computeCorners.m

function [cornies, cornyLoc, cornyhands] = computeCorners(anglematrix, boundy, opts)
% COMPUTE CORNERS. Calculates corners from the anglegram matrix. The
% anglegram is shrunk to ensure a better interpretation of the data.
%
% USAGE: 
%    [cornies, cornyLoc, cornyhands] = computeCorners(anglematrix, boundy, opts)
%
%    [cornies, cornyLoc, cornyhands] = computeCorners([], boundy, opts)
%

testag = false;
if isempty(anglematrix)
    testag = true;
    anglematrix = computeMultiAnglegram(boundy); 
end

if nargin < 3
    agsize = [64 64];
    offst = agsize(1)/2;
    statsfname = 'max';
else
    [agsize, offst, statsfname] = getoptions(opts);
end
wrapN = @(x, N) (1 + mod(x-1, N));

anglegram = imresize(anglematrix, agsize);
anglegram = anglegram(:,1:offst);

switch lower(statsfname)
    case 'max'
        statfn = @(x) max(x, [],2);
    case 'mean'
        statfn = @(x) mean(x, 2);
end

anglesumve = statfn(anglegram);
mam = mean(anglesumve);
stam = std(anglesumve);

[minval, minlocations] = findpeaks(-[anglesumve;anglesumve],...
    'MinPeakHeight',-mam+stam);
minval = -minval;

[minval, ic,~] = unique(minval, 'stable');
minlocations = wrapN(minlocations(ic), agsize(1));

cornyLoc = fix((minlocations./64)*size(boundy,1));
cornies = boundy(cornyLoc,:);

cornyhands.anglesumve = anglesumve;
cornyhands.minlocations = minlocations;
cornyhands.minval = minval;
cornyhands.mam = mam;
cornyhands.stam = stam;
if testag == true
    cornyhands.anglegram = anglematrix;
end

test = length(cornyhands.minval)>=4 && ...
    mean(minval)>=120;
if test == true
    fprintf('%s: Suspicious points found. Rearranging corner points..\n',...
        mfilename);
    cornyhands.allcornies = cornies;
    cornyhands.allcornyloc = cornyLoc;
    cornies = [];
    cornyLoc = [];
end

switch length(cornyLoc)
    case 0
        cornyhands.guesstype = 'circ';
        cornyhands.guesslabel = 1;
    case 1
        cornyhands.guesstype = 'drop';
        cornyhands.guesslabel = 2;
    case 2
        cornyhands.guesstype = 'bidrop';
        cornyhands.guesslabel = 3;
    case 3
        cornyhands.guesstype = 'tridrop';
        cornyhands.guesslabel = 4;
    otherwise
        cornyhands.guesstype = 'multidrop';
        cornyhands.guesslabel = -1;
end

end

function [agsize, offst, statsfname] = getoptions(opts)
%
agsize = [64 64];
offst = agsize(1)/2;
statsfname = 'max';

fnames = fieldnames(opts);
for ix=1:length(fnames)
    switch fnames{ix}
        case 'agsize'
            agsize = opts.(fnames{ix});
        case 'offst'
            offst = opts.(fnames{ix});
        case 'statsfname'
            statsfname = opts.(fnames{ix});
        otherwise
            fprintf('%s: ERROR, option %s not recognised.\n',...
                mfilename, upper(fnames{ix}));
    end
end
end