错误消息：与调用"(cv：：Rect) (cv：：Mat&， cv：:P oint_， cv：<int>:P oint， cv：：Scalar， int)"的调用不匹配

我到处找了不少，找不到我问题的答案。我试图从这个线程复制一个文本检测软件(提取文本OpenCV)但是在代码的最后，有一个消息错误说没有匹配的矩形，即使我在上面画了一个，我们进入循环。我已经测试了所有我能想到的值，一切似乎都是正确的。

这里是完整的代码;

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
#include <opencv2/imgproc/imgproc.hpp>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

using namespace cv;
using namespace std;


int main( int argc, char** argv )
{
namedWindow("source_window2",WINDOW_AUTOSIZE);
namedWindow("source_window3",WINDOW_AUTOSIZE);
Mat input = imread(argv[1], CV_LOAD_IMAGE_COLOR);
Mat in_gray = imread(argv[1],CV_LOAD_IMAGE_GRAYSCALE);
Mat gradient;
Mat Kernelellipse = getStructuringElement(MORPH_ELLIPSE, Size(3,3));
morphologyEx(in_gray, gradient, MORPH_GRADIENT, Kernelellipse);
Mat thresh;
//on convertit en binaire
threshold(gradient, thresh, 0.0, 255.0, THRESH_BINARY | THRESH_OTSU);
rectangle(input,Point(0,0),Point(50,50),Scalar(255,255,255),2);
Mat Kernelrectangle = getStructuringElement(MORPH_RECT, Size(9,1));
Mat fermee;
morphologyEx(thresh, fermee, MORPH_CLOSE, Kernelrectangle);
imshow("source_window3", fermee);
Mat noire = Mat::zeros(thresh.size(), CV_8UC1);
//on cheche les contours
vector<vector<Point> > contours;
vector<Vec4i> hierarchy;
findContours(fermee, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE, Point(0, 0));
for (int i = 0; i < contours.size(); ++i)
{
    Rect rectangle = boundingRect(contours[i]);
    Mat noirerectangle(noire, rectangle);
    noirerectangle = Scalar(0, 0, 0);
    //on les dessine
    drawContours(noire, contours, i, Scalar(255, 255, 255), CV_FILLED);
    double proportion_de_blanc = (double)countNonZero(noirerectangle)/(rectangle.width*rectangle.height);
    if (proportion_de_blanc > 0.45 && (rectangle.height > 8 && rectangle.width > 8))
    {
        rectangle(input,rectangle.tl(),rectangle.br(),Scalar(0,255,0),2);
    }

}
imshow("source_window2",input);


waitKey(0);
return(0);

}

我的问题是在最后一个循环:

    if (proportion_de_blanc > 0.45 && (rectangle.height > 8 && rectangle.width > 8))
    {
        rectangle(input,rectangle.tl(),rectangle.br(),Scalar(0,255,0),2);
    }