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  • opencv-识别手写数字

    首先拆分图片得到数据

    #include "stdafx.h"
    #include <iostream>
    #include "opencv2/opencv.hpp"
    
    using namespace std;
    using namespace cv;
    
    int mainss(int argc, const char** argv)
    {
    	char ad[128] = { 0 };
    	int  filename = 0, filenum = 0;
    	Mat img = imread("digits.png");
    	Mat gray;
    	cvtColor(img, gray, CV_BGR2GRAY);
    	int b = 20;
    	int m = gray.rows / b;   //原图为1000*2000
    	int n = gray.cols / b;   //裁剪为5000个20*20的小图块
    
    	for (int i = 0; i < m; i++)
    	{
    		int offsetRow = i*b;  //行上的偏移量
    		if (i % 5 == 0 && i != 0)
    		{
    			filename++;
    			filenum = 0;
    		}
    		for (int j = 0; j < n; j++)
    		{
    			int offsetCol = j*b; //列上的偏移量
    			sprintf_s(ad, "C:\Users\dongufang\Documents\Visual Studio 2015\Projects\opencvtest\opencvtest\data\%d\%d.jpg", filename, filenum++);
    			//截取20*20的小块
    			Mat tmp;
    			gray(Range(offsetRow, offsetRow + b), Range(offsetCol, offsetCol + b)).copyTo(tmp);
    			imwrite(ad, tmp);
    		}
    	}
    	return 0;
    }

    然后knn

    #include "stdafx.h"
    #include <iostream>
    #include <opencv2/opencv.hpp>
    #include <opencv2/ml/ml.hpp>  
    using namespace std;
    using namespace cv;
    using namespace ml;
    
    char ad[128] = { 0 };
    
    int main()
    {
    	Mat traindata, trainlabel;
    	int k = 5, testnum = 0, truenum = 0;
    	//读取训练数据 4000张
    	for (int i = 0; i < 10; i++)
    	{
    		for (int j = 0; j<400; j++)
    		{
    			sprintf_s(ad, "C:\Users\dongufang\Documents\Visual Studio 2015\Projects\opencvtest\opencvtest\data\%d\%d.jpg", i, j);
    			Mat srcimage = imread(ad);
    			srcimage = srcimage.reshape(1, 1);
    			traindata.push_back(srcimage);
    			trainlabel.push_back(i);
    		}
    	}
    	traindata.convertTo(traindata, CV_32F);
    	Ptr<KNearest> knn = KNearest::create();
    	knn->setDefaultK(k);
    	knn->setIsClassifier(true);
    
    	Ptr<TrainData> tdata = TrainData::create(traindata,ROW_SAMPLE, trainlabel);
    	knn->train(tdata);
    
    	cv::Mat nearests(1, k, CV_32F);
    	//读取测试数据  1000张
    	for (int i = 0; i < 10; i++)
    	{
    		for (int j = 400; j<500; j++)
    		{
    			testnum++;
    			sprintf_s(ad, "C:\Users\dongufang\Documents\Visual Studio 2015\Projects\opencvtest\opencvtest\data\%d\%d.jpg", i, j);
    			Mat testdata = imread(ad);
    			testdata = testdata.reshape(1, 1);
    			testdata.convertTo(testdata, CV_32F);
    			Mat result;
    			int  response = knn->predict(testdata, result);
    			if (response == i)
    			{
    				truenum++;
    			}
    			cout << "result:" << response << endl;
    		}
    	}
    	cout << "测试总数" << testnum << endl;
    	cout << "正确分类数" << truenum << endl;
    	cout << "准确率:" << (float)truenum / testnum * 100 << "%" << endl;
    	return 0;
    }

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  • 原文地址:https://www.cnblogs.com/mrcharles/p/11879789.html
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