Efficient lens re-distortion

Number: 9818201
Published: 2017-11-14
Filed: 2014-12-22
Assignee: LUCASFILM ENTERTAINMENT COMPANY LTD.
Inventors: Mallet; Ronald
CPC: G06T3/047; G06T5/80; G06T7/13; H04N5/2628
Verdict: Low Notable software
Source: Google Patents · FreePatentsOnline

The keeper's note

Efficiently applies known camera/lens distortion to source image data by segmenting the output image into regions with locally linear distortion.

Abstract

Methods and systems efficiently apply known distortion, such as of a camera and lens, to source image data to produce data of an output image with the distortion. In an embodiment, an output image field is segmented into regions so that on each segment the distortion function is approximately linear, and segmentation data is stored in a quadtree. The distortion function is applied to the segmented image field to produce a segmented rendered distortion image (SRDI) and a corresponding look-up table. To distort a source image, a location in the output image field is selected, and the uniquelycolored segment at the same location in the SRDI is found. The look-up table provides thelocal linear inverse of the distortion function, which is applied to determine from wherein the source image to take image texture data for the distorted output image.

Background

BRIEF DESCRIPTION OF THE DRAWINGS(1) FIG. 1 is a block diagram of a camera and lens system for capturing images, according to an embodiment.(2) FIG. 2 illustrates various types of image distortions.(3) FIG. 3 illustrates a use of a distortion function to modify a segmented image field.(4) FIG. 4A illustrates a method for correcting distortion in an image.(5) FIG. 4B illustrates a particular method for applying distortion to image data.(6) FIG. 4C is a flow chart illustrating one embodiment of the method of the invention;(7) FIG. 5A illustrates generating a segmented image field, according to an embodiment.(8) FIG. 5B illustrates generating a distorted segmented image field, according to an embodiment.(9) FIG. 5C illustrates an undistorted image field, according to an embodiment.(10) FIG. 5D illustrates an distorted image field, according to an embodiment.(11) FIG. 6 is a flow chart of another method for applying distortion to image data, according to an embodiment.(12) FIG. 7 illustrates a method of applying distortion using a segmented rendered distortion image, according to anembodiment.(13) FIG. 8 A illustrates a quadtree data structure, as used in an embodiment.(14) FIG. 8B illustrates a segmentation of an initial image field specified using polar coordinates, according to an embodiment.(15) FIG. 9 is flow chart of a method for generatinga segmented rendered distortion image, according to an embodiment.(16) FIG. 10 is a flow chart of a method of applying distortion to i

Claims

1. A method of processing an image, the method comprising: receiving, by a processor, a distorted image captured with a lens that generates distortion in the image; generating, with the processor, a corrected image by applying a distortion correction algorithm to correct for distortion in the distorted image; storing, in a computer-readable medium operatively coupled to the processor, a segmented rendered distortion image (SRDI) representing howthe distortion in the distorted image is generated, wherein the SRDI is generated by recursively subdividing the SRDI into segments until a distortion function for each of the segments has an approximate inverse function that can be readily calculated; and thereafter, generating, with the processor, a re-distorted image using the SRDI to re-distort the corrected image. 9. A non-transitory, computer-readable medium comprising instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising: receiving a distorted image captured with a lens that generates distortion in an image; generating a corrected image by applying a distortion correction algorithm to correct for distortion in the distorted image; storing a segmented rendered distortion image (SRDI) representing how the lens generates the distortion in the distorted image, wherein the SRDI is generated by recursively subdividing the SRDI into segments until a distortion function for each of the segments has an approximate inverse function that can be readily calculated; and generating a re-distorted image using the SRDI to re-distort the corrected image. 15. A computer system comprising: one or more processors; one or more memory devices comprising instructions that, when executed by the one or more processors, causethe one or more processors to perform operations comprising: receiving a distorted image captured with a lens that generates distortion in an image; generating a corrected image by applying a distortion correction algorithm to correct for distortion in the distorted image; storing a segmented rendered distortion image (SRDI) representing how the lens generates the distortion in the distorted image, wherein the SRDI is generated by recursively subdividing the SRDI into segments until a distortion function for each of the segments has an approximate inverse function that can be readily calculated; and generating a re-distorted image using the SRDI to re-distort the corrected image.