Publisher's Synopsis
Chapter 9: Convolutional Neural Networks (CNNs)
This chapter likely begins by revisiting the fundamental concepts of convolutional operations. It would meticulously explain how convolution works, including the roles of filters (kernels), strides, padding, and activation functions in extracting meaningful features from image data. The concept of feature maps, which represent the output of applying filters at different layers, would be thoroughly discussed, emphasizing how these maps capture hierarchical representations of visual information.
The chapter would then transition into exploring various influential CNN architectures.
- LeNet: This pioneering CNN architecture, designed for handwritten digit recognition, would be presented as a foundational example, illustrating the basic building blocks of a CNN. Its layers, including convolutional layers, pooling layers (like average pooling), and fully connected layers, would be explained in detail. The historical significance of LeNet in the development of modern CNNs would also likely be highlighted.
- AlexNet: This groundbreaking architecture, which achieved remarkable success in the ImageNet Large Scale Visual Recognition Challenge (ILSVRC), would be analyzed for its key innovations. These include the use of ReLU activation functions, dropout for regularization, and the utilization of multiple GPUs for training. The impact of AlexNet on the field of computer vision and the resurgence of deep learning would be emphasized.
- VGG (Visual Geometry Group): The chapter would delve into the VGG networks, known for their deep and uniform architectures consisting of small convolutional filters stacked together. The concepts of VGG16 and VGG19, along with their consistent use of 3×3 convolutional kernels, would be explained. The advantages and limitations of VGG networks, such as their depth and large number of parameters, would likely be discussed.
- ResNet (Residual Network): This architecture, which addressed the vanishing gradient problem in very deep networks through the introduction of residual connections (skip connections), would be thoroughly examined. The concept of identity mappings and how they facilitate the training of extremely deep networks would be explained. Different ResNet variants (e.g., ResNet-50, ResNet-101) and their performance benefits would likely be covered.
- Image Classification: This fundamental task of assigning a label to an entire image based on its content would be discussed. Different loss functions (e.g., cross-entropy) and evaluation metrics (e.g., accuracy, F1-score) used in image classification would be explained.
- Object Detection: This more complex task of identifying and localizing multiple objects within an image using bounding boxes would be introduced. Early object detection architectures and the fundamental challenges involved would likely be discussed, setting the stage for more advanced techniques covered in later chapters.
This chapter would shift focus to sequential data and how Recurrent Neural Networks (RNNs) are designed to process it. The fundamental concept of how RNNs maintain an internal state (memory) to handle sequences would be explained, along with the challenges associated with training vanilla RNNs, such as the vanishing and exploding gradient problems.
