poses

Absolute camera poses of RGB-D vSLAM key frames

Since R2024a

Syntax

camPoses = poses(vslam)

[camPoses,keyFrameIDs] = poses(vslam)

Description

camPoses = poses(vslam) returns the absolute camera poses camPoses of the key frames from the RGB-D visual simultaneous localization and mapping (vSLAM) object vslam.

[camPoses,keyFrameIDs] = poses(vslam) returns the IDs keyFrameIDs of the key frames corresponding to the camera poses. The IDs represent the order in which the image frames have been added to the vslam object by the addFrame object function.

Examples

RGB-D Visual SLAM Using TUM RGB-D Data Set

Perform RGB-D visual simultaneous localization and mapping (vSLAM) using the data from the TUM RGB-D Benchmark. You can download the data to a temporary directory using a web browser or by running this code:

baseDownloadURL = "https://vision.in.tum.de/rgbd/dataset/freiburg3/rgbd_dataset_freiburg3_long_office_household.tgz"; 
dataFolder = fullfile(tempdir,"tum_rgbd_dataset",filesep); 
options = weboptions(Timeout=Inf);
tgzFileName = dataFolder+"fr3_office.tgz";
folderExists = exist(dataFolder,"dir");

% Create a folder in a temporary directory to save the downloaded file
if ~folderExists  
    mkdir(dataFolder) 
    disp("Downloading fr3_office.tgz (1.38 GB). This download can take a few minutes.") 
    websave(tgzFileName,baseDownloadURL,options); 
    
    % Extract contents of the downloaded file
    disp("Extracting fr3_office.tgz (1.38 GB) ...") 
    untar(tgzFileName,dataFolder); 
end

Create two imageDatastore objects. One to store the color images and the other to store the depth images.

colorImageFolder = dataFolder+"rgbd_dataset_freiburg3_long_office_household/rgb/";
depthImageFolder = dataFolder+"rgbd_dataset_freiburg3_long_office_household/depth/";

imdsColor = imageDatastore(colorImageFolder);
imdsDepth = imageDatastore(depthImageFolder);

Select the synchronized pair of color and depth images.

data = load("rgbDepthPairs.mat");
imdsColor=subset(imdsColor, data.indexPairs(:, 1));
imdsDepth=subset(imdsDepth, data.indexPairs(:, 2));

Specify your camera intrinsic parameters, and use them to create an RGB-D visual SLAM object.

intrinsics = cameraIntrinsics([535.4 539.2],[320.1 247.6],[480 640]);
depthScaleFactor = 5000;
vslam = rgbdvslam(intrinsics,depthScaleFactor);

Process each pair of color and depth images, and visualize the camera poses and 3-D map points.

for i = 1:numel(imdsColor.Files)
    colorImage = readimage(imdsColor,i);
    depthImage = readimage(imdsDepth,i);
    addFrame(vslam,colorImage,depthImage);

    if hasNewKeyFrame(vslam)
        % Query 3-D map points and camera poses
        xyzPoints = mapPoints(vslam);
        [camPoses,viewIds] = poses(vslam);

        % Display 3-D map points and camera trajectory
        plot(vslam);
    end

    % Get current status of system
    status = checkStatus(vslam);
    
    % Stop adding frames when tracking is lost
    if status == uint8(0)
        break
    end
end 

Once all the frames have been processed, reset the system.

while ~isDone(vslam)
    plot(vslam);
end
reset(vslam);

Input Arguments

vslam — RGB-D visual SLAM object

rgbdvslam object

RGB-D visual SLAM object, specified as an rgbdvslam object.

Output Arguments

camPoses — Absolute camera poses of key frames

M-element array of rigidtform3d objects

Absolute camera poses of the key frames, returned as an M-element array of rigidtform3d objects.

keyFrameIDs — Key frame IDs for absolute camera poses

M-element array of integers

Key frame IDs for the absolute camera poses, returned as an M-element array of integers. Each element specifies the key frame ID for the camera pose in the corresponding element of camPoses. The IDs represent the order in which the image frames have been added to vslam by the addFrame object function.

Version History

Introduced in R2024a