Method and device for determining orientation of text

• US 20040252911A1
• Filed: 06/11/2003
• Published: 12/16/2004
• Est. Priority Date: 06/11/2003
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Zuniga, Oscar A.
• Granted Patent: US 7,298,920 B2
• Time in Patent Office: Days
• US Class Current: 382/290
• CPC Class Codes: G06V 10/242 by image rotation, e.g. by 90 degrees

Abstract

A method of determining the orientation of text is disclosed herein. An embodiment of the method may comprise measuring the contrasts associated with an upper edge of the text relative to a background. A first length of the upper edge of text having contrasts that are at least a first preselected value is measured. In addition to measuring the contrasts associated with the upper edge of the text, contrasts associated with a lower edge of the text are measured relative to the background. A second length of the lower edge of text having contrasts that are at least the first preselected value is then measured. The first length is compared to the second length, wherein the text is improperly oriented if the first length is greater than the second length.

Claims

1. A method of determining the orientation of text, said text extending substantially horizontal, said method comprising:

measuring the contrasts associated with an upper edge of said text relative to a background;

measuring a first length of said upper edge of text having contrasts that are at least a first preselected value;

measuring the contrasts associated with a lower edge of said text relative to said background;

measuring a second length of said lower edge of text having contrasts that are at least said first preselected value; and

comparing said first length to said second length, wherein said text is improperly oriented if said first length is greater than said second length.

2. The method of claim 1 and further comprising rotating said text one-hundred eighty degrees if said first length is greater than said second length.

3. The method of claim 1, wherein said measuring a first length comprises:

locating a first portion of said text having a contrast that exceeds a first preselected value; and

locating subsequent portions of said text having contrasts that exceed a second preselected value;

said first length being the distance between said first portion of said text and one of said subsequent portions of said text.

4. The method of claim 3, wherein said first preselected value is greater than said second preselected value.

5. The method of claim 3, wherein said first length is the longest distance between any of the portions of said text.

6. The method of claim 1, wherein said measuring a second length comprises:

locating a first portion of said text having a contrast that exceeds a first preselected value; and

locating subsequent portions of said text having contrasts that exceed a second preselected value;

said second length being the distance between said first portion of said text and one of said subsequent portions of said text.

7. The method of claim 6, wherein said second length is the longest distance between any of the portions of said text.

8. The method of claim 1, where said first length and said second length are compared to a third preselected value, and wherein said text is rotated ninety degrees if said first length and said second length are less than said third preselected value.

9. A method of determining the orientation of a text relative to a first axis, said method comprising:

measuring first contrasts relative to a background of at least one first edge of said text parallel to said first axis;

measuring at least one first length of said at least one first edge of text having contrasts that are at least a first preselected value;

measuring second contrasts relative to said background of at least one second edge of said text parallel to said first axis, said second edge being opposite said first edge;

measuring at least one second length of said at least one second edge of text having contrasts that are at least a second preselected value;

measuring third contrasts relative to said background of at least one second edge of said text parallel to a second axis, said second axis being perpendicular to said first axis;

measuring at least one third length of said at least one second edge of text having contrasts that are at least a third preselected value;

measuring fourth contrasts relative to said background of at least one fourth edge of said text parallel to said second axis, said fourth edge being opposite said third edge; and

measuring at least one fourth length of said at least one second edge of text having contrasts that are at least a fourth preselected value;

wherein the longer of either said first length, said second length, said third length, or said fourth length corresponds to the lower edge of said text.

10. The method of claim 9, wherein said first axis is horizontal, wherein said at least one first edge of said text is the lower edge of said text relative to said first axis, and wherein said at least one third edge of text is the left edge of said text relative to said second axis.

11. The method of claim 10, and further comprising:

rotating said text one-hundred eighty degrees if said second length is the longest length;

rotating said text ninety degrees counterclockwise if said third length is the longest length; and

rotating said text ninety degrees clockwise if said fourth length is the longest length.

12. The method of claim 9, wherein said measuring comprises:

locating a first portion of said text having at least one contrast that exceed a first preselected value; and

locating subsequent portions of said text having contrasts that exceed a preselected value that is lower than said first preselected value;

the corresponding length being the distance between said first portion of said text and one of said subsequent portions of said text.

13. The method of claim 9, wherein said first preselected value, said second preselected value, said third preselected value, and said fourth preselected value are equal.

