如何使用matplotlib循环绘制图像列表？ [复制]

Question

我有 10 个图像 ID。从每个 ID，我可以获得原始图像、基本事实、预处理、后处理路径。我会从每条路径中读取图像，并绘制一个带有子图的图：列表示第四类图像：raw、gt、pre、post，而行表示从 1 到 10 的图像 id。

目前，我使用gridspec 来定位每个图像的子图形和从 1 到 40 的轴。我使用循环读取列表中的图像，然后使用条件在每个轴中放置图像。但是，看起来很长的代码，我认为 Python 和 matplotlib 可以有更好的方法。你能给我建议一下方法吗？这是我目前的实现

if __name__ == "__main__":

    fig = plt.figure(figsize=(50, 50))
    fig.patch.set_facecolor('white')
    gs1 = gridspec.GridSpec(4, 10)
    gs1.update(wspace=0.01, hspace=0.01)  # set the spacing between axes.

    ax1 = plt.subplot(gs1[0])
    ..
    ax40 = plt.subplot(gs1[39])

    ax1.axis('off')
    ...
    ax40.axis('off')

    ax37.text(0.5, -0.1, "(a)", size=20, ha="center",
              transform=ax13.transAxes)
    ax38.text(0.5, -0.1, "(b)", size=20, ha="center",
              transform=ax14.transAxes)
    ax39.text(0.5, -0.1, "(c)", size=20, ha="center",
              transform=ax15.transAxes)
    ax40.text(0.5, -0.1, "(d)", size=20, ha="center",
              transform=ax16.transAxes)

    image_id_list=['2011_1', '2011_2', '2012_1', '2012_1'...] #10 images id

    for i in range (len(image_id_list)):
        image_id=image_id_list[i] 
        raw_image_path='./Images/+ image_id +'jpg' 
        gt_image_path='./GT/+ image_id +'jpg'
        pre_image_path='./Pre/+ image_id +'jpg' 
        post_image_path='./Post/+ image_id +'jpg'        
        raw_image=Image.open(raw_image_path)       
        gt_image=Image.open(gt_image_path)
        pre_image=Image.open(pre_image_path) 
        post_image=Image.open(post_image_path)    
        if (i==0):
            ax1.imshow(raw_image)
            ax2.imshow(gt_image)
            ax3.imshow(pre_image)
            ax4.imshow(post_image)
        if (i==1):
            ax5.imshow(raw_image)
            ax6.imshow(gt_image)
            ax7.imshow(pre_image)
            ax8.imshow(post_image)
        if (i==2):
            ax9.imshow(raw_image)
            ax10.imshow(gt_image)
            ax11.imshow(pre_image)
            ax12.imshow(post_image)
        if (i==3):
            ax13.imshow(raw_image)
            ax14.imshow(gt_image)
            ax15.imshow(pre_image)
            ax16.imshow(post_image)
        ...

    plt.show()
    fig.savefig('./result.png',bbox_inches='tight')  # save the figure to file
    plt.close(fig)  # close the figure

Answer 1

这个怎么样：

import os
import matplotlib.pyplot as plt
import PIL
%matplotlib inline

rows = 2
os.chdir('/home/brian/Desktop/cats/')
files = os.listdir('/home/brian/Desktop/cats/')

for num, x in enumerate(files):
    img = PIL.Image.open(x)
    plt.subplot(rows,6,num+1)
    plt.title(x.split('.')[0])
    plt.axis('off')
    plt.imshow(img)

Answer 2

“手动”打开 40 Axes 相当麻烦。特别是如果所有Axes 的大小相同，最好使用plt.subplots() 函数，它返回一个numpy 轴数组，可以轻松索引或循环遍历。看看这段代码是否适合你（很难测试，因为我们没有你的输入图像）：

from matplotlib import pyplot as plt
import numpy as np

fig,axes = plt.subplots(nrows = 4, ncols = 10, figsize=(50,50))

for ax in axes.flatten():
    ax.axis('off')

##edit this line to include your own image ids
image_id_list=['{}_{}'.format(i,j) for i in range(2011,2016) for j in range(1,3)]

for i,image_id in enumerate(image_id_list):
    raw_image_path='./Images/'+ image_id +'jpg'
    raw_image = Image.open(raw_image_path)
    axes[0,i].imshow(raw_image)

    gt_image_path='./Images/'+ image_id +'jpg'
    gt_image = Image.open(gt_image_path)
    axes[0,i].imshow(gt_image)

    pre_image_path='./Images/'+ image_id +'jpg'
    pre_image = Image.open(pre_image_path)
    axes[0,i].imshow(pre_image)

    post_image_path='./Images/'+ image_id +'jpg'
    post_image = Image.open(post_image_path)
    axes[0,i].imshow(post_image)

plt.show()