OpenCV、EmguCV和OpenCvSharp访问图像耗时测评(附源码)-尧图网站建设

📅 发布时间：2026/6/19 23:51:38

OpenCV、EmguCV和OpenCvSharp访问图像耗时测评(附源码)

背景介绍

EmguCV和OpenCvSharp都是OpenCV在.Net下的封装，常常会听到有人说EmguCV或OpenCvSharp同样的函数比OpenCV函数运行速度慢，到底是不是真的？博主暂时也没有去一一验证，本文主要对比下三者用指针方法读取像素的速度、耗时情况。

对比实验说明

提供2张图片做测试，分辨率分别是3000 x 3835 和 600 x 676：

分别使用OpenCV、EmguCV和OpenCvSharp指针方法来读取修改像素值，并计算所用时间。

测试图与结果图：

【1】OpenCV测试

代码如下：

// Read_Modify_Piexl_Value.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//#include "pch.h"
#include <iostream>
#include <opencv2/opencv.hpp>using namespace std;
using namespace cv;Mat readPixelNormal(Mat img, Mat thres)
{for (int i = 0; i < thres.rows; i++){for (int j = 0; j < thres.cols; j++){if (thres.at<uchar>(i, j) == 255)img.at<Vec3b>(i, j) = Vec3b(197, 247, 254); //BGR彩色图像素值改变}}return img;
}Mat readPixelFast(Mat img, Mat thres)
{for (int i = 0; i < thres.rows; i++){uchar *ptr = thres.ptr<uchar>(i);uchar *ptrColor = img.ptr<uchar>(i);for (int j = 0; j < thres.cols; j++){if (ptr[j] == 255){ptrColor[j * 3] = 197;ptrColor[j * 3 + 1] = 247;ptrColor[j * 3 + 2] = 254;}}}return img;
}int main()
{Mat img = imread("S.png");Mat gray, thres;cvtColor(img, gray, COLOR_BGR2GRAY);threshold(gray, thres, 0, 255, THRESH_BINARY | THRESH_OTSU);double start = static_cast<double>(getTickCount());//Mat result = readPixelNormal(img, thres);Mat result = readPixelFast(img, thres);double end = static_cast<double>(getTickCount());double useTime = ((double)end - start) / getTickFrequency() * 1000;cout << "use-time = " << useTime << "ms" << endl;imwrite("res.png", result);return 0;
}

测试结果：

3000 x 3835 图像耗时 12ms左右

600 x 676 图像耗时 0.7ms左右

【2】EmguCV测试

代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;using Emgu.CV;
using Emgu.Util;
using Emgu.CV.Structure;
using Emgu.CV.CvEnum;namespace Read_Modify_Pixel
{class Program{static void Main(string[] args){Mat img = CvInvoke.Imread("S.png");Mat gray = new Mat();Mat thres = new Mat();CvInvoke.CvtColor(img, gray, ColorConversion.Bgr2Gray);CvInvoke.Threshold(gray, thres, 0, 255, ThresholdType.Binary | ThresholdType.Otsu);DateTime startTime = DateTime.Now;unsafe{for (int i = 0; i < img.Rows; i++){IntPtr ptr = thres.DataPointer;IntPtr ptrColor = img.DataPointer;byte* data = (byte*)ptr.ToPointer();byte* dataColor = (byte*)ptrColor.ToPointer();for (int j = 0; j < img.Cols; j++){if (data[i * img.Cols + j] == 255){int index = (img.Step * i) + (j * 3);dataColor[index] = 197;dataColor[index + 1] = 247;dataColor[index + 2] = 254;}}}}DateTime stopTime = DateTime.Now;TimeSpan useTime = stopTime - startTime;Console.WriteLine("useTime: {0}ms", useTime.TotalMilliseconds);CvInvoke.Imwrite("res.png", img);}}
}

测试结果：

3000 x 3835 图像耗时 950ms左右

600 x 676 图像耗时 44ms左右

【3】OpenCvSharp测试

代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;using OpenCvSharp;namespace Read_Pixel_Value
{class Program{//指针方法修改像素值static void Main(string[] args){Mat img = Cv2.ImRead("S.png");Mat gray = new Mat();Mat thres = new Mat();Cv2.CvtColor(img, gray, ColorConversionCodes.BGR2GRAY);Cv2.Threshold(gray, thres, 0, 255, ThresholdTypes.Binary | ThresholdTypes.Otsu);DateTime startTime = DateTime.Now;//指针方法修改像素值unsafe{for (int i = 0; i < thres.Rows; i++){IntPtr ptr = thres.Ptr(i);IntPtr ptrColor = img.Ptr(i);for (int j = 0; j < thres.Cols; j++){byte* data = (byte*)ptr.ToPointer();byte* dataColor = (byte*)ptrColor.ToPointer();if (data[j] == 255){dataColor[j * 3] = 197;dataColor[j * 3 + 1] = 247;dataColor[j * 3 + 2] = 254;}}}}DateTime stopTime = DateTime.Now;TimeSpan useTime = stopTime - startTime;Console.WriteLine("useTime: {0}ms", useTime.TotalMilliseconds);Cv2.ImWrite("res.png", img);Console.WriteLine("Done!");}}
}

测试结果：

3000 x 3835 图像耗时 340ms左右

600 x 676 图像耗时 18ms左右

测试结果

由上面测试结果汇总成下表，明显看出C++ OpenCV指针方法访问像素值最快，其次是OpenCvSharp，最慢的则是EmguCV，以上结果仅供参考。

—THE END—

出处：https://cloud.tencent.com/developer/article/2121762