I am trying to get to the logical intuition of differences between stacking multiple features and passing it via a final block (which could comprise multiple layers and lets say a final classification layer) vis-a-vis passing these features via different layers and concatenate them before passing it via a final classification layer.
To give you a concrete example, if I am classifying images of different types,
I might pass them through a pre trained model(weights) and get a set of features, extract other features of image like maybe some blobs, histogram etc , ensure they have the same dimensionality and stack them and pass them through 1 model
OR i might pass the extracted features through 1 FC layer and then , say, the histogram features through another FC layer and concatenate them and finally pass this concatened output through a final FC layer to get the classification.
i would presume, 2 diff models + concatenation should be applied when the features are co-related but have different characteristics. For e.g. stock prices AND monthly employment numbers BUT if they are coming from the same image, they should be stacked ?? quite confused and any pointers would be manna from the heavens