LabVIEW not responding when I run this code. C++ code issue or LabVIEW issue?

For some background, I am compiling in Visual Studio 2019 and running the code inside LabVIEW 2017. The reason I am doing it in LabVIEW is for research to control a robotic gantry. This is the vision system and it is supposed to detect rectangles (wirebond pads for silicon detectors).

I need it to atleast show me a picture or something but when I run it in LabVIEW, it just says it is not responding and makes me hard close the program. So frustrating! If theres no huge errors in my C++ code then I know I have to dig deeper into my LabVIEW code.

The following code is my problem. I am fairly new to C++ and programming in general. I have done the step each line inside LabVIEW and when it stops responding is when it starts to grab the nominalHeight, xfov etc... or just when it goes into the WBPdetection function in general.

Any help is much appreciated. Or if someone could just point me in the right direction.

#include "stdafx.h"
#include "utils.h"
#include "WBPdetection.h"
#include "opencv2/opencv.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
#include <vector>

using namespace std;

void show3(cv::Mat img)
{
    cv::namedWindow("MyWindow", cv::WINDOW_AUTOSIZE);
    cv::imshow("MyWindow", img);
    cv::waitKey(0);
    cv::destroyWindow("MyWindow");
}

__declspec(dllexport) int __cdecl WBPdetection(
    char* imgPtr, 
    int imgLineWidth, 
    int imgWidth, 
    int imgHeight, 
    double percent_size, 
    double nominalWidth, 
    double nominalHeight,
    double tolerance,
    double xfov,
    double yfov)
{
    cv::Mat img(imgHeight, imgWidth, CV_8U, (void*)imgPtr, imgLineWidth);
    cv::resize(img, img, cv::Size(img.cols * percent_size, img.rows * percent_size), 0, 0);

    //PREPPING IMAGE FOR DETECTION ALGORITHIM
    cv::threshold(img, img, 125, 255, cv::THRESH_OTSU);
    cv::GaussianBlur(img, img, cv::Size(5, 5), 0);
    cv::erode(img, img, cv::Mat(), cv::Point(-1, -1), 2, 1, 1); 
    cv::dilate(img, img, cv::Mat(), cv::Point(-1, -1), 1, 1, 1);
    
    //USE FIND CONTOURS ALGORITHIM
    vector<vector<cv::Point>> contours;
    vector<cv::Vec4i> hierarchy; 
    cv::findContours(img, contours, hierarchy, cv::RETR_TREE, cv::CHAIN_APPROX_SIMPLE); 
    for( int i = 0; i < contours.size(); i++ ) 
    {   approxPolyDP( cv::Mat(contours[i]), contours_poly[i], 3, true ); 
        boundRect[i] = cv::boundingRect( cv::Mat(contours_poly[i]) ); 
     }

    vector<vector<double>> dimRects; //ex [ [w1,h1], [w2,h2], [w3,h3], ...]
    vector<cv::Point> centerRects; //ex [ [c1], [c2], [c3], ... ]

    //PUTTING DIMENSIONS OF ALL RECTANGLES IN VECTORS
    for (int i = 0; i < contours.size(); i++)
    {
        cv::Point center = ((boundRect[i].tl().x + boundRect[i].br().x) / 2, (boundRect[i].tl().y + boundRect[i].br().y) / 2); //what about even pixels
        double rectWidth = (boundRect[i].br().x - boundRect[i].tl().x) * (xfov / img.cols); //might not matter tbh
        double rectHeight = (boundRect[i].tl().y - boundRect[i].br().y) * (yfov / img.rows);
        dimRects[i].push_back(rectWidth);
        dimRects[i].push_back(rectHeight);
        centerRects.push_back(center);
    }

    //DEFINING minWidth, etc... FROM tolerance AND nominalWidth
    double minWidth = nominalWidth * (1 - tolerance);
    double maxWidth = nominalWidth * (1 + tolerance);
    double minHeight = nominalHeight * (1 - tolerance);
    double maxHeight = nominalHeight * (1 + tolerance);

  // DRAWING CONTOURS AND BOUNDING RECTANGLE + CENTER
    for( int i = 0; i< dimRects.size(); i++ )
     {
       cv::Scalar color = cv::Scalar(255,255,255); //creates color
       if ((dimRects[i][0] > minWidth && dimRects[i][0] < maxWidth) && (dimRects[i][1] > minHeight && dimRects[i][1] < maxHeight)) 
       {
           drawContours(img, contours_poly, i, color, 1, 8, vector<cv::Vec4i>(), 0, cv::Point()); 
           rectangle(img, boundRect[i].tl(), boundRect[i].br(), color, 2, 8, 0); 
           circle(img, centerRects[i], 1, cv::Scalar(0, 0, 255), 1, cv::LINE_8);
       }
    }

    show3(img);
    return 0;
}