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hi, i am involved with handwritten OCR application. I use MNIST digit database for training process here. I use following code for read pixels from the database and re-create the image. programs doesnt give any error but it gives meaningless image(totally black images and unclear pixels patterns) as output. can someone explain the reason for that? plz help

here is my code

int reverseInt(int i) {
unsigned char c1, c2, c3, c4;
c1 = i & 255;
c2 = (i >> 8) & 255;
c3 = (i >> 16) & 255;
c4 = (i >> 24) & 255;
return ((int)c1 << 24) + ((int)c2 << 16) + ((int)c3 << 8) + c4;
}

void create_image(CvSize size, int depth, int channels, unsigned char* data, int imagenumber) {
string imgname; ostringstream imgstrm;string fullpath;
imgstrm << imagenumber;
imgname=imgstrm.str();
fullpath="D:\\"+imgname+".jpg";

IplImage *imghead=cvCreateImageHeader(size, IPL_DEPTH_8U, channels);
imghead->imageData=(char *)data;
cvSaveImage(fullpath.c_str(),imghead);  
}

int main(){
ifstream file ("D:\\train-images.idx3-ubyte",ios::binary);
if (file.is_open())
{
    int magic_number=0; int number_of_images=0;int r; int c;
    int n_rows=0; int n_cols=0;CvSize size;unsigned char temp=0;

    file.read((char*)&magic_number,sizeof(magic_number)); 
    magic_number= reverseInt(magic_number);

    file.read((char*)&number_of_images,sizeof(number_of_images));
    number_of_images= reverseInt(number_of_images);

    file.read((char*)&n_rows,sizeof(n_rows));
    n_rows= reverseInt(n_rows);
    file.read((char*)&n_cols,sizeof(n_cols));
    n_cols= reverseInt(n_cols);


    for(int i=0;i<10;++i)
    {
        for(r=0;r<n_rows;++r)
        {
            for(c=0;c<n_cols;++c)
            {                 
                file.read((char*)&temp,sizeof(temp));
            }           
        }
        size.height=r;size.width=c;
        create_image(size, 16,3, &temp, i);
    }
}
return 0;
}

and this is one of result image

hi, i am involved with handwritten OCR application. I use MNIST digit database for training process here. I use following code for read pixels from the database and re-create the image. programs doesnt give any error but it gives meaningless image(totally black images and unclear pixels patterns) as output. can someone explain the reason for that? plz help

here is my code

int reverseInt(int i) {
unsigned char c1, c2, c3, c4;
c1 = i & 255;
c2 = (i >> 8) & 255;
c3 = (i >> 16) & 255;
c4 = (i >> 24) & 255;
return ((int)c1 << 24) + ((int)c2 << 16) + ((int)c3 << 8) + c4;
}

void create_image(CvSize size, int depth, int channels, unsigned char* data, int imagenumber) {
string imgname; ostringstream imgstrm;string fullpath;
imgstrm << imagenumber;
imgname=imgstrm.str();
fullpath="D:\\"+imgname+".jpg";

IplImage *imghead=cvCreateImageHeader(size, IPL_DEPTH_8U, channels);
imghead->imageData=(char *)data;
cvSaveImage(fullpath.c_str(),imghead);  
}

int main(){
ifstream file ("D:\\train-images.idx3-ubyte",ios::binary);
if (file.is_open())
{
    int magic_number=0; int number_of_images=0;int r; int c;
    int n_rows=0; int n_cols=0;CvSize size;unsigned char temp=0;

    file.read((char*)&magic_number,sizeof(magic_number)); 
    magic_number= reverseInt(magic_number);

    file.read((char*)&number_of_images,sizeof(number_of_images));
    number_of_images= reverseInt(number_of_images);

    file.read((char*)&n_rows,sizeof(n_rows));
    n_rows= reverseInt(n_rows);
    file.read((char*)&n_cols,sizeof(n_cols));
    n_cols= reverseInt(n_cols);


    for(int i=0;i<10;++i)
i=0;i<number_of_images;++i)
    {
        for(r=0;r<n_rows;++r)
        {
            for(c=0;c<n_cols;++c)
            {                 
                file.read((char*)&temp,sizeof(temp));
            }           
        }
        size.height=r;size.width=c;
        create_image(size, 16,3, &temp, i);
    }
}
return 0;
}

and this is one of result image

hi, i am involved with handwritten OCR application. I use MNIST digit database for training process here. I use following code for read pixels from the database and re-create the image. programs doesnt give any error but it gives meaningless image(totally black images and unclear pixels patterns) as output. can someone explain the reason for that? plz help

here is my code

int reverseInt(int i) {
unsigned char c1, c2, c3, c4;
c1 = i & 255;
c2 = (i >> 8) & 255;
c3 = (i >> 16) & 255;
c4 = (i >> 24) & 255;
return ((int)c1 << 24) + ((int)c2 << 16) + ((int)c3 << 8) + c4;
}

void create_image(CvSize size, int depth, int channels, unsigned char* data, int imagenumber) {
string imgname; ostringstream imgstrm;string fullpath;
imgstrm << imagenumber;
imgname=imgstrm.str();
fullpath="D:\\"+imgname+".jpg";

IplImage *imghead=cvCreateImageHeader(size, IPL_DEPTH_8U, IPL_DEPTH_16S, channels);
imghead->imageData=(char *)data;
cvSaveImage(fullpath.c_str(),imghead);  
}

int main(){
ifstream file ("D:\\train-images.idx3-ubyte",ios::binary);
if (file.is_open())
{
    int magic_number=0; int number_of_images=0;int r; int c;
    int n_rows=0; int n_cols=0;CvSize size;unsigned char temp=0;

    file.read((char*)&magic_number,sizeof(magic_number)); 
    magic_number= reverseInt(magic_number);

    file.read((char*)&number_of_images,sizeof(number_of_images));
    number_of_images= reverseInt(number_of_images);

    file.read((char*)&n_rows,sizeof(n_rows));
    n_rows= reverseInt(n_rows);
    file.read((char*)&n_cols,sizeof(n_cols));
    n_cols= reverseInt(n_cols);


    for(int i=0;i<number_of_images;++i)
    {
        for(r=0;r<n_rows;++r)
        {
            for(c=0;c<n_cols;++c)
            {                 
                file.read((char*)&temp,sizeof(temp));
            }           
        }
        size.height=r;size.width=c;
        create_image(size, 16,3, create_image(size,3, &temp, i);
    }
}
return 0;
}

and this is one of result image