Machine Learning
Interview Questions
πŸ”’ Convolutional Neural Networks

What is a Convolutional Neural Network? How is it Used in Computer Vision?

A convolutional neural network (CNN) is a type of deep learning neural network that is specifically designed for image processing and computer vision tasks. It is a popular architecture that uses a series of convolutional layers to extract relevant features from the input images and produce an output.

The intuition behind CNNs is inspired by the way the visual cortex in the brain works. The visual cortex contains neurons that respond to specific patterns and edges within an image. Similarly, CNNs use convolutional layers to apply filters to input images to detect specific patterns and features. These filters are learned during training, allowing the network to automatically extract relevant features from the input images.

An analogy for CNNs is that they function like a human brain, where each layer is responsible for recognizing a certain feature, such as edges or shapes, and the output layer combines these features to recognize the overall image.

Here are some of the most common parameters used in a convolutional neural network (CNN):

  • Number of filters: The number of filters determines the depth of the output volume.
  • Filter size: The size of the filter determines the size of the local receptive field.
  • Stride: The number of pixels by which the filter shifts its position in the input image.
  • Padding: Padding is used to add extra pixels around the boundary of the image, which helps in preserving the spatial dimensions of the output volume.
  • Pooling: Pooling is used to downsample the output volume by summarizing the information in a region.

One of the key advantages of using CNNs is their ability to handle images of varying sizes and shapes. This makes them very useful for image classification, object detection, and other computer vision tasks.


  • Effective for image processing and computer vision tasks
  • Can handle varying image sizes and shapes
  • Can automatically extract relevant features from input images
  • Achieves state-of-the-art performance in many tasks


  • Require large amounts of training data and computing power
  • Difficult to interpret how the network makes predictions
  • May suffer from overfitting, where the network becomes too specialized to the training data and performs poorly on new data.