It looks like the return spring adjustment screw on the pictured brake arm is threaded all the way in. While not necessarily wrong, it is atypical and could indicate other issues with brake adjustment. I generally keep all return springs adjusted as loose as possible but as tight as necessary. This generally improves brake lever feel and is a good foundation for the rest of the brake system adjustment.
In addition to checking out the Sheldon Brown link above, I'd thread the return spring adjustment screws all the way out and even verify that the spring pins are in the middle hole in the cantilever bosses (if multiple holes are present). Once you've verified the spring pins are in the middle hole, use the return spring adjustment screws only as necessary to center the brake arms on the rim.