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Captcha security for google

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Hritesh Saha
Hritesh Saha

Luis von Ahn discusses CAPTCHAs and the ESP Game, which are methods to utilize human brainpower to solve problems computers currently cannot. CAPTCHAs test whether a user is human by having them read distorted text, while the ESP Game labels images by having online partners try to describe the same image without communicating. Both work by crowdsourcing many small tasks. The ESP Game in particular has labeled over 1.5 million images with 15,000 players. The goal is to eventually label all images on the web to improve search, accessibility, and computer vision.

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CAPTCHA, THE ESP GAME, AND OTHER STUFF LUIS VON AHN CARNEGIE MELLON UNIVERSITY
Captcha security for google
CAPTCHA A PROGRAM THAT CAN TELL WHETHER ITS USER IS A HUMAN OR A COMPUTER
CAPTCHA A. MOST HUMANS CAN PASS B. CURRENT COMPUTER PROGRAMS CANNOT PASS A PROGRAM THAT CAN GENERATE AND GRADE TESTS THAT:
EXAMPLE PICKS RANDOM STRING OF LETTERS oamg RENDERS IT INTO A DISTORTED IMAGE
AND GENERATES A TEST: TYPE THE CHARACTERS THAT APPEAR IN THE IMAGE
P STANDS FOR PUBLIC ALL CODE AND DATA USED BY A CAPTCHA SHOULD BE PUBLICLY AVAILABLE
COMPLETELY AUTOMATED PUBLIC TURING TEST TO TELL COMPUTERS AND HUMANS APART
UTILIZING THE POWER OF HUMAN CYCLES CAPTCHA THE ESP GAME APPLICATIONS EXAMPLES DIRTY HACKS OTHER STUFF
APPLICATIONS OF CAPTCHAS
(FROM WWW.SLASHDOT.ORG) QUICKVOTE Which is the best Computer Science Grad School in the US? CMU MIT vote Berkeley StanfordCornell Princeton
FREE E-MAIL SERVICES DATA COLLECTION WORMS AND SPAM PREVENTING DICTIONARY ATTACKS (PINKAS AND SANDER 02) APPLICATIONS
FREE E-MAIL SERVICES DATA COLLECTION WORMS AND SPAM PREVENTING DICTIONARY ATTACKS (PINKAS AND SANDER 02) APPLICATIONS
FREE E-MAIL SERVICES DATA COLLECTION WORMS AND SPAM PREVENTING DICTIONARY ATTACKS (PINKAS AND SANDER 02) APPLICATIONS
FREE E-MAIL SERVICES DATA COLLECTION WORMS AND SPAM PREVENTING DICTIONARY ATTACKS (PINKAS AND SANDER 02) APPLICATIONS
EXAMPLES OF CAPTCHAS
PIX WHAT ARE THESE PICTURES OF?
PIX WHAT ARE THESE PICTURES OF? THE IMAGES NEED TO BE RANDOMLY DISTORTED
PIX WHAT ARE THESE PICTURES OF? THE IMAGES NEED TO BE RANDOMLY DISTORTED
PIX WHAT ARE THESE PICTURES OF? THE IMAGES NEED TO BE RANDOMLY DISTORTED
WHAT ARE THESE PICTURES OF?
