs to new vision region on mesh image, and includes with the tri patch that is related to as needing to be added using new vision region New tri patch in original scene grid structural library.In the present invention, new tri patch is completed using virtual image scheme Choose work.The corresponding scene grid structure of previous frame binocular image is obtained in system, present frame binocular image is corresponding Scene grid structure and two frame binocular images between motion information, according to principle of computer vision, it is available on Each point on left mesh image in one frame binocular image is incident upon in current binocular image after motion information effect Left mesh image on position, for a single point on the left mesh image in previous frame binocular image specific calculation such as Under:
If the homogeneous coordinates that pixel coordinate of this in the left mesh image in previous frame binocular image is fastened are Pp, this point It is z in the depth value at previous frame momentp, pixel coordinate of this in the left mesh image in present frame binocular image is fastened neat Secondary coordinate is Pc, depth value of this at the present frame moment is zc, the corresponding kinematic matrix of inter motion information be T, camera it is interior Parameter matrix is K, is calculated by following formula:
When all pixels with depth value acted on the process in the left mesh image in previous frame binocular image Later, so that it may obtain a secondary virtual image generated according to depth value and inter motion information, so far, which is band The image in cavity needs to repair the image by interpolation method, and what is taken in the present invention is based on Navier-Stokes equation Image repair scheme, as shown in Figure 8 it is demonstrated experimentally that the recovery scenario has reached satisfactory journey for the reparation result of image Degree, Fig. 8 (a) are the virtual image before image repair processing, and Fig. 8 (b) is image repair treated virtual image.It is being repaired After virtual image after multiple, the gray value of the image and the gray value of the left mesh image in present frame binocular image are compared Right, statistical average gray value error chooses gray value error and is higher than the tri patch of average gray value error as new vision area The composition dough sheet (white face panel region as shown in Figure 9 illustrates new vision area detection result) in domain, scene net to be added It formats in structural library, the scene grid topology update after being is prepared.
Figure 10 illustrates the local corresponding diagram in new vision region, wherein (a) (c) be previous frame in depth value inaccuracy or The incomplete part of visual information;(b) (d) is (a) (c) corresponding new vision area detection result.
Second stage, the scene grid topology update stage:
In order to which the scene grid structure for generating increment type is gridding structure continuous and without redundancy dough sheet, institute After the tri patch in the representative new vision region for having obtained handling on last stage, it is also necessary to selected original scene grid Which scene tri patch in structural library is that needs are optimised.In the present invention, the side based on interframe mapping is still taken Case completes this work.Process is embodied are as follows: (what is set in a particular embodiment is ten by several frames before present frame Frame) tri patch in corresponding scene grid structural library is mapped to present frame according to motion information, by in present frame The overlapping of new vision region or partly overlapping tri patch, which are considered as, answers optimised tri patch;Again by new vision area in present frame All tri patch in domain carry out connected region search, sort out all connected regions;Then according to these triangles to be optimized It is corresponding with all tri patch in present frame in new vision region that dough sheet is mapped to the image coordinate vertex after present frame Image coordinate vertex concentrates in together, and by Delaunay Triangulation technology, on the basis of each connected region, carries out again Triangulation work;Finally, delete these tri patch to be optimized in scene gridding structural library, and by new Delaunay tri- Scene grid structural library is added in divided region corresponding tri patch in angle.The operation is carried out frame by frame, just can obtain global scope On continuous scene grid structural remodeling result.As Figure 11 illustrates scene grid structural remodeling as a result, wherein Figure 11 (a) For grid configuration, for effect of visualization, structure more than certain depth is replaced with scatterplot, and Figure 11 (b) is that RGB renders form.
Finally it is pointed out that above embodiments are only the more representational examples of the present invention.Obviously, technology of the invention Scheme is not limited to above-described embodiment, and acceptable there are many deformations.Those skilled in the art can not depart from the present invention The invention state of mind under, various modifications or variation are made for above-described embodiment, thus protection scope of the present invention not by Above-described embodiment is limited, and should be the maximum magnitude for meeting the inventive features that claims are mentioned.

