Matlab：极坐标灰度图

问题描述

编辑：我决定将这个问题分成两部分，因为它实际上是两个问题：1。如何在MATLAB（这个问题）和

因为MATLAB将图像存储为矩阵，极坐标我不完全匹配矩阵的'bins'。因此，我们目前使用插值算法将极坐标放入方阵中。但是，这非常慢。我看到两种方法可以解决这个问题：

1. 让MATLAB直接将数据点绘制为极坐标。

一些基本信息：

输入矩阵大小：512×960

当前输出矩阵大小：1024×1024

解决方案

问题解决了（除了一个小缺陷），部分原因是KM Shihab Uddin指出了我正确的方向。不幸的是，使用冲浪意味着不断地在图中绘制图像，这也很慢。

因此，对于每个X和Y组合，我在X和Y值中都有单独的矩阵和灰度值（在一个名为C的矩阵中）。

我发现pcolor只是从顶部观察冲浪。所以我使用以下代码绘制我的图表。

 冲浪（X，Y，C * 255）
查看（[0,0,500]）
  

然而，这给了我一个完全黑色的图像。这是因为在我的情况下，surf（和pcolor）在径向上创建了960个网格线。解决方案是使用：

  surf（X，Y，img2 * 255，'EdgeColor'，'none'）
查看（[0,0,500]）
  

现在我有一个近乎完美的形象，就像我有之前。只有在我的960个径向线中，一个是白色的，所以我仍然必须解决这个问题。但是，我觉得这是函数surf的技术细节，回答这部分并不属于这个问题。

edit: I decided to split this question into two parts, because it were really two questions: 1. how to make a polar surface plot in MATLAB (this question) and 2. how to put fit polar data points into a coarse (and non-polar) matrix

I have a matrix that contains certain grey values (values between zero and one). These points are stored in a rectangular matrix, but really the data points are acquired by rotating the detector. This means that I actually have polar coordinates (I know the polar coordinates for every single pixel in my starting matrix).

I want to make a polar plot of the data points. I have the example of this below.

Because MATLAB stores images as matrices, the polar coordinates I have do not exactly match the 'bins' of the matrix. Therefore, we currently use an interpolation algorithm to put the polar coordinates into a square matrix. However, this is extremely slow. I see two methods to solve this issue:

1. let MATLAB directly plot the data points as polar.

Some basic information:

Input matrix size: 512×960

Current output matrix size: 1024×1024

解决方案

The question was solved (apart from a minor flaw), partially because K.M. Shihab Uddin pointed me in the right direction. Unfortunately, using surf means continuously really plotting the image in a figure, and this is slow as well.

So I have X and Y values both in separate matrices and greyscale values (in a matrix called C) for every X and Y combination.

I found out that pcolor is just surf with a viewpoint from the top. So I used the following code to plot my graph.

surf(X,Y,C*255)
view([0,0,500])

However, this gave me a completely black image. This is because surf (and pcolor) create 960 grid lines radially in my case. The solution is to use:

surf(X,Y,img2*255,'EdgeColor','none')
view([0,0,500])

Now I have an almost perfect image, like I had before. Only, of my 960 radial lines, one is left white, so I still have to solve that. However, I feel this is a technical detail of the function surf, and answering this part does not belong in this question.

The resulting image

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