CN106683173B - A method of Three-dimensional Gravity is improved based on neighborhood Block- matching and is laid foundations the dense degree of cloud - Google Patents
A method of Three-dimensional Gravity is improved based on neighborhood Block- matching and is laid foundations the dense degree of cloud Download PDFInfo
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Abstract
It Three-dimensional Gravity is improved based on neighborhood Block- matching lays foundations the method for the dense degree of cloud the invention discloses a kind of, include: to obtain coarse and sparse object point cloud using the three-dimensional reconstruction algorithm based on image sequence, obtains the transformation matrix of camera in three dimensions when each frame image taking;Original image is handled again, using the block matching algorithm based on neighborhood, to progress dense characteristic matching in image;Satisfactory characteristic point to obtained dense characteristic point to progress legitimacy inspection, and is mapped to corresponding position in three-dimensional point cloud by the next position according to obtained camera in space;An exterior point is carried out to obtained point cloud using the outer vertex deletion algorithm based on contour of object to filter, and carries out a color and remaps, and obtains the dense point cloud that quality is much better than original point cloud.The present invention can obtain quality and the dense point cloud for being much higher than traditional algorithm, can significantly improve the effect of primal algorithm, improve reconstruction quality;Universality is high, strong robustness.
Description
Technical field
The invention belongs to technical field of computer vision, more particularly to a kind of neighborhood Block- matching raising Three-dimensional Gravity that is based on to lay foundations
The method of the dense degree of cloud.
Background technique
Three-dimensional reconstruction based on image sequence is related to many subjects, belongs to the reverse process of camera imaging principle, studies model
It encloses and specifically includes that object target identifies, feature detection, the fields such as characteristic matching.Three-dimensional reconstruction has just become since birth
One of the hot spot of computer vision field and difficult point.Its input only needs general color image, and the high feature of universality exists
When to object modeling in real world, it is impayable convenient to provide.However, needing to count too much due to having in three-dimensional reconstruction
The parameter of measurement is calculated, therefore the reconstruction model for how obtaining high quality also becomes its difficult point for being difficult to capture.In general, Three-dimensional Gravity
The core procedure built is how to obtain the point cloud of the enough expression object model information of high quality.Usual three-dimensional reconstruction be divided into
Lower two categories: (1) based on the three-dimensional rebuilding method of image sequence.Three-dimensional rebuilding method based on image sequence passes through to object
It carries out surrounding shooting acquisition input picture.According to the characteristic matching between the feature and image detected in image, two frames are obtained
Between camera transformation mode.When error by minimizing all image camera positions finally determines each frame image taking,
Rotation and translation of the camera relative to world coordinate system can determine each characteristic point in space according to these information
Actual position, to obtain sparse cloud of object.Then the point cloud acquired again by some cloud growth algorithm increases
Consistency.(2) based on the three-dimensional rebuilding method of depth camera.Three-dimensional rebuilding method based on depth camera is by using depth
Degree camera captures image and depth map in real time.I.e. for each frame image, the frame each pixel can be obtained in space
In position.And with the movement of camera, the point cloud of next frame is constantly matched with the point cloud of the frame, phase between two frames is detected
The movement that seat in the plane is set is fused together the point cloud of different frame, obtains the dense point cloud of object.In the above methods, it is based on
The advantages of there is the three-dimensional reconstruction of image sequence input data easily to obtain, and there is shooting environmental to require low, strong robustness.But by
It is only capable of providing the information of two-dimensional space in image, therefore when reversely solving three dimensional space coordinate, has many mistakes in calculating
Difference and noise exist, for example hardly result in accurate matching characteristic point pair, so that often quality is not high enough for obtained point cloud, cause
Finally obtained modelling effect is unsatisfactory.And based on the method for depth camera due in the image of acquisition, each pixel
It can be taken as a characteristic point, therefore characteristic point dense enough can be obtained.But since it needs the depth phase of high quality
Machine, and be difficult to deal with apart from farther away shooting, while civilian depth camera maximum magnitude, therefore should about in 10m or so at present
Requirement of the method to shooting environmental and equipment is excessively high.And the three-dimensional reconstruction based on image sequence is not limited, as long as object exists
Enough features are showed in image.
