We considered coronal holes as a manifestation of the large-scale magnetic field Sun. The main goal this work was to study variations in largest areas and longitudinal widths solar observed daily polar mid-latitude zones on time scale 984 days. Statistical methods fast Fourier transform (FFT), wavelet transform, empirical mode decomposition (EMD) were used detect periodicity parameters. Long-te...

We undertake a systematic study of Lipschitz Normally Embedded normal complex surface germs. prove in particular that the topological type such germ determines combinatorics its minimal resolution which factors through blowup maximal ideal and Nash transform, as well polar curve discriminant generic plane projection, thus generalizing results Spivakovsky Bondil were known for singularities. In ...

Iris is one of the most reliable biometric traits due to its stability and randomness. Iris is transformed to polar coordinates by the conventional recognition systems. They perform well for the cooperative databases, but the performance deteriorates for the non-cooperative irises. In addition to this, aliasing effect is introduced as a result of transforming iris to polar domain. In this thesi...

Over the last decade, several studies on texture analysis propose to model texture as a probabilistic process that generates small texture patches. In these studies, texture is represented by means of a frequency histogram that measures how often texture patches from a codebook occur in the texture. In the codebook, the texture patches are represented by, e.g., a collection of filter bank respo...

Let λ ∈ (0, 1) and let T be a r × r complex matrix with polar decomposition T = U |T |. Then, the λAluthge transform is defined by ∆λ (T ) = |T | U |T |. Let ∆nλ(T ) denote the n-times iterated Aluthge transform of T , n ∈ N. We prove that the sequence {∆nλ(T )}n∈N converges for every r × r diagonalizable matrix T . We show regularity results for the two parameter map (λ, T ) 7→ ∆∞λ (T ), and w...

A zero-mean homogeneous random field is defined on a discrete polar raster. Given sample values inside a disk of finite radius, we wish to estimate the field’s power spectral density using linear prediction. Issues arising here include estimation of covariance lags and extendibility of a finite set of lag estimates into a positive semidefinite covariance extension (required for a meaningful spe...

This Traditional template matching methods are not appropriate for the situation of large angle rotation between two images in the online detection for industrial production. Aiming at this problem, Fourier transform algorithm was introduced to correct image rotation angle based on its rotatary invariance in timefrequency domain, orienting image under test in the same direction with reference i...

Computed Tomography is one of the most popular diagnostic tools available to medical professionals. However, its diagnostic power comes at a cost to the patientsignificant radiation exposure. The amount of radiation exposure is a function of the number of angular measurements necessary to successfully reconstruct the imaged volume. Compressed sensing on the other hand is a technique that allows...

Shearlab is a Matlab toolbox for digital shearlet transformation of two-D (image) data we developed following a rational design process. The Pseudo-Polar FFT fits very naturally with the continuum theory of the Shearlet transform and allows us to translate Shearlet ideas naturally into a digital framework. However, there are still windows and weights which must be chosen. We developed more than...

This paper proposed a method that combines Polar Fourier Transform, color moments, and vein features to retrieve leaf images based on a leaf image. The method is very useful to help people in recognizing foliage plants. Foliage plants are plants that have various colors and unique patterns in the leaf. Therefore, the colors and its patterns are information that should be counted on in the proce...