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Image Scrubber: tool for anonymizing photographs taken at protests

everestpipkin.github.io

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Re: Image Scrubber: tool for anonymizing photographs taken at protests

#31

Post by adge »

hirundo wrote: post #13

The protests were sparked by the lack of accountability of the police resulting in police brutality. The violent people among the protesters are subject to the same incentives. The more they expect to be held accountable, the more likely they will refrain from violence. Anonymizing photos of the violent ones is therefore likely to support their actions by making accountability less likely. To scrub ethically, limit i…

Many organizers of protests in Furguson, peaceful or otherwise, have since been found murdered in ways that suggest they were literally hunted down and killed for their involvement. Multiple have been found shot through the head in burned out cars to destroy all evidence. If they broke the law it still does not merit being executed in the street. (https://www.nbcnews.com/news/us-news/puzzling-number-men-tie...)

In a situation where police feel justified to kill extra-judicially over a possibly fake 20 dollar bill, what hope do we have that protesters won't be targeted in unfair ways? Or worse, that organizers won't be hunted down like animals and murdered like in Furguson? It would be unethical to not do everything in your power to protect those in this position.

secondly how do you plan to identify violent vs non-violent protesters from a static image? How would you find their identity afterwards? There is overwhelming evidence to suggest these methods are at best ineffective and at worst racist, and in either case will lead to innocent people being charged.

https://www.newscientist.com/article/2109887-police-mass-fac...

Re: Image Scrubber: tool for anonymizing photographs taken at protests

#33

Post by klyrs »

ibrarmalik wrote: post #26
leni536 wrote: post #14

How resilient is blurring against deconvolution?

Can deconvolution create new data? I thought it was just a way to upscale images.

If a blur filter uses a convolution, then it's invertible through a deconvolution.

Re: Image Scrubber: tool for anonymizing photographs taken at protests

#34

Post by JimDabell »

dabei wrote: post #25
aesh2Xa1 wrote: post #11

Earlier quoted context omitted.

The tool blurs faces.

Sure. I'm just interested to know what else in EXIF could be identifying.

Camera serial numbers. If you ever have your camera stolen, you can put the serial number into Stolen Camera Finder. It will show you the images uploaded to the Internet with your camera’s serial number so you can recover it.

https://www.stolencamerafinder.com

Re: Image Scrubber: tool for anonymizing photographs taken at protests

#35

Post by ivanbakel »

ibrarmalik wrote: post #26
leni536 wrote: post #14

How resilient is blurring against deconvolution?

Can deconvolution create new data? I thought it was just a way to upscale images.

Deconvolution is any attempt to recover data that has been passed through some known transformation. It can "create new data" because it is effectively mathematically-educated guesswork.

In the case of upscaling an image, deconvolution involves looking for images which, when scaled down, resemble the original image being upscaled. That kind of pre-image approach can be applied to blur as well (if the blur process is deterministic).

Re: Image Scrubber: tool for anonymizing photographs taken at protests

#36

Post by dmos62 »

elliekelly wrote: post #16
shivekkhurana wrote: post #5

I recently found myself in a position where I had to blur a ton of faces from multiple pictures (about 100/day). It’s really tedious to do it manually and something like OpenCV shines. We found a repo [1] with python code that automatically detects and blurs faces. This script was one of many, except it had a very high accuracy. Over 90%. Removing exif data is a great idea. [1] github.com/telesoho/faceblur

I’m reminded of a reddit thread a while back about the US government paying a large sum to create an “unblur” function for photoshop. Someone in the comments was able to rotate and flip a photo and use the photoshop blur tool to effectively undo a blur for free. Perhaps it’s better to remove the section of photo with a person’s face instead? Or draw a shape over their face and flatten the image? It seems to me as lon…

> rotate and flip a photo and use the photoshop blur tool to effectively undo a blur

I'm not sure I follow. Did he say "enhance" at any point during the process?

Re: Image Scrubber: tool for anonymizing photographs taken at protests

#38

Post by snazz »

JimDabell wrote: post #34
dabei wrote: post #25

Earlier quoted context omitted.

Sure. I'm just interested to know what else in EXIF could be identifying.

Camera serial numbers. If you ever have your camera stolen, you can put the serial number into Stolen Camera Finder. It will show you the images uploaded to the Internet with your camera’s serial number so you can recover it. https://www.stolencamerafinder.com

Is this data included in iPhone photos? I don't think so.

Re: Image Scrubber: tool for anonymizing photographs taken at protests

#39

Post by voisin »

adge wrote: post #31
hirundo wrote: post #13

The protests were sparked by the lack of accountability of the police resulting in police brutality. The violent people among the protesters are subject to the same incentives. The more they expect to be held accountable, the more likely they will refrain from violence. Anonymizing photos of the violent ones is therefore likely to support their actions by making accountability less likely. To scrub ethically, limit i…

Many organizers of protests in Furguson, peaceful or otherwise, have since been found murdered in ways that suggest they were literally hunted down and killed for their involvement. Multiple have been found shot through the head in burned out cars to destroy all evidence. If they broke the law it still does not merit being executed in the street. ( https://www.nbcnews.com/news/us-news/puzzling-number-men-tie... ) In…

This is shocking and should absolutely be more widely reported as it may change behaviour of present day activists. We need an anonymizing solution for protest organizing.

Re: Image Scrubber: tool for anonymizing photographs taken at protests

#40

Post by therealcamino »

dabei wrote: post #25
aesh2Xa1 wrote: post #11

Earlier quoted context omitted.

The tool blurs faces.

Sure. I'm just interested to know what else in EXIF could be identifying.

I guess that is more about hiding the identify of the photographer instead of the people pictured, but since browser fingerprinting works by combining seemingly innocuous data to identify individuals, that suggests that removing everything is probably safest. The camera model, software versions and other explicit labels are one obvious thing. The ISO, focal length, and shutter speed could narrow down what sensor was used and maybe what software, especially if you had multiple images from the same camera. Maybe manual settings changes that the photographer made could show up in the same data. Possibly small amounts of clock drift? If you saw the news story that combined multiple security cameras' footage with phone video around the time of George Floyd's arrest, clock disagreement was something they saw, and the events in the images themselves allowed them to figure out the clock difference (which was huge there, like 20 minutes, but you could still do for a smaller drift.)

Other things are external to the EXIF but could be combined with it. The sequence numbers in the filenames are the most obvious signal. The precise number of megapixels of the image might also tell you what sensor was used -- so maybe an anonymizer should resample the image to a new size.

I guess these seem unlikely to be investigated, but then again nobody initially thought that telling every web server what fonts you have installed on your machine would be used against you, or that the existence of "Do Not Track" would make browsers easier to track. It just depends on how much it's worth to someone to write this stuff once -- then it's free for all future uses.

I just looked at https://en.wikipedia.org/wiki/Exif and there are lots of interesting possibilities.

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