k-Wave User Forum » Topic: modification of makeCartCircle and makeCircle

k-Wave User Forum » Topic: modification of makeCartCircle and makeCircle http://www.k-wave.org/forum/topic/modification-of-makecartcircle-and-makecircle Support for the k-Wave MATLAB toolbox en-US Wed, 13 May 2026 00:22:13 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://www.k-wave.org/forum/search.php Bradley Treeby on "modification of makeCartCircle and makeCircle" http://www.k-wave.org/forum/topic/modification-of-makecartcircle-and-makecircle#post-1217 Tue, 05 Feb 2013 16:12:26 +0000 Bradley Treeby 1217@http://www.k-wave.org/forum/ Hi Chao, That's a useful modification - a few people have asked about doing exactly that. Thanks for posting! We'll look at incorporating into the next release. Brad. huangchao on "modification of makeCartCircle and makeCircle" http://www.k-wave.org/forum/topic/modification-of-makecartcircle-and-makecircle#post-1216 Tue, 05 Feb 2013 02:13:54 +0000 huangchao 1216@http://www.k-wave.org/forum/ Hi Dr. Treeby, In the original makeCartCircle and makeCircle functions, the argument arc_angle should be a scalar, which means the start point of the arc angle is fixed to be 0 radians. So to allow users to specify the start point and end point of the arc angle, I modified makeCartCircle and makeCircle so that arc_angle can be in form of [angle0, angle1], where angle0 and angle1 are the start and end of the arc angle, respectively. It requires 0<=angle0<angle1<=2*pi. Here are the modified codes: function circle = makeCartCircle(radius, num_points, center_pos, arc_angle, plot_circle) %MAKECARTCIRCLE Create a 2D Cartesian circle or arc. % % DESCRIPTION: % MakeCartCircle creates a 2 x num_points array of the Cartesian % coordinates of points evenly distributed over a circle or arc (if % arc_angle is given). % % USAGE: % circle = makeCartCircle(radius, num_points) % circle = makeCartCircle(radius, num_points, center_pos) % circle = makeCartCircle(radius, num_points, center_pos, arc_angle) % circle = makeCartCircle(radius, num_points, center_pos, arc_angle, plot_circle) % % INPUTS: % radius - circle radius [m] % num_points - number of points in the circle % % OPTIONAL INPUTS: % center_pos - [x, y] position of the circle center [m] % (default = [0, 0]) % arc_angle - arc angle for incomplete circle [radians] % (default = 2*pi) % plot_circle - Boolean controlling whether the Cartesian points % are plotted (default = false) % % OUTPUTS: % circle - 2 x num_points array of Cartesian coordinates % % ABOUT: % author - Bradley Treeby % date - 5th June 2009 % last update - 21st September 2012 % % This function is part of the k-Wave Toolbox (<a href="http://www.k-wave.org" rel="nofollow">http://www.k-wave.org</a>) % Copyright (C) 2009-2012 Bradley Treeby and Ben Cox % % See also cart2grid, makeCartSphere, makeCircle % This file is part of k-Wave. k-Wave is free software: you can % redistribute it and/or modify it under the terms of the GNU Lesser % General Public License as published by the Free Software Foundation, % either version 3 of the License, or (at your option) any later version. % % k-Wave is distributed in the hope that it will be useful, but WITHOUT ANY % WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS % FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for % more details. % % You should have received a copy of the GNU Lesser General Public License % along with k-Wave. If not, see <http://www.gnu.org/licenses/>. % check for plot_circle input if nargin < 5 plot_circle = false; end % check for arc_angle input if nargin < 4 angle0 = 0; angle_range = 2*pi; full_circle = true; elseif numel(arc_angle) == 1 angle0 = 0; angle_range = arc_angle; if arc_angle == 2*pi; full_circle = true; else full_circle = false; end else angle0 = arc_angle(1); angle_range = arc_angle(2) - arc_angle(1); if arc_angle(1) == 0 && arc_angle(1) == 2*pi full_circle = true; else full_circle = false; end end % check for center_pos input if nargin < 3 || isempty(center_pos) cx = 0; cy = 0; else cx = center_pos(1); cy = center_pos(2); end % ensure there is only a total of num_points including the endpoints when % arc_angle is not equal to 2*pi if ~full_circle num_points = num_points - 1; end % create angles angles = (0:(num_points))*angle_range/(num_points) + angle0 + pi/2; % discard repeated final point if arc_angle is equal to 2*pi if full_circle angles = angles(1:end-1); end % create cartesian grid % circle = flipud([radius*cos(angles); radius*sin(-angles)]); % B.0.3 circle = ([radius*cos(angles); radius*sin(-angles)]); % B.0.4 % offset