imshow:将标签作为图像索引的任意函数 [英] imshow: labels as any arbitrary function of the image indices

问题描述

imshow相对于其列索引(x轴)和行索引(y轴)绘制矩阵.我希望轴标签不是索引，而是索引的任意函数.

imshow plots a matrix against its column indices (x axis) and row indices (y axis). I would like the axes labels to not be indices, but an arbitrary function of the indices.

例如音调检测

imshow(A, aspect='auto')其中A.shape == (88200,8)

在x轴上的大约[11000, 22000, ..., 88000]处显示几个刻度线 在y轴上，显示频率槽[0,1,2,3,4,5,6,7]

in the x-axis, shows several ticks at about [11000, 22000, ..., 88000] in the y-axis, shows the frequency bin [0,1,2,3,4,5,6,7]

我想要的是:

x轴标记从样本标准化为秒.对于44.1kHz采样率的2秒音频，我想在[1,2]处打两个勾.

x-axis labeling are normalized from samples to seconds. For a 2 second audio at 44.1kHz sample rate, I want two ticks at [1,2].

y轴标记是音高，请注意.我想要标签在音高['c', 'd', 'e', 'f', 'g', 'a', 'b']的音符中.

y-axis labeling is the pitch as a note. i want the labels in the note of the pitch ['c', 'd', 'e', 'f', 'g', 'a', 'b'].

理想情况:

imshow(A, ylabel=lambda i: freqs[i], xlabel=lambda j: j/44100)

推荐答案

您可以结合使用Locator s和Formatter s

You can do this with a combination of Locators and Formatters (doc).

ax = gca()
ax.imshow(rand(500,500))

ax.get_xaxis().set_major_formatter(FuncFormatter(lambda x,p :"%.2f"%(x/44100)))
ax.get_yaxis().set_major_locator(LinearLocator(7))
ax.get_yaxis().set_major_formatter(FixedFormatter(['c', 'd', 'e', 'f', 'g', 'a', 'b']))
draw()

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