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Lappeenranta University of Technology (Finland). Lecture 3. Image Enhancement in Spatial Domain. Vladimir Botchko [email protected]. Image Enhancement. Simple intensity transformations Histogram processing (equalization) Image subtraction Image averaging - PowerPoint PPT Presentation
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Vladimir Botchko [email protected]
Lecture 3. Image Enhancement in Lecture 3. Image Enhancement in Spatial DomainSpatial Domain
Lappeenranta University of Technology (Finland)
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Image Enhancement
Simple intensity transformations Histogram processing (equalization) Image subtraction Image averaging Spatial filtering (smoothing, sharpening) Enhancement. First derivative (gradient)
Example of manual edge enhancement: made by artist.
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Simple intensity transformations
Contrast stretched
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Simple intensity transformations
Intensity level slicing: Original image (top) Thresholded (left) Gray-level slicing (lower right)
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Image Enhancement
Simple intensity transformations Histogram processing Image subtraction Image averaging Spatial filtering (smoothing, sharpening) Enhancement. First derivative (gradient).
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Histogram equalization
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Image Enhancement
Simple intensity transformations Histogram processing Image subtraction Image averaging Spatial filtering (smoothing, sharpening) Enhancement. First derivative (gradient).
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Image subtraction
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Image Enhancement
Simple intensity transformations Histogram processing Image subtraction Image averaging Spatial filtering (smoothing, sharpening) Enhancement. First derivative (gradient).
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Image averaging. Spatial filtering (smoothing)
Original image (upper left) Original + noise (upper right) Smoothed image (lower right) Median smoothing (lower left)
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Order-statistics filter for binary images (when numl=5 then it is
median) Rank filter is used for smoothing after recognition for segmentation. Simple Matlab
code is here:
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Order-statistics filter
First is median filtering result (rank 5 for 3x3 window). Upper part is input image lower part is smoothed image
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Order-statistics filter
Then the rank (rank 3 for 3x3 window). Original image upper, smoothed image is lower
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Sharpening
Second Derivatives. Laplacian
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Image Enhancement
Simple intensity transformations Histogram processing Image subtraction Image averaging Spatial filtering (smoothing, sharpening) Enhancement. First derivative (gradient).
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Median filter and Sobel operator
Gray-level images (from left to right from top to bottom): original texture
synthetic (computer generated) image, the result of recognition corrupted by classification errors, median filtering, edge extraction through Sobel operator, superposition a gray level image and image with edges.