BONGO VISUAL ANALOGY PROBLEMS (BONGARD 1951)
Captcha security for google
SOUND-BASED CAPTCHA HUMANS ARE BETTER THAN COMPUTERS AT UNDERSTANDING SPOKEN LANGUAGE
CREATE A CAPTCHA BASED ON LANGUAGE UNDERSTANDING OPEN PROBLEM
DIRTY HACKS
CAPTCHA SWEAT SHOPS SPAM COMPANIES HIRE HUMANS TO SOLVE CAPTCHAS ALL DAY LONG $2.50 PER HOUR FOR EACH HUMAN 720 CAPTCHAS PER HOUR PER HUMAN 1/3 CENT PER ACCOUNT
Free Nude Photos > NEXT
Type the word in the box if you want to see the next picture Free Nude Photos
UTILIZING THE POWER OF HUMAN CYCLES CAPTCHA THE ESP GAME APPLICATIONS EXAMPLES DIRTY HACKS OTHER STUFF
LABELING IMAGES WITH WORDS MARTHA STEWART FLOWERS SUPER EVIL STILL AN OPEN PROBLEM
IMAGE SEARCH ON THE WEB USES FILENAMES AND HTML TEXT
ACCESSIBILITY LESS THAN 10% OF THE WEB IS ACCESSIBLE TO THE VISUALLY IMPAIRED REASON: MOST IMAGES DONT HAVE PROPER CAPTIONS
DESIDERATA A METHOD THAT CAN LABEL ALL IMAGES ON THE WEB FAST AND CHEAP
USING HUMANS THE ESP GAME COULD LABEL ALL IMAGES ON THE WEB IN 30 DAYS! THE ESP GAME CLEVERLY
TWO-PLAYER ONLINE GAME PARTNERS DONT KNOW EACH OTHER AND CANT COMMUNICATE OBJECT OF THE GAME: TYPE THE SAME WORD THE ONLY THING IN COMMON IS AN IMAGE THE ESP GAME
PLAYER 1 PLAYER 2 GUESSING: CAR GUESSING: BOY GUESSING: CAR SUCCESS! YOU AGREE ON CAR SUCCESS! YOU AGREE ON CAR GUESSING: KID GUESSING: HAT THE ESP GAME
息 2004 Carnegie Mellon University, all rights reserved. Patent Pending.
4.1 MILLION LABELS WITH 23,000 PLAYERS THE ESP GAME IS FUN THERE ARE MANY PEOPLE THAT PLAY OVER 20 HOURS A WEEK
LABELING THE ENTIRE WEB INDIVIDUAL GAMES IN YAHOO! AND MSN AVERAGE OVER 5,000 PLAYERS AT A TIME 5000 PEOPLE PLAYING SIMULTANEOUSLY CAN LABEL ALL IMAGES ON GOOGLE IN 30 DAYS!
A FEW MILLION LABELS CAN IMPROVE IMAGE SEARCH CAN BE USED TO IMPROVE COMPUTER VISION
SINGLE PLAYER GAME A SINGLE PERSON CAN PLAY WITH PRE- RECORDED ACTIONS AS THEIR PARTNER WHEN 2 PEOPLE PLAY, WE RECORD EVERY ACTION WITH TIMING INFORMATION WE EMULATE PARTNER BY PLAYING PRE- RECORDED MOVES(0:12) CAR (0:15) HAT (0:21) KID (0:08) BOY (0:23) CAR NOTICE THAT THIS DOESNT STOP THE LABELING PROCESS!
WHAT ABOUT CHEATING? IF A PAIR PLAYS TOO FAST, WE DONT RECORD THE WORDS THEY AGREE ON
WE GIVE PLAYERS TEST IMAGES FOR WHICH WE KNOW ALL THE COMMON LABELS: WE ONLY STORE A PLAYERS GUESSES IF THEY SUCCESSFULLY LABEL THE TEST IMAGES WHAT ABOUT CHEATING?
SEARCH RESULTS
SAMPLE LABELS BEACH CHAIRS SEA PEOPLE MAN WOMAN PLANT OCEAN TALKING WATER PORCH
SADDAM MR. WILSON MAN FACE MOUSTACHE SAMPLE LABELS BUSH PRESIDENT DUMB YUCKYUCK COMING SOON: MEET YOUR SOUL MATE THROUGH THE GAME!
WHY DO PEOPLE LIKE THE ESP GAME?
