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Ask HN: Why does Cloudflare/hCaptcha care so much about buses, boats and trains?

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Re: Ask HN: Why does Cloudflare/hCaptcha care so much about buses, boats and trains?

#221

Post by rolph »

ncann wrote: post #166
Kletiomdm wrote: post #145

Earlier quoted context omitted.

They probably have some statistics in the background which tells them some form of Trustlevel. You also need to assume that there are potentially control pictures in it as well. I think this is a very liable approach.

Yeah, it's not like they will label something a train just because a single person says so. But if you have 10k responses with 95% confidence saying it's a train, it's very likely to be the case.

unless a properly obfusicated bot net has seeded the data set with -everything is a train- responses to the tune of >>10k responses with 95% confidence saying it's a train<<

Re: Ask HN: Why does Cloudflare/hCaptcha care so much about buses, boats and trains?

#222

Post by Sohcahtoa82 »

Hamuko wrote: post #58
thargor90 wrote: post #14

Earlier quoted context omitted.

captchas mix classified and unclassified data. Only if you get the classified data correct a users data is used to classify the unclassified data. Also the same picture is shown to multiple people to improve confidence.

The first version of reCAPTCHA made it very obvious as to which word was the classified one and which was the unclassified one, so people had a pretty easy way to inject bad data into the process.

Yeah, I remember my days on 4chan where people kept posting a campaign to substitute a racial slur for the one that looked unclassified.

Re: Ask HN: Why does Cloudflare/hCaptcha care so much about buses, boats and trains?

#223

Post by KennyBlanken »

brk wrote: post #41
q1w2 wrote: post #23

Earlier quoted context omitted.

It's odd that it never asks for pedestrians.

For the most part, human detection capabilities of modern NNs are very good. This would include detections from a variety of camera angles and resolutions. There are already a lot of labeled training sets available with people in various poses, heights, clothing types, etc. Bicycle detection is probably one of the more challenging elements as it relates to pedestrians and things you don't want a SD car to run into. D…

> For the most part, human detection capabilities of modern NNs are very good.

If you're white

> There are already a lot of labeled training sets available with people in various poses, heights, clothing types, etc

But not of various skin colors...

Re: Ask HN: Why does Cloudflare/hCaptcha care so much about buses, boats and trains?

#224

Post by bogomipz »

Spare_account wrote: post #25
thargor90 wrote: post #14

Earlier quoted context omitted.

captchas mix classified and unclassified data. Only if you get the classified data correct a users data is used to classify the unclassified data. Also the same picture is shown to multiple people to improve confidence.

One of my hobbies is figuring out which captcha prompts are the unclassified data so that I can answer wrong and stick it to the man.

How does one determine classified vs unclassified?

Re: Ask HN: Why does Cloudflare/hCaptcha care so much about buses, boats and trains?

#225

Post by throwawayboise »

notatoad wrote: post #206
jokethrowaway wrote: post #98

Earlier quoted context omitted.

I disagree, Google captchas in my experience are much quicker compared to hcaptcha When cloudflare switched to hcaptcha I definitely noticed it.

people tend to have very different experiences with google captchas based on how normal they are. if you block everything and try to anonymize your browsing as much as possible and otherwise do everything you can to look like a bot, you're going to get a very difficult captcha to somebody with all their browser settings on default.

Yeah I do my routine browsing in private mode, no 3rd party cookies, no history, and an ad blocker. I get captchas everwhere.

Re: Ask HN: Why does Cloudflare/hCaptcha care so much about buses, boats and trains?

#226

Post by bogomipz »

MegaDeKay wrote: post #106
potamic wrote: post #56

Earlier quoted context omitted.

Many a time I receive multiple challenges on a site despite having selected all images perfectly, and can't help but wonder, "Hey, are they getting me to do more work than necessary because they're running behind on their labelling backlog?". There's definitely a conflict of incentives in this case. If you're a website owner, you're better off choosing a different service which doesn't have adverse incentives, otherw…

I've found it isn't about "perfection". It is about selecting the same tiles as an "average" person would. I might stare hard at an image, think that one of the tiles contains a tiny fragment of a traffic light, and select it. That isn't what most other people have already done, so the captcha thinks I'm a bot and gives me tougher and tougher challenges. Ever since I stopped pixel-peeping and started quickly selectin…

I've noticed similar. Often with stop lights, where a tiny sliver of one does not neatly fit in the frame, spilling over ever so slightly to the next square which has no stop light otherwise. There's a none too subtle irony in that one is being punished for accuracy when the context is ultimately public safety.

