Course 4, Week 1, Edge detection video: cross-correlation or convolution?

Course Q&A Deep Learning Specialization Convolutional Neural Networks
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Screenshot from 2022-10-24 21-33-55
Screenshot from 2022-10-24 21-33-551116×430 125 KB

Here the filter is not flipped, so it is a cross correlation rather than a convolution operation?

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Hi Yiyuan,

Yes, you are correct, this operation is defined as cross-correlation in math but called ‘convolution’ in DNN by convention. I remember in one video of C4 Andrew mentioned about the different definitions of ‘convolution’ between math-book and ML literature.

Cheers,
Kezhen

1 Like
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Thank you for clarifying. It is the first time I know convolution is not convolution in DNN :rofl:. I think we should call CNN as cross-correlation neural networks