Book Image

Data Science with Python

By : Rohan Chopra, Aaron England, Mohamed Noordeen Alaudeen
Book Image

Data Science with Python

By: Rohan Chopra, Aaron England, Mohamed Noordeen Alaudeen

Overview of this book

Data Science with Python begins by introducing you to data science and teaches you to install the packages you need to create a data science coding environment. You will learn three major techniques in machine learning: unsupervised learning, supervised learning, and reinforcement learning. You will also explore basic classification and regression techniques, such as support vector machines, decision trees, and logistic regression. As you make your way through the book, you will understand the basic functions, data structures, and syntax of the Python language that are used to handle large datasets with ease. You will learn about NumPy and pandas libraries for matrix calculations and data manipulation, discover how to use Matplotlib to create highly customizable visualizations, and apply the boosting algorithm XGBoost to make predictions. In the concluding chapters, you will explore convolutional neural networks (CNNs), deep learning algorithms used to predict what is in an image. You will also understand how to feed human sentences to a neural network, make the model process contextual information, and create human language processing systems to predict the outcome. By the end of this book, you will be able to understand and implement any new data science algorithm and have the confidence to experiment with tools or libraries other than those covered in the book.
Table of Contents (10 chapters)

Image Data Preprocessing

In this section, we go over a few techniques that you can use as a data scientist to preprocess images. First, we look at image normalization, and then we learn how we can convert a color image into a greyscale image. Finally, we look at ways in which we can bring all images in a dataset to the same dimensions. Preprocessing images is needed because datasets do not contain images that are the same size; we need to convert them into a standard size to train machine learning models on them. Some image preprocessing techniques help by reducing the model's training time by either making the important features easier to identify for the model or by reducing the dimensions as in the case of a greyscale image.

Normalization

In the case of images, the scale of the pixels is of the same order and in the range 0 to 255. Therefore, this normalization step is optional, but it might help speed up the learning process. To reiterate, centering the data and scaling it to the...