Re:Ask HN: How does Google get data from ReCAPTCHA yet it kn...
by nostrademons on Sunday February 10, 2019 @01:32AM
(#19126629)
IIUC they mix known data in with unknown data.
If you get a lot of the known data wrong, they throw out your answer and make you answer the CAPTCHA again. If you get the known data right, they assume that your answers on the unknown data are correct and use that to label them, then start adding them in as the known data for other people. They might also show the same images to multiple people and see if they give the same answers - if so, it's probably correct and can be labeled, if not throw them out and make them answer the CAPTCHA again.
If you get a lot of the known data wrong, they throw out your answer and make you answer the CAPTCHA again. If you get the known data right, they assume that your answers on the unknown data are correct and use that to label them, then start adding them in as the known data for other people. They might also show the same images to multiple people and see if they give the same answers - if so, it's probably correct and can be labeled, if not throw them out and make them answer the CAPTCHA again.