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Articles by Gaurav Leekha
115 articles
A Beginner’s Guide to Image Classification using CNN (Python implementation)
Convolutional Neural Networks (CNNs) are specialized neural networks designed to process grid-like data such as images. CNNs automatically extract features through convolutional and pooling layers, then use fully connected layers for classification. This makes them ideal for image recognition tasks where important features may not be known beforehand. In this guide, we'll explore CNN architecture and implement a complete image classification model using Python and Keras on the MNIST handwritten digits dataset. CNN Architecture CNNs consist of three main layer types that work together to extract and classify image features ? Convolutional Layers Convolutional layers ...
Read More7 Easy Steps to Build a Machine Learning Classifier with Codes in Python
Machine Learning (ML), a branch of Artificial Intelligence (AI), is more than a buzzword right now. It is continuously growing and set to be the most transformative technology existing over the next decade. A few applications of machine learning that have already started having an impact on society include self-driving vehicles, fraud detection systems, and tumor detection. Classification, a task of supervised machine learning, is the process of assigning a label value to a specific class and then identifying a particular type to be one sort or another. One of the most basic examples of ML classification is an ...
Read MoreHow to implement linear classification with Python Scikit-learn?
Linear classification is one of the simplest machine learning problems. It uses a linear decision boundary to separate different classes. We'll use scikit-learn's SGD (Stochastic Gradient Descent) classifier to predict Iris flower species based on their features. Implementation Steps Follow these steps to implement linear classification with Python Scikit-learn ? Step 1 − Import necessary packages: scikit-learn, NumPy, and matplotlib Step 2 − Load the dataset and split it into training and testing sets Step 3 − Standardize features for better performance Step 4 − Create and train the SGD classifier using fit() method ...
Read MoreHow to transform Scikit-learn IRIS dataset to 2-feature dataset in Python?
The Iris dataset is one of the most popular datasets in machine learning, containing measurements of sepal and petal dimensions for three Iris flower species. It has 150 samples with 4 features each. We can use Principal Component Analysis (PCA) to reduce the dimensionality while preserving most of the variance in the data. What is PCA? PCA is a dimensionality reduction technique that transforms data into a new coordinate system where the greatest variance lies on the first coordinate (principal component), the second greatest variance on the second coordinate, and so on. Transforming to 2 Features ...
Read MoreHow to transform Sklearn DIGITS dataset to 2 and 3-feature dataset in Python?
The sklearn DIGITS dataset contains 64 features as each handwritten digit image is 8×8 pixels. We can use Principal Component Analysis (PCA) to reduce dimensionality and transform this dataset into 2 or 3-feature datasets. While this significantly reduces data size, it also loses some information and may impact ML model accuracy. Transform DIGITS Dataset to 2 Features We can reduce the 64-dimensional DIGITS dataset to 2 dimensions using PCA. This creates a simplified representation suitable for visualization and faster processing − # Import necessary packages from sklearn import datasets from sklearn.decomposition import PCA # Load ...
Read MoreHow to implement Random Projection using Python Scikit-learn?
Random projection is a dimensionality reduction technique that simplifies high-dimensional data by projecting it onto a lower-dimensional space using random matrices. It is particularly useful when traditional methods like Principal Component Analysis (PCA) are computationally expensive or insufficient for the data. Python Scikit-learn provides the sklearn.random_projection module that implements two types of random projection matrices ? Gaussian Random Matrix − Uses normally distributed random values Sparse Random Matrix − Uses mostly zero values with occasional +1 or -1 Gaussian Random Projection The GaussianRandomProjection class reduces dimensionality by projecting data onto a randomly generated matrix ...
Read MoreHow to create a random forest classifier using Python Scikit-learn?
Random Forest is a supervised machine learning algorithm that creates multiple decision trees on data samples and combines their predictions through voting. This ensemble approach reduces overfitting and typically produces better results than a single decision tree. The algorithm works by training multiple decision trees on different subsets of the data and features, then averaging their predictions for regression or using majority voting for classification. Steps to Create Random Forest Classifier Follow these steps to create a random forest classifier using Python Scikit-learn: Step 1 − Import the required libraries Step 2 − Load the dataset ...
Read MoreHow to get dictionary-like objects from dataset using Python Scikit-learn?
Scikit-learn datasets are returned as dictionary-like objects called Bunch objects. These objects contain structured data with several useful attributes that provide access to the dataset features, targets, and metadata. Dictionary-like Object Attributes Scikit-learn dataset objects contain the following key attributes − data − The feature matrix containing the data to learn. target − The target values for regression or classification. DESCR − Complete description of the dataset including characteristics. target_names − Names of the target variable(s). feature_names − Names of the feature columns. frame − Optional pandas DataFrame (when as_frame=True). Example 1: Accessing Dataset ...
Read MoreHow to binarize the data using Python Scikit-learn?
Binarization is a preprocessing technique used to convert numerical data into binary values (0 and 1). The scikit-learn function sklearn.preprocessing.binarize() transforms data based on a threshold value — features below or equal to the threshold become 0, while values above it become 1. In this tutorial, we will learn to binarize data and sparse matrices using Scikit-learn in Python. Basic Data Binarization Let's see how to binarize a numpy array using the Binarizer class ? # Importing the necessary packages import numpy as np from sklearn import preprocessing # Sample data X = [[0.4, ...
Read MoreHow to generate a symmetric positive-definite matrix using Python Scikit-Learn?
A symmetric positive-definite matrix is a square matrix where all eigenvalues are positive. Python Scikit-learn provides the make_spd_matrix() function to generate random symmetric positive-definite matrices, useful for testing algorithms and simulations. Basic Symmetric Positive-Definite Matrix The make_spd_matrix() function creates a symmetric positive-definite matrix of specified dimensions ? from sklearn.datasets import make_spd_matrix import pandas as pd # Generate a 4x4 symmetric positive-definite matrix spd_matrix = make_spd_matrix(n_dim=4, random_state=1) print("Generated SPD Matrix:") print(pd.DataFrame(spd_matrix)) Generated SPD Matrix: 0 ...
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