See this example: convnet quiz Udacity. How to get from input depth = 3 to output depth = 8? My assumption: In this example we have 8 filter (kernels) and each of them slides over the 3 inputs. So in total we have 24 convolutions. That would give me a depth of 24? So how to reduce to eight?
Update: I found this mapping table by Yann. LeNet5, see page 8 Table1. However the question is, whether this table is still used in the same fashion as in early convnets or today we might use a different mapping sheme? E.g. just sum 3 filtered maps into one of the 8 output maps?