Search results for " Fourier"

Thermoelastic stress analysis by means of an infrared scanner and a two-dimensional fast Fourier transform-based lock-in technique

2008

An infrared thermographic experimental set-up has been proposed and evaluated towards the capability to measure thermoelastic-effect-induced temperature changes. A standard infrared thermocamera with a nominal noise-equivalent temperature difference (NETD) resolution of 0.12 K has been employed to measure the temperature from unidirectional glass-reinforced plastic tensile coupons under cyclic sinusoidal loads. The raster scanning mode of the camera single detector produces a time delay in acquiring the signal from two succeeding pixels on the same row, and from consecutive scanned rows. By exploiting the acquired dwell times, it was possible to produce a periodic pattern on the thermal ma…

Soil Water Content Diachronic Mapping: An FFT Frequency Analysis of a Temperature–Vegetation Index

2020

Among the indirect estimation approaches of soil water content in the upper layer of the soil, the &ldquo

Silhouette encoding and synthesis using elliptic Fourier descriptors and applications to videoconferencing, Journal of Visual Language and Computing

2004

This paper investigates the use of elliptic Fourier descriptors as a shape descriptor for encoding the silhouette of a person. Shape descriptors are here used for predicting the shape of silhouettes in missing frames within a sequence. This prediction scheme is applied to the case of generating in-between images in a low frame rate videoconferencing system, where the reconstructed silhouette is used as a binary mask for reducing the computational time for the frame reconstruction.

A Transputer-Based System for Multi-Stroke Character Recognition

1992

A multi-stroke handwritten character recognition system is presented in this paper. A suitable set of Fourier Descriptors is used as features set to describe each stroke. A man-machine interactive algorithm was utilized to accomplish the learning phase and to recognize unknown samples. A PC based prototype was realized at first to test the system. In order to speed up the recognition process, the design and a first prototype of a Transputer-based system have been realized too. Some preliminary experimental results obtained applying these machines to handwritten numerals are reported in the paper.

Rilevamento del segnale termoelastico a campo intero mediante analisi lock-in in modalità off-line

2014

Il presente lavoro propone una procedura di post-processamento del segnale termografico misurato su provini sollecitati in modo ciclico al fine di ricavare il segnale termoelastico. Dopo aver descritto la Correlazione Lock-In, usata tradizionalmente dai sistemi commerciali per ricavare il segnale termoelastico, il lavoro mostra come tale procedura sia numericamente equivalente alla determinazione delle armoniche della Trasformata di Fourier Discreta (TFD) del segnale campionato. Viene quindi proposta ed implementata una procedura di filtraggio del segnale termoelastico basata sulla applicazione diretta della TFD, che ha il vantaggio di poter in alcune circostanze fare a meno di un segnale d…

Clifford Algebra based Edge Detector for Color Images

2012

Edge detection is one of the most used methods for feature extraction in computer vision applications. Feature extraction is traditionally founded on pattern recognition methods exploiting the basic concepts of convolution and Fourier transform. For color image edge detection the traditional methods used for gray-scale images are usually extended and applied to the three color channels separately. This leads to increased computational requirements and long execution times. In this paper we propose a new, enhanced version of an edge detection algorithm that treats color value triples as vectors and exploits the geometric product of vectors defined in the Clifford algebra framework to extend …

Comparison of the P-integral with Burkill's integrals and some applications to trigonometric series

2023

It is proved that the $P_r$-integral [9] which recovers a function from its derivative defined in the space $L^r$, 1 ≤r<∞, is properly included in Burkill’s trigonometric CP-and SCP-integrals. As an application to harmonic analysis, a de La Vallée-Poussin-type theorem for the $P_r$-integral is obtained: convergence nearly everywhere of a trigonometric series to a $P_r$-integrable function f implies that this series is the Pr-Fourier series of f.

Mirella Larizza, Fourier, a cura di Manuela Ceretta, Olschki, Firenze, 2003.

2004

Algorithm To Calculate Heart Rate By Removing Touch Errors And Algorithm Analysis

2018

Heart rate is one of the important physiological parameter to measure the stability of the health. This study shows analysis of a proposed algorithm to calculate heart rate with miss touch errors to make it more efficient. Android Smart phone with good quality camera has come to reach of common people and has become one of the most necessary and powerful device for today and of course, for future generation. We can use its powerful features to solve or assess heart state monitoring through capturing necessary data in the form of image. Mobile camera has a photo emitting diode and a photo detector. Light source illuminates the tissue and photo-detector calculates the small intensity variatio…

Space-variant simultaneous detection of several objects by the use of multiple anamorphic fractional-Fourier-transform filters.

2010

A fractional correlator that is based on the anamorphic fractional Fourier transform is defined. This new, to our knowledge, correlator has been extended to work with multiple filters. The novelty introduced by the suggested system is the possibility of the simultaneous detection of several objects in different parts of the input scene (when anamorphic optics are dealt with), thereby permitting an independent degree of space invariance in two perpendicular directions. Computer experiments as well as experimental optical implementation are presented.