实验4.2

#include <bits/stdc++.h>
#include "opencv2/core.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/video.hpp"
#include "opencv2/objdetect.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/ml.hpp"
#include <ctime>
#define inf 2333333333333333
#define N 100010
#define p(a) putchar(a)
#define For(i,a,b) for(int i=a;i<=b;++i)
typedef unsigned char uchar;
//by war
//2020.10.8
using namespace std;
using namespace cv;
int alpha_slider=1,m,cnt;
char TrackbarName[50];
Mat image,image0,image1,new_image,boxFilterDst;
double Sum[3][2010][2010];
double sigma,alpha,alpha_slider_max=100,eps=1e-7;

time_t t0, t1, t2;

void in(int &x){
    int y=1;char c=getchar();x=0;
    while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();}
    while(c<='9'&&c>='0'){ x=(x<<1)+(x<<3)+c-'0';c=getchar();}
    x*=y;
}
void o(int x){
    if(x<0){p('-');x=-x;}
    if(x>9)o(x/10);
    p(x%10+'0');
}

void on_trackbar(int, void*){
    alpha = (double) alpha_slider/(double) 10.0;
    if(1.0/6.0 - alpha>eps) alpha=1.0/6.0;
    sigma=alpha;
    m=6.0*sigma-1;
    m+=(m%2==0);
    t0 = clock();

    boxFilter(image, boxFilterDst, -1, cv::Size(m, m));

    t1 = clock();

    copyMakeBorder(image, image0, m/2, m/2, m/2, m/2, BORDER_REFLECT);
    For(i,0,image0.rows-1)//处理二维前缀和
        For(j,0,image0.cols-1)
            For(k,0,2){
                Sum[k][i][j]=(i>0?Sum[k][i-1][j]:0)+(j>0?Sum[k][i][j-1]:0)-((i>0 && j>0)?Sum[k][i-1][j-1]:0)+image0.at<Vec3b>(i,j)[k];
            }
    new_image = Mat::zeros(image.size(), image.type());
    For(i,0,image.rows-1)
        For(j,0,image.cols-1)
            For(k,0,2){
                auto temp = Sum[k][i+m-1][j+m-1]- (i>0?Sum[k][i-1][j+m-1]:0)- (j>0?Sum[k][i+m-1][j-1]:0) + ((i>0 && j>0)?Sum[k][i-1][j-1]:0);
                new_image.at<Vec3b>(i,j)[k]=temp/(m*m);
            }


    t2 = clock();

    cout<<"时间差为"<<(double)(t2-2.0*t1+t0)/CLOCKS_PER_SEC<<endl;
    imshow("Contrast", new_image);


}

signed main(){
    image = imread("/Users/war/Downloads/nk.jpg");
    namedWindow("Contrast", 1);
    sprintf(TrackbarName, "Contrast -> %lf", alpha_slider_max);
    createTrackbar(TrackbarName, "Contrast", &alpha_slider, alpha_slider_max, on_trackbar);
    on_trackbar( alpha_slider, 0 );
    waitKey(0);
    return 0;
}