Unicode-based image generation and testing

• US 9,710,637 B2
• Filed: 08/28/2015
• Issued: 07/18/2017
• Est. Priority Date: 08/28/2015
• Status: Active Grant

• Current Assignee: Salesforce.com, Inc.
• Original Assignee: Salesforce.com, Inc.
• Inventors: Kalra, Gursev Singh
• Primary Examiner(s): Vaughan, Michael R
• Application Number:
  US14/838,851
• Publication Number:
  US 20170061114A1
• Time in Patent Office: 690 Days
• Field of Search: None
• CPC Class Codes: G06F 21/36 by graphic or iconic representation
• CPC Class Codes: G06F 21/6218 to a system of files or objects, e.g. local or distributed file system or database
• CPC Class Codes: G06F 2221/2133 Verifying human interaction, e.g., Captcha

Abstract

Systems and methods for testing to tell computers and humans apart and generating said tests are described. An interface is generated that includes a challenge and a response. The challenge includes a plurality of challenge characters in a challenge region. The response includes a plurality of response characters that includes the plurality of challenge characters drawn in a response region. The drawing the response characters includes drawing a first response character, calculating a second set of coordinates for a second response character, and drawing the second response character. After all of the response characters have been drawn, locations of each of the challenge characters within the response are identified, and a maximum allowed distance is calculated based on the identified locations of the challenge characters within the response.

Claims

1. A method for generating, by a processor, an image for use in a test to tell computers and humans apart comprising:

receiving, by the processor, a selection of a range of characters from Unicode plane 0, the selected range of characters at least including the 8-bit ASCII character range;

receiving, by the processor, a selection of a challenge character count and a response character count;

generating, in response to receiving a request for the image, by the processor, a challenge comprising a plurality of challenge characters from the selected range of characters from Unicode plane 0, a number of characters in the plurality of challenge characters being equal to the challenge character count, the plurality of challenge characters being located in a challenge region;

generating, in response to receiving a request for an image, by the processor a response comprising a plurality of response characters from the selected range of characters from Unicode plane 0, a number of characters in the plurality of response characters being equal to the response character count, the response including the plurality of challenge characters, each character in the response having a font size selected from a range having a predetermined maximum, the generated challenge and the generated response together forming the generated image, the response characters being drawn in a response region, each response character being associated with a location having an x and y coordinate, the drawing comprising;

drawing a first response character in the response region;

identifying pixels within the response region occupied by the first challenge character;

calculating a reference coordinate for the first response character based on the identified pixels occupied by the first challenge character;

adapting the x and y coordinate for the first response character to calculate a second set of coordinates for a second response character; and

drawing the second response character at the second set of coordinates;

identifying by the processor, after all of the plurality of response characters have been drawn, locations associated with each of the plurality of challenge characters within the response; and

calculating, by the processor, a maximum allowed distance after all response characters have been drawn, the maximum allowed distance being a value based on the selected font size of each of the challenge characters included in the response.

2. The method of claim 1, further comprising determining, by the processor, placement of the challenge region, the determining comprising:

calculating an amount of blank space above the challenge region based on a maximum font size; and

calculating an amount of blank space below the challenge region based on a multiple of the maximum font size.

3. The method of claim 1, further comprising determining, by the processor, dimensions of the challenge region, the challenge region being a rectangle, the determining comprising:

calculating a starting point for the challenge region based on a maximum font size for the challenge characters;

calculating a challenge region width based on a multiple of the maximum font size for the challenge characters; and

calculating a challenge region height based on a height of the image and the maximum font size for the challenge characters.

4. The method of claim 1, further comprising drawing the first challenge character in the challenge region, the drawing the first challenge character comprising:

identifying a sub-region in the challenge region based on the challenge count and dimensions of the challenge region, the sub-region being placed such that all challenge characters may be drawn within the challenge region; and

randomly selecting a location within the sub-region for the first challenge character.

5. The method of claim 4, wherein the sub-region comprises an area that equals one divided by the challenge count multiplied by the area of the challenge region.

6. The method of claim 1, further comprising determining, by the processor, dimensions of the response region, the response region being a rectangle, the determining comprising:

calculating a starting point for the response region based on the predetermined maximum font size for the response characters;

calculating a response region width based on a multiple of the predetermined maximum font size for the response characters; and

calculating a response region height based on a height of the image and the predetermined maximum font size for the response characters.

7. The method of claim 6, further comprising calculating the predetermined maximum font size, the maximum font size being calculated from the smaller size value between a height and a width of the image.

8. The method of claim 1, wherein the maximum allowed distance is further based on a general usability multiplier for maximum permissible accumulated distance between user selections and an expected centers of each of the challenge characters included in the response.

9. The method of claim 1, further comprising automatically orienting the challenge characters vertically in response to a determination that a requesting client display has a width that is greater than or equal to a height of the requesting client display.

10. The method of claim 1, further comprising automatically orienting the challenge characters horizontally in response to a determination that a requesting client display has a width that is less than a height of the requesting client display.

11. A system for generating an image for use in a test to tell computers and humans apart comprising:

a web server, the web server receiving a request for an image from a client device; and

a test server, the test server being configured to;

receive the request for the image via the web server;

receive a selection of a range of characters from Unicode plane 0, the selected range of characters at least including the 8-bit ASCII character range;

receive a selection of a challenge character count and a response character count;

generate, in response to receiving a request for the image, a challenge comprising a plurality of challenge characters from the selected range of characters from Unicode plane 0, a number of characters in the plurality of challenge characters being equal to the challenge character count, the plurality of challenge characters being located in a challenge region;

generate, in response to receiving a request for an image, a response comprising a plurality of response characters from the selected range of characters from Unicode plane 0, a number of characters in the plurality of response characters being equal to the response character count, the response including the plurality of challenge characters, each character in the response having a font size selected from a range having a predetermined maximum, the generated challenge and the generated response together forming the generated image, the response characters being drawn in a response region, each response character being associated with a location having an x and y coordinate, the drawing comprising;

drawing a first response character in the response region;

identifying pixels within the response region occupied by the first challenge character;

calculating a reference coordinate for the first response character based on the identified pixels occupied by the first challenge character;

adapting the x and y coordinate for the first response character to calculate a second set of coordinates for a second response character; and

drawing the second response character at the second set of coordinates;

identify, after all of the plurality of response characters have been drawn, locations associated with each of the plurality of challenge characters within the response; and

calculate a maximum allowed distance after all response characters have been drawn, the maximum allowed distance being a value based on the selected font size of each of the challenge characters included in the response.

12. The system of claim 11, the test server being further configured to determine placement of the challenge region, the determining comprising:

calculating an amount of blank space above the challenge region based on a maximum font size; and

calculating an amount of blank space below the challenge region based on a multiple of the maximum font size.

13. The system of claim 11, the test server being further configured to determine dimensions of the challenge region, the challenge region being a rectangle, the determining comprising:

calculating a starting point for the challenge region based on the predetermined maximum font size for the challenge characters;

calculating a challenge region width based on a multiple of the predetermined maximum font size for the challenge characters; and

calculating a challenge region height based on a height of the image and the predetermined maximum font size for the challenge characters.

14. The system of claim 11, the test server being further configured to draw the first challenge character in the challenge region, the drawing the first challenge character comprising:

identifying a sub-region in the challenge region based on the challenge count and dimensions of the challenge region, the sub-region being placed such that all challenge characters may be drawn within the challenge region; and

randomly selecting a location within the sub-region for the first challenge character.

15. The system of claim 14, wherein the sub-region comprises an area that equals one divided by the challenge count multiplied by the area of the challenge region.

16. The system of claim 11, the test server being further configured to determine dimensions of the response region, the response region being a rectangle, the determining comprising:

calculating a starting point for the response region based on the predetermined maximum font size for the response characters;

calculating a response region width based on a multiple of the predetermined maximum font size for the response characters; and

calculating a response region height based on a height of the image and the predetermined maximum font size for the response characters.

17. A computer program product comprising computer-readable program code to be executed by one or more processors when retrieved from a non-transitory computer-readable medium, the program code including instructions to:

receive a selection of a range of characters from Unicode plane 0, the selected range of characters at least including the 8-bit ASCII character range;

receive a selection of a challenge character count and a response character count;

generate, in response to receiving a request for the image, a challenge comprising a plurality of challenge characters from the selected range of characters from Unicode plane 0, a number of characters in the plurality of challenge characters being equal to the challenge character count, the plurality of challenge characters being located in a challenge region;

generate, in response to receiving a request for an image, a response comprising a plurality of response characters from the selected range of characters from Unicode plane 0, a number of characters in the plurality of response characters being equal to the response character count, the response including the plurality of challenge characters, each character in the response having a font size selected from a range having a predetermined maximum, the generated challenge and the generated response together forming the generated image, the response characters being drawn in a response region, each response character being associated with a location having an x and y coordinate, the drawing comprising;

drawing a first response character in the response region;

identifying pixels within the response region occupied by the first challenge character;

calculating a reference coordinate for the first response character based on the identified pixels occupied by the first challenge character;

adapting the x and y coordinate for the first response character to calculate a second set of coordinates for a second response character; and

drawing the second response character at the second set of coordinates;

identify, after all of the plurality of response characters have been drawn, locations associated with each of the plurality of challenge characters within the response; and

calculate a maximum allowed distance after all response characters have been drawn, the maximum allowed distance being a value based on the selected font size of each of the challenge characters included in the response.

18. The computer program product of claim 17, the program code further including instructions to determine placement of the challenge region, the determining comprising:

calculating an amount of blank space above the challenge region based on a maximum font size; and

calculating an amount of blank space below the challenge region based on a multiple of the maximum font size.

19. The computer program product of claim 17, the program code further including instructions to determine dimensions of the challenge region, the challenge region being a rectangle, the determining comprising:

calculating a starting point for the challenge region based on the predetermined maximum font size for the challenge characters;

calculating a challenge region width based on a multiple of the predetermined maximum font size for the challenge characters; and

calculating a challenge region height based on a height of the image and the predetermined maximum font size for the challenge characters.

20. The computer program product of claim 17, the program code further including instructions to draw the first challenge character in the challenge region, the drawing the first challenge character comprising:

identifying a sub-region in the challenge region based on the challenge count and dimensions of the challenge region, the sub-region being placed such that all challenge characters may be drawn within the challenge region; and

randomly selecting a location within the sub-region for the first challenge character.