Understanding Convolutional Neural Networks (CNNs) Through Excel

Convolutional Neural Networks (CNNs) can be demystified by building a simplified version from the ground up in Excel. Using handwritten digits as an example, images are represented as numerical grids, and filters are designed to represent the average shape of each digit. The core operation of cross-correlation is then used to multiply the input image with each filter, producing a score that indicates the strength of the match. By selecting the filter with the highest score, the model makes a prediction, illustrating the fundamental mechanics of pattern detection in deep learning.