A common goal of many watermarking techniques is to produce a mark that remains detectable after the geometric transformations of Rotation, Scale and Translation; also known as RST invariance. We present a simple approach to achieving RST invariance using pixel-by-pixel addition of oscillating homogeneous patterns known as Logarithmic Radial Harmonic Functions [LRHFs]. LRHFs are the basis funct...

We study the problem of color constancy–infering from an image the spectrum of the illumination and the reflectance spectra of all the depicted surfaces. This estimation problem is underdetermined: many surface and illumination spectra can be described as a linear combination of 3 basis functions, giving 3 unknowns per pixel, plus 3 parameters for a global illumination. A trichromatic visual sy...

In the context of difference image analysis (DIA), we present a new method for determining the convolution kernel matching a pair of images of the same field. Unlike the standard DIA technique which involves modelling the kernel as a linear combination of basis functions, we consider the kernel as a discrete pixel array and solve for the kernel pixel values directly using linear least-squares. ...

This work extends the existing convergence analysis for discrete approximations of minimizers of convex regularization functionals. In particular, some solution concepts are generalized, namely the standard minimum norm solutions for squared norm regularizers and the R-minimizing solutions for general convex regularizers, respectively. A central part of the work addresses finite dimensional app...

This paper describes a new method for predicting the detectability of thin gaseous plumes in hyperspectral images. The novelty of this method is the use of basis vectors for each of the spectral channels of a collection instrument to calculate noise-equivalent concentration-pathlengths instead of matching scene pixels to absorbance spectra of gases in a library. This method provides insight int...

The aim of this paper is to propose two methods of detecting defects in industrial products by an analysis of gray level images with low contrast between the defects and their background. An additional difficulty is the high nonuniformity of the background in different parts of the same image. The first method is based on correlating subimages with a nondefective reference subimage and searchin...

many researchers adopt local binary pattern for pattern analysis. however, the long histogram created by local binary pattern is not suitable for large-scale facial database. this paper presents a simple facial pattern descriptor for facial expression recognition. local pattern is computed based on local gradient flow from one side to another side through the center pixel in a 3x3 pixels region...

A simple algorithm is proposed for detecting the red-eye defect in photographs on a pixel-by-pixel basis. The algorithm implements a support vector machine using the degree of redness in the surrounding context as features. Results are sub-par, chiming in at 9% false positives and 15% false negatives.

Most of us have noticed how saving an image in JPEG dramatically reduces the space it occupies in our hard drives (as oppose to file types that save the pixel value of each pixel in the image). The idea behind these compression methods is to exploit known structure in the images; although our cameras will record the pixel value (even three values in RGB) for each pixel, it is clear that most co...