我从matehat那里学到了这个技巧:

import matplotlib.pyplot as plt
import numpy as np

def make_image(data, outputname, size=(1, 1), dpi=80):
    fig = plt.figure()
    fig.set_size_inches(size)
    ax = plt.Axes(fig, [0., 0., 1., 1.])
    ax.set_axis_off()
    fig.add_axes(ax)
    plt.set_cmap('hot')
    ax.imshow(data, aspect='equal')
    plt.savefig(outputname, dpi=dpi)

# data = mpimg.imread(inputname)[:,:,0]
data = np.arange(1,10).reshape((3, 3))

make_image(data, '/tmp/out.png')

收益率

我从matehat那里学到了这个技巧:

import matplotlib.pyplot as plt
import numpy as np

def make_image(data, outputname, size=(1, 1), dpi=80):
    fig = plt.figure()
    fig.set_size_inches(size)
    ax = plt.Axes(fig, [0., 0., 1., 1.])
    ax.set_axis_off()
    fig.add_axes(ax)
    plt.set_cmap('hot')
    ax.imshow(data, aspect='equal')
    plt.savefig(outputname, dpi=dpi)

# data = mpimg.imread(inputname)[:,:,0]
data = np.arange(1,10).reshape((3, 3))

make_image(data, '/tmp/out.png')

收益率

这将删除所有的填充和边框:

from matplotlib import pyplot as plt

fig = plt.figure()
fig.patch.set_visible(False)

ax = fig.add_subplot(111)

plt.axis('off')
plt.imshow(data)

extent = ax.get_window_extent().transformed(fig.dpi_scale_trans.inverted())
plt.savefig("../images/test.png", bbox_inches=extent)

轴('off')方法比分别更改每个轴和边界更简洁地解决了其中一个问题。然而，它仍然在边界上留下了空白。在savefig命令中添加bbox_inch ='tight'几乎就可以实现了;你可以在下面的例子中看到，留下的空白要小得多，但仍然存在。

更新版本的matplotlib可能需要bbox_inch =0而不是字符串'tight'(通过@episodeyang和@kadrach)

from numpy import random
import matplotlib.pyplot as plt

data = random.random((5,5))
img = plt.imshow(data, interpolation='nearest')
img.set_cmap('hot')
plt.axis('off')
plt.savefig("test.png", bbox_inches='tight')

感谢大家的精彩回答……我也有同样的问题，想要绘制一个没有额外填充/空间等的图像，所以非常高兴能在这里找到每个人的想法。

除了没有填充的图像，我还希望能够轻松添加注释等，而不仅仅是一个简单的图像情节。

因此，我最终将David的回答与csnemes的回答结合起来，在图形创建时制作了一个简单的包装器。当你使用它时，你不需要对imsave()或其他任何东西进行任何更改:

def get_img_figure(image, dpi):
    """
    Create a matplotlib (figure,axes) for an image (numpy array) setup so that
        a) axes will span the entire figure (when saved no whitespace)
        b) when saved the figure will have the same x/y resolution as the array, 
           with the dpi value you pass in.

    Arguments:
        image -- numpy 2d array
        dpi -- dpi value that the figure should use

    Returns: (figure, ax) tuple from plt.subplots
    """

    # get required figure size in inches (reversed row/column order)
    inches = image.shape[1]/dpi, image.shape[0]/dpi

    # make figure with that size and a single axes
    fig, ax = plt.subplots(figsize=inches, dpi=dpi)

    # move axes to span entire figure area
    fig.subplots_adjust(left=0, right=1, top=1, bottom=0, wspace=0, hspace=0)

    return fig, ax

这对我去除虱子很有效:

fig, axes = plt.subplots(2, figsize=(15, 20))

for ax in axes:
    ax.get_xaxis().set_ticks([])
    ax.get_yaxis().set_ticks([])