summary of the invention:
The object of the invention is to overcome the deficiencies in the prior art, a kind of laser range finder and camera relative pose scaling method based on edge matching is provided.
The step of the laser range finder based on edge matching and camera relative pose scaling method is as follows:
1) by laser range finder, obtain the three-dimensional point cloud of surrounding environment, simultaneously by the image of this environment of collected by camera;
2) extract the edge contour of the some cloud that laser range finder collects, obtain representing the three-dimensional point set of three-dimensional edges
;
3), according to the performance parameter of laser range finder and error model, determine the probability distribution of three-dimensional edges point set
;
4) extract the edge contour of camera image, obtain representing the pixel set at two-dimentional edge
;
5), according to the performance parameter of camera and error model, determine the probability distribution of two-dimentional edge pixel
;
6) with one group, comprise rotation matrix
and translation matrix
coordinate conversion matrix represent the relative pose of laser range finder and camera, by three-dimensional edges point set
project under camera coordinates system, obtain two-dimentional edge point set
;
7) according to the probability distribution of three-dimensional edges point set
determine two-dimentional edge point set with projection relation
probability distribution
;
8) calculate the probability distribution of two probability distribution three-dimensional edges point sets
with two-dimentional edge point set
probability distribution
between symmetrical KL distance
, with
,
for parameter, to minimize symmetrical KL distance
for optimum target, try to achieve optimum laser range finder and camera relative pose transition matrix
.
Described step 2) be: a) for unordered some cloud, search for each point around radius be less than
quantity in scope is no more than
all nearest neighbor points, obtain point set
, for
fit Plane
, with point set
in plane
interior subpoint position is independent variable, point set
to plane
distance be functional value, matching Binary quadratic functions
, obtain Hessian matrix
, calculate Hessian matrix
eigenwert
with
, suppose
if,
and
,
,
be respectively respective threshold, think that this point is marginal point; B), for orderly some cloud, depth map, utilizes Canny algorithm to extract edge point set.
Described is point set
fit Plane
method be: calculate point set
average, obtain plane
center
; Calculate
proper vector, its minimal eigenvalue characteristic of correspondence vector is plane
normal vector
; Plane
center
and normal vector
represented that one through center
, normal vector is
plane.
Described matching Binary quadratic functions
and obtain Hessian matrix
method be: for point set
middle every bit
, suppose
another two eigenwert characteristic of correspondence vectors are respectively
with
, calculate one with
,
for independent variable,
for the key-value pair of value,
One group of final formation
to
key assignments mapping, and utilize least square method to ask for Hessian matrix
be expressed as
The probability distribution of three-dimensional edges point set in described step 3)
for:
Wherein
represent Gaussian distribution,
for point
uncertain covariance matrix, depends on sensor performance parameter and error model.
The method of extracting camera image edge contour in described step 4) is Canny algorithm.
The probability distribution of two-dimentional edge pixel in described step 5)
for:
for pixel
uncertain covariance matrix, depends on sensor performance parameter and error model.
In described step 6) by three-dimensional edges point set
projecting to the lower method of camera coordinates system is: for three-dimensional edges point set
in a bit
, the subpoint in its corresponding camera imaging plane
for
Wherein
with
be respectively rotation matrix and translation matrix.
In described step 7) according to three-dimensional edges point set
probability distribution
determine two-dimentional edge point set with projection relation
probability distribution
method be:
Wherein
?。
Probability distribution two dimension edge point set in described step 8)
probability distribution
probability distribution with two-dimentional edge pixel
between symmetrical KL distance
computing method be:
Minimize this symmetrical KL distance, can obtain module and carriage transformation matrix
.
The present invention compared with prior art, the beneficial effect having:
1. do not rely on specific environment structure, do not rely on the auxiliary objects such as scaling board;
2. can on-line operation, the relative pose of immediate updating laser range finder and camera;
3. the some cloud edge contour and the image border profile that extracted can be further used for other application such as environment object identification and location.
Embodiment
A kind of laser range finder and camera relative pose scaling method based on edge matching of the present invention, after demarcating, the some cloud of laser range finder collection can carry out corresponding accurately with the image of collected by camera.On the one hand, image can obtain colour point clouds for the colouring of some cloud, or pastes color texture for take the surface mesh that a cloud is summit, obtains grain surface model; On the other hand, the degree of depth that some cloud can indicating section image-region, for the application such as the identification based on image, location provide support.
