Image evaluation for reading mode in a reading machine

• US 20060008122A1
• Filed: 04/01/2005
• Published: 01/12/2006
• Est. Priority Date: 04/02/2004
• Status: Active Grant

• Current Assignee: National Federation of the Blind
• Original Assignee: K-NFB Reading Technology Inc.
• Inventors: Gibson, Lucy, Lvovsky, Lev, Albrecht, Paul, Kurzweil, Raymond C., Gashel, James
• Granted Patent: US 8,249,309 B2
• Time in Patent Office: Days
• US Class Current: 382/114
• CPC Class Codes: G06V 10/993 Evaluation of the quality of the acquired pattern
• CPC Class Codes: G06V 30/142 using hand-held instruments; Constructional details of the instruments

Abstract

A portable reading machine detects poor image conditions for performing optical character recognition processing. The portable reading machine receives an image of sufficient resolution to distinguish lines of text but not necessarily of sufficient resolution to distinguish individual characters and processes the image to determine imaging conditions from the image. The reading machine reports imaging conditions to the user.

Claims

1. A computer program product residing on a computer readable medium for causing a computing device to detect poor reading conditions for a portable reading machine;

comprising instructions for causing the machine to;

receive an image of sufficient resolution to distinguish lines of text but not necessarily of sufficient resolution to distinguish individual characters;

process the image to determine imaging conditions from the image; and

report imaging conditions to the user.

2. The computing program product of claim 1 wherein instructions to process the image to determine imaging conditions comprise instructions to cause the machine to:

determine the quality of the lighting conditions.

3. The computing program product of claim 2 wherein instructions to determine the quality of the lighting conditions, comprise instructions to:

examine contrast characteristics of different parts of the image; and

determine the brightness in different regions of the image; and

compute a distribution of light intensities across the image.

4. The computing program product of claim 1 wherein instructions to report imaging conditions to the user comprise instructions to cause the machine to:

report the lighting conditions determined by the determination of lighting quality to the user; and

report that the camera may be out of focus if the determination of lighting quality has determined that there is low contrast in a region of the image.

5. The computing program product of claim 1 wherein instructions to process the image to determine imaging conditions comprise instructions to cause the machine to:

detect the presence of glare in the captured image.

6. The computing program product of claim 1 wherein the program causes the device to determine if the plurality of characters are on the right side or the left side, and if on the left side, to report to the user that the text may be upside-down.

7. The computing program product of claim 1 wherein instructions to process the image to determine imaging conditions comprise instructions to:

determine that the text is too small.

8. The computing program product of claim 1 wherein instructions to process the image to determine imaging conditions comprise instructions to:

determine that the text is too large.

9. The computing program product of claim 1 wherein instructions to process the image to determine imaging conditions comprise instructions to cause the machine to:

detect that the image input device or the object was tilted and that as a result text in the captured image is rotated or distorted.

10. The computing program product of claim 1 wherein instructions to process the image to determine imaging conditions comprise instructions to cause the machine to:

detect that text is incomplete.

11. A reading machine comprises:

a processing device;

a computer program product residing on a computer readable medium for causing the processing device to detect poor reading conditions for the reading machine, comprising instructions for causing the machine to;

receive an image of sufficient resolution to distinguish lines of text but not necessarily of sufficient resolution to distinguish individual characters;

process the image to determine imaging conditions from the image; and

report imaging conditions to the user.

12. The reading machine of claim 11 wherein the computing program product further comprises instructions to:

examine contrast characteristics of different parts of the image; and

examine contrast characteristics of different parts of the image.

13. The reading machine of claim 11 wherein the computing program product further comprises instructions to:

detect and report incomplete or unreadable text.

14. The reading machine of claim 11 wherein the computing program product further comprises instructions to:

detect that the image input device or the object was tilted and that as a result text in the captured image is rotated or distorted.

15. A method of operating a reading machine, the method comprises:

receive an image of sufficient resolution to distinguish lines of text but not necessarily of sufficient resolution to distinguish individual characters;

process the image to determine imaging conditions from the image; and

report imaging conditions to the user.

16. The method of claim 15 further comprising:

examine contrast characteristics of different parts of the image; and

examining contrast characteristics of different parts of the image.

17. The method of claim 15 further comprising:

detect and report incomplete or unreadable text.

18. The method of claim 15 further comprising:

detecting that the image input device or the object was tilted and that as a result text in the captured image is rotated or distorted.