if needed circle(1, :) = circle(1, :) + cx; circle(2, :) = circle(2, :) + cy; % plot results if plot_circle % select suitable axis scaling factor [x_sc, scale, prefix] = scaleSI(max(abs(circle(:)))); % create the figure figure; plot(circle(2,:)*scale, circle(1,:)*scale, 'b.'); set(gca, 'YDir', 'reverse'); xlabel(['y-position [' prefix 'm]']); ylabel(['x-position [' prefix 'm]']); axis equal; end function circle = makeCircle(Nx, Ny, cx, cy, radius, arc_angle, plot_circle) %MAKECIRCLE Create a binary map of a circle within a 2D grid. % % DESCRIPTION: % makeCircle creates a binary map of a circle or arc (using the % midpoint circle algorithm) within a two-dimensional grid (the % circle position is denoted by 1's in the matrix with 0's % elsewhere). A single grid point is taken as the circle centre thus % the total diameter will always be an odd number of grid points. % % USAGE: % circle = makeCircle(Nx, Ny, cx, cy, radius) % circle = makeCircle(Nx, Ny, cx, cy, radius, arc_angle) % circle = makeCircle(Nx, Ny, cx, cy, radius, arc_angle, plot_circle) % % INPUTS: % Nx, Ny - size of the 2D grid [grid points] % cx, cy - centre of the circle [grid points], if set % to 0, the centre of the grid is used % radius - circle radius [grid points] % % OPTIONAL INPUTS: % arc_angle - arc angle for incomplete circle [radians] % (default = 2*pi) % plot_circle - Boolean controlling whether the circle is plotted % using imagesc (default = false) % % OUTPUTS: % circle - 2D binary map of a circle % % ABOUT: % author - Bradley Treeby % date - 1st May 2009 % last update - 20th December 2011 % % This function is part of the k-Wave Toolbox (<a href="http://www.k-wave.org" rel="nofollow">http://www.k-wave.org</a>) % Copyright (C) 2009-2012 Bradley Treeby and Ben Cox % % See also makeCartCircle, makeDisc % This file is part of k-Wave. k-Wave is free software: you can % redistribute it and/or modify it under the terms of the GNU Lesser % General Public License as published by the Free Software Foundation, % either version 3 of the License, or (at your option) any later version. % % k-Wave is distributed in the hope that it will be useful, but WITHOUT ANY % WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS % FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for % more details. % % You should have received a copy of the GNU Lesser General Public License % along with k-Wave. If not, see <http://www.gnu.org/licenses/>. % check for plot_circle input if nargin < 7 plot_circle = false; end % check for arc_angle input if nargin < 6 angle0 = 0; angle1 = 2*pi; elseif numel(arc_angle) == 1 angle0 = 0; angle1 = arc_angle; if angle1 > 2*pi angle1 = 2*pi; elseif angle1 < 0 angle1 = 0; end else angle0 = arc_angle(1); angle1 = arc_angle(2); end % force integer values Nx = round(Nx); Ny = round(Ny); cx = round(cx); cy = round(cy); radius = round(radius); % check for zero values if cx == 0 cx = floor(Nx/2) + 1; end if cy == 0 cy = floor(Ny/2) + 1; end % check the inputs if cx < 1 || cx > Nx || cy < 1 || cy > Ny error('The center of the circle must be within the grid'); end % define literals MAGNITUDE = 1; % create empty matrix circle = zeros(Nx, Ny); % initialise loop variables x = 0; y = radius; d = 1 - radius; % draw the first cardinal point try circle(cx, cy - y) = MAGNITUDE; catch error('The circle must fit within the grid'); end % draw the remaining cardinal points py = [cx, cx+y, cx-y]; px = [cy+y, cy, cy]; for point_index = 1:length(py) % check whether the point is within the arc made by arc_angle if (atan2(py(point_index) - cx, px(point_index) - cy) + pi) >= angle0 && (atan2(py(point_index) - cx, px(point_index) - cy) + pi) <= angle1 circle(py(point_index), px(point_index)) = MAGNITUDE; end end % loop through the remaining points using the midpoint circle algorithm while ( x < y - 1 ) x = x + 1; if ( d < 0 ) d = d + x + x + 1; else y = y - 1; a = x - y + 1; d = d + a + a; end % setup point indices py = [x+cx, y+cx, y+cx, x+cx, -x+cx, -y+cx, -y+cx, -x+cx]; px = [y+cy, x+cy, -x+cy, -y+cy, -y+cy, -x+cy, x+cy, y+cy]; % loop through each point for point_index = 1:length(py) % check whether the point is within the arc made by arc_angle if (atan2(py(point_index) - cx, px(point_index) - cy) + pi) >= angle0 && (atan2(py(point_index) - cx, px(point_index) - cy) + pi) <= angle1 circle(py(point_index), px(point_index)) = MAGNITUDE; end end end % create the figure if plot_circle figure; imagesc(circle, [-1 1]); colormap(getColorMap); axis image; xlabel('y-position [grid points]'); ylabel('x-position [grid points]'); end Hope they could be useful. Chao