mkline.m

这是一个基于MATLAB的机器视觉工具箱,里面用很多非常有价值的的程序

%MKLINE		Draw a line in a matrix
%
%	m = MKLINE(n, theta, c)
%	m = MKLINE(n, theta, c, val)
%
%	m = MKLINE(im, theta, c)
%	m = MKLINE(im, theta, c, val)
%
%	First form creates an NxN matrix of zeros and draws a line 
%	with vertical intercept C and angle THETA.  With the Xaxis to the left
%	and Yaxis downward, the Zaxis is into the screen.
%	Each pixel on the line is set to VAL (default 1).
%
%	The second form draws the line into an already existing matrix IM.
%
% SEE ALSO:	ihough, xyhough
%
%	Copyright (c) Peter Corke, 1999  Machine Vision Toolbox for Matlab

function im = mkline(n, theta, c, val)

	if ismatrix(n),
		im = n;
		[nr,nc] = size(im);
	else
		im = zeros(n, n);
		nr = n;
		nc = n;
	end

	if nargin < 4,
		val = 1;
	end

	x = 1:nc;
	y = round(x*tan(theta) + c);
	
	s = find((y >= 1) & (y <= nr));

	for k=s,	
		im(y(k),x(k)) = val;
	end