Gradient mesh vector graphics representation, used in commercial software, is a regular grid with specified position and color, and their gradients, at each grid point. Gradient meshes can compactly represent smoothly changing data, and are typically used for single objects. This paper advances the state of the art for gradient meshes in several significant ways. Firstly, we introduce a topolog...

Sparse representation model adopts an image patch as a linear combination of a few atoms chosen out from an overcomplete dictionary, and they have shown promising results in various image restoration applications. Gradient feature is important structure information in image processing. Their combination is not sensitive to noise, which can improve and enhance the accuracy of similarity measure,...

We propose a novel algorithm for unsupervised segmentation of color images. The proposed approach utilizes a dynamic color gradient thresholding scheme that guides the region growing process. Given a color image, a weighted vectorbased color gradient map is generated. Seeds are identified and a dynamic threshold is then used to perform reliable growing of regions on the weighted gradient map. O...

We propose an Adaptive Stochastic Conjugate Gradient (ASCG) optimization algorithm for temporal medical image registration. This method combines the advantages of Conjugate Gradient (CG) method and Adaptive Stochastic Gradient Descent (ASGD) method. The main idea is that the search direction of ASGD is replaced by stochastic approximations of the conjugate gradient of the cost function. In addi...

This paper applies a simple analysis of the statistical noise inherent in sensing concentrations of di!usible chemical factors to the problem of guidance of developing axons. We show that growth cones may be able to detect chemical changes of 0.5% across their width, and that guidance by a gradient is limited to distances below about 1 cm, even for a gradient of ideal shape. ( 1999 Elsevier Sci...

direction (blue) introduce a phase shift from echo to echo that increases with the distance form the isocenter. (b, c) Schematic example for acquiring three ROIs with two of them (ROIs B and C) overlapping with a conventional projection (dashed gray). With the phase shifts introduced by the blip gradients in the slice direction, the projection direction (dashed blue) is tilted by an angle that ...

We prove some properties of strong minimizers for functionals depending on free discontinuities, free gradient discontinuities and second derivatives, which are related to image segmentation.