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Catalogue of series articles FFT Use OpenCV to Fourier transform the image, use the FFT function available in Numpy, and some applications of Fourier transform Correlation function: cv.dft(), cv.idft() etc. 1. Theory Fourier transform is used to analyze the frequency characteristics of various filters. For the image, two-dimensional di ...

** preface ** Recently, I participated in the Dachuang project. The topic involves computer vision. My sister sent a blog link to correct the image, so I plan to use this topic to get started with OpenCV. Analyze problems The PPT area in the photo is always inclined along the X, y and Z axes (as shown in the figure below). To flip the photo ...

R329-opencv4_contrib-wechat_qrcode The CV team of wechat has opened the wechat QR code scanning engine and has joined opencv4_contrib module, let's try it today. Install opencv_contrib In the previous tutorial, we only installed the python version of OpenCV (in fact, it can be used without installation, because the C + + version and python v ...

   before starting the text, first know that the (0, 0) coordinate point in the screen is in the upper left corner and the maximum coordinate is in the lower right corner. 1, Drawing of basic graphics 1. Rectangle    the function of drawing rectangle in OpenCV is rectangle(). void rectangle(InputOutputArray img, Rect ...

I. overview Detectionbasedtracker provided by the official example Detectionbasedtracker under Java and JNI_ jni. CPP interactionWhen the project is migrated, the package name changes. If the content under JNI is copied to the new package, detectionbasedtracker Java cannot find detectionbasedtracker under JNI_ jni. Cpp fileRewrite the file und ...

Grayscale image output: import cv2 #The format read by opencv is BGR import numpy as np import matplotlib.pyplot as plt#Matplotlib is RGB %matplotlib inline img=cv2.imread('miku.png') img_gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY) img_gray.shape cv2.imshow("img_gray", img_gray) cv2.waitKey(0) cv2.destroyAllWindows() Picture output: ...

introduction File reading and writing is a function of many applications, and even some applications are developed around the processing of files in a certain format, so file reading and writing is a basic function of application development. Qt provides two basic methods for reading and writing plain text files: Use the IODevice read-write f ...

introduction Personally, the event mechanism is the most difficult and subtle part of Qt. There are two main types of events: Occurs when interacting with a user. For example, press the mouse (mousepress event) and hit the keyboard (keyPressEvent).The system automatically occurs, such as timer event, etc. When an event occurs (for example, pr ...

Excerpt: OpenCV parallel acceleration_ for_ ParallelLoopBody tutorialopencv parallel computing function parallel_for_ Use ofOfficial website: Parallel ProcessingGao Xiang, Zhang Tao, 14 lectures on visual SLAM In the process of using OpenCV, the amount of processing and calculation of pictures is still large, so how to calculate efficient ...

Welcome to my GitHub https://github.com/zq2599/blog_demos Content: classification and summary of all original articles and supporting source code, involving Java, Docker, Kubernetes, DevOPS, etc; Overview of this article stay Three minutes: fast experience JAVA version of target detection (YOLO4) In this article, we experienced the power ...