Re: Ask HN: Why does Cloudflare/hCaptcha care so much about buses, boats and trains?

#227

Post by PebblesRox »

raffraffraff wrote: post #212
jdavis703 wrote: post #8

First, I’m going to teach you to fish. Go to hCaptcha’s website, then scroll to the footer. Click around on the about links. It’ll reveal their business model. This trick also works for other businesses and NGOs. Now, if we look at https://www.hcaptcha.com/labeling we can tell they make money by labeling data sets for a fee. So as a guess, there’s someone out there that needs to improve computer vision detection of t…

So the safety of self-driving cars depends on regular folks not trolling the catpcha.

Hopefully they're able to account for Lizardman's Constant

https://slatestarcodex.com/2013/04/12/noisy-poll-results-and...

Re: Ask HN: Why does Cloudflare/hCaptcha care so much about buses, boats and trains?

#228

Post by rosndo »

skinnymuch wrote: post #218
rosndo wrote: post #190

Earlier quoted context omitted.

Oh no, I’d absolutely chip in. These people certainly deserve it.

Shouldn’t do this no matter what ofc. But why the devs? Sure the devs are well paid and privileged. That’s mostly relative to others in society. They are still more cogs than anything.

Easier target, a couple of google devs hanging on a public square would do much to disincentivize others from working on similar products in the future.

At least executives can dream of hiding behind private security, for mere developers earning 300k/yr the situation isn’t so rosy.

Re: Ask HN: Why does Cloudflare/hCaptcha care so much about buses, boats and trains?

#229

Post by hbarka »

MegaDeKay wrote: post #106
potamic wrote: post #56

Earlier quoted context omitted.

Many a time I receive multiple challenges on a site despite having selected all images perfectly, and can't help but wonder, "Hey, are they getting me to do more work than necessary because they're running behind on their labelling backlog?". There's definitely a conflict of incentives in this case. If you're a website owner, you're better off choosing a different service which doesn't have adverse incentives, otherw…

I've found it isn't about "perfection". It is about selecting the same tiles as an "average" person would. I might stare hard at an image, think that one of the tiles contains a tiny fragment of a traffic light, and select it. That isn't what most other people have already done, so the captcha thinks I'm a bot and gives me tougher and tougher challenges. Ever since I stopped pixel-peeping and started quickly selectin…

This. Captcha wants me to choose crosswalks and you can see there’s that sliver of a crosswalk in a few pixels off in another tile. You’re not wrong! But you’re not right. Regression to the mean.

A hexagon would be better as a frame instead of a square.

Re: Ask HN: Why does Cloudflare/hCaptcha care so much about buses, boats and trains?

#230

Post by pbhjpbhj »

Shared404 wrote: post #176
luckydata wrote: post #165

Earlier quoted context omitted.

That's about as much attention the average driver pays anyways. I drive a motorcycle, I KNOW that.

That's an interesting idea - maybe it would be smart to have captcha's do a "Point out all the motorcycles" or "Click all the pedestrians" setup.

I love a rant on this one...

Sometimes the bus/boat/truck has motorbikes sometimes bicycles. Is that a petrol-powered bicycle, or a motorbike to the [USAmerican?] person who wrote the rules!? Are all large yellow vehicles buses in USA or do you have minibuses, oh wait, are minibuses buses.

I've worked out fire engines are trucks for captchas, not sure about Transit-type vehicles, lorries are trucks apparently but goods trucks on railways are not trucks!

Is a traffic light only the lens/led array or the black light-holder too? Do pedestrian lights count as traffic lights? Are those weird lights hanging in the middle of junctions 'traffic lights'.

Wish they'd just tell you what counts.

I have noticed that times I realise after clicking that I missed a square they tend to go through whilst many times I get repeated captchas when I know I got it right. Success, as a user, seems impossible to predict.

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