Claims (6)

1. a kind of unmanned scene progressive mesh structural remodeling method based on binocular camera, which is characterized in that including Following steps:
1) the single frames binocular video frame in the scene acquired by vehicle-mounted binocular camera is inputted, to the single frames binocular video frame of input Carry out scene grid structural remodeling;
2) it is found in scene grid structure using network structure feature and the position of grid " sting " phenomenon occurs, and eliminate grid " sting " phenomenon recycles approximate Laplce's smoothing method to promote the smoothness of overall scenario network structure;
3) using the location information of Vehicular satellite navigation equipment acquisition scene, by location information resolve previous frame and present frame it Between motion information carry out new vision region detection later to obtain the transformation matrix that continuously moves of description interframe;New vision Region detection are as follows: according to the scene grid structure of transformation matrix and previous frame construct virtual image, using virtual image with work as Vision difference between previous frame determines that present frame compares the new vision region of previous frame;
4) using the camera position of present frame relative to the cumulative motion information of the camera position of initial frame and the entirety constructed Scene dough sheet in scene grid structure determines local scene grid to be updated in conjunction with the new vision region in step 3) Change locations of structures;
5) scene grid structure increment formula joining method: by new vision region and local scene gridding structure bit to be updated It sets after being associated, passes through the splicing that Delaunay Triangulation method carries out overall scenario gridding structure;
6) iteration step 1-5, until all single frames binocular video frames that vehicle-mounted binocular camera obtains are processed, most Overall scenario gridding structural remodeling result is obtained eventually.
2. the unmanned scene progressive mesh structural remodeling method according to claim 1 based on binocular camera, It is characterized by:
The step 1) specifically:
1.1) the visual signature point in the two images in the single frames binocular video frame acquired by binocular camera is extracted respectively;
1.2) visual signature point matching stage: the point of visual signature obtained in step 1.1) is based on violence and matches (Brute- Force Matcher) method matched to obtain visual signature point pair, calculate the parallax value of every a pair of of visual signature point;
1.3) camera coordinates system, root the visual signature point depth estimation stage: are established using left mesh camera initial position as coordinate origin According to the visual signature point of the left mesh image of parallax value computation vision characteristic point centering of visual signature point pair in step 1.2) in camera Three-dimensional position in coordinate system, specific calculating process are as follows:
1.3.1 the depth value of each visual signature point) is calculated, to obtain the sparse depth figure of left mesh image:
Wherein, d is parallax value, and b is binocular camera baseline length, and f is camera focus, and z is depth value;
1.3.2 three-dimensional position of the visual signature point of left mesh image in camera coordinates system) is calculated:
Pw=zK-1Puv
Wherein, K is the Intrinsic Matrix of binocular camera, PuvFor the homogeneous coordinates that visual signature point is fastened in image pixel coordinates, PwFor coordinate of the visual signature point in camera coordinates system, u is visual signature point transverse coordinate axis in image pixel coordinates system Upper corresponding position, v are that corresponding position, X are visual signature point to visual signature point in longitudinal coordinate axle in image coordinate system The corresponding position in x-axis in camera coordinates system, Y are that corresponding position, Z are visual signature point in y-axis in camera coordinates system Visual signature point corresponding position in z-axis in camera coordinates system;
1.4) it the triangulation stage: using Delaunay Triangulation method to subdivision is carried out inside visual signature point set, obtains Triangle gridding structure, wherein the visual signature point set is the set of visual signature point on left mesh image;
1.5) the grid subdivision stage: according to step 1.4) triangle gridding structure generated and the depth value of each grid vertex Depth interpolation is carried out to the triangle gridding structure of present frame, sub- iteration is described by Census and is found in integrated triangular net lattice structure Visual signature point on the left mesh image of depth error maximum preceding 5% is as visual signature point to be updated, and according to Hamming Distance matches visual signature point to be updated again, and visual signature point set is added in visual signature point to be updated, is being regarded again Feel and carry out Delaunay Triangulation inside feature point set, thus the scene grid structure after being segmented.
