MediaEval 2015 - MediaEval 2015 Drone Protect Task: Privacy Protection in Surveillance Systems Using False Coloring

MediaEval 2015 Drone Protect Task:Privacy Protection in Surveillance Systems

Using False Coloring

Serdar Çiftçi1, Pavel Korshunov2, Ahmet Oguz Akyüz1, TouradjEbrahimi2

1. Middle East Technical University, Ankara, Turkey2. Ecole Polytechnique Fedéralé de Lausanne, Switzerland

MEDIAEVAL 2015 Drone Protect Task

Serdar Çiftçi, Pavel Korshunov, Ahmet Oguz Akyüz, Touradj Ebrahimi (METU-EPFL)False Coloring for Visual Privacy September 15th 2015 1 / 18

Outline

1 Introduction

2 Related Work

3 False Color Based Privacy Protection

4 Experiments

5 Conclusion

6 References


Introduction

Video Surveillance Systems Surround Us


Related Work

Most Used Methods

Figure taken from [KMDE13].


Related Work

Warping

Figure taken from [KE13b].


Related Work

Morphing

Figure taken from [KE13a].


Related Work

Scrambling

Figure taken from [DE08].


Related Work

In-Painting

Figure taken from [CVP+09].


False Color Based Privacy Protection

Privacy Protection in Surveillance Systems Using False Coloring

Why we need a novel method?

Most methods are computer vision techniques dependent.

There is a trade off between privacy protection and intelligibility.

Reversibility may not be possible.

Pleasantness is an important issue.




The main steps are as follows:

Convert a color frame into grayscale.

Pixel intensities of the grayscaled frame are then used as keys toa look-up table that represents a color palette.




Reverse function steps are as following:Perform an inverse table look-up.

Reversion is only possible if one knows the properties of the colormap used during protection.


Experiments

Used Color Palettes

LOCS RBS

DEF

LOCS: Linearized optimal color scale (for Low Level Privacy)RBS: Rainbow color scale (for Medium Level Privacy)DEF: Radiance default color scale (for High Level Privacy)

Selection of the color palettes are based on our previous work published at SPIE Human Visionand Electronic Imaging XX 2015 conference.Using false colors to protect visual privacy of sensitive content,Serdar Çiftçi, Pavel Korshunov, Ahmet Oguz Akyüz, Touradj Ebrahimi.


Experiments

Example Results

Figure : False color results, a) original frame, c) protected frame, e)recovered frame.


Experiments

Subjective Evaluation Results

Privacy Intelligibility PleasantnessFC AVG FC AVG FC AVG

Expert 0.39 0.49 0.76 0.59 0.73 0.60Naïve 0.34 0.48 0.75 0.58 0.75 0.61

Average 0.365 0.49 0.755 0.59 0.74 0.60

Table : Evaluation results where FC and AVG respectively stand for falsecolor results and the average of all submissions. Expert and Naïve’s areparticipant groups which represent the people conducting research on visualprivacy protection and naïve observers.


Conclusion

Findings and Future Work

We described a simple and effective method for protecting privacyusing false coloring.Benchmarking evaluations indicated higher than average score forpleasantness and intelligibility.However, the privacy protection level was found to be lower thanaverage.Future work will investigate designing custom color scales toimprove privacy protection and the quality of reversibility whileenhancing security.


Conclusion

Thank you!


References

References I

[CVP+09] S-CS Cheung, MV Venkatesh, JK Paruchuri, J Zhao, andT Nguyen, Protecting and managing privacy information invideo surveillance systems, Protecting Privacy in VideoSurveillance, Springer, 2009, pp. 11–33.

[DE08] Frederic Dufaux and Touradj Ebrahimi, Scrambling forPrivacy Protection in Video Surveillance Systems, IEEETrans. on Circuits and Systems for Video Technology vol.18 (2008), no. no. 8, 1168–1174.

[KE13a] Pavel Korshunov and Touradj Ebrahimi, Using FaceMorphing to Protect Privacy, IEEE InternationalConference on Advanced Video and Signal-BasedSurveillance (AVSS), 2013.


References

References II

[KE13b] , Using Warping for Privacy Protection in VideoSurveillance, 18th International Conference on DigitalSignal Processing (DSP), 2013.

[KMDE13] Pavel Korshunov, Andrea Melle, Jean-Luc Dugelay, andTouradj Ebrahimi, A framework for objective evaluation ofprivacy filters in video surveillance, Proceedings of SPIEVolume 8856 (San Diego, California, USA), Spie-Int SocOptical Engineering, 2013.


MediaEval 2015 - MediaEval 2015 Drone Protect Task: Privacy Protection in Surveillance Systems Using False Coloring

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