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bundleAdjustmentMotion

Adjust collection of 3-D points and camera poses using motion-only bundle adjustment

Since R2020a

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Syntax

refinedPose = bundleAdjustmentMotion(xyzPoints,imagePoints,absolutePose,intrinsics)
[refinedPose,reprojectionErrors] = bundleAdjustmentMotion(___)
[___] = bundleAdjustmentMotion(___,Name,Value)

Description

refinedPose = bundleAdjustmentMotion(xyzPoints,imagePoints,absolutePose,intrinsics) returns the refined absolute camera pose that minimizes reprojection errors.

The motion-only refinement procedure is a special case of the Levenberg-Marquardt algorithm for bundle adjustment with 3-D points fixed during optimization. The 3-D points and the camera pose are placed in the same world coordinate system.

example

[refinedPose,reprojectionErrors] = bundleAdjustmentMotion(___) additionally returns an N-element vector containing the mean reprojection error for each 3-D world point using the arguments from the previous syntax.

[___] = bundleAdjustmentMotion(___,Name,Value) uses additional options specified by one or more name-value arguments. Unspecified arguments have default values.

Examples

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Open Live Script

Load data for initialization into the workspace.

data = load("globeMotionOnlyBA.mat");

Refine the absolute camera poses.

refinedPose = bundleAdjustmentMotion(data.xyzPoints,data.imagePoints,data.absPose,data.intrinsics);

Display the 3-D world points.

pcshow(data.xyzPoints,AxesVisibility="on",VerticalAxis="y",VerticalAxisDir="down",MarkerSize=45);
hold on

Plot the absolute camera poses before and after refinement. 

plotCamera(AbsolutePose=data.absPose,Color="r",Size=2);
plotCamera(AbsolutePose=refinedPose,Color="m",Size=2);

Figure contains an axes object. The axes object contains 21 objects of type line, text, patch, scatter.

Input Arguments

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Unrefined 3-D points, specified as an M-by-3 matrix of [x,y,z] locations.

Data Types: single | double

Image points, specified as an M-by-2 matrix or an M-element Point Feature Types array.

Absolute camera pose, specified as a rigidtform3d object.

Camera intrinsics, specified as a cameraIntrinsics object.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: "MaxIterations",50

Maximum number of iterations before the Levenberg-Marquardt algorithm stops, specified as a positive integer.

Absolute termination tolerance of the mean squared reprojection error in pixels, specified as a positive scalar.

Relative termination tolerance of the reduction in reprojection error between iterations, specified as a positive scalar.

Flag to indicate lens distortion, specified as false or true. When you set PointsUndistorted to false, the 2-D points in pointTracks must be from images with lens distortion. To use undistorted points, use the undistortImage function first, then set PointsUndistorted to true.

Display progress information, specified as false or true.

Output Arguments

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Refined absolute pose of the camera, returned as a rigidtform3d object.

Reprojection errors, returned as an M-element vector. The function projects each world point back into each camera. Then in each image, the function calculates the reprojection error as the distance between the detected and the reprojected point. The reprojectionErrors vector contains the average reprojection error for each world point.

References

[1] Lourakis, Manolis I. A., and Antonis A. Argyros. "SBA: A Software Package for Generic Sparse Bundle Adjustment." ACM Transactions on Mathematical Software 36, no. 1 (March 2009): 2:1–2:30.

[2] Hartley, Richard, and Andrew Zisserman. Multiple View Geometry in Computer Vision. 2nd ed. Cambridge, UK ; New York: Cambridge University Press, 2003.

[3] Triggs, Bill, Philip F. McLauchlan, Richard I. Hartley, and Andrew W. Fitzgibbon. "Bundle Adjustment — A Modern Synthesis." In Proceedings of the International Workshop on Vision Algorithms, 298–372. Springer-Verlag, 1999.

Extended Capabilities

Version History

Introduced in R2020a

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See Also

Objects

Functions

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