使用Python从PDF文件中按顺序提取图像

import PyPDF2
from PIL import Image

pdf_file = open('file.pdf', 'rb')
pdf_reader = PyPDF2.PdfFileReader(pdf_file)

num_pages = pdf_reader.numPages

for page_num in range(num_pages):
    page = pdf_reader.getPage(page_num)
    if '/XObject' in page['/Resources']:
        x_object = page['/Resources']['/XObject'].getObject()
        for obj in x_object:
            if x_object[obj]['/Subtype'] == '/Image':
                image = x_object[obj]
                if image['/ColorSpace'] == '/DeviceRGB':
                    mode = 'RGB'
                else:
                    mode = 'P'
                if '/Filter' in image:
                    if image['/Filter'] == '/FlateDecode':
                        img = Image.frombytes(mode, (image['/Width'], image['/Height']), image._data)
                        img.save('image{}.png'.format(page_num + 1))
                    elif image['/Filter'] == '/DCTDecode':
                        img = open('image{}.jpg'.format(page_num + 1), 'wb')
                        img.write(image._data)
                        img.close()
                    elif image['/Filter'] == '/JPXDecode':
                        img = open('image{}.jp2'.format(page_num + 1), 'wb')
                        img.write(image._data)
                        img.close()