THE ESP GAME GIVES ITS PLAYERS A WEIRD AND BEAUTIFUL SENSE OF ANONYMOUS INTIMACY. ON THE ONE HAND, YOU HAVE NO IDEA WHO YOUR PARTNER IS. ON THE OTHER HAND, THE TWO OF YOU ARE BRINGING YOUR MINDS TOGETHER IN A WAY THAT LOVERS WOULD ENVY. THE ESP GAME GIVES ITS PLAYERS A WEIRD AND BEAUTIFUL SENSE OF ANONYMOUS INTIMACY. ON THE ONE HAND, YOU HAVE NO IDEA WHO YOUR PARTNER IS. THE ESP GAME GIVES ITS PLAYERS A WEIRD AND BEAUTIFUL SENSE OF ANONYMOUS INTIMACY.
STRANGELY ADDICTIVE ITS SO MUCH FUN TRYNG TO GUESS WHAT OTHERS THINK. YOU HAVE TO STEP OUTSIDE OF YOURSELF TO MATCH ITS FAST-PACED HELPS ME LEARN ENGLISH
BLOGS IN OTHER CROWNING ACHEIVEMENTS, I HAVEN'T PLAYED IN AT LEAST A WEEK (PROBABLY LONGER), AND I AM STILL ON THE TOP TEN LIST OF PLAYERS ON THE ESP GAME. NUMBER EIGHT IF I REMEMBER CORRECTLY. GOD, MY LIFE IS SAD.
THERE ARE MANY FASCINATING THINGS ABOUT THE ESP GAME: HOW IT USES A GAME STRUCTURE TO BUILD AN INDEX OF IMAGES ON THE WEB WHAT WORDS BECOME TABOO FROM FREQUENT USE HOW INTERESTING SOME OF THE IMAGES PULLED RANDOMLY FROM THE WEB ARE BUT BY FAR THE MOST INTRIGUING ASPECT OF THE GAME IS HOW OFTEN YOUR RANDOM, UNKNOWN PARTNER IS A COMPLETE IDIOT.
OTHER GAMES
LOCATING OBJECTS IN IMAGES THE ESP GAME TELLS US IF AN IMAGE CONTAINS A SPECIFIC OBJECT, BUT DOESNT SAY WHERE IN THE IMAGE THE OBJECT IS SUCH INFORMATION WOULD BE EXTREMELY USEFUL FOR COMPUTER VISION RESEARCH
PAINTBALL GAME PLAYERS SHOOT AT OBJECTS ON THE IMAGE SHOOT THE: CAR WE GIVE POINTS AND CHECK ACCURACY BY GIVING PLAYERS IMAGES FOR WHICH WE ALREADY KNOW WHERE THE OBJECT IS
X% OF IMAGES (100-X)% OF IMAGES PAINTBALL GAME DONT KNOW
BALL
REVEALING IMAGES REVEALERGUESSER CAR PARTNERS GUESS GUESS BRUSH BRUSHCAR CAR
Captcha security for google
MEDIUM-TERM GOAL USE THE ESP GAME, ALONG WITH THE PAINT- BALL GAME AND THE REVEALING GAME TO CREATE THE MOST ACCURATE COMPUTER VISION ALGORITHMS TO RECOGNIZE A WIDE VARIETY OF OBJECT CATEGORIES
Captcha security for google
X OR NOT CAN BE USED TO CLASSIFY ALL IMAGES ON THE WEB AS HAVING PROPERTY X OR NOT WE GIVE PEOPLE 40% OF IMAGES WITH PROPERTY X 40% OF IMAGES WITHOUT PROPERTY X 20% OF UNKNOWN IMAGES IF PEOPLE LIKE IMAGES WITH PROPERTY X, WE CAN OFFER AN INCENTIVE: THE MORE ACCURATE A PLAYER IS, THE MORE IMAGES WITH PROPERTY X THEY GET $$$
THE POWER OF HUMAN CYCLES OPEN PROBLEM CAPTCHA GAME
Captcha security for google
OUR WORK ON CAPTCHA HAS APPEARED IN OVER 100 NEWSPAPERS AROUND THE WORLD
Captcha security for google
THE ESP GAME HAS APPEARED IN OVER 50 NEWSPAPERS AROUND THE WORLD
Captcha security for google
Name That Image Computers excel at sifting information, but they have trouble distinguishing a picture of a tree from one of a turtle. So researchers at Carnegie Mellon University knew they needed human volunteers to successfully label millions of unmarked images on the Web. Luis von Ahn, a graduate student in computer science, had the inspired idea of turning the laborious process into a two-player contest called the ESP Game (espgame.org). Each time you play, you are randomly paired with another anonymous player. You can't communicate with your partner, although you both see the same image. The goal is to guess the descriptive word your partner is typing for the image. Once you both type the same word, you see a new image. Since October the game has attracted 15,000 registered players, and they have created more than 1.5 million labels (a label is a single descriptive word; most photos require multiple labels). The site draws from a database of 200,000 Web images; another 200,000 are to be added soon. Mr. von Ahn said that properly labeling Web images would allow for more efficient image searching, improve the screen readers used by the visually impaired and help users block inappropriate images.
