Differentiating between human interaction and computer interaction using a natural perception of human eyes to identify human users

1. A computer-implemented method for differentiating between human interaction and computer interaction using a natural perception of human eyes to identify human users, at least a portion of the method being performed by a computing device comprising one or more processors, the method comprising:

displaying within a first test field on a first web page a first image to a user at a first refresh rate, wherein at the first refresh rate the first image is displayed for a duration that is equal to or more than a duration that is required for a human eye to perceive the first image;

displaying within a second test field on the first web page a second image to the user at a second refresh rate, wherein at the second refresh rate the second image is displayed for a duration that is less than a duration that is required for the human eye to perceive the second image;

receiving input from the user identifying all images that are perceived by the user;

determining that the user is a human user when the user identifies the first image but not the second image;

granting access to a second web page to users who are determined to be human; and

denying access to the second web page to users that are not determined to be human.

2. The method of claim 1 , wherein the first and second images are letters or numbers.

3. The method of claim 1 , wherein the duration that the first image is displayed at the first refresh rate is more than 60 ms.

4. The method of claim 1 , wherein the duration that the second image is displayed at the second refresh rate is less than 50 ms.

5. The method of claim 1 , wherein the first image is displayed in a plurality of instances and between instances of displaying the first image, the first test field is blank.

6. The method of claim 1 , wherein:

the second image is displayed in a plurality of instances,

between instances of displaying the second image, a plurality of instances of a third image is displayed,

each instance of the third image is displayed for a duration that is less than what is required for the human eye to perceive the third image, and

the user is determined to be a human user when the user identifies the first image but not the second image or the third image.

7. The method of claim 1 , wherein:

the first image is a letter,

the letter is displayed in a plurality of instances,

between instances of displaying the letter, other letters are displayed, and

the other letters that are displayed are displayed for durations that are less than what is required for the human eye to perceive the other letters.

8. One or more non-transitory computer-readable media comprising one or more computer-readable instructions that, when executed by one or more processors of a computing device, cause the computing device to perform a method for differentiating between human interaction and computer interaction using a natural perception of human eyes to identify human users, the method comprising:

displaying within a first test field on a first web page a first image to a user at a first refresh rate, wherein at the first refresh rate the first image is displayed for a duration that is equal to or more than a duration that is required for a human eye to perceive the first image;

displaying within a second test field on the first web page a second image to the user at a second refresh rate, wherein at the second refresh rate the second image is displayed for a duration that is less than a duration that is required for the human eye to perceive the second image;

receiving input from the user identifying all images that are perceived by the user;

determining that the user is a human user when the user identifies the first image but not the second image;

granting access to a second web page to users who are determined to be human; and

denying access to the second web page to users that are not determined to be human.

9. The one or more non-transitory computer-readable media of claim 8 , wherein the first and second images are letters or numbers.

10. The one or more non-transitory computer-readable media of claim 8 , wherein the duration that the first image is displayed at the first refresh rate is more than 60 ms.

11. The one or more non-transitory computer-readable media of claim 8 , wherein the duration that the second image is displayed at the second refresh rate is less than 50 ms.

12. The one or more non-transitory computer-readable media of claim 8 , wherein the first image is displayed in a plurality of instances and between instances of displaying the first image, the first test field is blank.

13. The one or more non-transitory computer-readable media of claim 8 , wherein:

the second image is displayed in a plurality of instances,

between instances of displaying the second image, a plurality of instances of a third image is displayed,

each instance of the third image is displayed for a duration that is less than what is required for the human eye to perceive the third image, and

the user is determined to be a human user when the user identifies the first image but not the second image or the third image.

14. The one or more non-transitory computer-readable media of claim 8 , wherein:

the first image is a letter,

the letter is displayed in a plurality of instances,

between instances of displaying the letter, other letters are displayed, and

the other letters that are displayed are displayed for durations that are less than what is required for the human eye to perceive the other letters.

15. A computing device comprising:

one or more processors; and

one or more non-transitory computer-readable media comprising one or more computer-readable instructions that, when executed by the one or more processors, cause the computing device to perform a method for differentiating between human interaction and computer interaction using a natural perception of human eyes to identify human users, the method comprising

displaying within a first test field on a first web page a first image to a user at a first refresh rate, wherein at the first refresh rate the first image is displayed for a duration that is equal to or more than a duration that is required for a human eye to perceive the first image;

displaying within a second test field on the first web page a second image to the user at a second refresh rate, wherein at the second refresh rate the second image is displayed for a duration that is less than a duration that is required for the human eye to perceive the second image;

receiving input from the user identifying all images that are perceived by the user;

determining that the user is a human user when the user identifies the first image but not the second image;

granting access to a second web page to users who are determined to be human; and

denying access to the second web page to users that are not determined to be human.

16. The computing device of claim 15 , wherein the first and second images are letters or numbers.

17. The computing device of claim 15 , wherein the duration that the first image is displayed at the first refresh rate is more than 60 ms.

18. The computing device of claim 15 , wherein the duration that the second image is displayed at the second refresh rate is less than 50 ms.

19. The computing device of claim 15 , wherein the first image is displayed in a plurality of instances and between instances of displaying the first image, the first test field is blank.

20. The computing device of claim 15 , wherein:

the second image is displayed in a plurality of instances,

between instances of displaying the second image, a plurality of instances of a third image is displayed,

each instance of the third image is displayed for a duration that is less than what is required for the human eye to perceive the third image, and

the user is determined to be a human user when the user identifies the first image but not the second image or the third image.