Method for autonomous image registration
First Claim
1. A method for registering multiple autonomously images of a target, the method comprising the steps of:
- detecting and recording the target at different geolocations to generate multiple, digitized images of the target;
storing the digital images in a storage area;
generating image registration in a processing unit receiving the digital images from the storage area by the steps of;
(a) dewarping the multiple digitized images into approximate registration using image geolocation information;
(b) generating an identification of areas of common coverage between the approximately registered digitized images;
(c) generating greatly reduced resolution digital images of areas of common coverage between the approximately registered images;
(d) phase correlating the areas of common coverage between the reduced resolution images to identify initial conjugate points;
(e) refining the identified initial conjugate points at increased image resolution to identify final conjugate points in the common coverage area between the approximately registered images; and
(f) dewarping the multiple images of the target into registration using the identified final conjugate points; and
stereoscopically displaying the registered multiple images at a display terminal.
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Accused Products
Abstract
A method for automatically registering an image pair having a common coverage area, wherein a pair of image data sets, each representing an image of an image pair, are processed to generate initial dewarping coefficients for the image data sets. The translational offset between the images is estimated using a phase correlation process. Next, the common coverage area of the data image sets is determined by finding the vertices defining the limits of the common coverage area. Conjugate point pairs are extracted from the common coverage area by defining a series of block and subblock grids and defining the center point of the grid as a conjugate point location. The determined conjugate point sets are used to generate geometrically corrected registered dewarping coefficients and the image data sets are resampled using the registered dewarping coefficients to generate a registered image pair.
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Citations
20 Claims
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1. A method for registering multiple autonomously images of a target, the method comprising the steps of:
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detecting and recording the target at different geolocations to generate multiple, digitized images of the target; storing the digital images in a storage area; generating image registration in a processing unit receiving the digital images from the storage area by the steps of; (a) dewarping the multiple digitized images into approximate registration using image geolocation information; (b) generating an identification of areas of common coverage between the approximately registered digitized images; (c) generating greatly reduced resolution digital images of areas of common coverage between the approximately registered images; (d) phase correlating the areas of common coverage between the reduced resolution images to identify initial conjugate points; (e) refining the identified initial conjugate points at increased image resolution to identify final conjugate points in the common coverage area between the approximately registered images; and (f) dewarping the multiple images of the target into registration using the identified final conjugate points; and stereoscopically displaying the registered multiple images at a display terminal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for displaying at a display terminal first and second digital images of a target in registration, the images detected and recorded in a storage area, the images autonomously detected at different geolocations, comprising the steps of:
- generating image registration in a processing unit receiving the digital images from the storage area by the steps of;
(a) converting the first and second digital images into the same scale in accordance with geolocation information for the images; (b) generating initially dewarped first and second images by rotating the converted first and second images in accordance with the geolocation information to horizontally orient an epipolar line; (c) comparing the initially dewarped first and second images to identify areas of common coverage between the first and second images; (d) generating greatly reduced resolution images of the areas of common coverage between the initially dewarped first and second images; (e) comparing the areas of common coverage between two reduced resolution images to identify initial conjugate points; (f) generating final conjugate points in the common coverage area between the initially dewarped first and second images by refining the identified initial conjugate points at increased image resolution; (g) converting the first and second images into the same scale in accordance with the registered final conjugate points; and (h) generating finally dewarped first and second images by rotating the converted first and second images into registration in accordance with the registered final conjugate points to horizontally orient the epipolar line of each image; and stereoscopically displaying the registered, finally dewarped first and second images at the terminal display. - View Dependent Claims (8, 9, 10, 11)
- generating image registration in a processing unit receiving the digital images from the storage area by the steps of;
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12. A method for extracting conjugate points from between two autonomous sensor images, comprising the steps of:
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(a) dewarping the two sensor images into approximate registration using sensor location information; (b) generating an identification of areas of common coverage between the approximately registered images; (c) generating greatly reduced resolution images of areas of common coverage between the approximately registered images; (d) phase correlating the areas of common coverage between the reduced resolution images to identify initial conjugate points; (e) adjusting the magnification of the phase correlated reduced resolution images; (f) comparing the magnification adjusted images to refine the identification of the initial conjugate points; (g) repeating steps (e) and (f) to establish a predetermined magnification; and (h) outputting the refined initial conjugate points at the predetermined magnification as set of final conjugate points between the two sensor images. - View Dependent Claims (13, 14)
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15. A method performed by a processing unit for registering images pairs having common scenery comprising:
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storing in memory of a processing unit image data sets of first and second digital images of a common target taken at different geolocations; initially sampling the image data sets of the first and second digital images stored in memory of the processing unit elements of at least one of the first and second images into a common coordinate system and scale according to initial dewarping parameters determined in response to sensor geolocation information for each image; determining areas of common coverage between the initially sampled first and second images; extracting from the first and second digital images pairs of conjugate points, one point in each pair from each of the first and second images, lying within the area of common coverage from the first and second images, the step of extracting including; dividing the common coverage area of the initially sampled first and second images into a plurality of image blocks; phase correlating corresponding image block pairs in the initially registered first and second images for determining average parallax over the entire block and predicting shift between blocks required to match the phases of the blocks; and if a corresponding pair of image blocks phase correlate to within a predetermined degree of confidence, storing in memory of the processing unit the center of each block, shifted according to the predicted shift, as a conjugate pair; and resampling a second time with the processing unit the first and second images according to refined dewarping parameters, the refined dewarping parameters being determined by geometric corrections of the initial dewarping parameters which result in at least a predetermined number of the conjugate pairs registering to within a predetermined minimum error after resampling. - View Dependent Claims (16, 17)
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18. An apparatus for automatically registering autonomous images pairs having common scenery comprising:
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a memory for storing first and second digital images taken at different camera locations containing scenes of common terrain in memory; means for determining, in response to receiving information describing sensor for each image, preliminary dewarping parameters; means for initially sampling elements of at least one of the first and second images into a common coordinate system with the other of the first and second images according to the preliminary dewarping parameters; means for determining areas of common coverage between the initially registered first and second images; means for dividing the common coverage area of the initially registered first and second images into a plurality of image blocks; means for phase correlating each image block in corresponding pairs of blocks by phase correlating them and predicting shift between image blocks required to match the image blocks; means for storing, for each pair of image blocks which correlate, the center of each image block, shifted according to the predicted shift, as a conjugate pair; means for geometrically correcting the initial dewarping parameters to produce refined dewarping parameters which result in at least a predetermined number of the conjugate pairs registering to within a predetermined minimum error; and means for finally resampling the first and second images using the refined dewarping parameters. - View Dependent Claims (19, 20)
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Specification