Captcha security for google
WWW.CAPTCHA.NET
WWW.ESPGAME.ORG
SLIDE DESIGN LUIS VON AHN CAPTCHA CREW LUIS VON AHN MANUEL BLUM NICHOLAS HOPPER JOHN LANGFORD THE ESP GAME CREW LUIS VON AHN LAURA DABBISH SPEAKERS ENTERTAINMENT PROVIDED BY HOMESTARRUNNER.COM SPECIAL THANKS TO ADITYA AKELLA JOSH BENALOH LENORE BLUM MANUEL BLUM ANDREW BORTZ SHUCHI CHAWLA LAURA DABBISH BILL GATES BRIGHTEN GODFREY NICK HOPPER SCOTT HUDSON TAKEO KANADE STEVEN KATZ JOHN LANGFORD JITENDRA MALIK WARDROBE PROVIDED BY THE GAP HAIRSTYLES ARNAUD SOME-FRENCH-LAST-NAME THIS WORK HAS BEEN AND WILL BE PARTIALLY SUPPORTED BY MANUEL BLUM THE ALADDIN CENTER MICROSOFT RESEARCH MY MOM YOUR TAX DOLLARS MORE SPECIAL THANKS UDI MANBER MONI NAOR LENORE RAMM CHUCK ROSENBERG RONI ROSENFELD DAVID STORK LATANYA SWEENEY SHINGO UCHIHASHI MANUELA VELOSO

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Captcha security for google

  • 1. CAPTCHA, THE ESP GAME, AND OTHER STUFF LUIS VON AHN CARNEGIE MELLON UNIVERSITY
  • 3. CAPTCHA A PROGRAM THAT CAN TELL WHETHER ITS USER IS A HUMAN OR A COMPUTER
  • 4. CAPTCHA A. MOST HUMANS CAN PASS B. CURRENT COMPUTER PROGRAMS CANNOT PASS A PROGRAM THAT CAN GENERATE AND GRADE TESTS THAT:
  • 5. EXAMPLE PICKS RANDOM STRING OF LETTERS oamg RENDERS IT INTO A DISTORTED IMAGE
  • 6. AND GENERATES A TEST: TYPE THE CHARACTERS THAT APPEAR IN THE IMAGE
  • 7. P STANDS FOR PUBLIC ALL CODE AND DATA USED BY A CAPTCHA SHOULD BE PUBLICLY AVAILABLE
  • 8. COMPLETELY AUTOMATED PUBLIC TURING TEST TO TELL COMPUTERS AND HUMANS APART
  • 9. UTILIZING THE POWER OF HUMAN CYCLES CAPTCHA THE ESP GAME APPLICATIONS EXAMPLES DIRTY HACKS OTHER STUFF
  • 11. (FROM WWW.SLASHDOT.ORG) QUICKVOTE Which is the best Computer Science Grad School in the US? CMU MIT vote Berkeley StanfordCornell Princeton
  • 12. FREE E-MAIL SERVICES DATA COLLECTION WORMS AND SPAM PREVENTING DICTIONARY ATTACKS (PINKAS AND SANDER 02) APPLICATIONS
  • 13. FREE E-MAIL SERVICES DATA COLLECTION WORMS AND SPAM PREVENTING DICTIONARY ATTACKS (PINKAS AND SANDER 02) APPLICATIONS
  • 14. FREE E-MAIL SERVICES DATA COLLECTION WORMS AND SPAM PREVENTING DICTIONARY ATTACKS (PINKAS AND SANDER 02) APPLICATIONS
  • 15. FREE E-MAIL SERVICES DATA COLLECTION WORMS AND SPAM PREVENTING DICTIONARY ATTACKS (PINKAS AND SANDER 02) APPLICATIONS
  • 17. PIX WHAT ARE THESE PICTURES OF?