Timing signal, allows laser range finder and camera image data simultaneously, and guarantees their most of coincidence of observation scope, and the some cloud that laser range finder is collected and the image of collected by camera are processed, and obtain online the relative pose of laser range finder and camera.
As described in Figure 1, the step of the laser range finder based on edge matching and camera relative pose scaling method is as follows:
1) by laser range finder, obtain the three-dimensional point cloud of surrounding environment, simultaneously by the image of this environment of collected by camera;
2) extract the edge contour of the some cloud that laser range finder collects, obtain representing the three-dimensional point set of three-dimensional edges
;
3), according to the performance parameter of laser range finder and error model, determine the probability distribution of three-dimensional edges point set
;
4) extract the edge contour of camera image, obtain representing the pixel set at two-dimentional edge
;
5), according to the performance parameter of camera and error model, determine the probability distribution of two-dimentional edge pixel
;
6) with one group, comprise rotation matrix
and translation matrix
coordinate conversion matrix represent the relative pose of laser range finder and camera, by three-dimensional edges point set
project under camera coordinates system, obtain two-dimentional edge point set
;
7) according to the probability distribution of three-dimensional edges point set
determine two-dimentional edge point set with projection relation
probability distribution
;
8) calculate the probability distribution of two probability distribution three-dimensional edges point sets
with two-dimentional edge point set
probability distribution
between symmetrical KL distance
, with
,
for parameter, to minimize symmetrical KL distance
for optimum target, try to achieve optimum laser range finder and camera relative pose transition matrix
.
Described step 2) be: a) for unordered some cloud, search for each point around radius be less than
quantity in scope is no more than
all nearest neighbor points, obtain point set
, for
fit Plane
, with point set
in plane
interior subpoint position is independent variable, point set
to plane
distance be functional value, matching Binary quadratic functions
, obtain Hessian matrix
, calculate Hessian matrix
eigenwert
with
, suppose
if,
and
,
,
be respectively respective threshold, think that this point is marginal point; B) for orderly some cloud, it is depth map, utilize Canny algorithm (Canny J. A computational approach to edge detection[J]. Pattern Analysis and Machine Intelligence, IEEE Transactions on, 1986 (6): 679-698.) extract edge point set.
Described is point set
fit Plane
method be: calculate point set
average, obtain plane
center
; Calculate
proper vector, its minimal eigenvalue characteristic of correspondence vector is plane
normal vector
; Plane
center
and normal vector
represented that one through center
, normal vector is
plane.
Described matching Binary quadratic functions
and obtain Hessian matrix
method be: for point set
middle every bit
, suppose
another two eigenwert characteristic of correspondence vectors are respectively
with
, calculate one with
,
for independent variable,
for the key-value pair of value,
One group of final formation
to
key assignments mapping, and utilize least square method to ask for Hessian matrix
,
The probability distribution of three-dimensional edges point set in described step 3)
for:
Wherein
represent Gaussian distribution,
for point
uncertain covariance matrix, depend on sensor performance parameter and error model (Bae K H, Belton D, Lichti D. A framework for position uncertainty of unorganised three-dimensional point clouds from near-monostatic laser scanners using covariance analysis[C] //Proceedings of the ISPRS Workshop " Laser scanning. 2005.).
The method of extracting camera image edge contour in described step 4) be Canny algorithm (Canny J. A computational approach to edge detection[J]. Pattern Analysis and Machine Intelligence, IEEE Transactions on, 1986 (6): 679-698.).
The probability distribution of two-dimentional edge pixel in described step 5)
for:
for pixel
uncertain covariance matrix, depend on sensor performance parameter and error model (De Santo M, Liguori C, Pietrosanto A. Uncertainty characterization in image-based measurements:a preliminary discussion[J]. Instrumentation and Measurement, IEEE Transactions on, 2000,49 (5): 1101-1107.).
In described step 6) by three-dimensional edges point set
projecting to the lower method of camera coordinates system is: for three-dimensional edges point set
in a bit
, the subpoint in its corresponding camera imaging plane
for
Wherein
with
be respectively rotation matrix and translation matrix.
In described step 7) according to three-dimensional edges point set
probability distribution
determine two-dimentional edge point set with projection relation
probability distribution
method be:
Wherein
Probability distribution two dimension edge point set in described step 8)
probability distribution
probability distribution with two-dimentional edge pixel
between symmetrical KL distance
computing method be:
Minimize this symmetrical KL distance, can obtain module and carriage transformation matrix
.