lecture 2

Question 1

what is afilter?

Answer 1

a mathematical operation that
modifies an incoming signal
→ get ridof noise or increase contrast

Question 2

Convolution?

Answer 2

convolution operation, a PSF (poiunt spread function) is „woven“
into the grid of our discrete image

Question 3

What is kernel

Answer 3

it is a PSF that is a discrete mathematical function ( matrix) the simplest one is the blur kernel

Question 4

Low pass filter - blurring

Answer 4

allow low-frequency components of a signal to pass through while attenuating (reducing) higher-frequency components.

Question 5

Allows high-frequency components to pass through while attenuating lower frequencies.

Answer 5

High-pass filters are often used for edge detection and enhancement of fine details in the image.

Question 6

Filters – summary I.

Answer 6

Blurring or low pass filters can supress
image noise, and smooth the image.
* Sharpening or high pass filters can enhance
the visibility of fine details, but increase the
visibility of reconstruction artifacts.

Question 7

k-space

Answer 7

refers to a mathematical representation of spatial frequency data acquired during the MRI process. The term “k-space” stands for “frequency space” or “k-vector space.”

Question 8

Fourier Transformation
on an image

Answer 8

modifying the magnitude and/or phase of the Fourier transform to emphasize or suppress certain frequency components. For example, applying a high-pass filter in the frequency domain emphasizes high-frequency components, which can enhance edges in the image.