complement 16 bit mat and then convert it to 8 bit

edit

invert every bit in an array

Converts an array to another data type with optional scaling.

Mat a=imread("lena.jpg",cv::IMREAD_UNCHANGED);

Mat b,c; bitwise_not(a,b); b.convertTo(c,CV_32F);

Mat imcomplement(Mat I)

{

/*Result the complement of a given image*/
if(I.channels()==3)
{
    for(int y = 0; y < I.rows; y++)  
    {  
        for ( int x = 0; x < I.cols; x++)  
        {  
            for(int i=0;i<3;i++)
                I.at<Vec3b>(y,x)[i]=255-I.at<Vec3b>(y,x)[i];
        }
    }
}

else
{
    for(int y = 0; y < I.rows; y++)  
    {  
        for ( int x = 0; x < I.cols; x++)  
        {  
            I.at<uchar>(y,x)=255-I.at<uchar>(y,x);
        }
    }
}
return I;

}