2-1創建TrackBar可調值

2-1創建TrackBar可調值

程式說明:

運行結果:

    以下我們可以把一張圖的不同RGB channel的比例做調整，下圖把Green的Channel的比例往下調整，
   可以觀察到影像就會偏紫色。

範例程式:

#include <iostream>
#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>

/// Global Variables
const int r_slider_max = 100;
const int g_slider_max = 100;
const int b_slider_max = 100;
int r_slider=50;
int g_slider=50;
int b_slider=50;


cv::Mat img;
cv::Mat imgResize;
cv::Mat imgOut;


void on_trackbarR(int value, void*)
{
    imgOut = imgOut.clone();
   
    int tmpValue = 0;
   
    for (int i = 0; i < imgResize.rows; i++)
    {
      for (int j = 0; j < imgResize.cols; j++)
      {
         tmpValue = (int)imgResize.at(i, j)[2] * (value) / 100;
         imgOut.at(i, j)[2] = tmpValue;
      }
    }
   
    cv::imshow("ImageRGBChannel", imgOut);
}

void on_trackbarG(int value, void*)
{
    imgOut = imgOut.clone();
   
    int tmpValue = 0;
   
    for (int i = 0; i < imgResize.rows; i++)
    {
       for (int j = 0; j < imgResize.cols; j++)
       {
          tmpValue = (int)imgResize.at(i, j)[1] * (value) / 100;
          imgOut.at(i, j)[1] = tmpValue;
       }
    }
   
    cv::imshow("ImageRGBChannel", imgOut);
}

void on_trackbarB(int value, void*)
{
    imgOut = imgOut.clone();
    int tmpValue = 0;
   
    for (int i = 0; i < imgResize.rows; i++)
    {
       for (int j = 0; j < imgResize.cols; j++)
       {
          tmpValue = (int)imgResize.at(i, j)[0] * (value) / 100;
          imgOut.at(i, j)[0] = tmpValue;
       }
    }
   
    cv::imshow("ImageRGBChannel", imgOut);
}

int main(int argc, char** argv)
{
    /// Read image ( same size, same type )
    img = cv::imread("Image.jpg");
   
    if (!img.data) {
       std::cout << "無法讀到檔案" << std::endl;
       return -1;
    }
   
    //將影像縮小四倍
    int width = img.cols;
    int height = img.rows;

    cv::resize(img, imgResize, cv::Size(width / 4, height / 4));
   
    imgOut = imgResize.clone();
    /// Initialize values
    r_slider = 0;
    g_slider = 0;
    b_slider = 0;
   
    /// Create Windows
    cv::namedWindow("ImageRGBChannel", 1);
   
    /// Create Trackbars
    char* RTrackbarName = "RChannel";
    char* GTrackbarName = "GChannel";
    char* BTrackbarName = "BChannel";
   
    cv::createTrackbar(RTrackbarName, "ImageRGBChannel", &r_slider, r_slider_max, on_trackbarR);
    cv::createTrackbar(GTrackbarName, "ImageRGBChannel", &g_slider, g_slider_max, on_trackbarG);
    cv::createTrackbar(BTrackbarName, "ImageRGBChannel", &b_slider, b_slider_max, on_trackbarB);
   
    /// Show some stuff
    on_trackbarR(r_slider, 0);
    on_trackbarG(g_slider, 0);
    on_trackbarB(b_slider, 0);
   
    /// Wait until user press some key
    cv::waitKey(0);
    return 0;
}