Most voted "opencv" questions
Opencv is a multiplatform and *open source* library for developing applications linked to Computer Vision.
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answers103
viewsProblems with Opencv - Eyes Cascade and Face Cascade
Hey! What’s up? I am making a program in C++ with Opencv and when running appears the error below This is the error that is occurring without Try-catch This is the error occurring with Try-catch int…
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answer113
viewsOpencv: How to import automatic lib
Good morning, I’m starting programming with Opencv in C++ with Mingw, but I’m having trouble with lib files. Every time I need to compile a program, I need to put, for example,…
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answers1234
viewsRemoving the background of an image - python
I’m developing a code to remove the background of an image, I’m trying to use the Canny border detector to elaborate a mask and try to remove a piece of pipe from the image: The code I’m working on…
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answer163
viewsJAVACV with Ma Ven?
I made the JAVACV clone https://github.com/bytedeco/javacv I’m trying to run the project build: clean install But when I run I find the following error: Exception in thread "main"…
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answer1039
viewsC++ - Convert Mat to Opencv integer array?
I’m doing an image manipulation project using the Opencv. I need to analyze the values of pixels of a "binarized" image, for this I am trying to convert my Mat file image to a array of integers,…
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answer755
viewsHow to save images to a server folder via sockets using python and opencv?
Hello I’m new in programming and I would like to know how to save images, (captured by opencv) in a folder created by code inside the server, I know you can do this with sockets but I have no idea…
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answer546
viewsHow to extract the face of a RG document from a scanned image
Ola, Personal I am developing a solution where I use Google Cloud Vision to analyze text in the image, this is already ready in my solution. I send the image and Google Vision returns the words…
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answers109
viewsProblems with Opencv in Qt Creator
Program shows no error when build, but when running the code it displays the following message: libopencv_core.so. 3.4: cannot open Shared Object file: No such file or directory the file . pro is…
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answer68
viewsLapis design effect with opencv and python
I want to get the result of the image further to the right, so I can only get to the middle image using a Canny filter and a Gaussian filter. Does anyone know how I can get this result? import cv2…
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answer1231
viewsOpencv error in Python:
Good afternoon Everybody, all right? I’m looking to learn about Face Detection in Python using Opencv, installed all necessary libs, however while running the file I come across the following error…
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answer376
viewsHow to eliminate noise in an image?
In relation to the image presented, I want to leave only visible the main trunk and the (secondary) branches of the plant (tomato). Depending on my attempts, what seems to me to give more…
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answer1847
viewsError reshaping an image | Valueerror: cannot reshape array of size 72000 into Shape (1.24000)
I’m trying to use Python with Opencv to then make a classification. However, at the time I will make popular the object, I have the following error: Valueerror: cannot reshape array of size 72000…
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answer67
viewsHow to create a loss function in Keras that uses opencv?
I am developing a machine Learning model using the Keras library and realize that the available loss functions are not giving the best results in my test suite. I’m using an Unet architecture, where…
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answer98
viewsBuild Opencvblobslib in Windows Environment
How to run the Opencvblobslib bilioteca compilation in Microsoft Visual Studio 2013 (works in previous versions)
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answer208
viewsOpencv Error: Assertion failed (ssize.area() > 0)
I am having the following error with the Opencv library in Java: Opencv Error: Assertion failed (ssize.area() > 0) in cv::resize, file ..... opencv modules imgproc src imgwarp.cpp, line 1834…
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answers384
viewsApply NDVI to images with Opencv and Java
Everybody, good afternoon, everybody. I am in need of an image processing help using the Opencv library. Basically I need to take a satellite image and apply the NDVI (vegetation index by normalized…
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answers249
viewsHow to zoom in on an image with opencv and C++?
I have to program an algorithm to zoom in on an image without using the opencv tools, but I’m not getting it. How to zoom in on an image using for loops? Mat img = imread("copo.jpg",…
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answers46
viewsWhen to use namespace in C++?
Here’s the thing, since I knew how to use using namespace std; was a bad practice I stopped using namespace. Only now I started studying the Opencv library and see in its documentation to use using…
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answers133
viewsLoad a DLL from inside a jar
Hello, I am currently working with a project where I need to create a java API for image processing and after that I have to integrate it into a mobile module and a web module. But when I tried to…
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answers1248
viewsHow to capture webcam images in Opencv in Java?
Hello, I’m a beginner in opencv with java, and my problem is this, I want to capture the real-time image of my webcam and stream it on a Jlabel, but I’m having a problem running the file, netbeans…
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answers73
viewsConvert Bitmap to Mat
Hello, I am trying to grab saved BLOBS in a Sqlite database and convert them to Bitmap. After that, I need to convert these Bitmaps into Mat, to use with Opencv. The problem is that when I open the…
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answers60
viewsHow can I use the Opencl functions available in Opencv?
I am creating a program in Python, which often ends up demanding more from the CPU and decided to research on how to use the GPU for processing. The Opencl databases I found had examples only in…
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answer2245
viewsScript to recognize similarity between images
Good afternoon Everybody, all right? I am starting my studies in Python together with Opencv, and I want to perform the reading of images and display the degree of similarity between them. Ex: I…
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answer82
viewsQT - View Webcam on a Qlabel using another Thread?
Hello, I’m doing a C++ project using QT GUI. In the project in question I need to display images of a camera in the window, but in doing so, the performance of the window is very compromised, all…
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answers1220
viewsAspect ratio of an image resized with Opencv?
