The CAV3D (Co-located Audio-Visual streams with 3D tracks) dataset for 3D speaker tracking was collected with a sensing platform (Fig. 1) consisting of a monocular colour camera co-located with an 8-element circular microphone array. The audio sampling rate is 96 kHz. Video was recorded at 15 frames per second. The sensing platform was placed on a table in a room with dimensions 4.77 x 5.95 x 4.5 m and reverberation time of approximately 0.7s to record up to three simultaneous speakers. In addition to the sensing platform, 4 hardware-triggered CCD colour cameras installed at the top corners of the room recorded the scene. The dataset is synchronized, calibrated and annotated.
Fig. 1 Recording environment. The region surrounded by the red dashed line is within the camera’s field of view (approximately 90 degrees).
Scenarios and annotation
The dataset contains 20 sequences, whose duration ranges from 15s to 80s. Sequences can be categorized in three types:
- CAV3D-SOT: 9 sequences with a single speaker (seq6-13, seq20)
- CAV3D-SOT2: 6 sequences with a single active speaker and a second interfering person (not speaking) (seq14-19)
- CAV3D-MOT: 5 sequences with multiple simultaneous speakers (seq22-26)
Figures 2 to 5 show some key frames. Speakers undergo abrupt direction changes, arrange objects, walk outside the camera’s FoV and often change their pose thus generating occlusions, non-frontal views and illumination changes. An air conditioner produces background noise that compounds with human-made noise (e.g. clapping and stomping).
|Figure 2 CAV3D-SOT2: seq18
|Figure 3 CAV3D-MOT: seq24
|Figure 4 CAV3D-SOT2: seq25
|Figure 5 CAV3D-MOT: seq26
Camera calibration parameters. Calibration parameters are initialized for each camera using Zhang’s method. This calibration is then used for 3D mouth annotation where we run an optimization based on Sparse Bundle Adjustment to obtain 3D trajectories, accurate calibration, and an algorithmic correction of the manual annotations by minimizing the re-projection error on all camera views and sequences simultaneously.
Audio-visual synchronization. Clapping was used at the start and end of each recording. Synchronization was done manually by aligning the same clapping across audio and video streams.
Mouth positions on the image plane. Manual annotation on the image plane at each frame from the five individual camera views. Frames from the same camera are displayed sequentially in a graphical user interface, with a superimposed 50 x 50 cropped image region centred at the position annotated at the previous frame. This provides a zoomed-in view of the candidate region on the frame, where the annotator can easily update the replicated mouth location with a mouse click.
Mouth positions in 3D. Given the manually annotated mouth positions from the 5 viewpoints, using bundle adjustment we simultaneously refine the camera calibration parameters and the 3D points, according to an optimal criterion involving the corresponding image projections.
Voice activity labels. The transcriber software, an editor which allows transcribing the time markers and identities of individual segments, is used to label the speech/non-speech frames.
If you use this dataset, please cite the following paper:
- X. Qian, A. Xompero, A. Brutti, O. Lanz, M. Omologo, A. Cavallaro, “3D mouth tracking from a compact microphone array co-located with a camera”, Proc. of IEEE Int. Conf. on Acoustics, Speech and Signal Processing (ICASSP), Calgary, Canada, April 15-20, 2018
Download data from here.
For further information, please contact brutti (at) fbk (dot) eu.