  • 18. PIX WHAT ARE THESE PICTURES OF? THE IMAGES NEED TO BE RANDOMLY DISTORTED
  • 19. PIX WHAT ARE THESE PICTURES OF? THE IMAGES NEED TO BE RANDOMLY DISTORTED
  • 20. PIX WHAT ARE THESE PICTURES OF? THE IMAGES NEED TO BE RANDOMLY DISTORTED
  • 21. WHAT ARE THESE PICTURES OF?
  • 24. SOUND-BASED CAPTCHA HUMANS ARE BETTER THAN COMPUTERS AT UNDERSTANDING SPOKEN LANGUAGE
  • 25. CREATE A CAPTCHA BASED ON LANGUAGE UNDERSTANDING OPEN PROBLEM
  • 27. CAPTCHA SWEAT SHOPS SPAM COMPANIES HIRE HUMANS TO SOLVE CAPTCHAS ALL DAY LONG $2.50 PER HOUR FOR EACH HUMAN 720 CAPTCHAS PER HOUR PER HUMAN 1/3 CENT PER ACCOUNT
  • 29. Type the word in the box if you want to see the next picture Free Nude Photos
  • 30. UTILIZING THE POWER OF HUMAN CYCLES CAPTCHA THE ESP GAME APPLICATIONS EXAMPLES DIRTY HACKS OTHER STUFF
  • 31. LABELING IMAGES WITH WORDS MARTHA STEWART FLOWERS SUPER EVIL STILL AN OPEN PROBLEM
  • 32. IMAGE SEARCH ON THE WEB USES FILENAMES AND HTML TEXT
  • 33. ACCESSIBILITY LESS THAN 10% OF THE WEB IS ACCESSIBLE TO THE VISUALLY IMPAIRED REASON: MOST IMAGES DONT HAVE PROPER CAPTIONS
  • 34. DESIDERATA A METHOD THAT CAN LABEL ALL IMAGES ON THE WEB FAST AND CHEAP
  • 35. USING HUMANS THE ESP GAME COULD LABEL ALL IMAGES ON THE WEB IN 30 DAYS! THE ESP GAME CLEVERLY
  • 36. TWO-PLAYER ONLINE GAME PARTNERS DONT KNOW EACH OTHER AND CANT COMMUNICATE OBJECT OF THE GAME: TYPE THE SAME WORD THE ONLY THING IN COMMON IS AN IMAGE THE ESP GAME
  • 37. PLAYER 1 PLAYER 2 GUESSING: CAR GUESSING: BOY GUESSING: CAR SUCCESS! YOU AGREE ON CAR SUCCESS! YOU AGREE ON CAR GUESSING: KID GUESSING: HAT THE ESP GAME
  • 38. 息 2004 Carnegie Mellon University, all rights reserved. Patent Pending.
  • 39. 4.1 MILLION LABELS WITH 23,000 PLAYERS THE ESP GAME IS FUN THERE ARE MANY PEOPLE THAT PLAY OVER 20 HOURS A WEEK
  • 40. LABELING THE ENTIRE WEB INDIVIDUAL GAMES IN YAHOO! AND MSN AVERAGE OVER 5,000 PLAYERS AT A TIME 5000 PEOPLE PLAYING SIMULTANEOUSLY CAN LABEL ALL IMAGES ON GOOGLE IN 30 DAYS!
