Create Mat from vector

Question

I am extremely new to computer vision and the opencv library. I've done some googling around to try to find how to make a new image from a vector of Point2fs and haven't found any examples that work. I've seen `vector` to `Mat` but when I use those examples I always get errors. I'm working from this example and any help would be appreciated. Code: I pass in occludedSquare. ``` resize(occludedSquare, occludedSquare, Size(0, 0), 0.5, 0.5); Mat occludedSquare8u; cvtColor(occludedSquare, occludedSquare8u, CV_BGR2GRAY); //convert to a binary image. pixel values greater than 200 turn to white. otherwize black Mat thresh; threshold(occludedSquare8u, thresh, 170.0, 255.0, THRESH_BINARY); GaussianBlur(thresh, thresh, Size(7, 7), 2.0, 2.0); //Do edge detection Mat edges; Canny(thresh, edges, 45.0, 160.0, 3); //Do straight line detection vector lines; HoughLines( edges, lines, 1.5, CV_PI/180, 50, 0, 0 ); //imshow("thresholded", edges); cout << "Detected " << lines.size() << " lines…

Accepted Answer

Should be as simple as

```
std::vector<cv::Point2f> points;
cv::Mat image(points);
//or
cv::Mat image = cv::Mat(points) 
```

The probably confusion is that a cv::Mat is an image `width*height*number` of channels but it also a mathematical matrix , `rows*columns*other dimension`.

If you make a Mat from a vector of 'n' 2D points it will create a 2 column by 'n' rows matrix. You are passing this to a function which expects an image.

If you just have a scattered set of 2D points and want to display them as an image you need to make an empty cv::Mat of large enough size (whatever your maximum x,y point is) and then draw the dots using the drawing functions http://docs.opencv.org/doc/tutorials/core/basic_geometric_drawing/basic_geometric_drawing.html

If you just want to set the pixel values at those point coordinates search SO for opencv setting pixel values, there are lots of answers

Create Mat from vector<point2f>

Solution

Problem

Related problems