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A simple assignment does not work. I am simply trying to assign a value to a matrix. Whats wrong here !? OpenCV complain

great solution ! thank you for the link.

Remove holes in an image without affecting the borders Following is an example image and I would like to remove all the

I have two images of unequal size -

and

Is there any way that I can get the intersection of the two images such that the final image is

The size of the final image is the same as the size of the ellipse..Maybe pictorally the size doesnt look the same here. The center of the images coincide.

thanks for your answer. Would be great if you could notify the developers, since I am new to opencv.

I was expecting a black image from the following code, but instead get a mix of black and white. Can someone explain what is hapenning?

int main(int argc, char *argv[]) {
    cv::Size image_size(1200,200);

    cv::Mat rectangle(image_size, CV_8UC3);

    cv::randu(rectangle, 0, 0);
    cv::imshow("rectangle", rectangle);
    cv::waitKey(0);
}

How does cv::randu works on images I was expecting a black image from the following code, but instead get a mix of black

this line is not clear - You must copy mask is an image with a size equal to original image example :

Intersection of two images I have two images of unequal size - and Is there any way that I can get the intersect

Intersection of two images I have two images of equal size - and Is there any way that I can get the intersectio

I have this image and would like to find the intersection points of the two objects ( blue vector and red vector ). Unfortunately, the find_intersection method between the vectors from the c++ standard library returns a size 0 because ofcourse there in no overlap of the edges where the two objects meet.

So, is there an elegant way to find the intersecting part of the blue and the red part using OpenCV? Maybe using findContours or CannyEdge or any convolving filter? I am not sure, how I should proceed.

Finding overlap of two objects in an image using OpenCV I have this image and would like to find the intersection points

Finding overlap of two objects in an image using OpenCV I have this image and would like to find the intersection points

initialise a 4 channel matrix opencv I am trying to initialise a 4 channel matrix with row = 1 and columns = 5, but I am

storing float in yaml file using FileStorage stores in exponential format I am storing simple numbers such as 0.1 in the

storing float in yaml file using FileStorage stores in exponential format I am storing simple numbers such as 0.1 in the

storing float in yaml file using FileStorage stores in exponential format I am storing simple numbers such as 0.9 in the

The way you access thelements. cv::Vec3f is a vector of 3 float elements and hence belongs to the class Vector. You acce

Is it possible to calculate the optical flow magnitude for rigid motion? For objects in 2D plane, it is pretty simple to

What is the difference between Optical Flow and CalcMotionHistory() ? Somehow both the algorithms ( optical flow using L

the question is when i want to display red, then the matrix values in 8UC3 are cv::Scalar (0,0,255). What is the corres

Decoding color from a 48 bit BGR matrix I have a matrix where the value is stored as 33088, 33000 and 1. I am aware of 8

it seems, that the round off is not required as it is done automatically by the function.

I am trying to understand the prev_pts and next_pts in the LK algorithm. How can I visualise these list of points intuitively? My expectation was that they are integer values basically pixel locations on the image, a location where a prospective goodFeaturesToTrack was found. Also, this question is related directly to the goodFeaturesToTrack function, where the function returns a feature array in float. How can I actually visualise this intuitively?

ah, i got it regarding the subpixel. Did not know that you can dig further into the resolution. can you please give an e

yes, the points are stored as floats and prev_pts and next_pts return float points. what is meant by subpixel accuracy a

Difference between a list of points and list of pixels. I am trying to understand the prev_pts and next_pts in the LK al

Difference between a list of points and list of pixels. I am trying to understand the prev_pts and next_pts in the LK al

Difference between a list of points and list of pixels. I am trying to understand the LK algorithm and it returns me a l

Difference between a list of points and list of pixels. I am trying to understand the LK algorithm and it returns me a l

so, if WITH_JPEG is OFF, then no jpeg files can be read, although a libjpeg package is installed in the system through a

jpeg library OpenCV not built My purpose is to build OpenCV with 3rd party jpeg support. By passing -D BUILD_JPEG=ON to

thnaks for the hint regarding the index. I have put my own answer for further clarification.

cv::Mat mat34(3,4, CV_32FC(3),cv::Scalar(20,30,40));

mat34.at<float>(3,3) = 1000;

std::cout << mat34.at<float>(3,3) << " and " << mat34.at<cv::Vec<float,3> >(3,3)[0] << std::endl;
std::cout << mat34 << std::endl;

Output

1000 and 0
[20, 30, 40, 20, 30, 40, 20, 30, 40, 20, 30, 40;
 20, 30, 40, 20, 30, 40, 20, 30, 40, 20, 30, 40;
 20, 30, 40, 20, 30, 40, 20, 30, 40, 20, 30, 40]

I dont understand the 3,3 part. Is the element 3,3 not direclty in the matrix? Was expecting to see 1000 somewhere in the entire matrix. Also, how can I access channels using cv::Vec? Since, I am learning I am not looking for alternative solutions, but just understanding how this works.