Try this to ask your user for an integer value for the threshold:
% Ask user for one integer number.
defaultValue = 45;
titleBar = 'Enter an integer value';
userPrompt = 'Enter the threshold';
caUserInput = inputdlg(userPrompt, titleBar, 1, {num2str(defaultValue)});
if isempty(caUserInput),return,end; % Bail out if they clicked Cancel.
% Round to nearest integer in case they entered a floating point number.
integerValue = round(str2double(cell2mat(caUserInput)));
% Check for a valid integer.
if isnan(integerValue)
% They didn't enter a number.
% They clicked Cancel, or entered a character, symbols, or something else not allowed.
integerValue = defaultValue;
message = sprintf('I said it had to be an integer.\nTry replacing the user.\nI will use %d and continue.', integerValue);
uiwait(warndlg(message));
end
