dinhtuyen's profile - activity

In matlab we have many function to perform an procedure for per element of matrix, example round, sin, cos, sqrt, atan2, mod, floor ......... here is an example:

A = [1.23 2.34 3; 5 6.78 7.89; 4.111 34.56 56.78]

A =

1.2300    2.3400    3.0000
5.0000    6.7800    7.8900
4.1110   34.5600   56.7800

B = round(A)

B =

 1     2     3
 5     7     8
 4    35    57

can you please give me some recommend to perform those function above.

example: cv::OutputArray round(cv::InputArray _src) { }

thank alot!

Thank you for your help! I have written a function to "extract a mat which have address in a mat from another mat":

cv::Mat extract(cv::Mat SRC, cv::Mat IDX)
{
    cv::Mat src = SRC.clone();
    cv::Mat idx = IDX.clone();
    cv::Mat dst = cv::Mat(idx.size(), src.type());
    src = src.t();
    idx.convertTo(idx, 4);
    for (int i = 0; i < idx.total(); i++)
    {
    //  dst.at<>(i) = src.at<>(idx.at<int>(i));
        switch (src.type())
            {
            case 0:
                dst.at<uchar>(i) = src.at<uchar>(idx.at<int>(i));
                break;
            case 1:
                dst.at<char>(i) = src.at<char>(idx.at<int>(i));
                break;
            case 2:
                dst.at<ushort>(i) = src.at<ushort>(idx.at<int>(i));
                break;
            case 3:
                dst.at<short>(i) = src.at<short>(idx.at<int>(i));
                break;
            case 4:
                dst.at<int>(i) = src.at<int>(idx.at<int>(i));
                break;
            case 5:
                dst.at<float>(i) = src.at<float>(idx.at<int>(i));
                break;
            default:
                dst.at<double>(i) = src.at<double>(idx.at<int>(i));
                break;
            }
    }
    return dst;
}

and call it in main function:

cv::Mat src = (cv::Mat_<double>(3, 3) << 4, 9, 8, 10, 3, 7, 5, 8, 4);
cv::Mat idx = (cv::Mat_<int>(2, 2) << 1, 2, 3, 4);

cv::Mat dst = extract(src, idx);
cout << "src = " << endl << " " << src << endl;
cout << "idx = " << endl << " " << idx << endl;
cout << "dst = " << endl << " " << dst << endl;

and result is similar to your program but i don't know my function had Optimized??? Can you please improve my function? Thank a lot !!!!

I have writen a function in matlab to write a matrix to a file .yml. after in opencv i read this file!!! Matlab function:

function TH0001_Matlab2OpenCV( variable, fileName, flag)

[rows cols] = size(variable);

% Beware of Matlab's linear indexing
variable = variable';

% Write mode as default
if ( ~exist('flag','var') )
    flag = 'w'; 
end

if ( ~exist(fileName,'file') || flag == 'w' )
    % New file or write mode specified 
    file = fopen( fileName, 'w');
    fprintf( file, '%%YAML:1.0\n');
else
    % Append mode
    file = fopen( fileName, 'a');
end

% Write variable header
fprintf( file, '    %s: !!opencv-matrix\n', inputname(1));
fprintf( file, '        rows: %d\n', rows);
fprintf( file, '        cols: %d\n', cols);
fprintf( file, '        dt: f\n');
fprintf( file, '        data: [ ');

% Write variable data
for i=1:rows*cols
    fprintf( file, '%.6f', variable(i));
    if (i == rows*cols), break, end
    fprintf( file, ', ');
    if mod(i+1,4) == 0
        fprintf( file, '\n            ');
    end
end

fprintf( file, ']\n');
fclose(file);

%==============================================================

% call this function in matlab

TH0001_Matlab2OpenCV( img11, 'img01.yml', 'img01');

//======================================================= //Function read file .yml in opencv

cv::Mat LoadDatafromymlfile(char* ymlfilename, char* varriablestring)
{
    cv::Mat temp;
    cv::FileStorage fs(ymlfilename, cv::FileStorage::READ);
    fs[varriablestring] >> temp;
    fs.release();
    return temp;
}

// Call this function

char *filenameyml = "D://img01.yml"; //location of file .yml
cv::Mat img11 = LoadDatafromymlfile(filenameyml, "img11");

Example in matlab:

A =

     4     9     8
    10     3     7
     5     8     4

>> b = [2 3; 4 5]

b =

     2     3
     4     5

>> A(b)

ans =

    10     5
     9     3

how to find A(b) in OpenCV???? Thank!!!!