WOZ acoustic data collection for interactive TV A. Brutti*, L. Cristoforetti*, W. Kellermann+, L. Marquardt+, M. Omologo* * Fondazione Bruno Kessler (FBK) - irst Via Sommarive 18, Povo (TN), ITALY + Multimedia Communications and Signal Processing, University of Erlangen-Nuremberg (FAU) Cauerstr. 7, Erlangen, GERMANY LREC 2008 – Marrakech, 28-30/05/08

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 The DICIT EU project  Distant-talking Interfaces for Control of Interactive TV  User-friendly human-machine interface to enable a speech-based interaction with a TV and related digital devices (STB)  Interaction in a natural and spontaneous way without a close-talk microphone 2

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 The DICIT EU project Distant-talking Interfaces for Control of Interactive TV 3

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 When did she speak? What does she say? What is the output from each loudspeaker? How is it at each microphone? Who is she? Robustness in a real reverberant environment Noise sources? Where is she? What is her head orientation? Other speakers? The DICIT EU project Distant-talking Interfaces for Control of Interactive TV

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 The DICIT Project  STREP Project – FP6  Strategic objective: – Multimodal Interfaces  Duration: October 2006 – September 2009

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 What is a Wizard of Oz (WOZ) experiment?  A subject is requested to complete specific tasks using an artificial system  The user is told that the system is fully functional and should try to use it in a intuitively way  The system is operated by a person (wizard) not visible to the subject  The wizard can react in a more comprehensive way and can create particular situations 6

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 Why a WOZ data collection?  We needed to collect an acoustic database for testing pre- processing algorithms: –acoustic scene analysis –speaker ID and verification –echo cancelation –blind source separation –beamforming –speaker localization and tracking –distant automatic speech recognition  With a WOZ, realistic scenarios can be simulated at a preliminary stage, allowing for repeatable experiments  There is no need to have a full-working system in order to collect real data  Naïve users, do not have the same behavior as expert users, they use the system in a realistic way 7

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 The DICIT WOZ  Experiments were conducted in the laboratories at FBK and FAU  A room was used as living room with TV, loudspeakers and seats An adjacent room was used by the wizard and the simulation system, not visible from the users  Users watched the TV and had to interact with it by voice and remote control, to change channels and to retrieve information from the teletext pages  At some point, they had to move around and speak with the system 8

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 Strategy for the recordings  Four users sit in the room, but one of them was the co- wizard, that ensured the regularity of the experiment and produced some acoustic events  Users were recorded by close talk and far microphones  Interactions will be recorded by 3 fixed cameras that allow the automatic tracking of users movements  Recordings were done on Italian/German/English groups 9

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 Hints for wizard and co-wizard  Wizard: –simulate some recognition errors –don’t accept speech for 10” after a volume change (for convergence of the algorithms)  Co-wizard (in the room): –lead the first phase (users registration) –produce noises during teletext interaction (key jingle, cough, phone ring, etc.) –keep the situation under control (give hints to the real users) 10

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 Script for the interaction (person A)  Enter in the room and sit on the seat marked A  Wait for user D to switch on the system and say your name, then read the four phonetically rich sentences on the screen  When user D gives you the remote control, try using it to change channels and volume (next/previous channel, volume up/down, mute)  Connect to the system using your voice “DICIT activate”  Use the voice to change channels and volume e.g., “I want to see CNN”  Select Euronews channel and start the teletext (using the voice or the remote control)  Use the teletext to obtain the requested news and weather info. Please move to different positions in the room when interacting with the system  Log off from the system “DICIT logoff” and give the remote control to user B 11

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 The FBK experimental room 12 A harmonic 15-electret-microphone array was developed on purpose and located over the TV

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 Audio and video sensor setup  A harmonic 15-electret-microphone array was developed on purpose and located over the TV  A NIST MarkIII 64-electret-microphone linear array was used for comparison  A table microphone and 2 side mics were used (omnidirectional pattern)  Every participant wore a close-talk mic for reference  3 video cameras recorded the sessions for monitoring and to derive 3D reference positions 13

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 Clip from a recorded session 14

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 WOZ preparation  12 video clips and 100 teletext pages were recorded from real TV, everything was available in 3 languages  Stereo audio channels were extracted and decorrelated (by FAU) for the echo canceller and clips were recreated to fit the simulation  The system was controlled by a PC running Elektrobit EB GUIDE Studio simulator tool  A remote control infrared receiver was integrated into the system and enabled the users to use a real remote control to pilot the TV 15

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 Recording hardware setup 3 PCs to record all the data, 2 Linux and 1 Windows machines 16

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 Recorded sessions  FBK and FAU recorded different sessions using a similar setup, in different languages  Each user interaction lasted about 10 minutes, in total 360 minutes of recordings  24 or 26 synchronous channels were recorded at 48kHz with 16-bit precision + 64 channels from the MarkIII array at 44.1kHz and 24 bits SiteLanguageNumber of sessions FBKItalian6 FAUGerman5 FAUEnglish1 17

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 Data annotation  The 6 Italian sessions have been manually transcribed and segmented at word level, using Transcriber  An automatic segmentation was obtained with a tool based on energy of the close-talk signals, then adjusted when necessary  A stereo file was created, with two channels for close-talk and environment sounds to ease the annotation process  Annotation comprises the speaker ID, the transcription of uttered sentence and any noise included in the acoustic event list  Specific labels for acoustic events have been introduced, following a defined guideline  Video data has been used to derive 3D coordinates for the head of the speaker and reference files were created with a frame rate of 5 labels per second 18

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 Data exploitation / testing  Data have been used for a preliminary evaluation of some FBK algorithms: –localization techniques, precision is around 30 cm – audio segments have been used for the acoustic event classification system, 92% of accuracy –data have been used to test the speaker verification and identification system, but close-talk is still better that beamformed signal  Room impulse response measurements have been carried out at both sites, in different positions. They are useful for i.e. speech contamination purposes 19

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 Transcriber session

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08Conclusions  This collection of data has been the first of its kind and is of significant benefit to acoustic front-end algorithms and dialogue strategies  36 naïve persons have been recorded, leading to 360 minutes of signals, on different channels recorded in a synchronous way (125 GB of data)  Users enjoyed the system and tolerated some recognition errors, they preferred voice modality over remote control interaction 21

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 Current status of the project  The project is in the second year  We just finished to integrate the first prototype  Ready to start the evaluation of the prototype  More information and demo clips can be found at 22

Luca Cristoforetti LREC 2008 – Marrakech, 28-30/05/08 Thank You!