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43
A Frequency Domain Approach to Registration of Aliased Images with Application to Super-resolution
, 2006
"... Super-resolution algorithms reconstruct a high-resolution image from a set of low-resolution images of a scene. Precise alignment of the input images is an essential part of such algorithms. If the low-resolution images are undersampled and have aliasing artifacts, the performance of standard regist ..."
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Cited by 104 (9 self)
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Super-resolution algorithms reconstruct a high-resolution image from a set of low-resolution images of a scene. Precise alignment of the input images is an essential part of such algorithms. If the low-resolution images are undersampled and have aliasing artifacts, the performance of standard registration algorithms decreases. We propose a frequency domain technique to precisely register a set of aliased images, based on their low-frequency, aliasing-free part. A high-resolution image is then reconstructed using cubic interpolation. Our algorithm is compared to other algorithms in simulations and practical experiments using real aliased images. Both show very good visual results and prove the attractivity of our approach in the case of aliased input images. A possible application is to digital cameras where a set of rapidly acquired images can be used to recover a higher-resolution final image.
Automatic and precise orthorectification, coregistration, and subpixel correlation of satellite images, application to ground deformation measurements
- IEEE Trans. Geosci. Rem. Sens
, 2007
"... Abstract—We describe a procedure to accurately measure ground deformations from optical satellite images. Precise orthorectification is obtained owing to an optimized model of the imaging system, where look directions are linearly corrected to compensate for attitude drifts, and sensor orientation u ..."
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Cited by 41 (2 self)
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Abstract—We describe a procedure to accurately measure ground deformations from optical satellite images. Precise orthorectification is obtained owing to an optimized model of the imaging system, where look directions are linearly corrected to compensate for attitude drifts, and sensor orientation uncertainties are accounted for. We introduce a new computation of the inverse projection matrices for which a rigorous resampling is proposed. The irregular resampling problem is explicitly addressed to avoid introducing aliasing in the ortho-rectified images. Image registration and correlation is achieved with a new iterative unbiased processor that estimates the phase plane in the Fourier domain for subpixel shift detection. Without using supplementary data, raw images are wrapped onto the digital elevation model and coregistered with a 1/50 pixel accuracy. The procedure applies to images from any pushbroom imaging system. We analyze its performance using Satellite pour l’Observation de la Terre (SPOT) images in the case of a null test (no coseismic deformation) and in the case of large coseismic deformations due to the Mw 7.1 Hector Mine, California, earthquake of 1999. The proposed technique would also allow precise coregistration of images for the measurement of surface displacements due to ice-flow or geomorphic processes, or for any other change detection applications. A complete software package, the Coregistration of Optically Sensed Images and Correlation, is available for download from the Caltech Tectonics
Statistical Performance Analysis of Superresolution Image Reconstruction
, 2004
"... Recently, there has been much work developing super-resolution algorithms for combining a set of low quality images to produce a set of higher quality images. In most cases, such algorithms must first register the collection of images to a common sampling grid and then reconstruct the high resolutio ..."
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Cited by 39 (9 self)
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Recently, there has been much work developing super-resolution algorithms for combining a set of low quality images to produce a set of higher quality images. In most cases, such algorithms must first register the collection of images to a common sampling grid and then reconstruct the high resolution image. While many such algorithms have been proposed to address each one of these subproblems, no work has addressed the overall performance limits for this joint estimation problem. In this paper, we analyze the performance limits from statistical first principles using the Cramer-Rao bound. We offer insight into the fundamental bottlenecks limiting the performance of multiframe image reconstruction algorithms and hence super-resolution.
A subspace identification extension to the phase correlation method
- IEEE Trans. Med. Imaging
, 2003
"... Abstract—The phase correlation method is known to pro-vide straightforward estimation of rigid translational mo-tion between two images. It is often claimed that the origi-nal method is best suited to identify integer pixel displace-ments, which has prompted the development of numerous subpixel disp ..."
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Cited by 27 (0 self)
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Abstract—The phase correlation method is known to pro-vide straightforward estimation of rigid translational mo-tion between two images. It is often claimed that the origi-nal method is best suited to identify integer pixel displace-ments, which has prompted the development of numerous subpixel displacement identification methods. However, the fact that the phase correlation matrix is rank one for a noise-free rigid translation model is often overlooked. This prop-erty leads to the low complexity subspace identification tech-nique presented here. The combination of non-integer pixel displacement identification without interpolation, robust-ness to noise, and limited computational complexity make this approach a very attractive extension of the phase cor-relation method. In addition, this approach is shown to be complementary with other subpixel phase correlation based techniques. Keywords—phase correlation method, SVD, subpixel im-age registration I.
Superresolution Images Reconstructed from Aliased Images
- U.S. DEPARTMENT OF AGRICULTURE, SCIENCE, AND EDUCATION ADMINISTRATION, CONSERVATION REPORT NO. 26
, 2003
"... In this paper, we present a simple method to almost quadruple the spatial resolution of aliased images. From a set of four low resolution, undersampled and shifted images, a new image is constructed with almost twice the resolution in each dimension. The resulting image is aliasing-free. A small ali ..."
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Cited by 18 (5 self)
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In this paper, we present a simple method to almost quadruple the spatial resolution of aliased images. From a set of four low resolution, undersampled and shifted images, a new image is constructed with almost twice the resolution in each dimension. The resulting image is aliasing-free. A small aliasing-free part of the frequency domain of the images is used to compute the exact subpixel shifts. When the relative image positions are known, a higher resolution image can be constructed using the Papoulis-Gerchberg algorithm. The proposed method is tested in a simulation where all simulation parameters are well controlled, and where the resulting image can be compared with its original. The algorithm is also applied to real, noisy images from a digital camera. Both experiments show very good results.
