System and method for removal of digital image vertical distortion

• US 20020118292A1
• Filed: 02/28/2001
• Published: 08/29/2002
• Est. Priority Date: 02/28/2001
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Baron, John M.
• Granted Patent: US 6,963,365 B2
• Time in Patent Office: Days
• US Class Current: 348/335
• CPC Class Codes: H04N 23/58 Means for changing the camera field of view without moving the camera body, e.g. nutating or panning of optics or image sensors
• CPC Class Codes: H04N 23/633 for displaying additional information relating to control or operation of the camera
• CPC Class Codes: H04N 23/695 Control of camera direction for changing a field of view, e.g. pan, tilt or based on tracking of objects
• CPC Class Codes: H04N 5/2628 Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation

Abstract

The invention relates to a device, preferably a digital camera, having an imaging sensor providing a digital representation of an image projected onto an imaging portion of the imaging sensor. A processor associated with the device identifies an image compression factor and progressively, over a selected region of the digital representation of the image, magnifies at least a portion of the digital representation of the image to reduce an apparent convergence distortion. Correction preferably occurs before lossy compression. The device preferably includes a display to provide a visual display of the digital representation of the image to a user who may use a user input to manually correct apparent distortion by following prompts generated on the display. The device also preferably includes a non-volatile memory configured to store the digital representation of the image.

Claims

1. A digital camera comprising:

an image sensor providing a digital representation of an optical image to be captured; and

a processor configured to selectively process said digital representation of said optical image to compensate for a linear convergence distortion of said optical image.

2. The digital camera according to claim 1 wherein said processor is configured to apply a varying magnification factor to said digital representation of said optical image along a first axis with respect to a second axis orthogonal to said first axis.

3. The digital camera according to claim 2 wherein said first and second axes correspond to a plane defined by an imaging surface of said image sensor on which said optical image is formed.

4. The digital camera according to claim 2 further comprising:

an input device configured to provide manual control of said magnification factor.

5. The digital camera according to claim 4 wherein said input device is further configured to provide manual positioning of said axes.

6. The digital camera according to claim 4 further comprising:

a display for displaying said optical image before and after processing by said processor.

7. The digital camera according to claim 1 wherein said processor is configured to apply a variable aspect ratio to said optical image to compensate for said linear convergence distortion of said optical image as formed on said image sensor.

8. The digital camera according to claim 7 wherein said linear distortion is caused by an orientation of an imaging surface of said optical sensor with respect to a subject corresponding to at least a portion of said optical image.

9. The digital camera according to claim 1 wherein said processor is configured to:

determine a linear distortion value relative to a baseline; and

progressively magnify, in two-dimensions, said digital representation so as to reduce apparent linear convergence.

10. The digital camera according to claim 9 wherein said processor is configured to determine said linear distortion value in response to identification of an offset from vertical of a line segment identified in said optical image.

11. The digital camera according to claim 9 wherein said processor is configured to determine said linear distortion value in response to identification of a difference in length between two line segments identified in said optical image.

13. The digital imaging device of claim 12 wherein said means for digitally representing comprises:

means for optoelectrically sensing image information from said image; and

means for converting said optoelectrically sensed image information into said digitally represented image.

14. The digital imaging device of claim 12 wherein said means for processing comprises:

means for identifying an image compression factor for convergence distortion in said digitally represented image; and

means for progressively magnifying at least a portion of said digitally represented image responsive to said identified image compression factor, wherein said progressive magnification reduces said convergence distortion.

15. The digital imaging device of claim 14 wherein said means for identifying includes:

means for lossy compressing said digitally represented image for providing and storing compressed image data.

16. The digital imaging device of claim 14 wherein said means for progressively magnifying occurs over a selected linear region of said digitally represented image.

19. The method of claim 17 wherein said identifying step includes the step of:

identifying a linear compression of one portion of said image with respect to another portion of said image.

20. The method of claim 16 further comprising the step of:

determining a vertical convergence factor.

12. A digital imaging device comprising:

means for digitally representing an image;

means for displaying said digitally represented image; and

means for processing said digitally represented image to reduce convergence distortion.

17. A method of compensating for perspective distortion of a digital image comprising the steps of:

identifying a linearly dependent compression ratio of said image; and

spatially expanding portions of said image as a function of said linear dependence.

18. The method of claim 17:

wherein said linearly dependent compression ratio is defined by a linear function; and

wherein said spatially expanding step includes the step of;

progressively magnifying portions of said image responsive to said linear function.