Establishing point correspondences is an important research topic in computer vision. Proposed is an algorithm using local similarity and global constraint to obtain point correspondence. The point correspondences are...
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Establishing point correspondences is an important research topic in computer vision. Proposed is an algorithm using local similarity and global constraint to obtain point correspondence. The point correspondences are obtained by comparing their associated colour codes, which are computed by image gradients, and using spatial relationships among neighbouring feature points. The approach assumes insignificant scaling and roll, and is suitable for real-time applications.
In computing 3D motion and structure from image correspondences, often called the structure from motion (SFM) problem, dimensions of the used variable set are very large because it contains both motion and structure p...
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In computing 3D motion and structure from image correspondences, often called the structure from motion (SFM) problem, dimensions of the used variable set are very large because it contains both motion and structure parameters. As a result, to solve the problem incurs much computational burden. However, in on-line applications of the SFM problem, computational efficiency needs to be stressed as some accuracy of the solutions is sacrificed. In this respect, various dimensional reduction methods are often introduced to improve computational efficiency and this usually leads to various reduced-form SFM problems. The so-obtained reduced-form SFM problems depend on fewer unknowns than the original SFM problem, thus allowing, in principle, for a less computationally intensive estimation, albeit potentially sacrificing accuracy of the results. It is thus interesting to study how much accuracy is lost. This is done by analytically proving results on equivalence or proximity of solutions for some example cases of the so-obtained reduced-form SFM problems. And then, based on the analysis, the author also proposes how to reduce the loss of accuracy in the reduced-form SFM problems (in the meaning of adjusting those reduced-form SFM problems to better approximate the original optimal SFM problem;that is, an optimal SFM problem that does not use any dimensional reduction methods). Experimental results are given to show the effect in practice. Finally, as an example application, a safety checking system using vision is considered.
We report on two generations of CMOS image sensors with digital output fabricated in a 0.6 mu m CMOS process. The imagers embed an ALOHA MAC interface for unfettered self-timed pixel read-out targeted to energy-aware ...
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We report on two generations of CMOS image sensors with digital output fabricated in a 0.6 mu m CMOS process. The imagers embed an ALOHA MAC interface for unfettered self-timed pixel read-out targeted to energy-aware sensor network applications. Collision on the output is monitored using contention detector circuits. The image sensors present very high dynamic range and ultra-low power operation. This characteristics allow the sensor to operate in different lighting conditions and for years on the sensor network node power budget.
This paper deals with the application of ultra-wide band time-domain subsurface radars, equipped with special signalprocessing techniques, to realize non-invasive image testing of the building walls' internal str...
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This paper deals with the application of ultra-wide band time-domain subsurface radars, equipped with special signalprocessing techniques, to realize non-invasive image testing of the building walls' internal structure that are made with brick, stone, concrete, reinforced concrete, and other construction materials. There are two normally associated problems: qualitative and quantitative, considered. Limitations and shortcomings of radar imaging, due to inherent physical features as well as signalprocessing improving the quality of radar images, are discussed. Actual field data are used to illustrate applications of subsurface radar for non-destructive testing of walls' internal regions.
Various applications such as industrial product inspection or low signal-to-noise situations ( as in thermal imaging) employ a time delay and integration (TDI) scanning imaging technique. Due to common vibration sourc...
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Various applications such as industrial product inspection or low signal-to-noise situations ( as in thermal imaging) employ a time delay and integration (TDI) scanning imaging technique. Due to common vibration sources such as the camera platform motion or the thermal detector's cooling system, the acquired image may be degraded by severe shift-variant geometric distortions and motion blur. We use these vibrations in terms of superresolution to create an improved high-resolution video sequence from the degraded lower resolution sequence, in two main stages: subpixel motion estimation with respect to translations and rotations, used for point spread function (PSF) estimation, followed by an efficient implementation of the projection onto convex sets (POCS) method. We generalize and considerably improve a previous technique for restoration of a single image captured by a translational vibrated staggered-TDI camera (Hochman et al., 2004). The proposed method is implemented with both simulated videos and real degraded thermal videos. A comparative analysis shows an advantage of the proposed method over others in restoring the vibrated videos. (C) 2006 SPIE and IS&T.
Thinning is a very important operation in the pre-processing stage of fingerprint recognition. With the availability of fast thinning hardware, real-time imageprocessingapplications can be achieved. The authors intr...
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Thinning is a very important operation in the pre-processing stage of fingerprint recognition. With the availability of fast thinning hardware, real-time imageprocessingapplications can be achieved. The authors introduce a detailed hardware architecture design of a thinning processor used in an embedded fingerprint recognition system. The proposed thinning algorithm has a parallel-pipelining structure suited to hardware realisation, which is implemented and verified using FPGA. Equipped with a modification unit array, a designated operating schedule, and an address generator based on systolic counter, this thinning processor is able to perform a thinning operation within 0.07 s at 40 MHz for a 512 x 512 picture, which is at least 40 times faster than software execution. Consequently, the proposed thinning processor was successfully integrated into a real-time fingerprint recognition system.
Markov Random Fields (MRF) are powerful methods to introduce contextual knowledge in imageprocessing. In this paper, we aim at showing that they are well adapted to deal with many SAR applications, specially when usi...
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ISBN:
(纸本)0819464600
Markov Random Fields (MRF) are powerful methods to introduce contextual knowledge in imageprocessing. In this paper, we aim at showing that they are well adapted to deal with many SAR applications, specially when using graphs of primitives. Three main applications are presented using the markovian framework : SAR image interpretation, road network detection and 3D reconstruction. For the last application, 3 situations are considered: interferometry, interferometry using an additional optical image and radargrammetry with optic. This paper gathers some previous and current works on the use of MRF for SAR image analysis.
For nonseparable bidimensional wavelet transforms, the choice of the dilation matrix is all-important, since it governs the downsampling and upsampling steps, determines the cosets that give the positions of the filte...
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ISBN:
(纸本)3540446303
For nonseparable bidimensional wavelet transforms, the choice of the dilation matrix is all-important, since it governs the downsampling and upsampling steps, determines the cosets that give the positions of the filters, and defines the elementary set that gives a tesselation of the plane. We introduce nonseparable bidimensional wavelets, and give formulae for the analysis and synthesis of images. We analyze several dilation matrices, and show how the wavelet transform operates visually. We also show some distorsions produced by some of these matrices. We show that the requirement of their eigenvalues being greater than 1 in absolute value is not enough to guarantee their suitability for imageprocessingapplications, and discuss other conditions.
Multiscale image analysis has been used successfully in a number of applications to segment image features according to their relative scale. In this paper, we present a new framework for the hierarchical segmentation...
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Multiscale image analysis has been used successfully in a number of applications to segment image features according to their relative scale. In this paper, we present a new framework for the hierarchical segmentation of gray level image. The proposed scheme comprises a nonlinear scale-space and morphological gradient watersheds. Our aim is to produce a meaningful hierarchy among the objects in the image. The scale-space is based on morphological anisotropic diffusion that uses reconstruction morphological operators. Furthermore, we introduce the method to reconstruct morphological operators and the principle of the dynamics of contours in scale-space that combines scale and contrast information. The performance of the proposed segmentation scheme is presented via experimental results obtained with a wide range of image including natural scenes.
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