Index: trunk/src/transform_field/ima_ratio.m
===================================================================
--- trunk/src/transform_field/ima_ratio.m	(revision 728)
+++ trunk/src/transform_field/ima_ratio.m	(revision 728)
@@ -0,0 +1,34 @@
+%'ima_ratio': take the ratio of two input images with same size
+%
+% the two fields are subtstracted when of the same nature (scalar or
+% vector), if the coordinates do not coincide, the second field is
+% interpolated on the cooridintes of the first one
+%
+% when scalar and vectors are combined, the fields are just merged in a single matlab structure for common visualisation
+%-----------------------------------------------------------------------
+% function SubData=sub_field(Field,XmlData,Field_1)
+%
+% OUPUT: 
+% SubData: structure representing the resulting field
+%
+% INPUT: 
+% Field: matlab structure representing the first field
+% XmlData: input calibration parameter, not used
+% Field_1:matlab structure representing the second field
+
+function DataOut=ima_ratio(DataIn,XmlData,DataIn_1)
+
+%% option to introduce input parameters when function is selected, skipped here
+DataOut=DataIn;
+if ~isstruct(DataOut)
+%     if ~isfield(DataIn,'A')
+%         msgbox_uvmat('ERROR','ima_ratio requires two images of the same size as input')
+    return
+    end
+
+
+%% actual calculation
+if exist('DataIn_1','var')
+    DataIn_1.A(DataIn_1.A==0)=1;
+    DataOut.A=double(DataIn.A)./double(DataIn_1.A);
+end