I have a project where I need to identify objects in an image, currently using the Opencv library in C++. I used the function warpPerspective() Opencv on a 605x141 size image to resize your…
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answer54
viewsDoubt regarding the Python syntax
Good evening guys, my question is about a piece of code I found in a book about Python and Opencv. The author created the function that I will put below: @property def frame(self): if…
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answer770
viewsCapture webcam image and save every 1 second?
I’m doing a project where the standard webcam takes photos every 1 second using opencv. In my code, at the click of the capture button you select the folder where you want and it captures a photo. I…
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answers1228
viewsReal-Time Facial Recognition on Android
Good morning! I’m creating a real-time facial recognition app. The app should compare the video image to a recorded image. In virtually all the researches I did the most suitable to be used was the…
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answer218
viewsCapture webcam images every 1 second using Javacv
A particular programmer is doing a project where the standard webcam takes photos every 1 second using Javacv. For now ,in this code, at the click of the capture button it captures a photo and saves…
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answer128
viewsI wanted to improve the performance of my program
Good Afternoon, I am currently creating an interface, for an application, but I have a problem, with the function I created. def contornos(self): self.im = cv2.imread(self.imagem) im_copia =…
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answer975
viewsHow to identify whether the area of an object is within another area desired by the user, drawn by the mouse
Hello! I recently started to venture into the Opencv library in C++. Today, I want to develop a program that applies a classifier to a polygonal ROI (5 points), obtained through 5 clicks with the…
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answer468
viewsmodule 'cv2.cv2' has no attribute 'COLOR_BRG2GRAY'
I am resizing images from a folder and am encountering the following error: module 'cv2.cv2' has no attribute 'COLOR_BRG2GRAY' Code: pathC = './cityscape/' dirs = os.listdir(pathC) #Resize para o…
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answer274
viewsHelp training Opencv
In a process of creating a haarcascade, I performed the procedures according to the tutorials of the Opencv library and arrived at the result of a vector with the number of 70 positive images named…
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answers255
viewsRoi (Region of interest) customized with Opencv and python
I detect people using Opencv and python, but I need to customize my ROI. I can only draw it rectangular, I would like a custom shape as in the picture.…
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answer639
viewsThe Pytesseract does not recognize only one letter
I need to recognize only one letter through the Pytesseract library in python but OCR is not able to recognize when it is only one letter. In this case, I’m trying to recognize the letter H, but…
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answer1033
viewsAdjust Image Range using Python
I’m a beginner in python, but I have experience with other programming languages. I need to do some college work, but I don’t know how to proceed. I would like to know how to adjust the range of an…
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answer2169
viewsPYTHON - How to know if there is an object on the screen from a reference?
Basically I wanted to know if there is the possibility of knowing if there is an object on the screen from a reference Example: There is a generic program on the screen that displays a closed lock,…
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answers51
viewsOpen large images with python Opencv
I am working on a software that processes very large images, between 10GB and 30GB. The images are too heavy to open at once. I would like to know if there is any way to use Opencv to open the image…
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answer279
viewsEncodings do not work in an Opencv file in Python 3
I followed the face detection tutorial using Opencv and wrote in Python 3. This file is not used print. I already know that Python 3 is international, is compatible with UTF-8 and does not need…
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answer38
viewsProblem with opencv on linux
I’m making a monitoring system with Opencv Python via streaming on my Windos 10 OS runs all correctly by irony on my Linux Mate I get the following error message when I try to run Nonmatching…
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answer185
viewsError finding the center of an Opencv Python object
Hello, I am studying opencv to use in a drone and while I was implementing a code of a tutorial that detected objects and drew a circle in the center of it, and for that you should take half the…
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answers16
viewsProblem running main components
Hello, I’m running an algorithm for sorting objects in an image. At the present moment I need to determine the coordinates of the center of the obejto to calculate the diameter and apply…
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answers91
viewsOpencv - C++ - Raspberry Pi
I want the function to check all the time if there is a fingerprint. If there is, I want you to start the capture scheme in sequence (the for nested), but the function I created is not working that…
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answers120
viewsDefine sections in a color recognition program
I am working on a project, which next year will become my TCC. I am learning the language of Python, and for now I have had some advances. I was reading about computer vision, but I still have some…
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answer72
viewsPoint-to-point operation on image
I am trying to perform a simple sum operation that adds 30 to the intensities on each channel, but the program only hangs without error output (probably some type error). I hit that reply //…
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answers123
viewsCreate samples of various positive Opencv images
I’m creating an Aarscade to find a part of the eye, but I can’t create the image samples. I have a file containing the path for all positive images and one for all negative images, but when it comes…
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answer722
viewsHow to plot graphically with the colors of each pixel of the image?
I am working on the color recognition of images, with this, I am converting the RGB image to Lab, because it is the color space closest to the human view. Once this is done, I take each of the 3…
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answer601
viewsTell what is the predominant color
Example: if the predominant color is a shade of red or red it appears a print saying it is red. the code works and returns a value in RGB, what I’m not getting and tell which is the predominant…
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answer73
viewsI cannot perform color conversion after image rotation
I’m developing an algorithm that rotates images every 10 degrees. For this, I am identifying the center of my region of interest, not the center of the image, because it has region of interest that…
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answer80
viewsDoubt Python Code and Opencv2
In this code I can do facial detection from a webcan. I use my notebook camera. I want this code to send a text message, for example "Detected Person" every time it detects a face. I tried to put an…