How to orthorectify an image

static void orthorectifyImage(IRasterDataset2 rpcDataset, IRasterDataset demDataset)
    throws Exception{
    //rpcDataset: represents a raster dastaset that has RPC information
    //demDataset: represents a raster dataset opened from a DEM of the same area

    //Get the RPCXform form the raster dataset
    IRaster2 raster = new IRaster2Proxy(rpcDataset.createFullRaster());
    IGeodataXform rpcXform = raster.getGeodataXform();

    //set DEM etc.
    ISensorXform sensor = new ISensorXformProxy(rpcXform);
    sensor.setDEMByRef(demDataset.createDefaultRaster());
    sensor.setCorrectGeoid(true);

    //save the result
    ISaveAs saveas = new ISaveAsProxy(raster);
    saveas.saveAs("c:/temp/orthorectify_output.img", null, "IMAGINE Image");
}