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Recognize traffic signs in a photograph

Recognize traffic signs in a photograph #!/usr/bin/env python3 # -*- coding: utf-8 -*- import cv2 import numpy as np import glob while (True): red,frame = cv2.imread("14.jpg") cv2.imshow("Frame",...

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datatype CV_16F in opencv.js

Hi everyone, is it possible to enable the new datatype cv.CV_16F in the webassembly version of opencv 4.0? I know that this is meant for GPU-based computing. However, given the fact that webassembly...

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Unclear how calibrateCamera estimates stdDeviations (perhaps wrong)

Hi, I'm researching camera calibration and uncertainty propagation. I'm trying to understand how calibrateCameraExtended estimates stdDeviationsIntrinsics and stdDeviationsExtrinsics. [The...

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pathname in imread()

I am giving a path name for img = cv2.imread('',1) but while checking print(img) I am getting none message I am coping the pathname by using-shift+rt click and copy path to get it but everytime I am...

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Types of Mats and decision making

Hi, I know that Mat has many different types, as detailed below. Its puzzles my how one should decide which one of those to choose ?. Just image quality ? what is the correct way to convert from one to...

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Configuration Error CMake 3.15.14 opencv contrib

Selecting Windows SDK version 10.0.16299.0 to target Windows 6.1.7601. Detected processor: AMD64 Could NOT find PythonInterp (missing: PYTHON_EXECUTABLE) (Required is at least version "2.7") Found...

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Camera Calibration Takes too long

Hey, I am currently working on implementing open Cv/ARuco to Unity3D using C#. I have managed to track the markers in 3d space and get the 3d pos (position/rotation). However i noticed that the...

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Guidline in building Object detection and its direction.

I am trying to build object detection and its direction ,The shape of Object can be anything. For example let say i am showing the water bottle or chocolate or any object in front of webcam and i want...

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C++ compilation issue migrating from 3.4.3 to 4.1.1 on Android

I am upgrading an Android JNI project from OpenCV 3.4.3 to 4.1.1. When building an issue came out : error: undefined reference to 'cv::dnn::dnn4_v20190621::Net::setInput(cv::_InputArray const&,...

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Error: Cannot find NvOf library.

Using Samples of cudaoptflow, I am trying to run Nvidia Optical Flow sdk. **code :** while(1) { Mat frame; cap >> frame; //read every frame if(frame.empty()) break; Mat reference_image =...

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Can I use cv2.putText on a window without an image?

Or is there any alternatives for me to do so? Thanks!

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Problems with Qt and dnn module

Hi people, I am having problems with my Qt app where I declare "cv::dnn::Net net" object. By just declaring it is enough to cause my app crash at runtime. I use Qt5 and OpenCV 4.1.1 64 bits compiled...

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What backend API to use with DAHENG MER-132 USB3 Vision camera

Hi, I have a DAHENG MER-132 USB3 Vision camera which I am trying to access with opencv (python 3.7, Win 10). I followed some example code to get my webcam working with `capture = cv.VideoCapture(0)`...

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Installing openCV from source troubles

Hi everyone, I am an electrical engineering student who is looking to convert my computer vision project from MATLAB to Python and openCV but am having trouble doing so. I've gotten close with the...

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Getting error with freeType -> putText function

I am getting an error no matching function for call to ‘cv::freetype::FreeType2::putText(IplImage*&, cv::String&, CvPoint&, int&, cv::Scalar_, int&, int&, bool) for the...

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How to install OpenCV on Windows xp 32 bit

I'm using Windows xp 32bit, and I have installed python 3.4 on it.. But I'm getting problem to install OpenCV - python on my system. I have tried to copy .pyd file in site libraries too but still it's...

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Building Error VS 2017

Hi I have some trouble with building my opencv on a windows. I will attache the CMAKE log file and the Output build from VS2017. Please rename the files to .txt...

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Meaning of Input Array and noArray()

Hi In the wiki I found the following description of a function: C++: Vec2d EM::predict(InputArray sample, OutputArray probs=noArray()) what does it mean exactly? I.e. a) What exact type can...

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KCF is not correctly finding tracked object

When I pass a frame and a bounding box to trackerKCF init the tracker properly initializes. If the tracked object has moved before calling the first update, the update returns a true and the bounding...

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does JetsonTX2 support CV.dnn ?

I ran this code [Real-time object detection with deep learning and OpenCV](https://www.pyimagesearch.com/2017/09/18/real-time-object-detection-with-deep-learning-and-opencv/), Numbers of the frame per...

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