The algorithm class vtkPolyDataNormals can be used to calculate normals of points and cells in polydata. The following example shows how to use it. Cube Create a cube in which every cell is a single square. All information can be found in polydata, we use vtkPolyDataNormals to handle it and 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 linear blend operator for two images: dst = α⋅src1+β⋅src2+γ we can use the following interface to support combine two pictures. CV_EXPORTS_W void addWeighted(InputArray src1, double alpha, InputArray src2, double beta, double gamma, OutputArray dst, int dtype = -1); Notice: we need to use the images which have the same Read more…
Capture an image from the camera. CurrentImage[] We can use function blur to change our image, the interface Manipulate will help us to display different levels dynamically. To find important colors in the image. Convert the original image to a white and black image: To find sharp changes in the Read more…
The interface Manipulate supports to display different scenes as parameter changed dynamically. eg: Manipulate[Plot[Sin[a*x], {x, 0, 10}], {a, 1, 5, 1}] If there is no step for variable a, it can vary continuously. Manipulate[Plot[x^a, {x, 0, 10}], {a, 1, 5}] It also lets us set up any number of Read more…
Sometimes the 3D model and 2D object will be overlapped as the above scene. I want to move the text to the top for avoiding overlap situation. My solution has these steps: 1. Calculate the bounding box of the sphere and convert it to a rectangle which wraps the image Read more…
We can put model in VTK display coordinate system. The following example is based on a previous article: Show Special Character In VTK . I add a line which start from (0,0) to left bottom corner of red string, the line is represented as 2D model. int *size = renderer->GetSize(); Read more…
We can use vtkTextActor to show string which contains special character. I use encoding value to represent math symbol and store it in QString object in the following example. #include <vtkActor.h> #include <vtkPolyData.h> #include <vtkRenderer.h> #include <vtkRenderWindow.h> #include <vtkRenderWindowInteractor.h> #include <vtkSmartPointer.h> #include <vtkTextActor.h> #include <vtkSphereSource.h> #include <vtkPlaneSource.h> #include <vtkPolyDataMapper.h> #include Read more…
We always use function Graphics and Graphics3D to represent items in the Wolfram Language. Use RegularPolygon to draw a triangle. Graphics[RegularPolygon[3]] Make a red octagon. Graphics[Style[RegularPolygon[8], Red]] Make a list whose elements are disks with hues varying from 0 to 1 in steps of 0.1. Table[Graphics[Style[Disk[ ], Hue[n]]], {n, 0, Read more…