In conclusion the point cloud quality that the three-dimensional reconstruction based on image sequence obtains is not high enough, there are biggish errors;Base
It is excessively high to shooting environmental requirement in the method for depth camera, the depth camera of high quality is needed, and be difficult to deal with distance farther out
Shooting.
Summary of the invention
It Three-dimensional Gravity is improved based on neighborhood Block- matching lays foundations the method for the dense degree of cloud the purpose of the present invention is to provide a kind of,
The point cloud quality for aiming to solve the problem that the three-dimensional reconstruction based on image sequence obtains is not high enough;Based on the method for depth camera to shooting ring
Border requirement is excessively high, needs the depth camera of high quality, and be difficult to the problem of dealing with apart from farther away shooting.
The invention is realized in this way a method of Three-dimensional Gravity is improved based on neighborhood Block- matching and is laid foundations the dense degree of cloud,
It is described based on neighborhood Block- matching improve Three-dimensional Gravity lay foundations the dense degree of cloud method the following steps are included:
Step 1 obtains coarse and sparse object point cloud using the three-dimensional reconstruction algorithm based on image sequence, obtains every
The transformation matrix of camera in three dimensions when one frame image taking;
Step 2 is again handled original image, thick to carrying out in image using the block matching algorithm based on neighborhood
Close characteristic matching;
Step 3, the following position according to obtained camera in space, to obtained dense characteristic point to closing
Method is examined, and satisfactory characteristic point is mapped to corresponding position in three-dimensional point cloud;
Step 4 carries out an exterior point to obtained point cloud using the outer vertex deletion algorithm based on contour of object and filters, and
It carries out a color to remap, obtains the dense point cloud that final mass is much better than original point cloud.
Further, described the lay foundations method of the dense degree of cloud of Three-dimensional Gravity is improved based on neighborhood Block- matching to specifically include following step
It is rapid:
The first step carries out traditional three-dimensional reconstruction using around bat image sequence;
Second step chooses the dense characteristic generating algorithm that adjacent image carries out the Block- matching based on neighborhood, determines neighborhood
Step-length n, i.e. each image can carry out the calculating of dense characteristic with each two images in its left and right;
Third step after determining the matched step-length n of adjacent image, traverses whole image sequence, on the basis of every piece image
Image carries out the block matching algorithm based on neighborhood with the n frame image at its rear;In original image, along row and column direction every
How many a pixels take a point conduct to need to carry out matched characteristic point, for the feature calculation based on Block- matching;
4th step after determining sample rate r, needs to carry out the image (P of matching characteristic for every a pair1, P2) needed
The P to be calculated1In matching point set Pt;All characteristic points are selected around it centered on each characteristic point in traversal Pt
Its ranks is all extended for original 8 times using interpolation algorithm, is denoted as I by the image block for taking X*Y sizesrc;In P2In, with same
Coordinate points centered on, choose the image block of M*N size, its ranks be all equally extended for original 8 times using interpolation algorithm,
It is denoted as Idist;
5th step, works as IdistWhen tile size is sufficiently large, image block I can be foundsrcCorresponding image block Imatch;
Image block I at this timematchCenter figure P2In position namely construct image block IsrcThe characteristic point of Shi Suoyong is in image P2On
Corresponding match point;
6th step, after completing characteristic matching, what is needed schemes the dense characteristic pair between opposite;For image sequence
In each frame, by with it carried out characteristic matching calculating image be denoted as P2;P will be shot1And P2When camera photocentre position point
C is not denoted as it1And C2;Traverse P1Feature point set Pt in all characteristic point position, find in phase plane in three dimensions
Position Pt where it1 ;Pt is found simultaneously1In image P2On the match point position Pt in phase plane in three dimensions2 ’;And
Ray C is in three dimensions1Pt1' and C2Pt2 ’.Obtain ray L1And L2;
7th step, for obtained ray L1With L2For, if matching double points Pt1With Pt2It is correct match point, that
L1With L2It should intersect in the corresponding points of object model in space;One threshold value T is set, when this two different surface beelines it
Between the distance between closest approach when being less than T, this pair of of match point is legal matching double points;
8th step, for obtained legal matching double points, if be ray L1With L2It meets at a bit, then using intersection point as new
Characteristic point be supplemented in initial point cloud;If L1With L2It is less than the different surface beeline of threshold value T for closest approach distance;Then take L1And L2's
The midpoint of proximity pair is added in initial point cloud as new three-dimensional point;
9th step carries out the miscellaneous point based on contour of object and filters out, and for each frame image, extracts contour of object, by
Point in contour area is retained the position of Dian Yun back projection phase plane into three-dimensional space by the camera transformation matrix arrived;And
After back projection, in any one frame, the point outside contour of object is appeared in, all deletes it from cloud.
