Image Transforms and Feature Extraction Flashcards
Aims of image transformation? (4)
- REMOVE or CORRECT degradations
- IMPROVE appearance
- IDENTIFY and QUANTIFY structures
- TRANSFORM to different representation
Why would we want to transform an image to a different representation?
Some operations might be easier to perform
Name 3 types of Point transformations
- Grey scale
- Thresholding
- Histogram Manipulation
What are the two simplest ways to do grey scale manipulation?
- add constant
- scale by multiplier
What is the purpose of adding a constant or scaling by a multiplier?
IMPROVING appearance ( for human)
What does applying g’ = g*k to each point do?
Adjust CONSTRAST
What does applying g’ = g+k to each point do?
Adjust BRIGHTNESS
What is thresholding?
An operation that transforms a monochrome or colour image into a BINARY image.
What is a binary image?
An image who’s pixels only take one of two values
Give an example of Histogram manipulation?
Histogram equalisation
Name 3 types of Image transforms (based on area covered)
Point
Local
Geometrical
What is the fundamental to local transforms operation?
Convolution
What are four applications of the convolution operation?
- Smoothing
- Sharpening (edge detection)
- Corner detection
- Template matching
What does smoothing do to an image?
REMOVE SHARP, sudden changes in BRIGHTNESS function
Why would we wanna smooth?
- improve signal/noise ratio
- reduce some artefacts distracting effect
