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I've been trying to integrate OpenCV into my iOS project, but have been having trouble with a null pointer exception. I installed version 3.4.2 using Cocoapods, and the following code snippet works fine:

#import <opencv2/opencv.hpp>
#import <opencv2/imgproc/imgproc.hpp>
#import <opencv2/imgcodecs/ios.h>

#import "OpenCVWrapper.h"

@implementation OpenCVWrapper

+ (UIImage *) process:(UIImage *) image {
    cv::Mat m;
    UIImageToMat(image, m);

    // this works fine

    return MatToUIImage(gray);
}

But when I try to do a simple color conversion (or any type of manipulation for that matter) I get an EXC_BAD_ACCESS and it crashes my app

#import <opencv2/opencv.hpp>
#import <opencv2/imgproc/imgproc.hpp>
#import <opencv2/imgcodecs/ios.h>

#import "OpenCVWrapper.h"

@implementation OpenCVWrapper

+ (UIImage *) process:(UIImage *) image {
    cv::Mat m;
    UIImageToMat(image, m);

    cv::Mat gray;
    cv::cvtColor(m, gray, cv::COLOR_BGR2GRAY); // crashes here

    return MatToUIImage(gray);
}

I tried version 2 of opencv and tried stepping through the assembly, but wasn't able to figure out what was causing the problem.

I've been trying to integrate OpenCV into my iOS project, but have been having trouble with a null pointer exception. I installed version 3.4.2 using Cocoapods, and the following code snippet works fine:

#import <opencv2/opencv.hpp>
#import <opencv2/imgproc/imgproc.hpp>
#import <opencv2/imgcodecs/ios.h>

#import "OpenCVWrapper.h"

@implementation OpenCVWrapper

+ (UIImage *) process:(UIImage *) image {
    cv::Mat m;
    UIImageToMat(image, m);

    // this works fine

    return MatToUIImage(gray);
MatToUIImage(m);
}

But when I try to do a simple color conversion (or any type of manipulation for that matter) I get an EXC_BAD_ACCESS and it crashes my app

#import <opencv2/opencv.hpp>
#import <opencv2/imgproc/imgproc.hpp>
#import <opencv2/imgcodecs/ios.h>

#import "OpenCVWrapper.h"

@implementation OpenCVWrapper

+ (UIImage *) process:(UIImage *) image {
    cv::Mat m;
    UIImageToMat(image, m);

    cv::Mat gray;
    cv::cvtColor(m, gray, cv::COLOR_BGR2GRAY); // crashes here

    return MatToUIImage(gray);
}

I tried version 2 of opencv and tried stepping through the assembly, but wasn't able to figure out what was causing the problem.