Tenth step, the phase plane Dian Yun back projection to each frame in space record each pixel in phase plane and exist
Point when back projection in the point cloud nearest apart from it, is assigned to this closest to him point for the pixel value of the pixel on image
Point in cloud, to complete remapping for a cloud color.
Further, the camera transformation matrix include camera photocentre position relative to world coordinate system origin rotation and
Translation is [R | T], and wherein R is spin matrix, and T is translation vector.
Further, using the style of shooting of 5 ° of rotation between every two frame in the step 2, the step-length used is 2.
Further, the sample rate that a pixel is taken every 2 rows 2 column is used in the step 3;The pixel number of selection
The time overhead of mesh and algorithm is directly proportional.
Further, the value of M and N is respectively necessary for being greater than X and Y in the step 4;Using X, ginseng that Y 40, M and N are 80
Number setting.
Further, in the step 5, the formula of calculating position (x, y) coefficient R is as follows:
Wherein:
Wherein, T (x, y) representative image IsrcThe pixel value of middle coordinate (x, y) position, I (x, y) representative image IdistMiddle seat
Mark the pixel value of the position (x, y).W and h respectively represents the width and height of image.
Further, in the step 6, when finding characteristic point in the phase plane of each frame, the transformation using camera is needed
Matrix [R | T], the focal length taken pictures are f, and in a certain frame F, the position of characteristic point is (x, y), rotational translation matrix on the image
For [R | T], then the calculation formula of its three-dimensional coordinate (X, Y, Z) in world coordinate system is as follows:
Further, in the step 7, two ray L are thought in setting1With L2Legal threshold value is 1e-2;
In the step 8, parameter k is 5;
In the step 9, the method for the phase plane of Dian Yun back projection to the i-th frame is needed to the transformation matrix using camera
[R|T];In point cloud a bit (X, Y, Z), it is projected in the calculation formula of the coordinate (u, v) in the i-th frame are as follows:
Wherein, f is the focal length of the i-th frame;
In the step 10, if multiple phase planes are all by the pixel-map of some point therein a to point in cloud
Pt, then the RGB of Pt takes the pixel mean value of the corresponding points of these planes.
Another object of the present invention is to provide neighborhood Block- matching is based on described in a kind of application, to improve Three-dimensional Gravity cloud of laying foundations thick
The computer vision system of the method for close degree.
It is provided by the invention Three-dimensional Gravity is improved based on neighborhood Block- matching to lay foundations the method for the dense degree of cloud, for image sequence
There is no particular/special requirement, the inexcessive dependence of the adjustment for parameter can improve the quality and consistency of point cloud with high degree.
The present invention further expands obtained point cloud, it is complete to increase its on the basis of the three-dimensional reconstruction based on image sequence
Whole degree and consistency.On the basis of existing three-dimensional reconstruction obtains the algorithm of sparse cloud, point Yun Tezheng is increased considerably, thus
Promote the algorithm of maximal end point cloud result.
