16-bit conversion problem
While printing values from a 16-bit Mat I'm getting only the lower 8-bit part of the number. For example if the number is 324, I'm getting the printed value as 68 which is 324-256. In the code below Ix_Ix is the element-wise multiplication of Ix, but it does not print values greater than 255. Instead it gives the lower 8 bits. Is there a problem with my code? How do I get the correct values?
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
#include <stdlib.h>
#include <stdio.h>
using namespace cv;
int main()
{
Mat orig_img, img_blur, img_gray;
orig_img = imread("Lenna.png");
GaussianBlur(orig_img, img_blur, Size(3,3), 0, 0, BORDER_DEFAULT);
cvtColor(img_blur, img_gray, CV_RGB2GRAY);
namedWindow("features", CV_WINDOW_AUTOSIZE);
Mat Ix, Iy;
Sobel(img_gray, Ix, CV_16U, 1, 0, 3, 1, 0, BORDER_DEFAULT);
Sobel(img_gray, Iy, CV_16U, 0, 1, 3, 1, 0, BORDER_DEFAULT);
Mat Ix_Ix, Iy_Iy, Ix_Iy;
Ix_Ix = Ix.mul(Ix);
Iy_Iy = Iy.mul(Iy);
Ix_Iy = Ix.mul(Iy);
int i, j;
for(i = 0; i < Ix_Ix.rows; i++)
{
for(j = 0; j < Ix_Ix.cols; j++)
{
printf("%d\n", Ix.data[Ix.step[0]*i + Ix.step[1]*j]);
printf("%d\n", Ix_Ix.data[Ix_Ix.step[0]*i + Ix_Ix.step[1]*j]);
printf("\n");
}
}
Mat Ix_Ix_blur, Iy_Iy_blur, Ix_Iy_blur;
GaussianBlur(Ix_Ix, Ix_Ix_blur, Size(5,5), 0, 0, BORDER_DEFAULT);
GaussianBlur(Iy_Iy, Iy_Iy_blur, Size(5,5), 0, 0, BORDER_DEFAULT);
GaussianBlur(Ix_Iy, Ix_Iy_blur, Size(5,5), 0, 0, BORDER_DEFAULT);
imshow("feature", Ix_Ix);
waitKey(0);
return 0;
}