OpenCV

Webcam doesn't read through OpenCV but does with guvcview

由 不羁岁月 提交于 2021-01-27 07:37:33
问题 I have a webcam of sorts that is quite old. I've been attempting to get it to work. I started out with guvcview which works, however it only gives me the first frame captured then stops. That's fine for now. I'm trying to recreate this behaviour using OpenCV. I'm on linux and using python. It is my understanding that my best bet here is to have OpenCV use v4l2 which is what guvcview is using. My long term idea is to get the first frame only, but do this in a loop to sort of get "video" but at

How do I detect vertical text with OpenCV for extraction

由 女生的网名这么多〃 提交于 2021-01-27 07:33:56
问题 I am new to OpenCV and trying to see if I can find a way to detect vertical text for the image attached. In this case on row 3 , I would like to get the bounding box around Original Cost and the amount below ($200,000.00). Similarly I would like to get the bounding box around Amount Existing Liens and the associated amount below. I then would use this data to send to an OCR engine to read text. Traditional OCR engines go line by line and extract and loses the context. Here is what I have

Reverse of OpenCV projectPoints

由 穿精又带淫゛_ 提交于 2021-01-27 06:08:06
问题 I have a camera facing the equivalent of a chessboard. I know the world 3d location of the points as well as the 2d location of the corresponding projected points on the camera image. All the world points belong to the same plane. I use solvePnP: Matx33d camMat; Matx41d distCoeffs; Matx31d rvec; Matx31d tvec; std::vector<Point3f> objPoints; std::vector<Point2f> imgPoints; solvePnP(objPoints, imgPoints, camMat, distCoeffs, rvec, tvec); I can then go from the 3d world points to the 2d image

Reverse of OpenCV projectPoints

由 不想你离开。 提交于 2021-01-27 06:04:29
问题 I have a camera facing the equivalent of a chessboard. I know the world 3d location of the points as well as the 2d location of the corresponding projected points on the camera image. All the world points belong to the same plane. I use solvePnP: Matx33d camMat; Matx41d distCoeffs; Matx31d rvec; Matx31d tvec; std::vector<Point3f> objPoints; std::vector<Point2f> imgPoints; solvePnP(objPoints, imgPoints, camMat, distCoeffs, rvec, tvec); I can then go from the 3d world points to the 2d image

对于opencv全面貌的认识和理解

由 喜你入骨 提交于 2021-01-27 05:59:27
1、opencv其实最开始只有源码，也就是sources中的代码，sources中有个modules，进入里面是各个我们平常使用的模块，如下图。 进入任意一个模块，比如calib3d，其中有include，头文件，有src，实现头文件定义的类的cpp，src文件夹下面还有一个main函数，从理论上来说我们可以把calib3d中的头文件和cpp放在一个vs的项目中，来生成解决方案，也就是做编译和执行。 但是opencv不像我们这样子做，opencv要在不同的操作系统上编译出适合本系统的静态链接库和动态链接库，之后如果我作为一个程序员，想调用calib3d的头文件中的某一个类，那么就#include <opencv2/calib3d/calib3d.hpp>就可以了。 也就是说，我们没有必要拿calib3d中的所有cpp和头文件都放在解决方案中，一个个来编译，只需要简单的一行#include调用头文件就可以了。 链接库挺方便的，关于为什么要使用链接库而不是一大堆的cpp和头文件，这个链接给出了答案 https://segmentfault.com/a/1190000008634703 ，谢谢作者的分享。 2、下载的源码sources文件夹中必定有cmakelists，这是cmake的根据。在linux系统上，cmake指令根据cmakelists生成makefile

Changing image DPI for usage with tesseract

由 折月煮酒 提交于 2021-01-27 05:28:34
问题 I am working on a project to recognize text in Business Cards and map them to appropriate fields.I am using opencv for image processing.I need to feed the preprocessed image to Tesseract-OCR engine for text recognition.This link states that images should have atleast a DPI of 300.My image pixel size is 2560x1536 with 72 DPI. How to increase the DPI to 300? It is also said that it is beneficial to resize image.How to resize my image optimally for good OCR results Tesseract works best on images

Changing image DPI for usage with tesseract

由 北城余情 提交于 2021-01-27 05:28:33
问题 I am working on a project to recognize text in Business Cards and map them to appropriate fields.I am using opencv for image processing.I need to feed the preprocessed image to Tesseract-OCR engine for text recognition.This link states that images should have atleast a DPI of 300.My image pixel size is 2560x1536 with 72 DPI. How to increase the DPI to 300? It is also said that it is beneficial to resize image.How to resize my image optimally for good OCR results Tesseract works best on images

Using OpenCV in eclipse

由 主宰稳场 提交于 2021-01-27 05:26:47
问题 I am trying to setup opencv in eclipse Luna. I have written a sample application as follows : #include <cv.h> #include <highgui.h> #include<iostream> using namespace cv; int main( int argc, char** argv ) { Mat image; image = imread( argv[1], 1 ); if( argc != 2 || !image.data ) { printf( "No image data \n" ); return -1; } namedWindow( "Display Image", CV_WINDOW_AUTOSIZE ); imshow( "Display Image", image ); waitKey(0); return 0; } In my project properties i have included /usr/local/include

Using OpenCV in eclipse

由 我是研究僧i 提交于 2021-01-27 05:24:58
问题 I am trying to setup opencv in eclipse Luna. I have written a sample application as follows : #include <cv.h> #include <highgui.h> #include<iostream> using namespace cv; int main( int argc, char** argv ) { Mat image; image = imread( argv[1], 1 ); if( argc != 2 || !image.data ) { printf( "No image data \n" ); return -1; } namedWindow( "Display Image", CV_WINDOW_AUTOSIZE ); imshow( "Display Image", image ); waitKey(0); return 0; } In my project properties i have included /usr/local/include

Need help combining two 3 channel images into 6 channel image Python

由 假如想象 提交于 2021-01-27 05:24:14
问题 I am trying to combine two different RGB images into a single 6 channel image (Tiff is best) using nothing but Python. What I have is an RGB image taken from a normal camera as well as another RGB image that is a normal map based on a SfM reconstruction. The images have identical dimensions and I simply need to overlay one image on the other so that I can run an image classification based on the combined channel information. I've been looking into using openCV for this, but I'm getting hung
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