ReCaptcha

PROJECT

Url:http://www.google.com/recaptcha
Start date:
End date: Still open

TEAM

Official team page:
Leader: Google

PROJECT DEFINITION

---

Subject

Engineering and technology > (other)

Description

reCAPTCHA is a user-dialogue system originally developed by Luis von Ahn, Ben Maurer, Colin McMillen, David Abraham and Manuel Blum at Carnegie Mellon University's main Pittsburgh campus, and acquired by Google in September 2009. Like the CAPTCHA interface, reCAPTCHA asks users to enter words seen in distorted text images onscreen. By presenting two words it both protects websites from bots attempting to access restricted areas and helps digitize the text of books. The reCAPTCHA service supplies subscribing websites with images of words that optical character recognition (OCR) software has been unable to read. The subscribing websites (whose purposes are generally unrelated to the book digitization project) present these images for humans to decipher as CAPTCHA words, as part of their normal validation procedures. They then return the results to the reCAPTCHA service, which sends the results to the digitization projects.

Purpose.

reCAPTCHA has worked on digitizing the archives of The New York Times and books from Google Books. As of 2012, thirty years of The New York Times had been digitized and the project planned to have completed the remaining years by the end of 2013. Wikipedia, retrieved July 2013

.

ABOUT PARTICIPANT TASKS

---

Tasks description.

Scanned text is subjected to analysis by two different optical character recognition programs. Their respective outputs are then aligned with each other by standard string-matching algorithms and compared both to each other and to an English dictionary. Any word that is deciphered differently by both OCR programs or that is not in the English dictionary is marked as "suspicious" and converted into a CAPTCHA. The suspicious word is displayed, out of context, along with a control word already known. The system assumes that if the human types the control word correctly, then the response to the questionable word is accepted as probably valid. (Wikipedia, retrieved July 2013)

.

Grey typology	Participation typology	Contribution type:
Computing: NO Thinking: NO Sensing: NO Gaming: NO	Crowdsourcing ☑ Distributed intelligence ☐ Participatory science ☐ Extreme citizen science ☐ Science outreach ☐	Data collection ☐ Data analysis ☐ Data interpretation ☑--------
Gaming
Genre:	Gaming elements:
Interface
Data type to manipulate: pictures	interface enjoyment: Interface usability:	Member profiles::no Member profile elements:

ABOUT GUIDANCE AND FEEDBACK

---

Guidance	Feedback on
Tutorial and documentation: SOMEWHAT Training sequence: SOMEWHAT Peer to peer guidance: SOMEWHAT	individual performance: NO collective performance: NO research progress: Somewhat

.

COMMUNITY

---

Tools	News & Events
Communication: website Social Network: N/A	Main news site: Frequency of project news updates: N/A Type of events: Frequency of events :
Community description
Community size (volounteers based): Role: Interaction form: Has official community manager(s): no Has team work N/A

Other information about community:
Community led additions:

OTHER PROJECT INFORMATION

---

Yes [[has completion level::Low]

Yes

Engineering and technology other [[Has project purpose::reCAPTCHA has worked on digitizing the archives of The New York Times and books from Google Books. As of 2012, thirty years of The New York Times had been digitized and the project planned to have completed the remaining years by the end of 2013.

Wikipedia, retrieved July 2013]]

reCaptcha [[Has participant task description::Scanned text is subjected to analysis by two different optical character recognition programs. Their respective outputs are then aligned with each other by standard string-matching algorithms and compared both to each other and to an English dictionary. Any word that is deciphered differently by both OCR programs or that is not in the English dictionary is marked as "suspicious" and converted into a CAPTCHA. The suspicious word is displayed, out of context, along with a control word already known. The system assumes that if the human types the control word correctly, then the response to the questionable word is accepted as probably valid. (Wikipedia, retrieved July 2013)]] data interpretation none crowdsourcing pictures, other: Thinking: no Computing: no Sensing: no Gaming: no

N/A N/A N/A no no somewhat

no

no website N/A

N/A

N/A

Low

free text test;

BIBLIOGRAPHY

reCAPTCHA: Human-Based Character Recognition via Web Security Measures. Luis von Ahn, Benjamin Maurer, Colin McMillen, David Abraham, Manuel Blum (2008)

http://dx.doi.org/10.1126/science.1160379

Luis von Ahn, Benjamin Maurer, Colin McMillen, David Abraham and Manuel Blum. 2008. "reCAPTCHA: Human-Based Character Recognition via Web Security Measures" Science 12 September 2008: Vol. 321 no. 589

High Transcription Accuracy.

http://www.google.com/recaptcha/digitizing

(At google)

Developer's Guide.

https://developers.google.com/recaptcha/intro

(At Google)

Labeling Images with a Computer Game. Luis von Ahn, Laura Dabbish (2005)

http://www.cs.cmu.edu/~biglou/captcha_cacm.pdf

Luis von Ahn and Laura Dabbish. Labeling Images with a Computer Game. ACM Conf. on Human Factors in Computing Systems, CHI 2004. pp 319-326.