使用 plt.imshow() 显示多张图片

Question

如何使用matlib函数plt.imshow(image)显示多张图片？

例如我的代码如下：

for file in images:
    process(file)

def process(filename):
    image = mpimg.imread(filename)
    <something gets done here>
    plt.imshow(image)

我的结果表明，只有最后处理的图像有效地覆盖了其他图像

Answer 1

您可以使用以下方法设置框架以显示多个图像：

import matplotlib.pyplot as plt
import matplotlib.image as mpimg

def process(filename: str=None) -> None:
    """
    View multiple images stored in files, stacking vertically

    Arguments:
        filename: str - path to filename containing image
    """
    image = mpimg.imread(filename)
    # <something gets done here>
    plt.figure()
    plt.imshow(image)

for file in images:
    process(file)

这将垂直堆叠图像

Answer 2

要显示多个图像，请使用 subplot()

plt.figure()

#subplot(r,c) provide the no. of rows and columns
f, axarr = plt.subplots(4,1) 

# use the created array to output your multiple images. In this case I have stacked 4 images vertically
axarr[0].imshow(v_slice[0])
axarr[1].imshow(v_slice[1])
axarr[2].imshow(v_slice[2])
axarr[3].imshow(v_slice[3])

Answer 3

首先，将文件中的图像加载到 numpy 矩阵中

from typing import Union,List
import numpy
import cv2
import os
def load_image(image: Union[str, numpy.ndarray]) -> numpy.ndarray:
    # Image provided ad string, loading from file ..
    if isinstance(image, str):
        # Checking if the file exist
        if not os.path.isfile(image):
            print("File {} does not exist!".format(imageA))
            return None
        # Reading image as numpy matrix in gray scale (image, color_param)
        return cv2.imread(image, 0)

    # Image alredy loaded
    elif isinstance(image, numpy.ndarray):
        return image

    # Format not recognized
    else:
        print("Unrecognized format: {}".format(type(image)))
        print("Unrecognized format: {}".format(image))
    return None

然后您可以使用以下方法绘制多个图像：

import matplotlib.pyplot as plt
def show_images(images: List[numpy.ndarray]) -> None:
    n: int = len(images)
    f = plt.figure()
    for i in range(n):
        # Debug, plot figure
        f.add_subplot(1, n, i + 1)
        plt.imshow(images[i])

    plt.show(block=True)

show_images 方法接受输入的图像列表，您可以使用load_image 方法迭代地读取这些图像。