The present invention compares and the three-dimensional reconstruction algorithm based on SIFT feature, the point cloud consistency of acquisition, integrity degree, Yi Jiyan
Chromatic rendition degree is all much better than universal algorithm.Meanwhile the region smoother for feature SIFT is correctly special it is difficult to extract going out
Point is levied, and the present invention is based on fast matched methods, can maximally utilize the information of each pixel peripheral neighborhood, as far as possible
Increase correct characteristic point.Meanwhile based on the calculated camera transformation square arrived, it is inaccurate to eliminate traditional fast matching algorithm
The shortcomings that, it can be a large amount of, missing or excessively sparse point cloud supplement are accurately become into quality and preferably put cloud.
Compared to the method based on depth image, since this method needs the corresponding depth image of each frame and adjacent
Displacement cannot be excessive between frame, so being difficult have true use value in the scene that can not obtain depth map.It is civilian at present
High-resolution depth camera be often only capable of detection 10 meters within depth bounds.Although and laser acquisition is reached apart from enough
Less than enough precision.As long as the present invention can obtain simple image, can be realized the Model Reconstruction of high quality, and two frames it
Between displacement be not based on required for the method for depth image accurately, increase universality and ease for use;Using around bat image
Carry out traditional three-dimensional reconstruction based on SIFT feature;Determine neighborhood matching step-length n;It is matched to determine that sampling step length needs to carry out
Characteristic point;Image sequence is traversed, to calculative image to carrying out the feature extraction based on neighborhood Block- matching;Based on obtaining in 1
Matching characteristic obtained in the camera matrix taken and 4 is filtered the feature in 4;Based on image outline to the point in space
Cloud is filtered out again and color correction.The present invention can obtain quality and the dense point cloud for being much higher than traditional algorithm, energy
Enough effects for significantly improving primal algorithm, improve reconstruction quality;It is that a kind of universality is high, the improvement three-dimensional reconstruction of strong robustness
The method of maximal end point cloud quality.
Detailed description of the invention
Fig. 1 is provided in an embodiment of the present invention to improve Three-dimensional Gravity based on neighborhood Block- matching and lay foundations the method stream of the dense degree of cloud
Cheng Tu.
Fig. 2 is the flow chart of embodiment 1 provided in an embodiment of the present invention.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to embodiments, to the present invention
It is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, it is not used to
Limit the present invention.
Application principle of the invention is explained in detail with reference to the accompanying drawing.
It Three-dimensional Gravity is improved based on neighborhood Block- matching lays foundations the dense degree of cloud as shown in Figure 1, provided in an embodiment of the present invention
Method the following steps are included:
S101: coarse and sparse object point cloud is obtained using traditional three-dimensional reconstruction algorithm based on image sequence, is obtained
The transformation matrix of camera in three dimensions when to each frame image taking;
S102: again being handled original image, dense to carrying out in image using the block matching algorithm based on neighborhood
Characteristic matching, the matched method of this feature can obtain dense enough, but the lower matching characteristic pair of precision;
S103: the next position according to obtained camera in space, it is legal to carrying out to obtained dense characteristic point
Property examine, and satisfactory characteristic point is mapped to corresponding position in three-dimensional point cloud;
S104: exterior point is carried out to obtained point cloud using the outer vertex deletion algorithm based on contour of object and is filtered, is gone forward side by side
Color of row remaps, and obtains the dense point cloud that final mass is much better than original point cloud.
Application principle of the invention is further described combined with specific embodiments below.
Embodiment 1:
It is provided in an embodiment of the present invention based on neighborhood Block- matching improve Three-dimensional Gravity lay foundations the dense degree of cloud method include with
Lower step:
Step 1: target object being carried out to surround shooting, obtains the image of all angles.
Step 2: being rebuild using traditional three-dimensional rebuilding method based on SIFT feature matching algorithm, obtain each frame
Camera spin matrix when shooting.
Step 3: determining the step-length for carrying out images match, and use the Feature Correspondence Algorithm based on neighborhood Block- matching, extract
Dense matching characteristic point.Feature point extraction formula has a detailed description in the explanation of S5.
Step 4: after obtaining dense matching characteristic point, carrying out the inspection of legitimacy to it in three dimensions, will be discontented with
The characteristic point of sufficient threshold condition is concentrated from and is deleted, and meet threshold condition calculates its actual position in space.
