Tuesday, October 23, 2007

Can you “identify” the person walking down the street?

I recently posted a blog on Google’s Lat Long Blog about Street View and privacy.

I’d like to add a few personal observations to that post.

Some people might have wondered why Google posted a blog about what a future launch of Street View would look like in some non-US countries, especially since, so far, it only includes images from 15 US cities. We felt the need to respond to concerns that we had heard recently, in particular concerns from Canada’s privacy regulators, that a launch of the US-style of Street View in Canada might not comply with Canadian privacy regulations. And we wanted to be very clear that we understood privacy regimes are different in some countries, such as Canada, and for that matter, much of Europe, compared to the US tradition of “public spaces.” And of course, that we would respect those differences, when/if we launched Street View in those countries.

Basically, Street View is going to try not to capture “identifiable faces or identifiable license plates” in its versions in places where the privacy laws probably wouldn’t allow them (absent consent from the data subjects, which is logistically impossible), in other words, in places like Canada and much of Europe. And for most people, that pretty much solves the issue. If you can’t identify a person’s face, then that person is not an “identifiable” human being in privacy law terms. If you can’t identify a license plate number, then that car is not something that can be linked to an identifiable human being in privacy law terms.

How would Street View try not to capture identifiable faces or license plates? It might be a combination of blurring technology and resolution. The quality of face-blurring technology has certainly improved recently, but there are still some unsolved limitations with it. As one of my engineering colleagues at Google explained it to me: “Face detection and obscuring technology has existed for some time, but it turns out not to work so well. Firstly, face recognition misses a lot of faces in practice, and secondly, a surprising number of natural features (bits of buildings, branches, signs, chance coincidence of all of the above) look like faces. It’s somewhat surprising when you run a face recognition program over a random scene and then look closely at what it recognises. These problems are also exacerbated by the fact that you have no idea of scale, because of the huge variations in distance that can occur.”

Lowering the quality of resolution of images is another approach to try not to capture identifiable faces or license plates. If the resolution is not great, it’s hard (or even impossible) to identify them. Unfortunately, any such reduction in resolution would of course also reduce the resolution of the things we do want to show, such as buildings. So, it’s a difficult trade-off.

Some privacy advocates raise the question of how to circumscribe the limits of “identifiability”. Can a person be considered to be identifiable, even if you cannot see their face? In pragmatic terms, and in privacy law terms, I think not. The fact is that a person may be identifiable to someone who already knows them, on the basis of their clothes (e.g., wearing a red coat), plus context (in front of a particular building), but they wouldn’t be “identifiable” to anyone in general. Others raise the issue of whether properties (houses, farms, ranches) should be considered to be “personal data” (so that their owners or residents could request them to be deleted from these geo sites, like Google Earth)? Last month, various German privacy officials made these arguments in a Bundestag committee hearing. They reasoned that a simple Internet search can often combine a property’s address with the names of the property’s residents. Others see this reasoning as a distortion of privacy concepts, which were not meant to be extended to properties. And the consequences of that reasoning would mean that satellite and Street View imagery of the world might be full of holes, as some people (disproportionately, celebrities and the rich, of course) would try to block their properties from being discoverable.

Google will have to be pragmatic, trying to solve privacy issues in a way that doesn’t undermine the utility of the service or the ability of people to find and view legitimate global geographic images. I personally would like to see the same standard of privacy care applied to Street View across the globe: namely, trying not to capture identifiable faces or license plates, even in the US, regardless of whether that’s required by law or not. But I recognize that there are important conflicting principles at play (i.e., concepts of “public spaces”), and “privacy” decisions are never made in a bubble.

We’re engaged in a hard debate, inside Google and outside: what does privacy mean in connection with images taken in “public spaces”, and when does a picture of someone become “identifiable”? Can we have a consistent standard around the world, or will we have to have different standards in different countries based on local laws and culture? This isn’t the first time (and I hope, not the last time) that Google has launched a new service, letting people access and search for new types of information. Those of us in the privacy world are still debating how to address it.

I think the decisions taken by the Street View team have been the right ones, even for the US launch, at least at this point in time, and given the current state of technology. But a more privacy-protective version in other countries (and someday, maybe in the US too?) would be a good thing, at least for privacy.


Anonymous said...

You suggest that "Google will have to be pragmatic, trying to solve privacy issues in a way that doesn’t undermine the utility of the service or the ability of people to find and view legitimate global geographic images"
Doesn't this betray a starting bias - the utility of the service should not trump reasonable privacy expectations? Appreciate this is a difficult issue, but it doesn't help to start with a presumption of technological determinism :-)
Nigel Waters, Australia

Anonymous said...


May be this ruling could be of your interest: