Scanning images for pornography

1. A method of scanning image files for pornographic image content, the method comprising:

maintaining a list of items of copyright information deemed to indicate that the image file is one of acceptable or unacceptable; and

processing an image file by:

examining any copyright data fields of the image file containing copyright information to detect the presence of any item of copyright information in said list;

in the event that there is not detected the presence of an item of copyright information in said list, analysing the image content of the image file to detect the presence of pornographic image content, and outputting data indicating that the image file does or does not contain pornographic image content on the basis of the analysis;

in the event that there is detected the presence of an item of copyright information deemed to indicate that the image file is acceptable, outputting data indicating that the image file does not contain pornographic image content, without analysing the image content of the image file; and

in the event that there is detected the presence of an item of copyright information deemed to indicate that the image file is unacceptable, outputting data indicating that the image file does contain pornographic image content, without analysing the image content of the image file.

2. A method according to claim 1 , wherein the items of copyright information in said list comprise the names of copyright owners deemed to indicate that the image file is acceptable.

3. A method according to claim 1 , wherein the items of copyright information in said list comprise the names of copyright owners deemed to indicate that the image file is unacceptable.

4. A method according to claim 1 , wherein the items of copyright information in said list comprise words associated with pornography as items deemed to indicate that the image file is unacceptable.

5. A method according to claim 1 , wherein all the items of copyright information in said list are deemed to indicate that the image file is acceptable.

6. A method according to claim 1 , wherein all the items of copyright information in said list are deemed to indicate that the image file is unacceptable.

7. A method according to claim 1 , wherein the step of examining any copyright data fields of the image file is performed in respect of image files in a TIFF format or in a JPEG format.

8. A method according to claim 1 , further comprising storing said output data.

9. A computer system operable to scan image files for pornographic image content, the computer system storing a list of items of copyright information deemed to indicate that the image file is one of acceptable or unacceptable, and comprising:

a pre-filter operable on an image file to examine any copyright data fields of the image file containing copyright information to detect the presence of any item of copyright information in said list; and

an image scanner operable on an image file to analyse the image content of the image file to detect the presence of pornographic image content,

the computer system being arranged to process an image file by initially operating the pre-filter on the image file, and only in the event that the pre-filter does not detect the presence of an item of copyright information in said list, then operating the image scanner on the image file,

the computer system being further arranged to output data indicating that the image file does not contain pornographic image content in the event that the pre-filter detects the presence of an item of copyright information deemed to indicate that the image file is acceptable, to output data indicating that the image file does contain pornographic image content in the event that the pre-filter detects the presence of an item of copyright information deemed to indicate that the image file is unacceptable, and otherwise to output data indicating that the image file does or does not contain pornographic image content on the basis of any analysis performed by the image scanner.

10. A system according to claim 9 , wherein the items of copyright information in said list comprise the names of copyright owners deemed to indicate that the image file is acceptable.

11. A system according to claim 9 , wherein the items of copyright information in said list comprise the names of copyright owners deemed to indicate that the image file is unacceptable.

12. A system according to claim 9 , wherein the items of copyright information in said list comprise words associated with pornography as items deemed to indicate that the image file is unacceptable.

13. A system according to claim 9 , wherein all the items of copyright information in said list are deemed to indicate that the image file is acceptable.

14. A system according to claim 9 , wherein all the items of copyright information in said list are deemed to indicate that the image file is unacceptable.

15. A system according to claim 9 , wherein the step of examining any copyright data fields of the image file is performed in respect of image files in a TIFF format or in a JPEG format.

16. A system according to claim 9 , wherein the computer system is further arranged to store said output data.

17. A computer system operable to scan image files for pornographic image content, the computer system storing a list of items of copyright information deemed to indicate that the image file is acceptable, and comprising:

a pre-filter operable on an image file to examine any copyright data fields of the image file containing copyright information to detect the presence of any item of copyright information in said list; and

an image scanner operable on an image file to analyse the image content of the image file to detect the presence of pornographic image content,

the computer system being arranged to process an image file by initially operating the pre-filter on the image file, and only in the event that the pre-filter does not detect the presence of an item of copyright information in said list, then operating the image scanner on the image file,

the computer system being further arranged to output data indicating that the image file does not contain pornographic image content in the event that the pre-filter detects the presence of an item of copyright information deemed to indicate that the image file is acceptable, and otherwise to output data indicating that the image file does or does not contain pornographic image content on the basis of any analysis performed by the image scanner.

18. A computer system operable to scan image files for pornographic image content, the computer system storing a list of items of copyright information deemed to indicate that the image file is unacceptable, and comprising:

a pre-filter operable on an image file to examine any copyright data fields of the image file containing copyright information to detect the presence of any item of copyright information in said list; and

an image scanner operable on an image file to analyse the image content of the image file to detect the presence of pornographic image content,

the computer system being arranged to process an image file by initially operating the pre-filter on the image file, and only in the event that the pre-filter does not detect the presence of an item of copyright information in said list, then operating the image scanner on the image file,

the computer system being further arranged to output data indicating that the image file does contain pornographic image content in the event that the pre-filter detects the presence of an item of copyright information deemed to indicate that the image file is unacceptable, and otherwise to output data indicating that the image file does or does not contain pornographic image content on the basis of any analysis performed by the image scanner.