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transformScan

Transform laser scan based on relative pose

Description

example

transScan = transformScan(scan,relPose) transforms the laser scan specified in scan by using the specified relative pose, relPose.

example

[transRanges,transAngles] = transformScan(ranges,angles,relPose) transforms the laser scan specified in ranges and angles by using the specified relative pose, relPose.

Examples

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Create a lidarScan object. Specify the ranges and angles as vectors.

refRanges = 5*ones(1,300);
refAngles = linspace(-pi/2,pi/2,300);
refScan = lidarScan(refRanges,refAngles);

Translate the laser scan by an [x y] offset of (0.5,0.2).

transformedScan = transformScan(refScan,[0.5 0.2 0]);

Rotate the laser scan by 20 degrees.

rotateScan = transformScan(refScan,[0,0,deg2rad(20)]);

Use the matchScans function to find the relative transformation between two lidar scans. Then, transform the second scan into the coordinate frame of the first scan.

Load a pair of lidar scans as a pair of lidarScan objects. They are two scans of the same scene with a change in relative pose.

load tb3_scanPair.mat
plot(s1)
hold on
plot(s2)
hold off

The relative pose is estimated from an odometry sensor and provided as a variable, initGuess, as [x y theta].

disp(initGuess)
   -0.7000    0.1500   -0.3254

Use scan matching to find the relative pose between the two laser scans and specify the initial guess for the pose.

pose = matchScans(s2,s1,"InitialPose",initGuess);
disp(pose)
   -0.7213    0.1160   -0.2854

Transform the second scan to the coordinate frame of the first scan. Plot the two scans to see that they now overlap.

s2Transformed = transformScan(s2,pose);
plot(s1)
hold on
plot(s2Transformed)
hold off

Input Arguments

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Lidar scan readings, specified as a lidarScan object.

Range values from scan data, specified as a vector in meters. These range values are distances from a sensor at specified angles. The vector must be the same length as the corresponding angles vector.

Angle values from scan data, specified as a vector in radians. These angle values are the specific angles of the specified ranges. The vector must be the same length as the corresponding ranges vector.

Relative pose of current scan, specified as [x y theta], where [x y] is the translation in meters and theta is the rotation in radians.

Output Arguments

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Transformed lidar scan readings, specified as a lidarScan object.

Range values of transformed scan, returned as a vector in meters. These range values are distances from a sensor at specified transAngles. The vector is the same length as the corresponding transAngles vector.

Angle values of transformed scan, returned as a vector in radians. These angle values are the specific angles of the specified transRanges. The vector is the same length as the corresponding ranges vector.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Introduced in R2017a