Evaluation procedure

Goals
The aims of the evaluation metrics are twofold:
 measure the degree of accuracy of the endocardial surface. This will be done
through global and local measures of similarity with the reference contours;
 measure the degree of accuracy of the derived clinical indices.
Distance error metrics
To measure the degree of accuracy of the endocardial border, three standard metrics will be used:
 Modified Dice similarity index: the modified Dice similarity index, D*, is computed as a measure of
overlap between the surface volume (V) from automatic method and the reference surface volume
(V_{ref}), giving a measurement value between 0 (full overlap) and 1 (no overlap).
This value will be computed for both End Diastolic D*_{ED} and End systolic D*_{ES} instances.
 Mean surface distance: the mean surface distance, d_{mean}, between the surface (S) from automatic method and the reference surface (S_{ref}) defined as:
where d(S,S_{ref}) is the mean of distances between every surface voxel in S and the closest surface voxel in S_{ref}, while d(S_{ref},S) is computed in a similar way. This value will be computed for both End Diastolic d_{mean,ED} and End systolic d_{mean,ES} instances.
 Hausdorff surface distance: the Hausdroff distance, d_{H}, measures the local maximum distance between the two surfaces S and S_{ref}. This value will be computed for both End Diastolic d_{H,ED} and End systolic d_{H,ES} instances.
Clinical indice metrics
To measure the ability of the algorithms in extracting relevant clinical indices, modified correlation (corr*=1corr), bias and standard deviation (std) measurements will be computed from End Diastolic Volumes (EDV), End Systolic Volumes (ESV) and Ejection Fraction (EF) measurements. The following notation will be used
 Modified correlation computed from EDV measurements: EDV_{corr*}
 Bias computed from EDV measurements: EDV_{bias}
 Standard deviaton computed from EDV measurements: EDV_{std}
Ranking strategy
The challengers scores will be ranked according to the following measurements:
 Global distance errors measure
 Global clinical indices measure
 Global error measure
The ranking will be performed on the global error measure obtained by each participant.MIDAS mesh distance visualization
Each participant will have the possibility to visualize the distance between his uploaded result mesh and the corresponding reference one thanks to WebGL technique. A typical visualization that will be provided through the dedicated MIDAS website is presented bellow (the colormap provides a direct information on distance between two meshes).  measure the degree of accuracy of the endocardial surface. This will be done
through global and local measures of similarity with the reference contours;