overview of mediaeval 2012 visual privacy task
DESCRIPTION
TRANSCRIPT
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Visual Privacy Task Overview
Tomas Piatrik, Queen Mary University of London
Atta Badii, University of Reading
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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.
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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)
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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)
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User Study
Questionnaires • General Evaluation
• Clip Evaluation - cropped obscured face
• Clip Evaluation – whole frames
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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?• …
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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
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Results – User Study
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Results – User Study
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Thank You