In the previous post, you saw that OpenCV can extract features from an image using a technique called the Histogram of Oriented Gradients (HOG). In short, this is to convert a “patch” of an image into a numerical vector. This vector, if set up appropriately, can identify key features within that patch. While you can […]
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Extracting Histogram of Gradients with OpenCV
Besides the feature descriptor generated by SIFT, SURF, and ORB, as in the previous post, the Histogram of Oriented Gradients (HOG) is another feature descriptor you can obtain using OpenCV. HOG is a robust feature descriptor widely used in computer vision and image processing for object detection and recognition tasks. It captures the distribution of […]
Image Feature Extraction in OpenCV: Keypoints and Description Vectors
In the previous post, you learned some basic feature extraction algorithms in OpenCV. The features are extracted in the form of classifying pixels. These indeed abstract the features from images because you do not need to consider the different color channels of each pixel, but to consider a single value. In this post, you will […]
Image Feature Extraction in OpenCV: Edges and Corners
In the world of computer vision and image processing, the ability to extract meaningful features from images is important. These features serve as vital inputs for various downstream tasks, such as object detection and classification. There are multiple ways to find these features. The naive way is to count the pixels. But in OpenCV, there […]
K-Nearest Neighbors Classification Using OpenCV
The OpenCV library has a module that implements the k-Nearest Neighbors algorithm for machine learning applications. In this tutorial, you will learn how to apply OpenCV’s k-Nearest Neighbors algorithm for classifying handwritten digits. After completing this tutorial, you will know: Several of the most important characteristics of the k-Nearest Neighbors algorithm. How to use the […]