Image Processing and Pattern Recognition Jouko Lampinen
Dec 20, 2015
Image Processing and Pattern Recognition
Jouko Lampinen
About this presentation
• In this set of slides we illustrate a bigger problem which uses both morphological operations and other operations that will be introduced soon.
• In most cases we use morphological operations together with other operations.
• The most important reason of using them is speed and non-linear processing.
Image analysis of grain material in concrete production
• Images captured by standard
1200 dpi color scanner • Grain shape inputs
• angularity, flakiness• Grain texture inputs
• Boundary & surface texture• FFT based texture features
• Image Analysis Tool:
Matlab standalone application• Quality Control Tool:
Excel macro package for running
and analyzing the Bayesian
models (to be discussed)
Example of grains (1.6-2.0 mm sieve fraction)
Grain FeaturesGrain Features Measured from the Image
• Area• Major Axis • Minor Axis• Eccentricity• Convex Area• Equivalent Diameter• Solidity• Perimeter• Compactness• Borderline FFT (5 features related to roughness)• Texture 2D FFT (5 features related to surface structure) • Morphological Spectrum (roundness)
Most of these parameters will be presented in next lectures
Object size and shape characterization
• Bounding box (rotated along principal axes)• Ellipsoid determined by the principal axes • Convex hull
Original sand grain image (natural sand)
Thresholded image (natural grains)
Objects filled
Morphological opening (yellow pixels removed)
Labelled objects
Bounding boxes and minor/major axes
Original sand grain image (crushed)
Thresholded image (crushed)
Objects filled
Morphological opening (yellow pixels removed)
Labelled objects
Bounding boxes and minor/major axes
Grain shape analysis: angularity
Sharp angles in grains break under compression
Measurement: simulate the erosion due to Ice Age by morphological erosion
Morphological spectrum:
S(r)
Amount of material removed by circular structure element of radius r
Feature space!!
Example of Morphological Spectra and Angularity
Crushed gravel Natural gravel (manufactured by Ice Age)
Morphological spectrumWe can scientifically
compare various gravels