画出C ++ / OpenCV的频率直方图 [英] Draw a frequency histogram in C++/OpenCV
本文介绍了画出C ++ / OpenCV的频率直方图的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
频率的数组创建。
int arr[10];
arr[0] = 24;
arr[1] = 28;
arr[2] = 23;
arr[3] = 29;
//and so on
如何绘制下使用OpenCV的++的阵列上的直方图?
How do i draw a histogram using OpenCV in C++ based on the array?
推荐答案
OpenCV的是不是真的适合绘图。然而,对于简单的直方图,可以画出一个矩形为每列(最终以交替的颜色)
OpenCV is not really suited for plotting. However, for simple histograms, you can draw a rectangle for each column (eventually with alternating colors)
这是code:
#include <opencv2\opencv.hpp>
#include <algorithm>
using namespace std;
using namespace cv;
void drawHist(const vector<int>& data, Mat3b& dst, int binSize = 3, int height = 0)
{
int max_value = *max_element(data.begin(), data.end());
int rows = 0;
int cols = 0;
if (height == 0) {
rows = max_value + 10;
} else {
rows = max(max_value + 10, height);
}
cols = data.size() * binSize;
dst = Mat3b(rows, cols, Vec3b(0,0,0));
for (int i = 0; i < data.size(); ++i)
{
int h = rows - data[i];
rectangle(dst, Point(i*binSize, h), Point((i + 1)*binSize-1, rows), (i%2) ? Scalar(0, 100, 255) : Scalar(0, 0, 255), CV_FILLED);
}
}
int main()
{
vector<int> hist = { 10, 20, 12, 23, 25, 45, 6 };
Mat3b image;
drawHist(hist, image);
imshow("Histogram", image);
waitKey();
return 0;
}
由此产生的直方图是这样的:
The resulting histogram would be like:
如果您需要从静态数组转换为矢量
:
If you need to convert from static array to vector
:
#define N 3
int arr[N] = {4, 3, 9};
vector<int> hist(arr, arr + N);
更新
有关此绘图功能的更新版本,看看我的其他帖子
For an updated version of this drawing function, have a look at my other post
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