extract->SetVOI( region.minX, region.maxX, region.minY, region.maxY,
region.minZ, region.maxZ );
extract->SetSampleRate( 1, 1, 1 );
extract->SetVOI( region.minX, region.maxX, region.minY, region.maxY,
region.minZ, region.maxZ );
extract->SetSampleRate( 1, 1, 1 );