3. the unmanned scene progressive mesh structural remodeling method according to claim 1 based on binocular camera, It is characterized by:
The step 2) specifically:
2.1) grid " sting " removes the stage: handling to traversal formula each grid vertex in scene grid structure, works as grid The depth on vertex is more than or less than the depth of all of its neighbor grid vertex, and between the mean depth on all of its neighbor vertex When absolute value of the difference is greater than threshold value, with the depth of the mean depth substitution grid vertex on all of its neighbor vertex;
2.2) network smoothing stage: with a kind of approximate Laplce's smoothing method to the grid top in scene grid structure Point is smoothed one by one, and the calculation of approximate Laplce's smoothing method is as follows:
Wherein, ZcFor the depth value of grid vertex to be processed, ZnFor the mean depth on all of its neighbor vertex of grid vertex to be processed Value, α is the damping parameter manually set, PwFor position of the grid vertex to be processed in camera coordinates system, PoFor grid to be processed Position of the vertex after optimization in camera coordinates system.
4. the unmanned scene progressive mesh structural remodeling method according to claim 1 based on binocular camera, It is characterized by: the detection method in new vision region is to detect present frame in a manner of based on virtual image in the step 3) In new vision region, it is specific as follows:
Building obtains virtual after each pixel of left mesh image in previous frame single frames binocular video frame is handled as follows Image:
PpFor the homogeneous coordinates that the pixel coordinate of left mesh image of the pixel in previous frame single frames binocular video frame is fastened, zpFor Depth value of the pixel at the previous frame moment, PcFor the pixel of left mesh image of the pixel in present frame single frames binocular video frame Homogeneous coordinates on coordinate system, zcDepth value for pixel at the present frame moment, T are the corresponding movement square of inter motion information Battle array, K are the Intrinsic Matrix of binocular camera;
Image repair is carried out to virtual image using Navier-Stokes equation, then compares the virtual image after repairing and works as Vision difference in the left mesh image of previous frame on each tri patch region obtains vision difference value, the specific meter of vision difference value Calculation mode is as follows:
Wherein, n is sum of all pixels in tri patch region, gpiFor gray value of the ith pixel position in virtual image, gciFor In the gray value of the left mesh image of present frame, d is vision difference value;
It finally chooses vision difference value and is higher than composition dough sheet of the tri patch of average visual difference value as new vision region, it is complete At the detection in new vision region.
5. the unmanned scene progressive mesh structural remodeling method according to claim 1 based on binocular camera, It is characterized in that,
The step 4) is specific as follows: using following calculation method by the triangular facet in the overall scenario gridding structure constructed Piece projects on present frame:
Wherein, PwFor position of the vertex in the world coordinate system using first frame as origin of tri patch, z is depth, and T is to work as Cumulative motion information of the camera position of previous frame relative to the camera position of initial frame, K are the Intrinsic Matrix of binocular camera, Puv The homogeneous coordinates fastened for the vertex of the tri patch projected on present frame in pixel coordinate;
, will be Chong Die with the new vision region in present frame or partly overlap in the overall scenario gridding structure constructed, and Tri patch position of the space length within 5 meters between new vision region corresponding to present frame is considered as to be updated Local scene gridding locations of structures.
6. the unmanned scene progressive mesh structural remodeling method according to claim 1 based on binocular camera, It is characterized by:
Scene grid structure increment formula joining method in the step 5) specifically: will be in the new vision region of present frame All tri patch carry out connected region search, all connected regions are sorted out, by each connected region and office to be updated The position that portion's scene grid locations of structures projects on the left mesh image of present frame carries out Delaunay triangle again after concentrating and cuts open Point, overall scenario gridding structure is updated with this.
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