the size of training data set in the context of computer vision
Generally speaking, for training a machine learning model, the size of training data set should be bigger than the number of predictors. For a neural network, or even a deep learning model, the number of parameters are usually tens of thousands or even millions. It seems that in practice, the number of training data set, i.e., the number of images, is usually less than the number of parameters. How to explain this? I know, we can claim that the pre-trained model may remove the requirement of having that many images. Is this the only reason, or we should use number of pixels multiplied by the number of images to measure the size of training data set.