兩張圖片做差提取白色區域，之前用matlab寫了一下感覺沒啥問題，效果也理想，最近開始學opencv，就像也實作一下matlab做過的這個功能，但是遇到了一些問題，還望大神解答！感覺是opencv圖片儲存方式不能直接做差嗎？
f1圖片
bg圖片
matlab處理結果
opencv處理結果
matlab代碼
bg=imread('bg.jpg');
f1=imread('f1.jpg');
bg=rgb2gray(bg);
f1=rgb2gray(f1);
distance=f1-bg;
imshow(distance);
opencv代碼
import cv2
import numpy as np
bg=cv2.imread("bg.JPG")
f1=cv2.imread("f1.JPG")
bg=cv2.cvtColor(bg,cv2.COLOR_BGR2GRAY)
f1=cv2.cvtColor(f1,cv2.COLOR_BGR2GRAY)
distance=bg-f1
cv2.namedWindow('test', cv2.WINDOW_NORMAL)
cv2.imshow("test",distance)
cv2.waitKey(0)
uj5u.com熱心網友回復：
matlab 給設定誤差了，opencv的應該是準確的uj5u.com熱心網友回復：
僅供參考：#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/imgproc/imgproc_c.h"
using namespace std;
using namespace cv;
Mat img,smallImg,gray,bw;
vector<Vec4i> hierarchy;
vector<vector<Point> > contours;
int threshval=128;
Rect r;
Rect maxrect,brect;
int idx,n;
const static Scalar colors[15]={
CV_RGB( 0, 0,128),
CV_RGB( 0,128, 0),
CV_RGB( 0,128,128),
CV_RGB(128, 0, 0),
CV_RGB(128, 0,128),
CV_RGB(128,128, 0),
CV_RGB(128,128,128),
CV_RGB(160,160,160),
CV_RGB( 0, 0,255),
CV_RGB( 0,255, 0),
CV_RGB( 0,255,255),
CV_RGB(255, 0, 0),
CV_RGB(255, 0,255),
CV_RGB(255,255, 0),
CV_RGB(255,255,255),
};
Scalar color;
void gamma_correct(Mat& img, Mat& dst, double gamma) {
Mat temp;
CvMat tmp;
img.convertTo(temp, CV_32FC1, 1.0/255.0, 0.0);
tmp=temp;
cvPow(&tmp, &tmp, gamma);
temp.convertTo(dst , CV_8UC1 , 255.0 , 0.0);
}
int main() {
cvNamedWindow("display",1);
img=imread("image.jpg",1);
r.x=img.cols/10;
r.y=img.rows/3;
r.width=img.cols*8/10;
r.height=img.rows*2/3;
smallImg=img(r);
cvtColor(smallImg,gray,CV_BGR2GRAY);
// medianBlur(gray,gray,5);
equalizeHist(gray,gray);
gamma_correct(gray,gray,4.0);
imshow("display",gray);
waitKey(0);
bw=(gray>threshval);
imshow("display",bw);
waitKey(0);
Mat Structure0=getStructuringElement(MORPH_RECT,Size(3,3));
erode(bw,bw,Structure0,Point(-1,-1));
Mat Structure1=getStructuringElement(MORPH_RECT,Size(6,6));
dilate(bw,bw,Structure1, Point(-1,-1));
imshow("display",bw);
waitKey(0);
findContours(bw,contours,hierarchy,RETR_EXTERNAL,CHAIN_APPROX_SIMPLE);
if (!contours.empty()&&!hierarchy.empty()) {
idx=0;
n=0;
vector<Point> approx;
for (;idx>=0;idx=hierarchy[idx][0]) {
color=colors[idx%15];
// drawContours(smallImg,contours,idx,color,1,8,hierarchy);
approxPolyDP(Mat(contours[idx]), approx, arcLength(Mat(contours[idx]), true)*0.005, true);//0.005為將毛邊拉直的系數
const Point* p = &approx[0];
int m=(int)approx.size();
polylines(smallImg, &p, &m, 1, true, color);
circle(smallImg,Point(p[0].x,p[0].y),3,color);
circle(smallImg,Point(p[1].x,p[1].y),2,color);
for (int i=2;i<m;i++) circle(smallImg,Point(p[i].x,p[i].y),1,color);
n++;
if (1==n) {
maxrect=boundingRect(Mat(contours[idx]));
} else {
brect=boundingRect(Mat(contours[idx]));
CvRect mr(maxrect),br(brect);
maxrect=cvMaxRect(&mr,&br);
}
}
circle(smallImg,Point(maxrect.x+maxrect.width/2,maxrect.y+maxrect.height/2),2,CV_RGB(255,0,0));
}
imshow("display",smallImg);
waitKey(0);
cvDestroyWindow("display");
return 0;
}
uj5u.com熱心網友回復：
opencv的Mat好像沒有多載operator - （）函式，應該不是opencv的問題吧，你用純opencv看看uj5u.com熱心網友回復：
出現這種問題我覺得應該是轉灰度影像時兩張圖的相同部分像素點灰度值不一樣造成的，你可以對做過差的影像再來一次二值化。轉載請註明出處，本文鏈接：https://www.uj5u.com/gongcheng/78361.html
標籤：圖形處理/算法