Currently, I use RasterExtentsCoercer to get a closely define edge with my raster images. The raster's I'm using tend to have a 0,0,0 nodata border around it. However within the whole of the image, there are small areas of 0,0,0, for example inside dense forestry areas. 

 

 

Because of these areas, the processing time when using the Data Extents mode is increased significantly. The machine will process it but it really limits my processing ability.

 

 

Is there a better way to pull accurate extents which follow closely within the nodata ?

 

It cannot be assumed all edges are straight. So far using any of the "bounds" transformers has resulted in no exact bounding boxes.