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Synthetic Image Generator/retrieve_marker_coord.m

+function [Coord,corners_cam] = retrieve_marker_coord(calibname)
+
+% This function opens a DaVis 'MarkPositionTable.xml' file and retrieves the
+% the position of markers. In raw image coordinate system (Image plane), 
+% [X,Y] coordinates are given in pixels while in the world coordinate system
+% (Object plane), [x,y,z] coordinates are in mm. This is then returned in 
+% two matrices corresponding to each camera. This script uses 'xml2struct'.  
+% It must be searchable in the MATLAB path [Download link:
+% https://uk.mathworks.com/matlabcentral/fileexchange/28518-xml2struct]
+% 
+% INPUT VARIABLES:
+% filename = pathname of xml file
+% 
+% OUTPUT VARIABLES:
+% Coord       = Image and object plane coordinates for left and right camera
+%               Format: 1st column - image plane x coordinates [in pixels]
+%                       2nd column - image plane y coordinates [in pixels]
+%                       3rd column - object plane x coordinates [in mm]
+%                       4th column - object plane y coordinates [in mm]
+%                       5th column - objetc plane z coordinates [in mm]
+% corners_cam = The pixels of the camera's corners
+%
+%--------------------------------------------------------------------------
+% Version 1.0
+% Girish K. Jankee (26 January 2018)
+% 
+% Version 2.0
+% Eduardo Rodriguez-Lopez (24 April 2018)
+% Determination of distance between 2 z-planes is now automated.
+%
+% Version 2.1
+% Girish K. Jankee (26 April 2018)
+% Added feature extracts the coordinates of the camera's corners.
+%--------------------------------------------------------------------------
+%% MAIN CODE
+a = xml2struct(calibname);
+for i = 1:2
+    if i == 1
+        cam_L = cell2mat(a.MarkTable(1).Camera{1,i}.View(1,1).Mark);
+    else
+        cam_R = cell2mat(a.MarkTable(1).Camera{1,i}.View(1,1).Mark);
+    end
+end
+
+% Left Camera
+posL = zeros(length(cam_L),5);
+for j = 1:length(cam_L)
+    posL(j,1) = str2num(cam_L(j).RawPos(1).Attributes(1).x);
+    posL(j,2) = str2num(cam_L(j).RawPos(1).Attributes(1).y);    
+    posL(j,3) = str2num(cam_L(j).WorldPos(1).Attributes(1).x);
+    posL(j,4) = str2num(cam_L(j).WorldPos(1).Attributes(1).y);    
+    posL(j,5) = str2num(cam_L(j).WorldPos(1).Attributes(1).z);
+end
+% keyboard
+thickL=abs(mean(posL( posL(:,5)~=0, 5 )));
+posL( abs(posL(:,5)+thickL)<1e-10, 5 ) = -thickL/2 ;
+posL( abs(posL(:,5)-0     )<1e-10, 5 ) =  thickL/2 ;
+
+% Right Camera
+posR = zeros(length(cam_R),5);
+for j = 1:length(cam_R)
+    posR(j,1) = str2num(cam_R(j).RawPos(1).Attributes(1).x);
+    posR(j,2) = str2num(cam_R(j).RawPos(1).Attributes(1).y);    
+    posR(j,3) = str2num(cam_R(j).WorldPos(1).Attributes(1).x);
+    posR(j,4) = str2num(cam_R(j).WorldPos(1).Attributes(1).y);    
+    posR(j,5) = str2num(cam_R(j).WorldPos(1).Attributes(1).z);
+end
+
+thickR=abs(mean(posR( posR(:,5)~=0, 5 )));
+posR( abs(posR(:,5)+thickR)<1e-10, 5 ) = -thickR/2 ;
+posR( abs(posR(:,5)-0     )<1e-10, 5 ) =  thickR/2 ;
+
+
+if thickR~=thickL
+    error('thickness are not the same!!!')
+end
+
+Coord.Left = posL;
+Coord.Right = posR;
+
+height = str2num(a.MarkTable(1).Camera{1,1}.Attributes.Height);
+width = str2num(a.MarkTable(1).Camera{1,1}.Attributes.Width);
+corners_cam    = [0 width width    0
+                  0    0 height height];          % the pixels of the camera's corners