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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