Patent attributes
A human interaction proof may restrict access to computer systems by testing the image orientation detection capabilities of the user making the access attempt. The human interaction proof includes a challenge where a plurality of images is presented. The images in the challenge may be drawn from image databases or the Internet, and may be part of a set of images that have been screened for difficulty with respect to computers. Some of the presented images are rotated away from their proper orientations. A user presented with the challenge is asked to differentiate the rotated images from the non-rotated images. A correct response leads to a grant of access, and an incorrect answer leads to a denial of access. The images in the challenge may be further modified with regard to color, lighting, cropping, etc. before presentation; the modifications increase the difficulty of the challenge for computers.
