Make the Size of Beams Same between Two Images

In order to analyze data of dual frequency observation, the size of the beams have to be made same before taking ratio. The method is as follows,
IDL> norh_rd_img,file0,index0,data0 $<$CR$>$
IDL> norh_rd_img,file1,index1,data1 $<$CR$>$
IDL> norh_convol,index1,index0,data0,index0c,data0c $<$CR$>$
By norh_convol, data data0 is convolved by a beam associated with index1. The pixel size of the result array data0c will become the coarser one between the beam and the image. Similarly,
IDL> norh_convol,index0,index1,data1,index1c,data1c $<$CR$>$
then data0c and data1c have the same beam and the same pixel size.