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Flashcards in Section 6 Deck (24):

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


What are the two types of edge detection filters?

Non directional: deal with linear features in all directions.

Directional: accentuate feature in one direction


What is a LaPlacian filter?

A non directional filter that is an edge detection filter. It emphasizes the maximum values in the image


What is a compass gradient filter?

A directional edge detection filter. It enhances features according to compass directions


What is a filter similar to a compass gradient filter, but is a non linear filter?

Sobel filter


What is the purpose of using a band ratio?

The enhance differences in brightness between surfaces


What is principal component analysis?

It reduces the amount of bands but keeps information. It decorrelates data while maintaining statistical value. Correlates spectral bands


What is the tasselled cap transformation?

It creates a soil, green and wetness index


What is a band moment analysis?

A transformation to get statistical data, it looks through the spectral data of a pixel and creates a cube.


What are three types of data enhancement for image production?

Contrast stretch
Spatial filtering
Edge enhancement