c++ - OpenCV 断言在 r​​oi 内失败？

Question

#include <fstream>
#include <iostream>
#include <string>
#include <stdlib.h>
#include <stdio.h>
#include <iomanip>
#include <stdio.h>

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>

using namespace cv;
using namespace std;

int main(int argc, char** argv)
{
    ofstream fout("E:\\FYP\\image analysis\\ImageAnalysis\\ImageAnalysis\\Cropped_Image\\Details.txt");

    Mat image = imread("rsz_2rsz_2iron-man.png", -1);

    //Declare global parameters
    int     kernel = 3;                     //to be input
    int     levels = 16;                    //to be input
    int     gap = 5;                        //to be input in mm
    double  depth_gap = 0.2;                //to be input in mm
    int     feedrate = 300;                 //to be input
    int     background = 0;
    int     width = image.cols;
    int     height = image.rows;
    double  x_window = width / kernel;
    double  y_window = height / kernel;
    int     x_anchor = 0;
    int     y_anchor = 0;
    double  height_threshold = 0;
    double  width_threshold = 0;

    int   max_img_width = 570; //in mm
    int   max_img_height = 480; //in mm

    cout << width << "x " << height << endl;
    cout << "(Physical Dimension    : " << x_window * gap << " mm x " << y_window *gap << " mm)" << endl << endl;

    height_threshold = ceil((y_window *gap) / max_img_height);
    width_threshold = ceil((x_window * gap) / max_img_width);

    int   width_panel = (x_window * gap) / width_threshold;
    int   height_panel = (y_window *gap) / height_threshold;
    int   no_panels = height_threshold * width_threshold;

    cout << "No. of panels = " << height_threshold * width_threshold << endl;
    cout << width_threshold << " (x-axis) x " << height_threshold << " (y-axis)" <<  endl << endl;

    cout << "Size of each panels : " << (x_window * gap) / width_threshold << "mm (x-axis) by " << (y_window *gap) / height_threshold << "mm (y-axis)" << endl << endl;

    //imshow("Original Image", image);

    int image_width = width / width_threshold;
    int image_height = height / height_threshold;

    cout << image_height << " vs " << image_width << endl;

    vector<Mat> smallImages;

    for (int y = 0; y < height; y += image_height)
    {
        for (int x = 0; x < width; x += image_width)
        {
            Rect rect = Rect(x, y, image_width, image_height);
            smallImages.push_back(Mat(image, rect));
        }
    }


    //For displaying and saving cropped image
    for (int panel = 0; panel < no_panels; panel += 1)
    {
        string num_panel = to_string(panel);
        string filetype = ".png";
        string filename = "Image " + num_panel + filetype;
        //cout << num_panel << endl;
        //imshow(filename, smallImages[panel]);
        //waitKey(0);
        string location = "E:\\FYP\\image analysis\\ImageAnalysis\\ImageAnalysis\\Cropped_Image\\" + filename;
        imwrite(location, smallImages[panel]);
    }

    fout << "Kernel = " << kernel << endl;
    fout << "Levels = " << levels << endl;
    fout << "Gap = " << gap << endl;
    fout << "Max Height = " << max_img_width << endl;
    fout << "Max Width = " << max_img_height << endl;
    fout << "Number of Panels = " << height_threshold * width_threshold << endl;
    fout << "Size of each panels : " << (x_window * gap) / width_threshold << "mm (x-axis) by " << (y_window *gap) / height_threshold << "mm (y-axis)" << endl << endl;

    waitKey(0);
    system("PAUSE"); 
    //return 0;
}

这个程序是根据给定的最大宽度和高度以及其他一些属性将大图像分成多个图像。

当我用不同的内核大小运行程序时，有时它给出断言失败，有时则正常。

错误:

OpenCV Error: Assertion failed (0 <= roi.x && 0 <= roi.width && roi.x + roi.width <= m.cols && 0 <= roi.y && 0 <= roi.height && roi.y + roi.height <= m.rows) in cv::Mat::Mat, file C:\builds\master_PackSlave-win64-vc12-shared\opencv\modules\core\src\matrix.cpp, line 508
OpenCV Error: Assertion failed (0 <= roi.x && 0 <= roi.width && roi.x + roi.width <= m.cols && 0 <= roi.y && 0 <= roi.height && roi.y + roi.height <= m.rows) in cv::Mat::Mat, file C:\builds\master_PackSlave-win64-vc12-shared\opencv\modules\core\src\matrix.cpp, line 508
OpenCV Error: Assertion failed (0 <= roi.x && 0 <= roi.width && roi.x + roi.width <= m.cols && 0 <= roi.y && 0 <= roi.height && roi.y + roi.height <= m.rows) in cv::Mat::Mat, file C:\builds\master_PackSlave-win64-vc12-shared\opencv\modules\core\src\matrix.cpp, line 508
OpenCV Error: Assertion failed (0 <= roi.x && 0 <= roi.width && roi.x + roi.width <= m.cols && 0 <= roi.y && 0 <= roi.height && roi.y + roi.height <= m.rows) in cv::Mat::Mat, file C:\builds\master_PackSlave-win64-vc12-shared\opencv\modules\core\src\matrix.cpp, line 508
OpenCV Error: Assertion failed (0 <= roi.x && 0 <= roi.width && roi.x + roi.width <= m.cols && 0 <= roi.y && 0 <= roi.height && roi.y + roi.height <= m.rows) in cv::Mat::Mat, file C:\builds\master_PackSlave-win64-vc12-shared\opencv\modules\core\src\matrix.cpp, line 508

Answer 1

您得到的是图像之外的矩形。这是因为 for 循环中的错误条件。使用:

 for (int y = 0; y <= (height - image_height); y += image_height)
 {
     for (int x = 0; x <= (width - image_width); x += image_width)
     {
          Rect rect = Rect(x, y, image_width, image_height);
          smallImages.push_back(Mat(image, rect));
     }
 }

只有当 height 和 width 分别是 image_height 和 image_width 的倍数时，您的原始条件才是正确的。