Converting a std::vector<float> to mxArray using ocvMxArrayFromVector
5 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Hello,
I'm currently working with mex matlab and OpenCV libraries. I'm using the results of the computation of HOG features, which is of type std::vector<float>, and need it as an output of the mex function.
I'm therefore trying to use the ocvMxArrayFromVector function, which is supposed to conver a vector of a given type to the required mxArray data type output.
The part of code I'm using is:
vector<float> descriptorValues(outDim);
hog->compute(croppedImg, descriptorValues, Size(0,0), Size(0,0), locations);
plhs[0] = ocvMxArrayFromVector(descriptorValues);
But when compiling it returns the following error:
Error using mexOpenCV (line 122)
/tmp/mex_1394440023880_2588/HOGDescriptorOCV.o: In function `computeHOGFeatures(int, mxArray_tag**, mxArray_tag
const**)':
HOGDescriptorOCV.cpp:(.text+0xb24): undefined reference to `ocvMxArrayFromVector(std::vector<float,
std::allocator<float> > const&)'
collect2: error: ld returned 1 exit status
I'm compiling using g++ on an Ubuntu, matlab version R2016b.
I would be very thankful for your help.
David
0 Kommentare
Antworten (2)
James Tursa
am 28 Sep. 2016
I don't know about the ocvMxArrayFromVector routine, or how to advise you to link everything in properly, but here is a short example that takes a C++ vector of floats and copies it into an mxArray for output:
#include <vector>
using namespace std;
#include <string.h>
#include "mex.h"
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
int i, n=5;
vector<float> descriptorValues(n);
// Load up some sample data
for( i=0; i<n; i++ ) {
descriptorValues[i] = (float) (i + 1);
}
// Pretend we don't know the size and get it dynamically
n = descriptorValues.size();
// Create the output mxArray and copy the data
plhs[0] = mxCreateNumericMatrix( 1, n, mxSINGLE_CLASS, mxREAL );
memcpy( mxGetData(plhs[0]), &descriptorValues[0], n*sizeof(float) );
}
1 Kommentar
cui,xingxing
am 27 Mär. 2019
Bearbeitet: cui,xingxing
am 27 Mär. 2019
preference here, perhas helps
0 Kommentare
Siehe auch
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!