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Category: OpenCV

CamCal 002 Weak Perspective

Highlights: In this post we will talk about how human vision can be tricked with a Perspective Projection model, and we will present one new model, which is called Weak Perspective. Tutorial Overview: Human vision Weak perspective 1. Human vision Humans are very sensitive to this structure of parallel lines and what they convey to us. Probably most of you have seen this Muller-Lyer illusion. Which one of these lines is longer? And you probably…
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OpenCV #010 Circle Detection Using Hough Transform

Highlights: In this post we will learn about analysing a given image to find circles detected in that image. Tutorial Overview: Intro Detecting Circles with Hough Hough Transform for Circles Code 1. Intro In the previous post, we saw how we can detect and find lines on images using Hough Transform. Now let’s move to something just a little bit more complicated, circles. Let’s start with the equation of a circle: $$ ( x_{i}-a )^{2}+(…
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OpenCV #009 Line Detection Using Hough Transform

  Highlights: In this post, we will learn how to analyze images and detect basic features: lines! We will describe a well known Hough transform that will help us to do this task. Let’s roll! Tutorial Overview: Line Detection Hough Space Polar Representation for Lines Code for Detecting Lines in Python and C++ 1. Line Detection Human driver on a regular day performs lane detection. This is a crucial task in order to keep the…
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OpenCV #008 Canny Edge Detector

Digital Image Processing using OpenCV (Python & C++) Highlights: In this post, we will learn about the Canny Edge Detector. In the last few posts, we explained why edges are important for better understanding of the image, and how we can use Laplacian and Sobel filter to detect them. At the places where this method does not give good results, we can use the Canny Edge Detector and dramatically improve the obtained results. Tutorial Overview:…
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OpenCV #013 Harris Corner Detector – Experiment

Highlights: In this post we will continue working on Harris Corner Detector. In the previous post we presented the basic idea behind this algorithm, and here we will wrap this up and show how this method works in OpenCV. Tutorial Overview: Interpreting the Second Moment Matrix Interpreting the Eigenvalues Harris Corner Response Function Harris Detector Algorithm Code 1. Interpreting the Second Moment Matrix Let’s first consider the case, where the gradient at every point in…
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