Overview of MediaEval 2012 Visual Privacy Task

Visual Privacy Task Overview

Tomas Piatrik, Queen Mary University of London

Atta Badii, University of Reading

Task Description

• Visual privacy protection of people occurred in a video taking into consideration the acceptability and attractiveness of the resulting obscured or scrambled region.

Data

200 videos • 30s-90s• 25fps, 30fps• 640x480, 704x576• Daytime• Evening • People wearing accessories (hat, scarf, sunglasses)

Evaluation Set – 12 videos (4 per each category)

Evaluation Methodology

1. Objective Evaluation• Accuracy of the bounding boxes• Anonymity – evaluated by automatic face detection• Intelligibility – evaluated by object tracking• Quality: SSIM & PSNR – similarity between the

original and obscured images

2. User Study (subjective evaluation)• 20 subjects • 2-range score (0,1; 0-0,5-1)

User Study

Questionnaires • General Evaluation

• Clip Evaluation - cropped obscured face

• Clip Evaluation – whole frames

User Study

Questionnaire: • Is the person of interest wearing sunglasses? … • What is the person’s gender?• What is the person’s ethnicity?• Is it possible to guess the person’s facial expression?• Is the masking hiding sufficient features? • Do you feel that this masking technique could protect

your identity if used on CCTV systems?• Do you find the masking effect distracting?• Do you find the masking effect irritating?• …

Results – objective evaluation

Participants:

Objective evaluation:

co-organising team

Accuracy Anonymity Intelligibility SSIM PSNR

EPFL 0.24 1.00 0.85 0.92 28.26

Eurecom 0.37 1.00 0.82 0.93 32.89

UoR 0.50 1.00 0.93 0.96 35.80

Results – User Study

Results – User Study

Thank You