14. A method of determining the orientation of text relative to an axis, said text being represented by image data comprising a plurality of pixel values, said method comprising:

generating an array of pixel value groupings, said array comprising pluralities of pixel value groupings extending perpendicular to said axis;

sampling at least one pixel value in each of said pixel groupings;

calculating first differences between adjacent sampled pixel values in said pluralities of pixel groupings, said first differences corresponding to a first edge of said text;

locating a first difference among said first differences, said first difference exceeding a first preselected value;

locating a first line of differences of said first differences including said first difference, said first line of differences being the greatest differences between subsequent ones of said pluralities of pixel groupings that exceed a second preselected value;

calculating the length of said first line;

calculating second differences between adjacent sampled pixel values in said pluralities of pixel groupings, said second differences corresponding to a second edge of said text, wherein said second edge is opposite said first edge;

locating a second difference among said second differences, said second difference exceeding a third preselected value;

locating a second line of differences of said second differences including said second difference, said second line of differences being the greatest differences between subsequent ones of said pluralities of pixel groupings that exceed a fourth preselected value; and

calculating the length of said second line;

wherein said text is oriented properly if said first line is greater than said second line.

15. The method of claim 14, wherein said text is oriented horizontally and wherein said first edge of said text is the lower edge of said text.

16. The method of claim 15, and further comprising rotating said text one-hundred eighty degrees if said first line is shorter than said second line.

17. The method of claim 14, wherein said sampling at least one pixel value comprises calculating the average pixel value of at least two of said pixel values.

18. The method of claim 14, wherein said sampling at least one pixel value comprises applying bicubic sampling of at least two of said pixel values.

19. The method of claim 14, wherein said sampling at least one pixel value comprises applying weighted averaging to at least two of said pixel values.

20. The method of claim 14, wherein said calculating the differences between adjacent sampled pixel values comprises applying an edge detection algorithm to the sampled pixel values.

21. The method of claim 14, wherein said calculating the differences between adjacent sampled pixel values comprises applying a minus one over one kernel to the sampled pixel values.

22. The method of claim 14, wherein said first preselected value is equal to said second preselected value.

23. The method of claim 14, wherein said first preselected value is greater than said second preselected value.

24. The method of claim 14, wherein said first preselected value is the negative of said third preselected value and wherein said locating a first difference comprises locating a first difference in one of said pluralities of pixel groupings, said first difference being less than said first preselected value

25. The method of claim 14, wherein at least one of said pixel value groupings is rectangular and comprises a first number of pixel values extending parallel to said axis and a second number of pixel values extending perpendicular to said axis, said first number of pixel values being greater than said second number of pixel values.

26. The method of claim 25, wherein said first number of pixels is about four.

27. The method of claim 25, wherein said second number of pixels is about sixty-four.

28. A device for determining the orientation of text, said text extending substantially horizontal, said device comprising:

first measuring means for measuring the contrasts associated with an upper edge of said text relative to a background, and for measuring the contrasts associated with a lower edge of said text relative to said background;

second measuring means for measuring a first length of said upper edge of text having contrasts that are at least a first preselected value, and for measuring a second length of said lower edge of text having contrasts that are at least said first preselected value; and

comparing means for comparing said first length to said second length, wherein said text is improperly oriented if said first length is greater than said second length.

29. The device of claim 28, and further comprising a third measuring means for measuring said contrasts associated with said lower edge of said text relative to said background.

30. The device of claim 28, and further comprising a fourth measuring means for measuring said second length of said lower edge of text having contrasts that are at least said first preselected value.

31. The device of claim 28 and further comprising a rotating means for rotating said text one-hundred eighty degrees if said first length is greater than said second length.

32. The device of claim 28, wherein said measuring a first length comprises:

locating a first portion of said text having a contrast that exceeds a first preselected value; and

locating subsequent portions of said text having contrasts that exceed a second preselected value;

said first length being the distance between said first portion of said text and one of said subsequent portions of said text.

33. The device of claim 32, wherein said first preselected value is greater than said second preselected value.

34. The device of claim 32, wherein said first length is the longest distance between any of the portions of said text.

35. The device of claim 28, wherein said measuring a second length comprises:

locating a first portion of said text having a contrast that exceeds a first preselected value; and

locating subsequent portions of said text having contrasts that exceed a second preselected value;

said second length being the distance between said first portion of said text and one of said subsequent portions of said text.

36. The device of claim 35, wherein said second length is the longest distance between any of the portions of said text.

37. The device of claim 28, where said first length and said second length are compared to a third preselected value, and wherein said text is rotated ninety degrees if said first length and said second length are less than said third preselected value.