Step 5: legal cloud all in step 4 being added in original cloud, the consistency of original cloud and complete is promoted
Whole degree.
Step 6: miscellaneous filtering algorithm and color correction algorithm based on profile are carried out, to filter off a small amount of existing wrong point,
And the color of the point cloud of expansion is corrected, to complete entire algorithm flow.
More dense complete high quality point cloud is finally obtained according to above step.
It is provided in an embodiment of the present invention the lay foundations method of the dense degree of cloud of Three-dimensional Gravity is improved based on neighborhood Block- matching specifically to wrap
Include following steps:
S1, which is used, carries out traditional three-dimensional reconstruction around bat image sequence, since traditional three-dimensional reconstruction is calculated based on SIFT feature
Method, and SIFT accuracy is higher, is able to carry out the extraction of sub-pixel another characteristic, therefore phase in accurate three-dimensional space can be obtained
The transformation matrix that seat in the plane is set.
S2 chooses the dense characteristic generating algorithm that adjacent image carries out the Block- matching based on neighborhood.Firstly, determining neighborhood
Step-length n, i.e. each image can carry out the calculating of dense characteristic with each two images in its left and right.
After S3 determines the matched step-length n of adjacent image, whole image sequence is traversed, using every piece image as benchmark image,
The block matching algorithm based on neighborhood is carried out with the n frame image at its rear.The algorithm is firstly the need of sample rate r is determined, i.e., original
In image, takes a point to be used as every how many a pixels along row and column direction and need to carry out matched characteristic point, for being based on
The feature calculation of Block- matching.
After S4 determines sample rate r, need to carry out the image (P of matching characteristic for every a pair1, P2) obtained needing to count
The P of calculation1In matching point set Pt.All characteristic points choose X* centered on each characteristic point around it in traversal Pt
Its ranks is all extended for original 8 times using interpolation algorithm, is denoted as I by the image block of Y sizesrc.In P2In, similarly to sit
Centered on punctuate, the image block of M*N size is chosen, its ranks is all equally extended for original 8 times using interpolation algorithm, is denoted as
Idist。
S5 based on the assumption that, it is believed that when camera to image when carrying out surrounding shooting, the motion amplitude between adjacent two frame is very
It is small.Therefore in S4, work as IdistWhen tile size is sufficiently large, image block I can be found whereinsrcCorresponding image block
Imatch.And image block I at this timematchCenter figure P2In position namely construct image block IsrcThe characteristic point of Shi Suoyong exists
Image P2Upper corresponding match point, due to interpolation work before, the precision of the Block- matching finally carried out is 1/8 pixel.
After S6 completes the characteristic matching in S5, what is needed schemes the dense characteristic pair between opposite.But due to object
Between the two images due to the variation of photo angle, can only accomplish in IdistMiddle searching is as close possible to IsrcImage block.Cause
This, the characteristic matching extracted in this way needs to be further processed to there is biggish noise.In S1, shooting image has been obtained
The position of camera in three dimensions when each frame.In S5, the matching characteristic point pair between image pair has been obtained.For image
Each frame in sequence, with P1For, the image for carrying out characteristic matching calculating with it is denoted as P2.P will be shot1And P2When
Camera photocentre position is denoted as C respectively1And C2.Traverse P1Feature point set Pt in all characteristic point position, with point Pt1For,
The position Pt where it is found in phase plane in three dimensions1 ’.Pt is found simultaneously1In image P2On match point in three-dimensional
Position Pt in space in phase plane2 ’.And ray C is in three dimensions1Pt1 ’And C2Pt2 ’.Obtain ray L1And L2。
S7 is for ray L obtained in S61With L2For, if matching double points Pt1With Pt2It is correct match point, then
L1With L2It should intersect in the corresponding points of object model in space.However, various errors and floating-point due to being introduced in calculating
The constant error of calculating, is difficult to find and really meets at the case where a bit.Therefore, in most cases, L1With L2It is two antarafacials
Straight line, and a threshold value T can be set in algorithm, when the distance between the closest approach between this two different surface beelines is less than T, just
Think that this pair of of match point is legal matching double points.
