Yep
Bottom-up processing - Think about seeing an object (say a flower) for the first time. You notice the flower and you process all the features of the flower and put them together to make you perceive this object, because you have no experience seeing this object before. This is evidently a purely physiological process.
Bottom-up processing could thus be defined as where "the system takes in individual elements of the stimulus and than combines them into a unified perception." (Passer & Smith, 2008, p.150)
Top-down processing - One you've seen a object, when you see the flower again, you don't need to have sensed all of the features of the flower. Your memory of flowers helps 'fill the gaps'. This type of processing would be faster than bottom-up processing, but more prone to error (think some of the ambiguous figures you've learnt in Psychology here). Both a physiological and psychological process.
Top-down processing could be defined as where "sensory informaiton is interpreted in light of existing knowledge, concepts, ideas, and expectations." (Passer & Smith, 2008, p.150)
Hope that helps.
References:
Passer, M. W., & Smith, R. E. (2008). Psychology: The science of mind and behavior (4th Ed.). New York: McGraw-Hill.