You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: GetBndPatchIds.m
    path of file: ./repos/MCITF/Code/MCITF/Feat
    
    the code of the file until where you have to start completion: function bdIds = GetBndPatchIds(idxImg, thickness)

    
function bdIds = GetBndPatchIds(idxImg, thickness)
% Get super-pixels on image boundary
% idxImg is an integer image, values in [1..spNum]
% thickness means boundary band width

% Code Author: Wangjiang Zhu
% Email: wangjiang88119@gmail.com
% Date: 3/24/2014

if nargin < 2
    thickness = 8;
end