There are several different ways in FME to convert from raster to vector. However, because the data models are so different, any such conversion is always an interpretation, so you have to think exactly how you want to interpret your raster before you can do this kind of conversion. For example, you could take an integer raster, interpret it as grey scale, and then look for lines that you want to interpret as vector lines. Or you could take the same raster, interpret it as elevation, and then generate a vector surface model TIN based on those elevation points. So you can get radically different results based on your interpretation. Perhaps you want to classify your integer raster. This is not that hard to do though it takes a few transformers and some processing. In fact, any vector / raster conversion is always process intensive.