  • 41. A FEW MILLION LABELS CAN IMPROVE IMAGE SEARCH CAN BE USED TO IMPROVE COMPUTER VISION
  • 42. SINGLE PLAYER GAME A SINGLE PERSON CAN PLAY WITH PRE- RECORDED ACTIONS AS THEIR PARTNER WHEN 2 PEOPLE PLAY, WE RECORD EVERY ACTION WITH TIMING INFORMATION WE EMULATE PARTNER BY PLAYING PRE- RECORDED MOVES(0:12) CAR (0:15) HAT (0:21) KID (0:08) BOY (0:23) CAR NOTICE THAT THIS DOESNT STOP THE LABELING PROCESS!
  • 43. WHAT ABOUT CHEATING? IF A PAIR PLAYS TOO FAST, WE DONT RECORD THE WORDS THEY AGREE ON
  • 44. WE GIVE PLAYERS TEST IMAGES FOR WHICH WE KNOW ALL THE COMMON LABELS: WE ONLY STORE A PLAYERS GUESSES IF THEY SUCCESSFULLY LABEL THE TEST IMAGES WHAT ABOUT CHEATING?
  • 48. WHY DO PEOPLE LIKE THE ESP GAME?
  • 49. THE ESP GAME GIVES ITS PLAYERS A WEIRD AND BEAUTIFUL SENSE OF ANONYMOUS INTIMACY. ON THE ONE HAND, YOU HAVE NO IDEA WHO YOUR PARTNER IS. ON THE OTHER HAND, THE TWO OF YOU ARE BRINGING YOUR MINDS TOGETHER IN A WAY THAT LOVERS WOULD ENVY. THE ESP GAME GIVES ITS PLAYERS A WEIRD AND BEAUTIFUL SENSE OF ANONYMOUS INTIMACY. ON THE ONE HAND, YOU HAVE NO IDEA WHO YOUR PARTNER IS. THE ESP GAME GIVES ITS PLAYERS A WEIRD AND BEAUTIFUL SENSE OF ANONYMOUS INTIMACY.
  • 50. STRANGELY ADDICTIVE ITS SO MUCH FUN TRYNG TO GUESS WHAT OTHERS THINK. YOU HAVE TO STEP OUTSIDE OF YOURSELF TO MATCH ITS FAST-PACED HELPS ME LEARN ENGLISH
  • 51. BLOGS IN OTHER CROWNING ACHEIVEMENTS, I HAVEN'T PLAYED IN AT LEAST A WEEK (PROBABLY LONGER), AND I AM STILL ON THE TOP TEN LIST OF PLAYERS ON THE ESP GAME. NUMBER EIGHT IF I REMEMBER CORRECTLY. GOD, MY LIFE IS SAD.
  • 52. THERE ARE MANY FASCINATING THINGS ABOUT THE ESP GAME: HOW IT USES A GAME STRUCTURE TO BUILD AN INDEX OF IMAGES ON THE WEB WHAT WORDS BECOME TABOO FROM FREQUENT USE HOW INTERESTING SOME OF THE IMAGES PULLED RANDOMLY FROM THE WEB ARE BUT BY FAR THE MOST INTRIGUING ASPECT OF THE GAME IS HOW OFTEN YOUR RANDOM, UNKNOWN PARTNER IS A COMPLETE IDIOT.
