CNN | object detection and classification | Practicle guide

A Practical Guide to Selecting CNN Architectures for Computer Vision Applications

From LeNet to EfficientNet: Choosing the Best CNN Architecture for Your Project

Chinmay Bhalerao
Level Up Coding
Published in
6 min readMar 29, 2023

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Credits: Stanford

Working in computer vision and machine learning is amazing because every few months, someone comes up with something crazy that completely changes your perspective on what is feasible.

Convolutional Neural Networks (CNNs) are a type of artificial neural network that has revolutionized the field of computer vision, particularly in image recognition and classification tasks. CNNs have numerous architecture designs that cater to different use cases and applications. There are many blogs and papers online explaining the architectures of CNN models in detail but I am directly explaining when to use particular architecture [I attached links to understand each network in detail so you can go through that also]. Here are some of the most popular CNN architectures and when to use them.

LeNet: LeNet was one of the first convolutional neural networks, and it has been around since the 1990s. This architecture is relatively simple, with only 7 layers.

The architecture of LeNet[Credits: Official paper]

When to use: It works well for small-scale image classification tasks, such as recognizing handwritten digits, but it is not suitable for more complex tasks that require a deeper network.

AlexNet: AlexNet was the first CNN to win the ImageNet Large Scale Visual Recognition Challenge in 2012, which marked a breakthrough in the field of computer vision. AlexNet is a deep CNN with 8 layers.

The architecture of AlexNet[Credits: official paper]

When to use: It works well for large-scale image classification tasks. It is particularly suitable for tasks that require a high degree of accuracy and a large dataset.

VGGNet: VGGNet is a deeper CNN than AlexNet, with up to 19 layers. It uses small convolutional filters to achieve high accuracy in image classification tasks.

The architecture of AlexNet[Credits: GeeksforGeeks]

When to use: VGGNet is particularly suitable for fine-grained classification tasks, such as identifying different breeds of dogs or different types of flowers.

GoogLeNet: GoogLeNet is a CNN architecture that uses inception modules, which are blocks of convolutional layers that have multiple filter sizes. These modules allow for more efficient use of computational resources and higher accuracy in image classification tasks.

The architecture of AlexNet[Credits: official paper]

When to use: GoogLeNet is particularly suitable for large-scale image classification tasks, such as object detection and segmentation.

ResNet: ResNet is a CNN architecture that uses residual connections, which are shortcuts between layers that allow the network to learn the residual mapping. This architecture can go as deep as 152 layers while maintaining high accuracy in image classification tasks.

The architecture of AlexNet[Credits: Official Paper]

When to use: ResNet is particularly suitable for tasks that require a very deep network, such as recognizing fine details in images.

DenseNet: DenseNet is a CNN architecture that connects each layer to every other layer in a feed-forward fashion. This architecture maximizes feature reuse and allows for better gradient flow, which leads to higher accuracy in image classification tasks.

A deep DenseNet with three dense blocks [Credits: Official Paper]

When to use: DenseNet is particularly suitable for tasks that require a large number of parameters, such as medical image analysis.

MobileNet: MobileNet is a CNN architecture that is designed for mobile and embedded devices. It uses depth-wise separable convolutions, which separate the spatial and channel-wise convolution operations, to reduce the number of parameters and computation required.

MobileNet Body Architecture [Credits: official Paper]

When to use: MobileNet is particularly suitable for real-time image classification tasks on devices with limited computational resources.

EfficientNet: EfficientNet is a CNN architecture that uses a compound scaling method to balance the number of parameters, computational cost, and accuracy. This architecture achieves state-of-the-art accuracy on various image classification tasks with fewer parameters and less computation.

EfficientNet-B0 baseline network [Credits: Official Paper]

When to use: EfficientNet is particularly suitable for tasks that require high accuracy and computational efficiency.

In summary, the choice of CNN architecture depends on the complexity of the image classification task, the size of the dataset, the available computational resources, and the desired level of accuracy.

There is no one-size-fits-all answer to this question as it depends on various factors such as the size and complexity of the dataset, the specific task at hand, and the available computational resources. However, here are some general guidelines and thumb rules:

If the input data is small and simple, such as images with low resolution, then a smaller CNN architecture such as LeNet or AlexNet might be sufficient.

If the input data is large and complex, such as high-resolution images or videos, then a larger and more complex CNN architecture such as VGG, Inception, or ResNet might be needed to extract relevant features.

If the task involves object detection or segmentation, then architectures like YOLO, RCNN, or Mask R-CNN might be suitable.

If the task involves processing sequential data such as speech or text, then architectures such as Convolutional LSTM or Time Distributed CNN might be used.

If the available computational resources are limited, then smaller architectures with fewer layers and parameters may be preferred to reduce training time and memory usage.

Ultimately, the choice of CNN architecture should be based on a thorough understanding of the data and the task at hand, as well as experimentation and evaluation to determine the most effective approach.

“The choice of CNN architecture depends on the complexity of the image classification task, the size of the dataset, the available computational resources, and the desired level of accuracy.”

Resources for CNN:

All CNN architectures: Understanding of basic CNN architectures

CNN Architectures by Michigan online

CNN by Andrej Karpathy (2016)

CNN by Stanford University School of Engineering (2017)

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AI-ML Researcher & Developer | 3 X Top writer in Artificial intelligence, Computer vision & Object detection | Mathematical Modelling & Simulations