OpenCV result changes between Debug / Release and on other machine - c++

Question

I have a program that tries to detect rectangular objects on an image (i.e. solar modules). For that I use c++ with opencv 3 and Visual Studio 2015 Update 1.
In general my program uses GaussianBlur -> morphologyEx -> Canny -> HoughLines -> findContours-> approxPolyDP. Since, I have problems to find optimal parameters I tried to run many parameter combinations in order to get an optimal parameter setting.
The problem I have is that I get different results between "Debug in Visual Studio", "Debug by using the generated .exe", "Release in Visual Studio", "Release by using the generated .exe". Additionally running the .exe files on other machines once again changes the result.
Running the program on the same machine with the same settings does not change the result (i.e. it seems to be deterministic). There is also no concurrency in the program (except there is some in opencv I am not aware of).
Any idea why there is such a huge mismatch between the different settings ( parameter combinations that detect a solar module with 99% accuracy in one setting do not detect the module at all in the other)?.
EDIT:
I tried to create a minimum working example (see below) where I included the code until I get the first mismatch (perhaps there are more mismatches later on). I tried to initialize every variable I found.
The identifier paramterset is an instance of an object that contains all parameters I modify to find the optimum. I checked that those parameters were all initialized and are identical in Debug and Relase.
With this code, the first 3 images created by writeIntermediateResultImage (which basically just uses the opencv method imwrite and only specifies the path the image is stored to) are identical but the morphology image differs (by 13.43% according to some online image comparer I found). One difference is that the left and upper edge of the morphology image in Release mode is black for some pixels but there are additional differences within the image, too.
Edit: It seems that when running the code with the generated .exe file in Release mode, the morphology algorithm isn't applied at all but the image is just shifted left and down leaving a black edge at the top and bottom.
Edit: This shift seems to dependent on the machine it is running on. On my notebook I have the shift without the applying of morphology and on my desktop morphology is applied without a shift and black edges.
void findSquares(const Mat& image, vector<vector<Point> >& squares, string srcName)
{
// 1) Get HSV channels
Mat firstStepResult(image.size(), CV_8U);
Mat hsvImage(image.size(), CV_8UC3);
// Convert to HSV space
cvtColor(image, hsvImage, CV_BGR2HSV);
writeIntermediateResultImage("HSV.jpg", hsvImage, srcName);
// Transform Value channel of HSV image to greyscale
Mat channel0Mat(image.size(), CV_8U);
Mat channel1Mat(image.size(), CV_8U);
Mat channel2Mat(image.size(), CV_8U);
Mat hsv_channels[3]{ channel0Mat, channel1Mat, channel2Mat };
split(hsvImage, hsv_channels);
firstStepResult = hsv_channels[parameterset.hsvChannel];
writeIntermediateResultImage("HSVChannelImage.jpg", firstStepResult, srcName);
// 2) Gaussian Denoising
Mat gaussImage = firstStepResult;
GaussianBlur(gaussImage, gaussImage, Size(parameterset.gaussKernelSize, parameterset.gaussKernelSize), 0, 0);
writeIntermediateResultImage("GaussianBlur.jpg", gaussImage, srcName);
// 3) Morphology
Mat morphologyImage = gaussImage;
morphologyEx(morphologyImage, morphologyImage, parameterset.morphologyOperator, Mat(parameterset.dilateKernelSize, parameterset.dilateKernelSize, 0), cv::Point(-1, -1), parameterset.numMorpholgies);
writeIntermediateResultImage("Morphology.jpg", morphologyImage, srcName);
}
I also checked the library paths and the right libraries are used in the right compile mode (Debug with 'd', Release without).

Answer 1

I found the error in my code and I now get the same result in each configuration. The problem was the line that used the morphology operator.
morphologyEx(morphologyImage, morphologyImage, parameterset.morphologyOperator, Mat(parameterset.dilateKernelSize, parameterset.dilateKernelSize, 0), cv::Point(-1, -1), parameterset.numMorpholgies);
Even though the created Mat object (Mat(parameterset.dilateKernelSize, parameterset.dilateKernelSize, 0)) worked as a structuring element in Debug, it kind of messed up everything in Release.
Using
getStructuringElement(MORPH_RECT, Size(parameterset.dilateKernelSize, parameterset.dilateKernelSize))
as the structuring element did the trick.