如何在 Matlab warp 中使用极轴？

Question

我想在warp 对象上使用polaraxes 在极地演示文稿的半圆周上。没有 polaraxes 但有 warp

的代码

close all; clear all; clc; 

% 
load clown;
img = ind2rgb(X,map);
[h,w,~] = size(img);
s = min(h,w)/2;
[rho,theta] = meshgrid(linspace(0,s-1,s), linspace(0,pi));
[x,y] = pol2cart(theta, rho);
z = zeros(size(x));

f1=figure();  
hax=axes('Parent', f1); 
imagesc(img, 'Parent', hax);
box(hax, 'off');
axis(hax, 'off');
set(hax, 'yTickLabel', []);
set(hax, 'xTickLabel', []); % for polar presentation
set(hax, 'Ticklength', [0 0]); % 

f2=figure();
hax2=axes('Parent', f2); 
h=warp(x, y, z, img); 
view(hax2, 2); 
axis(hax2, 'square'); 
axis(hax2, 'tight');

图1 当前输出笛卡尔小丑，图 2 半圆周但没有极轴的极地小丑，图 3 故障排除后第 2 节的输出 (EBH, masi)

使用 polaraxes 和 warp 伪代码失败；我只能用 polarplot 做 polaraxes ，这里还不够

hax2=polaraxes('Parent', f2); 
h=warp(x,y,z, img);

预期输出：半圆周上的极轴

2 测试 EBH 的提议

pax=polaraxes, 2. loop, 3. warp(I) into pax - 添加循环
隐式命令视图和轴失败 - 添加了测试代码 af = figure('Name', 'Do Not Touch'); 以显示隐式命令失败的原因
使用 FastPeakFind 和更多测试图像、图像绘制和图像方向修复的测试代码

总结

close all; clear all; clc;

fp=figure('Name', 'Test', ...
    'Position',[200 200 851 404],'Resize','off'); % only half circle in polaraxes although warp can do eclipses
ThetaTicks = 0*pi:pi/10:1*pi;
pax = polaraxes( 'ThetaAxisUnits', 'radians', ...
    'ThetaLim',[min(ThetaTicks) max(ThetaTicks)],...
    'Color','none',...
    'GridAlpha',1,...
    'GridColor',[1 1 1],...
    'ThetaTick',ThetaTicks, ...
    'Parent', fp);

af = figure('Name', 'Do Not Touch');

testImages = { 'peppers.png', 'bag.png', 'glass.png', 'circles.png', 'fabric.png', 'testpat1.png', 'office_1.jpg', ...
'onion.png', 'pears.png', 'rice.png', 'westconcordorthophoto.png', 'coins.png' };
imax = axes('Parent', fp, 'Visible', 'off');
for testImage=testImages
    I = imread(testImage{1,1});
    angleRadians=-pi;
    [x, y, z]=makePolar(I, angleRadians);
    fp=figure(fp); % put this every time you switch between figures to go back to 'fp'
    imax.Children = warp(x, y, z, I); 
    set(imax,'view',[-180 -90],'Visible','off')
    axis(imax,'tight'); 
    pause(1);

    % 
    Ip=getframe(pax);
    Ip=Ip.cdata;
    imwrite(Ip, '/tmp/testMasi.png', 'png');
    assert(isa(Ip, 'uint8'), sprintf('I is not uint8 but %s', class(Ip)));
    p=FastPeakFind(Ip);
    imagesc(Ip, 'Parent', imax);
    axis(imax, 'off');
    hold(imax, 'on');
    plot(p(1:2:end),p(2:2:end),'r+', 'Parent', imax);
    hold(imax, 'off');
    drawnow; 
end

图 3 中的输出，其中有错误的雷达轴；尝试在线程 How to integrate Java swing black background toolbar into polaraxes?

中对其进行故障排除

Matlab: 2016b
OS：Debian 8.5 64 位
硬件：华硕 Zenbook UX303UA

Answer 1

这里的想法是在极轴上绘制扭曲图像，每个轴使用不同的轴：

% first we create a figure with defined size, because 'polaraxes' are always
% half a circle, and we need to keep the output surface of 'warp' in this
% shape, and not in an ellipse. Switching off the 'Resize' is just an option
fp = figure('Name', 'Test', ...
    'Position',[200 200 851 404],'Resize','off'); 
% Then we define the polaraxes:
ThetaTicks = 0:pi/10:pi; % for the opposite side use pi:pi/10:2*pi
pax = polaraxes( 'ThetaAxisUnits', 'radians', ...
    'ThetaLim',[min(ThetaTicks) max(ThetaTicks)],...
    'ThetaTick',ThetaTicks, ...
    'Parent', fp);

testImages = {'peppers.png', 'bag.png', 'glass.png', 'circles.png',...
    'fabric.png', 'testpat1.png', 'office_1.jpg', 'pears.png',...
    'rice.png', 'westconcordorthophoto.png', 'coins.png'};

figure(fp) %<-- put this every time you want to bring the focuse back to 'fp'
imax = axes('Parent',fp); % this will be the axes for the image
for testImage = testImages
    I = imread(testImage{1,1});
    angleRadians = -pi; % for the opposite side use pi
    [h,w,~] = size(I);
    s = min(h,w)/2;
    [rho,theta] = meshgrid(linspace(0,s-1,s), linspace(0,angleRadians,s));
    [x,y] = pol2cart(theta, rho);
    z = zeros(size(x));
    imax.Children = warp(x, y, z, I); % display the image in 3D surface
    set(imax,'view',[0 90],'Visible','off'); % rotate to a top view and hide the axes
    axis(imax,'tight') % calibrate the image to the figure size
    drawnow;
    pause(0.5)
end

主要注意事项是polaraxes创建半圆，而warp创建半椭圆取决于图形的大小，因此您必须正确设置图形大小。

如何在 Matlab warp 中使用极轴？

How to use polar axes with Matlab warp?

matlab

matlab-figure

polar-coordinates

2 测试 EBH 的提议