topic 4 - spatial filtering

Question 1

what is the purpose of spatial filtering?

Answer 1

Image smoothing

Noise removal

Image sharpening

Edge detection

Inpainting

Pre-processing.

Question 2

how do you define a filter using spatial filtering?

Answer 2

3x3 averaging filter

Smooths image content

Identical weights

Weights sum to 1 (preserves overall image brightness)

Question 3

how do you identify an image neighbourhood using spatial filtering?

Answer 3

Filter operates on this pixel to determine the intensity at the same position in the output image.

Question 4

what is an un-sharp mask and how does it sharpen an image?

Answer 4

The unsharp mask sharpens edges within an image.

The name is derived from the fact that the process involves blurring the original image.

If J is the output image then it is defined in terms of the original image, I, as follows:

J = I + A x [I - Iblur]

Where A is a scaling factor that can varied to control the strength of the sharpening effect.