Section 6 Flashcards
What are the three types of data manipulation for digital analysis
Multispectral band ratioing
Linear data transformation
Band-moment transformations
What are the four classes of image quality?
Low radiance/albedo
High radiance/albedo
Low contrast
High contrast
What is contrast stretching?
It expands the original brightness values in an image to increase contrast of the image. This can be done linear or non linear
What is a linear stretch?
It increases the contrast while preserving the original radiance relationships of the pixels
What is a non linear stretch?
A stretch similar to the linear stretch in that the original radiance relationships were not maintained
What is an example of a nonlinear enhancement?
Histogram equalization
Define spatial filtering.
The extraction of information contained in the spatial domain instead of the spectral. This is done in a kernel of pixels
Name the two types of spatial filtering
Convolution (low pass) Non convolution (high pass)
What is a convolution filter?
A low pass spatial filter. This smooths an image, blurring it slightly.
What is a non convolution filter?
A spatial high pass filter. It enhances abrupt changes
What is low frequency distribution?
When the brightness changes very little or it is gradual change
What is high frequency distribution?
Values that change very dramatically
What is a Fast Fourier Transform?
It can be a high or low pass filter that breaks an image down into frequency and direction. It removes repetitive noise.
What are two types of FFT?
Pass procedure: creates a mask and only inside the mask is kept
Cut procedure: creates a mask and only outside the mask is kept
What does an edge detection filter do?
Enhance linear features in an image. A high pass filter is an example of this
