view histogram/plothist_lin.m @ 61:eff6bddf82e3 tip

Finally implemented perceptual brightness thing.

function z=plothist_lin(h,m)
% plothist_lin - Plot histogram assuming triangular kernel (linear interpolation)
%
% plothist_lin :: [[N]->natural], dmap(N-1) -> handle.

	e=edges(m);
	e=[2*e(1)-e(2),e,2*e(end)-e(end-1)];

	z=ezplot(@pdf,[e(1),e(end)]);

	function p=pdf(x)
%		if ~isscalar(x), error('must be scalar'); end
%		j=find(x>e(1:end-2) & x<e(3:end));
		p=0;
		for i=1:length(h) %j
			p=p+triangle(e(i:i+2),h(i));
		end

		function y=triangle(a,h)
			y=zeros(size(x));
			I1=(x>a(1) & x<=a(2));
			I2=(x>a(2) & x<a(3));
			y(I1)=h*((x(I1)-a(1))/(a(2)-a(1)));
			y(I2)=h*((x(I2)-a(3))/(a(2)-a(3)));
		end
	end
end