Find a local partial region on the surface of the sphere, mark it by red color. Finally, we will compute the normal of the partial region and show it by a green line. The whole scene is just like the following image. Here are a few steps about the process. Read more…
A JSON file stores data objects in JavaScript Object Notation(JSON) format. It’s lightweight and readable, the developer uses it to transmit simple data. The article shows how to create and read the JSON file in the Qt environment. I planed to save two books’ information to a simple JSON file Read more…
The interface vtkObjectBase::UnRegister will reduce the reference count for pointer and delete the pointer if the reference count becomes zero. vtkObjectBase::Delete <= vtkObjectBase::UnRegister <= vtkObjectBase::UnRegisterInternal <= delete ptr vtkSmartPointerBase::~vtkSmartPointerBase { vtkObjectBase* object = this->Object; if(object) { this->Object = nullptr; object->UnRegister(nullptr); } } We can get the reference count and consumer Read more…
I want to save a little data into a local file that we read it. It is best done conveniently through C Plus Plus. The following example shows the entire logic. #include <iostream> #include <vector> #include <fstream> using namespace std; std::string filePath = “txt”; void WriteData() { double origin[3] = Read more…
We can use XML to store the OpenCV matrix and read it to recover the whole image. A simple example is in the following code snippet. We write an original image data to Untitled1.xml, then read it to generate another Mat object and show it. #include <stdio.h> #include <opencv2/opencv.hpp> #include Read more…
I want to fill the image to become a square one. The interface copyMakeBorder can help us to expand the original image to a bigger size. /* @param top @param bottom @param left @param right Parameter specifying how many pixels in each direction from the source image rectangle to extrapolate. Read more…
The article is based on How to use the OpenCV parallel_for_ to parallelize your code, the example project uses OpenCV parallel_for_ to speed up the computing process. Now I plan to use the algorithm class vtkSMPTools in VTK to get the same positive effect. The unit computing task is put Read more…
Gamma correction is a very useful method to make the original image brighter. It is a non-linear transform for every input value, the relevant math equation is in the following section. O：output value I：input value #include <stdio.h> #include <opencv2/opencv.hpp> using namespace cv; int main(int argc, char** argv ) { Mat Read more…
The original image and project are in the following part. CMakeLists.txt macro(use_cxx11) if (CMAKE_VERSION VERSION_LESS “3.1”) if (CMAKE_CXX_COMPILER_ID STREQUAL “GNU”) set (CMAKE_CXX_FLAGS “${CMAKE_CXX_FLAGS} -std=gnu++11”) endif () else () set (CMAKE_CXX_STANDARD 11) endif () endmacro(use_cxx11) cmake_minimum_required(VERSION 2.8) project( cvMat ) use_cxx11() find_package( OpenCV REQUIRED ) add_executable( ${PROJECT_NAME} “main.cpp” ) target_link_libraries( ${PROJECT_NAME} Read more…