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The early reCAPTCHA, launched in 2007, showed two hard-to-read words. One was already known and checked that you were human; the other came from a scanned old book or newspaper that a computer had failed to read, so millions of people typing it helped digitise printed text.

Science, 2008

Technology

The story behind the card

A CAPTCHA is a small test that computers find hard and people find easy, used to keep automated programs, or bots, out of sign-up forms and comment boxes. The name stands for 'Completely Automated Public Turing test to tell Computers and Humans Apart'; it was coined in 2003 by Luis von Ahn, Manuel Blum and colleagues at Carnegie Mellon University. Von Ahn realised that people were spending millions of hours in total on these puzzles, and reCAPTCHA put that effort to use. Scanned pages were read by optical character recognition (OCR), software that turns pictures of letters into text; words it was unsure of became puzzles, and several people's answers were compared. The system helped digitise The New York Times archive and was then used for Google Books. Google bought reCAPTCHA in 2009, and from 2014 it moved to image puzzles and a simple 'I'm not a robot' box.

Türkçe oku
2007'de kullanılmaya başlanan ilk reCAPTCHA, okunması zor iki kelime gösteriyordu. Biri önceden bilinen bir kelimeydi ve karşıdakinin insan olup olmadığını denetliyordu. Öteki, bilgisayarın okuyamadığı, taranmış eski bir kitap ya da gazeteden geliyordu; bu kelimeyi yazan milyonlarca kişi, basılı metinlerin dijitalleşmesine yardım etti.
Science dergisi, 2008

CAPTCHA, bilgisayarların zorlandığı ama insanların kolayca çözdüğü küçük bir testtir; otomatik programları, yani botları kayıt formlarından ve yorum kutularından uzak tutmak için kullanılır. Adı, İngilizcede “bilgisayarları ve insanları ayırt etmek için tamamen otomatik, herkese açık Turing testi” anlamına gelen ifadenin kısaltmasıdır. Terimi 2003'te Carnegie Mellon Üniversitesi'nden Luis von Ahn, Manuel Blum ve arkadaşları ortaya attı. Von Ahn, insanların bu bulmacalara toplamda milyonlarca saat harcadığını fark etti; reCAPTCHA bu emeği işe yarar bir şeye dönüştürdü. Taranan sayfalar, harf görüntülerini metne çeviren optik karakter tanıma (OCR) yazılımıyla okunuyordu. Yazılımın emin olamadığı kelimeler bulmacaya dönüşüyor, birkaç kişinin yanıtı karşılaştırılıyordu. Sistem New York Times arşivinin dijitalleşmesine yardım etti, ardından Google Books için de kullanıldı. Google 2009'da reCAPTCHA'yı satın aldı; 2014'ten itibaren kelimelerin yerini resim bulmacaları ve basit bir “Ben robot değilim” kutucuğu aldı.

Sources and further reading

Background reading: ReCAPTCHA
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