Method and apparatus for determining positional guidelines of handwritten data

• US 5,633,957 A
• Filed: 09/16/1994
• Issued: 05/27/1997
• Est. Priority Date: 09/16/1994
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Robinson, Tony
• Primary Examiner(s): Powell, Mark R.
• Assistant Examiner(s): Breene, John E.
• Application Number:
  US08/307,374
• Time in Patent Office: 984 Days
• Field of Search: 382/186-187, 382/189, 382/203, 382/286, 382/292, 382/179, 395/155-161, 395/149, 395/148, 364/419.1, 364/419.17, 345/173-183
• US Class Current: 382/292
• CPC Class Codes: G06V 30/10 Character recognition
• CPC Class Codes: G06V 30/146 Aligning or centring of the image pick-up or image-field

Abstract

The present invention provides a method and apparatus for determining a positional guideline, such as a baseline or ascender line, of handwritten data. This positional guideline allows for accurate positioning of the data on a computer display. It is calculated by counting the number of pixels per horizontal row in the block of data. These counts of pixels per row are then filtered using a wide moving average. The filtered rows of pixels are then analyzed per row to determine the positional guideline for the given block of handwritten data.

Claims

1. A device for positioning handwritten data on a display comprising:

a receiver for receiving input of handwritten data;

a display for displaying said handwritten data;

a data entry device for entering a handwritten block of said handwritten data;

a positional identifier for identifying a positional guideline for said handwritten block; and

a data positioner for positioning said handwritten block on said display based on said positional guideline of said handwritten block.

2. The device of claim 1 wherein said positional identifier comprises:

a counter for determining the number of pixels per horizontal row of said handwritten block;

a filter for determining the number of filtered pixels per row by filtering said number of pixels per horizontal row; and

an analyzer for analyzing said filtered pixels per row to determine said positional guideline for said handwritten block.

3. The device of claim 2 wherein said filter determines the number of filtered pixels per row from the number of pixels per horizontal row using a wide moving average.

4. The device of claim 3 wherein for each horizontal row, said wide moving average is the average of the number of pixels in said horizontal row, and at most a predetermined number of horizontal rows before and after said horizontal row.

5. The device of claim 4 wherein said predetermined number is 16.

6. The device of claim 2 wherein said counter comprises:

a stroke identifier for identifying the strokes of said handwritten data;

a point identifier for identifying the points of said strokes;

a row identifier for identifying the row locations of said points of said strokes;

an incrementor for incrementing the number of pixels per horizontal row for each row between the row locations of said points of said strokes.

7. The device of claim 2 wherein said number of filtered pixels per row can be represented by a curve, said device further comprising:

a most filtered pixels row identifier for identifying a row with the most filtered pixels on said curve;

a fewest filtered pixel row identifier for identifying the first row with the fewest filtered pixels scanned in a scan starting from said row with the most filtered pixels;

a plateau row identifier for identifying a plateau of rows, said plateau of rows comprising a predetermined number of consecutive rows with the same filtered pixel value; and

a first row identifier for identifying the first row of said plateau of rows scanned in a scan starting from said row with the most filtered pixels.

8. The device of claim 7 wherein said analyzer determines said positional guideline to be the first row, scanned in a scan starting from said row with the most filtered pixels, that is one of (a) said row with the fewest filtered pixels, and (b) said first row in said plateau of rows.

9. The device of claim 7 wherein the number of filtered pixels in said first row of said plateau of rows is less than or equal to a predetermined percentage of the number of filtered pixels in said row with the most filtered pixels.

10. The device of claim 9 wherein said predetermined percentage is about 50%.

11. The device of claim 9 wherein said predetermined percentage is about 66%.

12. The device of claim 9 wherein said predetermined number of consecutive rows is the difference between the row numbers of (a) said row with the most filtered pixels and (b) the first row, after said row with the most filtered pixels, whose number of filtered pixels is less than or equal to said predetermined percentage of the number of filtered pixels in said row with the most filtered pixels.

13. The device of claim 1 wherein said positional guideline is a baseline of said handwritten block.

14. The device of claim 1 wherein said positional guideline is an ascender line of said handwritten block.

15. The device of claim 1 wherein said display is a receiver for receiving input.

16. The device of claim 1 wherein said data entry device is a pen.

17. A method for positioning handwritten data on a display comprising:

receiving input of handwritten data;

displaying said handwritten data;

entering a handwritten block of said handwritten data;

identifying a positional guideline for said handwritten block; and

positioning said handwritten block on said display based on said positional guideline of said handwritten block.

18. The method of claim 17 wherein said identifying a positional guideline comprises:

determining the number of pixels per horizontal row of said handwritten block;

determining the number of filtered pixels per row by filtering said number of pixels per horizontal row; and

analyzing said filtered pixels per row to determine said positional guideline for said handwritten block.

19. The method of claim 18 wherein determining the number of pixels per horizontal row comprises:

identifying the strokes of said handwritten data;

identifying the points of said strokes;

identifying the row locations of said points of said strokes;

incrementing the number of pixels per horizontal row for each row between the row locations of said points of said strokes.

20. The method of claim 18 wherein said number of filtered pixels per row can be represented by a curve, said method further comprising:

identifying a row with the most filtered pixels on said curve;

identifying row with the fewest filtered pixels on said curve;

identifying the first row with the fewest filtered pixels scanned in a scan starting from said row with the most filtered pixels;

identifying a plateau of rows, said plateau of rows comprising a predetermined number of consecutive rows with the same filtered pixel value; and

identifying the first row of said plateau of rows scanned in a scan starting from said row with the most filtered pixels.

21. The method of claim 20 wherein said positional guideline is determined to be the first row, scanned in a scan starting from said row with the most filtered pixels, that is one of (a) said row with the fewest filtered pixels, and (b) said first row in said plateau of rows.

22. The method of claim 20 wherein the number of filtered pixels in said first row of said plateau of rows is less than or equal to a predetermined percentage of the number of filtered pixels in said row with the most filtered pixels.

23. The method of claim 22 wherein said predetermined percentage is about 50%.

24. The method of claim 22 wherein said predetermined percentage is about 66%.

25. The method of claim 22 wherein said predetermined number of consecutive rows is the difference between the row numbers of (a) said row with the most filtered pixels and (b) the first row, after said row with the most filtered pixels, whose number of filtered pixels is less than or equal to said predetermined percentage of the number of filtered pixels in said row with the most filtered pixels.

26. The method of claim 17 wherein said positional guideline is a baseline of said handwritten block.

27. The method of claim 17 wherein said positional guideline is an ascender line of said handwritten block.

28. The method of claim 17 wherein said display receives and displays said handwritten data.

29. The method of claim 17 wherein a pen is used to enter said handwritten block of said handwritten data.

30. The method of claim 18 wherein a wide moving average is used to determine the number of filtered pixels per row from the number of pixels per horizontal row.

31. The method of claim 30 wherein for each horizontal row, said wide moving average is the average of the number of pixels in said horizontal row, and at most a predetermined number of horizontal rows before and after said horizontal row.

32. The method of claim 31 wherein said predetermined number is 16.