S8 is for legal matching double points obtained in S7, if be ray L1With L2It meets at a bit, then using intersection point as new
Characteristic point is supplemented in initial point cloud.If L1With L2It is less than the different surface beeline of threshold value T for closest approach distance.Then take L1And L2Most
The midpoint of near point pair is added in initial point cloud as new three-dimensional point.The point being newly supplemented in three-dimensional point cloud, around it
Mean value apart from nearest k colors is as the color newly put.The point cloud color obtained in this way has error, specific to correct
Method is shown in S10.
Although S9 result obtained in S8 has filtered off most of error matching points, still there is fraction
There is errors for match point, therefore carry out the miscellaneous point based on contour of object to it and filter out.For each frame image, object wheel is extracted
It is wide.It, can be by the position of Dian Yun back projection phase plane into three-dimensional space by camera transformation matrix obtained in S1.Herein it
Afterwards, the point in contour area is retained.And after back projection, in any one frame, the point outside contour of object is appeared in, all will
It is deleted from cloud.
The color for the point cloud that S10 is newly increased at present still has error, again by the method in S9 Dian Yun back projection
To the phase plane of each frame in space.It records in the point cloud that each pixel is nearest apart from it in back projection in phase plane
Point.The pixel value of the pixel on image is assigned to the point in this closest to him point cloud, to complete a cloud color
It remaps.
Camera transformation matrix obtained in the step S1 includes camera photocentre position relative to world coordinate system origin
Rotation and translation be [R | T], wherein R is spin matrix, and T is translation vector.
The matching step-length maximum value chosen in the step S2 is depending on the amplitude size moved in camera shooting process.?
In this algorithm, the style of shooting of 5 ° of rotation between every two frame is used, the step-length used is 2.Amplitude of variation between every two frame
Bigger, then corresponding step-length should be smaller, and vice versa.
Sample rate in the step S3 will affect the number of the match point ultimately generated.In the method, it has used every
The sample rate of a pixel is taken every 2 rows 2 column.The pixel number of selection and the time overhead of algorithm are directly proportional.
The value of M and N is respectively necessary for being greater than X and Y in the step S4.In algorithm experimental, X, Y 40, M and N have been used
For 80 parameter setting.
In the S5 step, in IdistMiddle searching image block IsrcThe image matching algorithm based on related coefficient is used.I.e.
By image block IsrcIn image block IdistOn from left to right, move from top to bottom, calculate each position IsrcThe I covered with itdist
Region image block coefficient R, and choose I in the maximum position of related coefficientsrcThe region covered, as image
Block Imatch.In sliding IsrcDuring, by IsrcThe upper left corner is in IdistIn coordinate (x, y) be denoted as the coordinate of current location.Meter
The formula for calculating position (x, y) coefficient R is as follows:
Wherein:
Wherein, T (x, y) representative image IsrcThe pixel value of middle coordinate (x, y) position, I (x, y) representative image IdistMiddle seat
Mark the pixel value of the position (x, y).W and h respectively represents the width and height of image.
In step S6, when finding characteristic point in the phase plane of each frame, the transformation matrix [R | T] using camera is needed.
Specific formula is as follows, it is assumed that the focal length taken pictures is f, and in a certain frame F, the position of characteristic point is (x, y), rotary flat on the image
Moving matrix is [R | T], then its three-dimensional coordinate calculation formula in world coordinate system is as follows:
In step S7, what is be arranged in test thinks two ray L1With L2Legal threshold value is 1e-2。
In step S8, selection for parameter k uses in test 5.
In step S9, by the method for the phase plane of Dian Yun back projection to the i-th frame need using camera transformation matrix [R |
T].In postulated point cloud a bit (X, Y, Z), it is projected in the calculation formula of the coordinate (u, v) in the i-th frame are as follows:
Wherein, f is the focal length of the i-th frame.
In step S10, if multiple phase planes all by the pixel-map of some point therein to a point Pt in cloud,
The RGB of Pt takes the pixel mean value of the corresponding points of these planes.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all in essence of the invention
Made any modifications, equivalent replacements, and improvements etc., should all be included in the protection scope of the present invention within mind and principle.
