The bottom of the picture reads “Col. Cann, 1st Regiment” then possibly "ST off" meaning ??staff officers?? You said he was born in Nova Scotia maybe he was Canadian Army --- The sleeve looks like it has a Canadian Maple Leaf on it and the three bars would indicate a Lieutenant Colonel in the Canadian Army.
check out: http://army.ca/info/ranks.php
This page for the modern Canadian Army.
I found an Arthur Cann listed as a veteran of Canadian Army in World War I could he be related as well?
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