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catalogue 1, What is document scanning Document scanning steps 2, Introduction to functions and variables used Variable introduction Function introduction 3, Practical operation 1 image preprocessing 2 obtain image contour 3 extract and mark document edges 4 reorder edges 5 trim trim edges 1, What is document scanning Document scanning ...

Histogram based on OpenCV4 Image histogram is an important statistical feature of an image. It represents the statistical relationship between each gray level in a digital image and the frequency of the gray level (the number of gray levels). According to the definition of histogram, it can be expressed as: ...

Some image processing operations with opencv are very simple and convenient, but for students who want to understand the details, it is best to write the generation of filter core and filter function. Understanding the change process of Gaussian function is of great help to our in-depth study of image processing. Function of image filtering ...

catalogue 1. Basic principle of Zhang's calibration method 1.1 camera pinhole model 1.2 homography matrix H 1.3 internal parameters of camera 1.4 external parameters of camera   1.5 optimization parameters 1.6 summary 2.OpenCV implementation 2.1 feature point detection and target coordinate initialization 2.2 camera calibration ...

brief introduction Super resolution refers to the process of enlarging or improving image details. When increasing the size of the image, additional pixels need to be interpolated in some way. Traditional image processing techniques can not get good results because they do not take the surrounding environment as the background when zooming in. ...

Fourier concept Introduction to Fourier Fourier transform, which means that a function satisfying certain conditions can be expressed as a trigonometric function (sine and / or cosine function) or a linear combination of their integrals. In different research fields, Fourier transform has many different variants, such as Continuous Fourie ...

color space Change color space (cv2.cvtColor()) There are more than 150 color space conversion methods in OpenCV. However, we only need to study the two most commonly used methods: BGR to GRAY and BGR to HSV. We use the cv.cvtColor(input_image, flag) function for color conversion, where flag determines the type of conversion. For BGR ...

openCV Window, mouse and keyboard operation Comprehensive example Generate a 500 * 500 pure black canvas, create a window, add mouse events to the window, and use the window to display images import cv2 import numpy as np # Generate 500 * 500 pure black canvas convas = np.zeros(shape=(512, 512, 3), dtype=np.uint8) # crea ...

First, why do we need crops? Clipping is to remove all unnecessary objects or areas from the image or to highlight a special feature of the image. Unlike Numpy, which uses slicing to achieve clipping, OpenCV does not have a specific function to perform clipping. Each image read is stored in a 2D array (for each color channel). Just specify the ...

About Anaconda installation cv2 Before learning opencv, we must first install the library functions of OpenCV. Let's demonstrate the mistake first First, we enter the following command in the Anaconda Prompt window: conda install opencv-python Then an error will appear: PackagesNotFoundError: The following packages are not available ...