Claims (8)
- It Three-dimensional Gravity is improved based on neighborhood Block- matching lays foundations the method for the dense degree of cloud 1. a kind of, which is characterized in that is described based on neighbour Domain Block- matching improve Three-dimensional Gravity lay foundations the dense degree of cloud method the following steps are included:Step 1 obtains coarse and sparse object point cloud using the three-dimensional reconstruction algorithm based on image sequence, obtains each frame The transformation matrix of camera in three dimensions when image taking;Step 2 is again handled original image, using the block matching algorithm based on neighborhood, to carrying out dense spy in image Sign matching;Step 3, the position of the camera that next basis obtains in space, to obtained dense characteristic point to progress legitimacy It examines, and satisfactory characteristic point is mapped to corresponding position in three-dimensional point cloud;Step 4 carries out an exterior point to obtained point cloud using the outer vertex deletion algorithm based on contour of object and filters, and carries out One time color remaps, and obtains the dense point cloud that final mass is much better than original point cloud;It is described based on neighborhood Block- matching improve Three-dimensional Gravity lay foundations the dense degree of cloud method specifically includes the following steps:The first step carries out three-dimensional reconstruction using around bat image sequence;Second step chooses the dense characteristic generating algorithm that adjacent image carries out the Block- matching based on neighborhood, determines neighborhood step-length N, i.e. each image can carry out the calculating of dense characteristic with each two images in its left and right;Third step after determining the matched step-length n of adjacent image, traverses whole image sequence, using every piece image as benchmark image, The block matching algorithm based on neighborhood is carried out with the n frame image at its rear;In original image, along row and column direction every multiple pictures Vegetarian refreshments takes a point conduct to need to carry out matched characteristic point, for the feature calculation based on Block- matching;4th step after determining sample rate r, needs to carry out the image (P of matching characteristic for every a pair1, P2) obtained needing to count The P of calculation1In matching point set Pt;All characteristic points choose X* centered on each characteristic point around it in traversal Pt Its ranks is all extended for original 8 times using interpolation algorithm, is denoted as I by the image block of Y sizesrc;In P2In, similarly to sit Centered on punctuate, the image block of M*N size is chosen, its ranks is all equally extended for original 8 times using interpolation algorithm, is denoted as Idist;5th step, works as IdistWhen tile size is sufficiently large, image block I can be foundsrcCorresponding image block Imatch;At this time Image block ImatchCenter figure P2In position namely construct image block IsrcThe characteristic point of Shi Suoyong is in image P2Upper correspondence Match point;6th step, after completing characteristic matching, the dense characteristic pair between image pair that is needed;For in image sequence The image for carrying out characteristic matching calculating with it is denoted as P by each frame2;P will be shot1And P2When camera photocentre position remember respectively Make C1And C2;Traverse P1Feature point set Pt in all characteristic point position, find its institute in phase plane in three dimensions Position Pt1;Pt is found simultaneously1In image P2On the match point position Pt in phase plane in three dimensions2';And three Ray C is in dimension space1Pt1' and C2Pt2';Obtain ray L1And L2;7th step, for obtained ray L1With L2For, if matching double points Pt1With Pt2It is correct match point, then L1With L2It should intersect in the corresponding points of object model in space;One threshold value T is set, when between this two different surface beelines most When the distance between near point is less than T, this pair of of match point is legal matching double points;8th step, for obtained legal matching double points, if be ray L1With L2It meets at a bit, then using intersection point as new spy Sign point is supplemented in initial point cloud;If L1With L2It is less than the different surface beeline of threshold value T for closest approach distance;Then take L1And L2It is nearest The midpoint of point pair is added in initial point cloud as new three-dimensional point;9th step carries out the miscellaneous point based on contour of object and filters out, and for each frame image, extracts contour of object, passes through what is obtained Point in contour area is retained the position of Dian Yun back projection phase plane into three-dimensional space by camera transformation matrix;And it counter throws After shadow, in any one frame, the point outside contour of object is appeared in, all deletes it from cloud;Tenth step, the phase plane Dian Yun back projection to each frame in space record each pixel in phase plane and throw counter Point when shadow in the point cloud nearest apart from it, the pixel value of the pixel on image is assigned in this closest to him point cloud Point, to complete remapping for a cloud color.
