OpenCV創建從二進制浮點數墊

Question

我有一個256字節的二進制Mat（1x256）（CV_8UC1）。我需要創建另一個具有1x64尺寸浮標的Mat（CV_32F）。這意味着每個4個字節在結果矩陣中構造一個浮點值。

有沒有辦法在OpenCV中做到這一點？或者任何其他的C++方式？

Answer 1

#include "opencv2/opencv.hpp" 
using namespace cv; 
#include <assert.h> 

int main() 
{ 
    Mat floatOrig = Mat::zeros(1,64,CV_32FC1); 
    Mat ucharConverted = Mat::zeros(1,256,CV_8UC1); 
    Mat floatConverted = Mat::zeros(1,64,CV_32FC1); 

    //construct some data 
    RNG rng = theRNG(); 
    for(int i=0;i<floatOrig.cols;++i) 
    { 
     floatOrig.at<float>(0,i)=rng.gaussian(1.); 
    } 

    //save them into uchar first 
    for(int i=0;i<ucharConverted.cols;++i) 
    { 
     ucharConverted.at<uchar>(0,i)= floatOrig.at<uchar>(0,i); 
    } 

    //now convert them back into float 
    //uchar b[4] = {0}; uncomment for big endian data 
    for(int i=0;i<floatConverted.cols;++i) 
    { 
     /* uncomment for big endian ordering 
     b[0]=ucharConverted.at<uchar>(0,i*4+3); 
     b[1]=ucharConverted.at<uchar>(0,i*4+2); 
     b[2]=ucharConverted.at<uchar>(0,i*4+1); 
     b[3]=ucharConverted.at<uchar>(0,i*4+0); 
     memcpy(&floatConverted.at<float>(0,i),&b, sizeof(float)); 
     */ 
     memcpy(&floatConverted.at<float>(0,i),&ucharConverted.at<uchar>(0,i*4), sizeof(float)); 
    } 

    //verify 
    for(int i=0;i<floatConverted.cols;++i) 
    { 
     assert(floatConverted.at<float>(0,i)-floatOrig.at<float>(0,i)==0.); 
    } 

    // now lets try saving that to file 
    FILE* fp = fopen("c:/data/float64.bin","wb"); 
    for(size_t i=0;i<floatConverted.cols;++i) 
    { 
     fwrite(&floatConverted.at<float>(0,i),sizeof(float),1,fp); 
    } 
    fclose(fp); 

    floatConverted=0;//we gonna try to load it back 

    fp = fopen("c:/data/float64.bin","rb"); 
    for(size_t i=0;i<floatConverted.cols;++i) 
    { 
     fread( &floatConverted.at<float>(0,i),sizeof(float),1,fp); 
    } 
    fclose(fp); 

    //verify data read from file 
    for(int i=0;i<floatConverted.cols;++i) 
    { 
     assert(floatConverted.at<float>(0,i)-floatOrig.at<float>(0,i)==0.); 
    } 
    getchar(); 
}