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R8218/ShoulderCase/@Scapula/setCoordinateSystemWithLandmarks.m
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setCoordinateSystemWithLandmarks.m
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function setCoordinateSystemWithLandmarks(obj)
% Calculate the (EPFL) scapular coordinate system
% The EPFL scapular coordinate system is defined for a right scapula see
% paper (10.1302/0301-620X.96B4.32641). The X axis is
% antero-posterior, the Y axis is infero-superior, the Z axis
% is meddio-lateral. This system is right-handed.
% This orientation corresponds approximatively to the ISB
% recommendadtion (doi:10.1016/j.jbiomech.2004.05.042).
% For left scapula we keep the x axis as postero-anterior and
% get a left-handed coordinate system.
if (length(obj.groove) < 2)
error(['Can''t set scapular coordinate system with actual',...
' obj.groove']);
return;
end
% The four following methods have to be called in this specific order
setPAAxis(obj);
setMLAxis(obj);
setISAxis(obj);
setOrigin(obj);
end
function setPAAxis(obj)
% Set the postero-anterior axis to be the scapula plane normal
obj.coordSys.PA = obj.plane.normal;
end
function setMLAxis(obj)
% Set the media-lateral axis to be the line fitted to the projection of
% the groove points on the scapula plane
lateral = obj.spinoGlenoidNotch;
medial = obj.trigonumSpinae;
groovePointsProjection = obj.plane.projectOnPlane(obj.groove);
grooveAxis = fitLine(groovePointsProjection);
grooveAxis = (grooveAxis/norm(grooveAxis))';
obj.coordSys.ML = orientVectorToward(grooveAxis,(lateral-medial));
end
function setISAxis(obj)
% Set the infero-superior axis to be orthogonal with the two other axes
superior = obj.spinoGlenoidNotch;
inferior = obj.angulusInferior;
obj.coordSys.IS = cross(obj.coordSys.PA,obj.coordSys.ML);
obj.coordSys.IS = orientVectorToward(obj.coordSys.IS,(superior-inferior));
end
function setOrigin(obj)
% Set the origin of the coordinate system to the spino-glenoid notch
% projected on the scapular axis
spinoGlenoid = obj.spinoGlenoidNotch;
grooveMeanProjection = mean(obj.plane.projectOnPlane(obj.groove));
obj.coordSys.origin = grooveMeanProjection + ...
dot((spinoGlenoid - grooveMeanProjection),obj.coordSys.ML)*obj.coordSys.ML;
end
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