16bit raw file stream analysis

edit

Instead of the 256x256 loop, it is probably faster to use

Mat imAcq=Mat(256,256,CV_16UC1,&tmp,256*2).clone()

The optional ".clone()" makes an independent copy of the image, allowing you to reuse tmp for the next image or to dispose of it without corrupting imAcq.
guy

Hi, I got back to this and I am stuck bit further.. this code:

    int main( int argc, char** argv )
{
        ifstream fs;
        fs.open(argv[1], ios::in | ios::binary);
        unsigned short *tmp = new unsigned short[256*256];
        fs.seekg(256);
        fs.read(reinterpret_cast<char*>(tmp), 256*256*sizeof(unsigned short) );
        fs.close();

    Mat imAcq=Mat(256,256,CV_16UC1,&tmp,256*256*sizeof(unsigned short));
    for (long i=0; i<30000; i++)
    {
    cout << " "  << tmp[i]/256;
    }

creates tmp array with everything 256 x bigger, then if it is read in Mat imAcq=Mat(... it gets to segmentation fault. I am pretty sure my file is 16bit (unsigned short) and if I display values of tmp as in example it gets it right, any suggestions for quick, non all array fix?

Size is wrong (see Mat::Mat(int rows, int cols, int type, void* data, size_t step=AUTO_STEP)

int main(int argc, char** argv)
{
    ifstream fs;
    fs.open("14254110395737044.txt", ios::in | ios::binary);
    unsigned short *tmp = new unsigned short[256 * 256];
    fs.seekg(256);
    fs.read(reinterpret_cast<char*>(tmp), 256 * 256 * sizeof(unsigned short));
    fs.close();

    Mat imAcq = Mat(256, 256, CV_16UC1,tmp);// , tmp, 256 * 256 * sizeof(unsigned short));
    imshow("tets", imAcq);
    waitKey();

}

OK thanks, that one works fine now. Other problem is now endians. Value 1 is given as 256 in my Mat. Is there any simple workaround? (if I multiply whole array by 256 in imageJ it gives me 1 for same pixel)

I do not understand 0x0100 = 256 and you want 0x0001 if yes I think something like that could be good

unsigned char*c = (unsigned char*)tmp;
    for (int i = 0; i < 65536*2; i += 2)
        swap(c[i], c[i + 1]);
    Mat imAcq = Mat(256, 256, CV_16UC1,tmp);// , tmp, 256 * 256 * sizeof(unsigned short));

and if you don't want most significant byte

unsigned char*c = (unsigned char*)tmp;
unsigned char cc[65536];
for (int i = 0; i < 65536 * 2; i += 2)
{
    swap(c[i], c[i + 1]);
    cc[i / 2] = c[i];
}
Mat imAcq = Mat(256, 256, CV_8UC1,cc);// , tmp, 256 * 256 * sizeof(unsigned short));

this seems to work:

Mat imAcq=Mat(256,256,CV_16UC1,tmp);
Mat mat1;
mat1 = imAcq/256;
imAcq = (imAcq - (256*mat1))*256+mat1;

v =0xFEDC

v/256=0xFE

0xFEDC-256*0xFE=0xDC

0xDC*256+mat1=0xDCFE

that's only the swap!

ok, I am not programmer as is clear I think :) is your suggestion faster?

Much more faster it's only a memory swap no arithmetic operation. If your camera is 16 bits why all Most significant bits are 0?

thanks for help, camera itself has 12bit counter and this is saved as 16bit raw file. It depends on our experiment how much of this space is filled. Counts are <20 in my example file (waste of space), but we do not have direct access to drivers or FPGA card which saves datasets. I'm doing analysis of data in proprietary software but I want to try something different.