- 2. improving Three-dimensional Gravity based on neighborhood Block- matching as described in claim 1 to lay foundations the method for the dense degree of cloud, feature exists Rotation and translation i.e. [R | T] for including camera photocentre position relative to world coordinate system origin in, the camera transformation matrix, Wherein R is spin matrix, and T is translation vector.
- 3. improving Three-dimensional Gravity based on neighborhood Block- matching as described in claim 1 to lay foundations the method for the dense degree of cloud, feature exists In the second step chooses the dense characteristic generating algorithm that adjacent image carries out the Block- matching based on neighborhood, determines that neighborhood walks Each two images of long n, i.e. each image meeting and its left and right carry out in the calculating of dense characteristic using 5 ° of rotation between every two frame Style of shooting, the step-length used are 2.
- 4. improving Three-dimensional Gravity based on neighborhood Block- matching as described in claim 1 to lay foundations the method for the dense degree of cloud, feature exists In after the third step determines the matched step-length n of adjacent image, traversal whole image sequence is schemed on the basis of every piece image Picture carries out the block matching algorithm based on neighborhood with the n frame image at its rear;In original image, along row and column direction every more A pixel takes a point conduct to need to carry out matched characteristic point, for use in the feature calculation based on Block- matching every 2 Row 2 arranges the sample rate for taking a pixel;The pixel number of selection and the time overhead of algorithm are directly proportional.
- 5. improving Three-dimensional Gravity based on neighborhood Block- matching as described in claim 1 to lay foundations the method for the dense degree of cloud, feature exists In the value that the 4th step chooses M and N in the image block of M*N size is respectively necessary for being greater than X and Y;It is using X, Y 40, M and N 80 parameter setting.
- 6. improving Three-dimensional Gravity based on neighborhood Block- matching as described in claim 1 to lay foundations the method for the dense degree of cloud, feature exists In the 5th step image block ImatchCenter figure P2In position namely construct image block IsrcThe characteristic point of Shi Suoyong In image P2In upper corresponding match point, the formula of calculating position (x, y) coefficient R is as follows:Wherein:Wherein, T representative image Isrc, I representative image Idist。
- 7. improving Three-dimensional Gravity based on neighborhood Block- matching as described in claim 1 to lay foundations the method for the dense degree of cloud, feature exists In, after the 6th step completes characteristic matching, the dense characteristic pair between image pair that is needed;For in image sequence Each frame, by with it carried out characteristic matching calculating image be denoted as P2In, characteristic point is found in the phase plane of each frame When, it needs to be f using the transformation matrix [R | T] of camera, the focal length taken pictures, in a certain frame F, the position of characteristic point is on the image (x, y), rotational translation matrix are [R | T], then its three-dimensional coordinate calculation formula in world coordinate system is as follows:
- 8. improving Three-dimensional Gravity based on neighborhood Block- matching as described in claim 1 to lay foundations the method for the dense degree of cloud, feature exists In, the 7th step for obtained ray L1With L2Two ray L1With L2Legal threshold value is 1e-2;8th step is for obtained legal matching double points, if be ray L1With L2It meets at a bit, then using intersection point as new Characteristic point is supplemented in initial point cloud;If L1With L2It is less than the different surface beeline of threshold value T for closest approach distance;Then take L1And L2Most Initial point Yun Zhongzhong is added as new three-dimensional point in the midpoint of near point pair, and parameter k is 5;In 9th step, by the method for the phase plane of Dian Yun back projection to the i-th frame need using camera transformation matrix [R | T];In point cloud a bit (X, Y, Z), it is projected in the calculation formula of the coordinate (u, v) in the i-th frame are as follows:Wherein, f is the focal length of the i-th frame;In tenth step, if multiple phase planes all by the pixel-map of some point therein to a point Pt in cloud, The RGB of Pt takes the pixel mean value of the corresponding points of these planes.
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