```
function out = findWaldo(im, filter) 

% convert image (and filter) to grayscale
im_input = im;
im = rgb2gray(im);
im = double(im);
filter = rgb2gray(filter);
filter = double(filter);
filter = filter/sqrt(sum(sum(filter.^2)));
out = normxcorr2(filter, im);

```

Question1: Why we first do rgb2gray on im and filter?

Question2: What does the last second line actually do? Namely,

```
filter = filter/sqrt(sum(sum(filter.^2)));

```