Howtosignalprocessing
- What is the relationship between a point in k-space and a point in the image?
- What is spatial frequency formula?
- What does each point in k-space correspond to?
- What is k-space and how does it can it affect image contrast?
- How is spatial frequency measured?
What is the relationship between a point in k-space and a point in the image?
The relationship between k-space data and image data is the Fourier transformation. The data acquisition matrix contains raw data before image processing. In 2-dimensional (2D) Fourier transform imaging, a line of data corresponds to the digitised MR signal at a particular phase encoding level.
What is spatial frequency formula?
As spatial frequency = k/2π, this gives 1/2π wavelengths per metre and the wavelength λ = 2π/k = 2π/1 = 2π m.
What does each point in k-space correspond to?
Each k-space point contains spatial frequency and phase information about every pixel in the final image. Conversely, each pixel in the image maps to every point in k-space. Points along the kx-axis represent frequency components along the x-direction of the image.
What is k-space and how does it can it affect image contrast?
[right half black circle] k-space is the Fourier transform of the image: the center of k-space holds low-spatial-frequency information (image contrast), whereas the periphery of k-space holds high-spatial-frequency information (image details).
How is spatial frequency measured?
The SI unit of spatial frequency is cycles per meter (m). In image-processing applications, spatial frequency is often expressed in units of cycles per millimeter (mm) or equivalently line pairs per mm.
