How can I detect elements of GUI using opencv?

1. How to detect objects using OpenCV CascadeClassifier?
2. How to detect ellipse in OpenCV?
3. What algorithm is used to detect lines in OpenCV?

How to detect objects using OpenCV CascadeClassifier?

Haar-cascade Detection in OpenCV

First, a cv::CascadeClassifier is created and the necessary XML file is loaded using the cv::CascadeClassifier::load method. Afterwards, the detection is done using the cv::CascadeClassifier::detectMultiScale method, which returns boundary rectangles for the detected faces or eyes.

How to detect ellipse in OpenCV?

To identify circles, ellipses, or in general, any shape in which the pixels are connected we use the SimpleBlobDetector() function of OpenCV.

What algorithm is used to detect lines in OpenCV?

The Hough Transform is a method that is used in image processing to detect any shape, if that shape can be represented in mathematical form. It can detect the shape even if it is broken or distorted a little bit.