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Table 4 Exportable features

From: SHERPA: an image segmentation and outline feature extraction tool for diatoms and other objects

Name of feature

Description

Source Image

Path to raw image data file

Area

Object area

Perimeter

Object perimeter

Width

Object width (along major axis)

Height

Object height (perpendicular to major axis)

Rotation Angle

Rotation angle of the major axis

Segmentation Method

Segmentation method used to derive the object shape

Optimization Method

Optimization method applied to the object shape

Best Template (EFDIs)

Path to the best matching template (according to matching of elliptic Fourier descriptor invariants)

Template Difference (EFDIs)

Value for matching of elliptic Fourier descriptor invariants between object and best matching template

Hu-match for best EFDIs-Template

Value of matching of Hu invariants between object shape and best matching template

Standard Deviation

Standard deviation of texture gray levels within the inner 50% of the object boundaries

Width/Height-Ratio

Aspect ratio of the object shape

Smoothed Perimeter Ratio

Ratio between the perimeters of the smoothed and the original contour; smoothing is performed by Gaussian filtering of the contour coordinates.

Quality Index

Number of fulfilled quality indicators

Template is convex

Indicator showing if the best matching template is convex

Convexity is used

Indicator showing if convexity was judged directly to calculate convexity indicators (use of absolute convexity measures)

Rectangularity

Heuristic descriptor

Compactness

Heuristic descriptor

Ellipticity

Heuristic descriptor

Triangularity

Heuristic descriptor

Roundness

Heuristic descriptor

Convexity by perimeter

Heuristic descriptor

Convexity by area

Heuristic descriptor

Formfactor

Heuristic descriptor

CDF

Convexity defect measure

PCAF

Convexity defect measure

CHMDF

Convexity defect measure

CDF-Match

Ratio of CDF between object and template

PCAF-Match

Ratio of PCAF between object and template

Compactness-Match

Ratio of heuristic descriptor "formfactor" between object and template

Convexity Defect Index

Number of fulfilled absolute or relative convexity indicators

Ranking Index

Ranking for object shape, i.e. estimation of quality and relevance of result

Contour Image

Name of the file containing the image data cropped to the object area

Contour Image top left Corner

Coordinates of the top left corner of the cropped object image with respect to the raw data

Image Moments (mu)

Image moments of the object shape

Hu Invariants (Hu)

Hu-Invariants of the object shape