  • 54. LOCATING OBJECTS IN IMAGES THE ESP GAME TELLS US IF AN IMAGE CONTAINS A SPECIFIC OBJECT, BUT DOESNT SAY WHERE IN THE IMAGE THE OBJECT IS SUCH INFORMATION WOULD BE EXTREMELY USEFUL FOR COMPUTER VISION RESEARCH
  • 55. PAINTBALL GAME PLAYERS SHOOT AT OBJECTS ON THE IMAGE SHOOT THE: CAR WE GIVE POINTS AND CHECK ACCURACY BY GIVING PLAYERS IMAGES FOR WHICH WE ALREADY KNOW WHERE THE OBJECT IS
  • 56. X% OF IMAGES (100-X)% OF IMAGES PAINTBALL GAME DONT KNOW
  • 57. BALL
  • 60. MEDIUM-TERM GOAL USE THE ESP GAME, ALONG WITH THE PAINT- BALL GAME AND THE REVEALING GAME TO CREATE THE MOST ACCURATE COMPUTER VISION ALGORITHMS TO RECOGNIZE A WIDE VARIETY OF OBJECT CATEGORIES
  • 62. X OR NOT CAN BE USED TO CLASSIFY ALL IMAGES ON THE WEB AS HAVING PROPERTY X OR NOT WE GIVE PEOPLE 40% OF IMAGES WITH PROPERTY X 40% OF IMAGES WITHOUT PROPERTY X 20% OF UNKNOWN IMAGES IF PEOPLE LIKE IMAGES WITH PROPERTY X, WE CAN OFFER AN INCENTIVE: THE MORE ACCURATE A PLAYER IS, THE MORE IMAGES WITH PROPERTY X THEY GET $$$
  • 63. THE POWER OF HUMAN CYCLES OPEN PROBLEM CAPTCHA GAME
  • 65. OUR WORK ON CAPTCHA HAS APPEARED IN OVER 100 NEWSPAPERS AROUND THE WORLD
  • 67. THE ESP GAME HAS APPEARED IN OVER 50 NEWSPAPERS AROUND THE WORLD
  • 69. Name That Image Computers excel at sifting information, but they have trouble distinguishing a picture of a tree from one of a turtle. So researchers at Carnegie Mellon University knew they needed human volunteers to successfully label millions of unmarked images on the Web. Luis von Ahn, a graduate student in computer science, had the inspired idea of turning the laborious process into a two-player contest called the ESP Game (espgame.org). Each time you play, you are randomly paired with another anonymous player. You can't communicate with your partner, although you both see the same image. The goal is to guess the descriptive word your partner is typing for the image. Once you both type the same word, you see a new image. Since October the game has attracted 15,000 registered players, and they have created more than 1.5 million labels (a label is a single descriptive word; most photos require multiple labels). The site draws from a database of 200,000 Web images; another 200,000 are to be added soon. Mr. von Ahn said that properly labeling Web images would allow for more efficient image searching, improve the screen readers used by the visually impaired and help users block inappropriate images.
  • 73. SLIDE DESIGN LUIS VON AHN CAPTCHA CREW LUIS VON AHN MANUEL BLUM NICHOLAS HOPPER JOHN LANGFORD THE ESP GAME CREW LUIS VON AHN LAURA DABBISH SPEAKERS ENTERTAINMENT PROVIDED BY HOMESTARRUNNER.COM SPECIAL THANKS TO ADITYA AKELLA JOSH BENALOH LENORE BLUM MANUEL BLUM ANDREW BORTZ SHUCHI CHAWLA LAURA DABBISH BILL GATES BRIGHTEN GODFREY NICK HOPPER SCOTT HUDSON TAKEO KANADE STEVEN KATZ JOHN LANGFORD JITENDRA MALIK WARDROBE PROVIDED BY THE GAP HAIRSTYLES ARNAUD SOME-FRENCH-LAST-NAME THIS WORK HAS BEEN AND WILL BE PARTIALLY SUPPORTED BY MANUEL BLUM THE ALADDIN CENTER MICROSOFT RESEARCH MY MOM YOUR TAX DOLLARS MORE SPECIAL THANKS UDI MANBER MONI NAOR LENORE RAMM CHUCK ROSENBERG RONI ROSENFELD DAVID STORK LATANYA SWEENEY SHINGO UCHIHASHI MANUELA VELOSO