TD_DFFT2 Function | Teradata Vantage - TD_DFFT2 - Teradata Vantage

Database Unbounded Array Framework Time Series Functions

Deployment
VantageCloud
VantageCore
Edition
Enterprise
IntelliFlex
VMware
Product
Teradata Vantage
Release Number
17.20
Published
June 2022
Language
English (United States)
Last Update
2024-10-04
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TD_DFFT2 takes a matrix (two-dimensional array) as an input, and returns a result matrix whose elements are the compute two-dimension Fourier coefficients for the input matrix. The coefficients can be output as complex numbers in either rectangular (real, imaginary) or polar (amplitude, phase) form.

The function is used to analyze images and signals. It takes a signal, and converts it into a frequency domain representation.

The matrix is computed using the two-dimensional Fast Fourier Transform (FFT). This algorithm takes advantage that the transform can be computed using smaller segments, and are performed more efficiently.

TD_DFFT2 applies a one-dimensial transform to the rows and columns of the input signal separately. This process parses the signal into its frequency components, which can be visualized as a two-dimensional grid of values known as a frequency spectrum.

The frequency spectrum represents the amplitude and phase of the components that make the input signal. The amplitude represents the strength of each frequency component, while the phase represents the relative timing or offset of each component.

TD_DFFT2 has applications in image and signal processing, including image compression, pattern recognition, and filtering. By manipulating the frequency spectrum, you can perform operations such as noise reduction, edge detection, and image enhancement.