Among the myriad of techniques used in estimating motion vector fields, perhaps the most popular and accurate methods are the so called gradient-based methods. A critical step in the gradient-based estimation process is the estimation of image gradients using derivative filters. It is well known that the gradientbased estimators contain significant deterministic bias relating the gradient calcu...

Image edge gradient direction not only contains important information of the shape, but also has a simple, lower complexity characteristic. Considering that the edge gradient direction histograms and edge direction autocorrelogram do not have the rotation invariance, we put forward the image retrieval algorithm which is based on edge gradient orientation statistical code (hereinafter referred t...

nowadays, sar imaging systems have become more interesting for scientists. high spatial resolution of recent sar images has become a key factor for their accurate applications such as interferometry, radargrammetry and change detection. in these applications, sar image matching procedure is a critical step for conjugate point extraction which is much more difficult than the optical images. the ...

ABTRACT Digital watermarking is the art of hiding of information or data in documents, where the embedded information or data can be extracted to resist copyright violation or to verify the uniqueness of a document which leads to security. Protecting the digital content has become a major issue for content owners and service providers. Watermarking using gradient direction quantization is based...

In this paper we propose a simple but efficient methodology for text detection in video frames. The method is based on the gradient information and edge map selection. In the proposed method we first find the gradient of the image and then enhance the gradient information. We later binarized the enhanced gradient image and select the edges by taking the intersection of the edge map with the bin...

In this study, a fast gradient-based compressive sensing (FGB-CS) for noise image and video is proposed. Given a noise image or video, the authors first make it sparse by orthogonal transformation, and then reconstruct it by solving a convex optimisation problem with a novel gradient-based method. The main contribution is twofold. Firstly, they deal with the noise signal reconstruction as a con...

A method to extract and recognize isolated characters in license plates is proposed. In extraction stage, the proposed method detects isolated characters by using Difference-ofGaussian (DOG) function, The DOG function, similar to Laplacian of Gaussian function, was proven to produce the most stable image features compared to a range of other possible image functions. The candidate characters ar...

The paper presents two methods that improve gradient estimation in 3D voxel space. The gradient estimation is an important step in the rendering and shading process to obtain realistic and smooth final images of visualized objects. The most used gradient estimation methods, gray-level gradient methods, Z-buffer gradient methods and binary gradient methods in some cases produce artifacts that ap...