Your links didn't work at all, so I can't give specific comments.
On Fri, Feb 28, 2014 at 1:02 PM, Aalekh Nigam aalekh1993@rediffmail.comwrote:
1)Alphabetical order captcha:We can use Html5's drag and drop Api to list a particular Set of images into one category .for example in the example mentoined in the demo here ,i made a collection of diff words starting with letters A,B,C ....as an output i grouped up words with starting letter A diff from words with starting letter B,C....As,i used text in this example we can use images of diff animals such as cat's and dog.....and by drag and drop we can group images of cat and that of dog in diff categories.
What if someone thinks your picture of a dog is "wolf", or "puppy", or "hound", or "terrier", or "animal", etc? Or what if the user identifies your images in Spanish or Chinese rather than English, resulting in a different order?
Also, how easy would it be for the spambot to download the entire list of images+names and just brute force it?
And what are the bot's chances by randomly guessing? If there are 8 images to sort, it's a 1/40320 chance. Which isn't very good as far as captchas go, 6 letters A-Z is 1/308915776.
2)Annotation captcha:We can use Images With annotations from commons determine the subcategoriy the annotations belongs to and then give relevant options to the users ;for example in the file we can search from names of different annotations to which they corresponds to from wikipedia(names given here are those of mountain) and then give the the option's much relevant to the image.
What's to stop the spambot from finding the image on Commons?
And looking at that category, are users really going to be able to reliably identify the "Fiat Grande Punto" in https://commons.wikimedia.org/wiki/File:%22_01_-_ITALY_-_ALFA_ROMEO_SPIDER_S..., or figure out WTF "UP 5" and "UP 6" are supposed to be in https://commons.wikimedia.org/wiki/File:%22_12_-_ITALY_-_Serie_UP_di_Gaetano..., or Colli Euganei in https://commons.wikimedia.org/wiki/File:%22_12_-_ITALY-_Sunset_in_Cavarzere_..., or identify the birds by scientific name in https://commons.wikimedia.org/wiki/File:-_Plastic_boxes_-.jpg, or guess which chloroplast (in German!) to pick in https://commons.wikimedia.org/wiki/File:03-10_Mnium2.jpg?
3)Effect captcha:We can use image as a question which are changed by the effect produced php's gd library and the use the same file with another effect and then ask user to match the two files.....for example:the image1 can be used as a question asking user to click on the image that matches with the question image and as an answer we can give this spiral image of the original image.Similarly we can give filters to different images producing different options asking user for right answer.
Spambots already solve this sort of thing when OCRing text captchas.
4)Direct captcha:We can ask to user direct questions like ask for selecting cat out of options consisting of images of cats and humans.....an example by pginer demonstrate this example
I just replied to this idea at http://lists.wikimedia.org/pipermail/wikitech-l/2014-February/074816.html
5)Ask User to click on given effect: Asking user to click on images consisting of spiral effect's out of options which consist of images with spiral and other effects(example:greyscale).
That requires people actually know what the effects names are, which doesn't seem particularly accessible. And again, OCRing is probably harder for bots.
6)Drag and Drop character in Correct Place: We can use drag and drop api of html5 to ask user to form an particular alphabet or no out of the pieces of character provided .Here is an example to form an character "A" and an digit "8" out of the same pieces of character.This drag and drop capability can be further enhance to form a particular shapes.For example form a clip art from a particular set of piece of shapes....for example the image given hereinserts the correct nose as asked in the in the questions out of the possible options provided.Most,Importantly i think creation of an index system would be fruitful since it would rank the inappropriate images on the basis of users response (rank is negative for an image if user needs to reload a captcha) to a provided captcha.This as the time passes will provide us with relevant images which are user friendly and equivalently secure to use.......In addition i sincerely appreciate a point mentioned by Gmansi of creation of jigsaw puzzle for the images but in my view point there will be listing of some particular category of images and those ranked higher in indexing system to be used as jigsaw puzzle.as an additonal help we can use Extension Assira to make our extension smarter.please give your valuable suggestions as we can work to improve this amazing project. at https://www.mediawiki.org/wiki/Talk:CAPTCHA :)
Computers can solve jigsaw puzzles, and probably faster than humans can. For example, http://www.popsci.com/technology/article/2010-05/new-software-assembles-jigs...