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2018-09-09 15:59:44 -0500 asked a question double free or corruption mistake

double free or corruption mistake I have a function called coefficients2(), where I decompose image in low and high fre

2018-09-06 15:40:22 -0500 received badge  Editor (source)
2018-09-06 15:40:22 -0500 edited question cv::mean() and cv::calcCovarMatrix() returns different mean

cv::mean() and cv::calcCovarMatrix() returns different mean I have two pictures in grayscale of the same size MxN, img1

2018-09-06 15:17:35 -0500 commented question function works on video frames and images differently

I changed a way to copy data, instead I used the way you proposed earlier. And the problem described in this post is gon

2018-09-06 15:12:50 -0500 marked best answer get float value from Mat

I have a matrix of size [2 x 2], of type 64FC1, named eigenvectors.

[0.707152069011339, 0.7070614904610364;
 -0.7070614904610364, 0.707152069011339]

If I write cout<<(float)eigenvectors.at<float>(0,0); or cout<<eigenvectors.at<float>(0,0); I get number 5.25957e+19 instead of 0.707152069011339. How can I get exactly number 0.707152069011339 or any of numbers of this matrix?

2018-09-06 15:12:50 -0500 received badge  Scholar (source)
2018-09-04 14:47:35 -0500 asked a question function works on video frames and images differently

function works on video frames and images differently I want to fuse two videos and record fused video. Two videos have

2018-09-03 07:19:15 -0500 marked best answer strange result of transformation of frame of VideoCapture

I have a code

VideoCapture cap("test.mp4"); 
 if(!cap.isOpened()){
    cout << "Error opening video stream or file" << endl;
    return -1;
  }
while(1){

        Mat frame; 

    // Capture frame-by-frame 
    cap >> frame;

    // If the frame is empty, break immediately
    if (frame.empty())
      break;   
    // Display the resulting frame    
    imshow( "Fr", test(frame ));

    // Press  ESC on keyboard to  exit
    char c = (char)waitKey(1);
    if( c == 27 ) 
      break;
  }
  cap.release();

and function test()

Mat test(Mat frame){
for(int i = 0; i < frame.rows; i++){
for(int j = 0; j < frame.cols; j++){
frame.at<uchar>(i,j) = 250;
}
}
return frame;
}

I expected that this function will return a transformed frame, totally white. But instead, it returns me a frame where 1/3 of columns white: image description

if I transform code above

for(int j = 0; j < 2*frame.cols; j++){

instead of

for(int j = 0; j < frame.cols; j++){

I got this:

image description

and if I change code like this:

for(int j = 0; j < 3*frame.cols; j++){

I eventually got that I expected, white frame. image description

Why it works so weird? I have a loop on all rows and columns and yet I don't get totally white picture. If I use this function test() on usual picture, it returns white Mat. But with frame of VideoCapture result is different. Why?

2018-09-02 15:25:51 -0500 asked a question strange result of transformation of frame of VideoCapture

strange result of transformation of frame of VideoCapture I have a code VideoCapture cap("test.mp4"); if(!cap.isOpene

2018-08-28 13:25:09 -0500 asked a question cv::mean() and cv::calcCovarMatrix() returns different mean

cv::mean() and cv::calcCovarMatrix() returns different mean I have two pictures in grayscale of the same size MxN, img1

2018-08-21 14:58:43 -0500 asked a question get float value from Mat

get float value from Mat I have a matrix of size [2 x 2], of type 64FC1, named eigenvectors. [0.707152069011339, 0.70

2018-08-16 01:48:29 -0500 received badge  Student (source)
2018-08-16 01:32:19 -0500 asked a question cv::multiply doesn't work

cv::multiply doesn't work I tried to multiply matrix, created from a picture, to transposed of this matrix. Transposed m