What is the concept that schema is opposed to
There are approaches in cognitive psychology that either emphasize top down or bottom up perceptual processes, or in some cases a combination of two. Psychology began using those terms after being radically influenced by the information processing framework. So I think that if a proper distinction is to be made, it would be better to put it in those terms namely, top down vs bottom up processing.

Having said that schemas are associated with top down processes as they involve the influence of knowledge on perception. So an opposite concept to schemas, if this is the right way to put it, would possibly be the concept of affordances which is associated with bottom up processes. James Gibson in his theory of affordances states that a sufficient amount of information is contained in the environment itself. Affordances in this sense, are "action possibilities" latent in the environment and are objectively measured contrary to schemas which are subjective by definition