opencv c++ equivalent for arraylist in java

Vahid Dnt
11 ●1 ●2

Whats the equivalent of the following lines in open cv c++? The first lines have written with java language.

ArrayList<integer> x = new ArrayList<integer>(); is this its correct equivalent? std::vector< int > x = std::vector<int>();
x.add(i); is this its correct equivalent? x.push_back(i);
Mat[] m = new Mat[mCount]; is this its correct equivalent? std::vector<cv::mat> m = std::vector<cv::mat> (mCount);
float[] fl = new float[flLength]; is this its correct equivalent? std::vector< float > fl = std::vector< float >(flLength);
A.get(0, 0, ALists); is this its correct equivalent? ALists.push_back((float)A.at< float >(0,0));
cv::Mat cropped = rotated.submat(offset, offset + cropSize, offset, offset + cropSize); is this its correct equivalent?
cv::Mat tmpMat0 = rotated.rowRange(offset,offset + cropSize).colRange(offset,offset + cropSize); cv::Mat cropped; tmpMat0.copyTo(cropped);

Thanks for your help

berak
32993 ●7 ●81 ●312

then we have:

yes, but you'd rather just skip the assignment, std::vector< int > x; is all you need.
yes ;)
similar to 1., just use: std::vector<cv::Mat> m(mCount);
see 3.
now here it gets difficult. if you need a single pixel: float v = A.at< float >(row,col); note that is this is only valid IF the type of the Mat is float, usually, for a bgr image it would look like: Vec3b pixel = A.at<Vec3b>(r,c); you have to carefully adjust the type in the brackets (and the return value) to that. all in all, code that uses this for the whole image should be avoided !
well that's plain wrong. luckily, cv::Mat has an overloaded () operator, that can be used quite similar to your java code: cv::Mat cropped = rotated(yoffset, yoffset + cropSize, xoffset, xoffset + cropSize);

Comments

@berak how convert arraylist<integer> to Mat ??

rainY ( 2018-08-27 21:58:08 -0600 )edit