Episode_4_Little_Tricks_Capture_Camera_in_WinForm

After you can capture camera with OpenCV in console application (Episode 3). Now I give you some tricks, how to capture camera in windows forms application. This is very important if you want your program to be more complex.

Before I give you the tricks . you must configure OpenCV directories and include OpenCV library to the Linker input (Episode 2). After that, you must change "common language runtime support" to common language runtime support (/clr).

• General->common language runtime support->common language runtime support(/clr).

picture 0_change_common_language_runtime_support

Now design your form like this (there are button, picture box, and timer). You can get it all in toolbox option, and you just drop it in your windows forms. in picture box, change its size to 320x240 in properties and size mode "Normal" to "StrecthImage". Why? because it need to fit in camera frame size with your picture box so we can get better image.

picture 1_form_application

Double click "Start Button" to start your listing program and modify your listing program such as;

initialize component on top listing program

#pragma once
#include 
#include 

//initialize component here to get access public class
CvCapture* capture;
IplImage* frame;

namespace Tutorial {

using namespace System;
using namespace System::ComponentModel;
using namespace System::Collections;
using namespace System::Windows::Forms;
using namespace System::Data;
using namespace System::Drawing;

the main program

 private: System::Void button1_Click(System::Object^  sender, System::EventArgs^  e) {
capture = cvCaptureFromCAM(0);
timer1->Start();
}

private: System::Void timer1_Tick(System::Object^  sender, System::EventArgs^  e) {
frame = cvQueryFrame(capture);

pictureBox1->Image  = gcnew    //replacement of cvShowImage
System::Drawing::Bitmap(frame->width,frame->height,frame->widthStep,
System::Drawing::Imaging::PixelFormat::Format24bppRgb,(System::IntPtr) frame->imageData);
pictureBox1->Refresh();
}

Now you can capture camera in form application, so what do you think?

picture 2_the_result

Heeii !! I have a good news, I have got a new trick

How to convert 1-channel image to 3-channel image

picture 3_grayscale_convert

just add the source code with this "cvMerge".

the main program

private: System::Void Form1_Load(System::Object^  sender, System::EventArgs^  e) {
 capture = cvCaptureFromCAM(0);
 frame = cvQueryFrame(capture);
 img = cvCreateImage( cvGetSize(frame), 8,1 ); // Allocate a 1-channel byte image
 img2 = cvCreateImage( cvGetSize(frame), 8,3 ); // Allocate a 3-channel float image
}

private: System::Void button1_Click(System::Object^  sender, System::EventArgs^  e) {
 timer1->Start();
}

private: System::Void timer1_Tick(System::Object^  sender, System::EventArgs^  e) {
 frame = cvQueryFrame(capture);
 cvCvtColor(frame,img,CV_BGR2GRAY);
 cvMerge(img , img, img, NULL, img2);  //Composes a multi-channel array from several single-channel arrays or inserts a single channel into the array.

 pictureBox1->Image  = gcnew    //replacement of cvShowImage
 System::Drawing::Bitmap(img2->width,img2->height,img2->widthStep,
 System::Drawing::Imaging::PixelFormat::Format24bppRgb,(System::IntPtr) img2->imageData);
 pictureBox1->Refresh();
}

The Downloads

1. Form_application