Yes, this question is really about theories of how we perceive the world. Representative Theory of Perception, also known as Indirect realism and epistemological dualism, is a philosophical concept. It states that we do not (and can not) perceive the external world directly; instead we know only our ideas or interpretations of objects in the world. However, an indirect realist believes our ideas come from sense data of a real, material, external world (unlike idealists). The doctrine states that in any act of perception, the immediate (direct) object of perception is only a sense-datum that represents an external object.
This immediately raises a question: How well do sense-data represent external objects, properties, and events? Indirect realism creates deep epistemological problems, such as solipsism and the problem of the external world. Nonetheless, Indirect realism has been popular in the history of philosophy and has been developed by many philosophers including Bertrand Russell, Spinoza, René Descartes, and John Locke.
Whereas, Idealism is a class of positions in ontology and epistemology. Idealism as an epistemological position asserts that everything we experience is of a mental nature. That is, we can only have direct, immediate knowledge of the contents of our mind. We can never directly know or experience an external object itself. As an ontological position Idealism asserts either that only minds and the objects of mind exist, or that everything is composed of mental realities (e.g., thoughts, feelings, perceptions, ideas, or will). As a foundation for cosmology, or an approach to understanding the nature of existence, idealism is often contrasted with materialism, both belonging to the class of monist as opposed to dualist or pluralist ontologies. (Note that this contrast between idealism and materialism is approximately as to whether the substance of the world is at base mental or physical — it has nothing to do with thinking that things should be idealized, or with coveting goods.)
So, representative realism says we CAN perceive the world, but that we do it indirectly.
And idealism says that we CAN NEVER perceive the objective physical world because such a world doesn't exist. The whole of reality is mental.