The angular difference function and its application to image registration
- IEEE Transactions on Pattern Analysis and Machine Intelligence
, 2005
"... Abstract—The estimation of large motions without prior knowledge is an important problem in image registration. In this paper, we present the angular difference function (ADF) and demonstrate its applicability to rotation estimation. The ADF of two functions is defined as the integral of their spect ..."
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Cited by 13 (5 self)
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Abstract—The estimation of large motions without prior knowledge is an important problem in image registration. In this paper, we present the angular difference function (ADF) and demonstrate its applicability to rotation estimation. The ADF of two functions is defined as the integral of their spectral difference along the radial direction. It is efficiently computed using the pseudopolar Fourier transform, which computes the discrete Fourier transform of an image on a near spherical grid. Unlike other Fourier-based registration schemes, the suggested approach does not require any interpolation. Thus, it is more accurate and significantly faster. Index Terms—Global motion estimation, Fourier domain, pseudopolar FFT, image alignment. æ 1
Optimal Registration Of Aliased Images Using Variable Projection With Applications To Super-Resolution
, 2007
"... Accurate registration of images is the most important and challenging aspect of multiframe image restoration problems such as super-resolution. The accuracy of super-resolution algorithms is quite often limited by the ability to register a set of low-resolution images. The main challenge in register ..."
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Cited by 12 (4 self)
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Accurate registration of images is the most important and challenging aspect of multiframe image restoration problems such as super-resolution. The accuracy of super-resolution algorithms is quite often limited by the ability to register a set of low-resolution images. The main challenge in registering such images is the presence of aliasing. In this paper, we analyse the problem of jointly registering a set of aliased images and its relationship to super-resolution. We describe a statistically optimal approach to multiframe registration which exploits the concept of variable projections to achieve very efficient algorithms. Finally, we demonstrate how the proposed algorithm offers accurate estimation under various conditions when standard approaches fail to provide sufficient accuracy for super-resolution.
Double Resolution from a Set of Aliased Images
- IN SPIE/IS&T ELECTRONIC IMAGING CONFERENCE
, 2004
"... In this paper, we present a super-resolution method to approximately double image resolution in both dimensions from a set of four low resolution, aliased images. The camera is shifted and rotated by small amounts between the di#erent image captures. Only the low frequency, aliasing-free part of the ..."
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Cited by 10 (5 self)
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In this paper, we present a super-resolution method to approximately double image resolution in both dimensions from a set of four low resolution, aliased images. The camera is shifted and rotated by small amounts between the di#erent image captures. Only the low frequency, aliasing-free part of the images is used to find the shift and rotation parameters. When the images are registered, it is possible to reconstruct a higher resolution, aliasing-free image from the four low resolution images using cubic interpolation. We applied our algorithm in a simulation, where all parameters are known and controlled, as well as in a practical experiment using images taken with a real digital camera. The results obtained in both tests prove the validity of our method.
Discontinuous non-rigid motion analysis of sea ice using c-band synthetic aperture radar satellite imagery
- In: ANM ’04: Proceedings of the Computer Vision and Pattern Recognition Workshop
, 2004
"... Sea-ice motion consists of complex non-rigid motions involving continuous, piece-wise continuous and discrete particle motion. Techniques for estimating non-rigid motion of sea ice from pairs of satellite images (generally spaced three days apart) are still in the developmental stages. For interior ..."
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Cited by 6 (5 self)
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Sea-ice motion consists of complex non-rigid motions involving continuous, piece-wise continuous and discrete particle motion. Techniques for estimating non-rigid motion of sea ice from pairs of satellite images (generally spaced three days apart) are still in the developmental stages. For interior Arctic and Antarctic pack ice, the continuum assumption begins to fail below the 5 km scale with evidence of discontinuities already revealed in models and remote sensing products in the form of abrupt changes in magnitude and direction of the differential velocity. Using a hierarchical multi-scale phase-correlation method and profiting from known limitations of cross correlation methods, we incorporate the identification of discontinuities into our motion estimation algorithm, thereby descending below the continuum threshold to examine the phenomenon of discontinuous non-rigid sea-ice motion. 1.
ROBUST PHASE CORRELATION BASED FEATURE MATCHINIG FOR IMAGE CO-REGISTRATION AND DEM GENERATION
"... This paper presents a robust phase correlation based sub-pixel feature matching technique and its application in motion flow estimation, pixel-to-pixel image-co-registration and DEM generation. We propose to use a phase fringe filter and a highly robust technique in the direct Fourier-based phase co ..."
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Cited by 4 (2 self)
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This paper presents a robust phase correlation based sub-pixel feature matching technique and its application in motion flow estimation, pixel-to-pixel image-co-registration and DEM generation. We propose to use a phase fringe filter and a highly robust technique in the direct Fourier-based phase correlation algorithm for translational shift estimation in sub-pixel accuracy. Noting the problem that local phase correlation based feature matching may fail in areas either featureless or with significant spectral differences between an image pair, a direct frequency based motion estimation assessment technique and a novel motion flow refinement scheme are designed to improve the unreliable local motion estimates around these areas. With the robust phase correlation based local matching algorithm, we are able to derive accurate pixel-to-pixel image co-registration and disparity mapping for DEM generation in most synthetic and real images from different sensor platforms or different spectral bands. 1.
