MLAD Challenge

Usage

Dataset Structure

• reference sequence: recording_2020-04-07_10-20-32
• training sequence: recording_2020-03-24_17-36-22
• validation sequence: recording_2020-03-03_12-03-23
• test sequence: recording_2020-03-24_17-45-31, recording_2020-04-23_19-37-00

Dataset Preparation

For the re-localization challenge, we provide 5 different traversals of the same sequence at different times. We provide a reference map, which contains high-accurate ground truth. We also do provide another traversal with ground truth to be used for training. One sequence can be used for validation and the two remaining sequences will be used as test sequences. The directory of the reference map has the following structure:

.
├── Calibration
│   ├── undistorted_calib_0.txt
│   ├── undistorted_calib_1.txt
│   └── undistorted_calib_stereo.txt
├── KeyFrameData
├── RelocalizationFilesTest
│   ├── relocalizationFile_recording_2020-03-24_17-45-31_easy.txt
│   ├── relocalizationFile_recording_2020-03-24_17-45-31_hard.txt
│   ├── relocalizationFile_recording_2020-03-24_17-45-31_moderate.txt
│   ├── relocalizationFile_recording_2020-04-23_19-37-00_easy.txt
│   ├── relocalizationFile_recording_2020-04-23_19-37-00_hard.txt
│   └── relocalizationFile_recording_2020-04-23_19-37-00_moderate.txt
├── RelocalizationFilesTrain
│   └── relocalizationFile_recording_2020-03-24_17-36-22.txt
├── RelocalizationFilesVal
│   └── relocalizationFile_recording_2020-03-03_12-03-23.txt
├── keyframe_accuracy.txt
├── poses.txt
├── times.txt
└── undistorted_images
    ├── cam0
    └── cam1

Here,

• Calibration contains both the intrinsic and extrinsic calibration of the stereo camera.
• KeyFrameData contains the KeyFrameFiles.
• RelocalizationFilesTest contains the re-localization files between the source (reference) and the target sequence.
• RelocalizationFilesTrain contains the re-localization files between the source (reference) and the training sequence together with the relative poses.
• RelocalizationFilesVal contains the re-localization files between the source (reference) and the validation sequence together with the relative poses.
• keyframe_accuracy.txt is a list of keyframes with a translational accuracy lower than 0.05m.
• poses.txt is a list of 6DOF poses for all keyframes from the left camera to world coordinates.
• times.txt is a list of times in unix timestamps, and exposure times for each keyframe.
• undistorted_images contains both the images from the left and right camera, respectively.

The KeyFrameData folder contains a .txt file for each keyframe. Each Keyframe file contains the following data: timestamp, camera intrinsics, camToWorld transformation, exposure time and point cloud data. Each point is saved with the following properties:

• u,v image coordinates of depth point in pixels
• idepth_scaled inverse depth value in 1/m
  • metric 3D camera coordinates are obtained as follows: x=(u-cx)/(fx*idepth_scaled); y=(v-cy)/(fy*idepth_scaled); z=1/idepth_scaled
• idepth_hessian hessian component of the corresponding inverse depth
  • estimated inverse depth variance is obtained as follows: var=1/idepth_hessian
• maxRelBaseline maximum relative stereo baseline
• numGoodRes not relevant
• status not relevant
• color information color values of an 8 pixel patch around the depth pixel (see https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7898369 for definition)

The 6DOF poses are specified as translation (t_x, t_y, t_z), and quaternion (q_x, q_y, q_z, q_w). The test re-localization files are provided as easy, moderate, and hard version, which differ mainly in a larger translational distance between the source and target frame.

The directories of the test sequences should have the following structure:

.
├── Calibration
│   ├── undistorted_calib_0.txt
│   ├── undistorted_calib_1.txt
│   └── undistorted_calib_stereo.txt
├── times.txt
└── undistorted_images
    ├── cam0
    └── cam1

Task

Each re-localization file contains a list of first the keyframe from the source (reference) sequence, and the target keyframe. The task is to provide the relative pose between the source and the target. Note that the relative pose for the validation file is from cam0 of the source sequence to cam0 of the target sequence, respectively.

Submission

For the test sequences, the ground truth is withheld. For submitting your results to the challenge, please refer to the steps described at: https://sites.google.com/view/mlad-eccv2020/challenge.