Python 图片处理

Step1

提取PDF中的图片，并另存

Step2

去除灰色纸张背景

import PyPDF2
from PIL import ImageEnhance,Image,ImageFilter
import cv2
import numpy as np
from skimage.filters import unsharp_mask
from skimage.filters import gaussian
from skimage.restoration import denoise_tv_chambollelocal = './'pdf_file = open(local+'001.pdf', 'rb')
pdf_reader = PyPDF2.PdfReader(pdf_file)num_pages = len(pdf_reader.pages)
print("num : "+str(num_pages))
pic_n=0
# 遍历每一页
for page_num in range(num_pages):# 获取当前页对象page_obj = pdf_reader.pages[page_num]# 获取当前页中的所有对象page_objs = page_obj['/Resources']['/XObject'].get_object()# 遍历每个对象for obj_name in page_objs:# 判断对象是否为图片if page_objs[obj_name]['/Subtype'] == '/Image':# 获取图片对象img_obj = page_objs[obj_name]# 获取图片数据img_data = img_obj.get_data()# 将图片数据保存为文件with open(local+"/99_tmp.jpg", 'wb') as img_file:img_file.write(img_data)
###################################################################################### 图片处理image = Image.open(local+"/99_tmp.jpg")#饱和度enhancer = ImageEnhance.Color(image)C_image = enhancer.enhance(0.001)C_image.save("./0_tmp.jpg")img = cv2.imread('./0_tmp.jpg')# 对每个像素进行对比度调整 alpha=对比度  beta=亮度img_contrast = cv2.convertScaleAbs(img, alpha=1.4, beta=0)####################################################################################pnum=str(page_num).zfill(4)pic_str=str(pic_n).zfill(4)img_path ="./image_heibai/"+ pic_str + "_" +"page_"+pnum + '.jpg'cv2.imwrite(img_path,img_contrast) print("image : "+img_path)pic_n=pic_n+1

Step3 

去除黑色边框

Step4

去除阴影部分，字清晰