lib/ocr_1.py

from PIL import Image, ImageFilter
import cv2
import pytesseract
from pytesseract import Output
from os import listdir
from os.path import isfile, join
import numpy as np
import json
import matplotlib.pyplot as plt
from pdf2image import convert_from_path
from matplotlib import pyplot as plt
import re

def processFiles(pdfs, verbose = False) :
    images_per_pdf_2d = [convert_from_path(file) for file in pdfs]
    
    images_per_pdf = []
    docfilenames = []
    pagenames = []
    fileindices = []
    for i in range(len(images_per_pdf_2d)) :
        docfilenames.append(pdfs[i][:-4])
        pageindices = []
        for j in range(len(images_per_pdf_2d[i])) :
            images_per_pdf.append(images_per_pdf_2d[i][j])
            pagenames.append(pdfs[i][:-4] + '_page_' + str(j))
            pageindices.append(len(pagenames) - 1)
            # print(i, j, len(pagenames) - 1, pagenames[-1])
    
        fileindices.append(pageindices)
    
    gray_images_per_pdf_cropped = []
    for i in range(len(images_per_pdf)) :
        image = images_per_pdf[i]
        crop = image.convert("L").crop((
                                    750, 150,      # left top point
                                    1654, 850       # right bottom point
                                    ))
        gray_images_per_pdf_cropped.append(crop)
    
    texts = [pytesseract.image_to_string(image, lang='rus') for image in gray_images_per_pdf_cropped]
    fulltexts = [pytesseract.image_to_string(image, lang='rus') for image in images_per_pdf]
    
    cropped_images = gray_images_per_pdf_cropped
    init_size = cropped_images[0].size
    thresh_imgs = [
                image.resize(
                    (init_size[0] //4, init_size[1] // 4)
                    ).point(
                        lambda x: 0 if x < 220 else 255
                        ).filter(
                            ImageFilter.MedianFilter(5)
                            ).filter(
                                ImageFilter.MinFilter(15) #15
                                )  for i,(name,image) in enumerate(zip(pagenames, cropped_images)) 
    ]
    
    masks = thresh_imgs
    masks_arr = [np.array(img) for img in masks]
    mask_shape = masks_arr[0].shape
    
    str_size = 7
    masks = []
    masks_bw = []
    for name, mask in zip(pagenames, masks_arr):
        cleaned_mask = mask.copy()
    
        for iter in range(mask_shape[0] // str_size):
            temp_mean = int(cleaned_mask[iter*str_size : iter*str_size + str_size, :].mean())
    
            if (temp_mean < 49) or (temp_mean > 160):
                cleaned_mask[iter*str_size : iter*str_size + str_size, :] = 255
    
        vertical_threshold = 200
    
        for i in range(mask_shape[1] // str_size + 1):
            if (i*str_size + str_size) > mask_shape[1]:
                temp_mean_vertical = int(cleaned_mask[:, i*str_size : mask_shape[1]].mean())
    
                if temp_mean_vertical > vertical_threshold:
                    cleaned_mask[:, i*str_size : mask_shape[1]] = 255
            else:
                temp_mean_vertical = int(cleaned_mask[:, i*str_size : i*str_size + str_size].mean())
    
                if temp_mean_vertical > vertical_threshold:
                    cleaned_mask[:, i*str_size : i*str_size + str_size] = 255
        
        image = Image.fromarray(cleaned_mask).filter(
                                        ImageFilter.MedianFilter(13)
                                    ).filter(
                                        ImageFilter.MinFilter(25) #15
                                    )
        masks.append(image)
        masks_bw.append(image.convert('1'))
    
    masks_bw_arr = [np.array(img) for img in masks_bw]
    
    # check which pages have address box: if there is no address box the mask is empty
    
    addressexists = [bool((~mask_bw).sum()) for mask_bw in masks_bw_arr]
    
    # this is a list of CB names that may be used in address
    
    CBnames = [
        'цб рф',
        'центральный банк',
        'центрального банка',
        'банк россии',
        'банка россии',
    ]
    
    # check which pages have address box addressed to CB
    
    toCB = []
    for i in range(len(addressexists)) :
        iftoCB = False
        for j in range(len(CBnames)) :
            if addressexists[i] and CBnames[j] in texts[i].lower() :
                iftoCB = True
                break
    
        toCB.append(iftoCB)
    
    # build 3-level list: file -> doc -> page
    
    docindices = []
    doctypes = []
    for i in range(len(fileindices)) :
        docs = []
        types = []
        pages = []
        doctype = False
        for j in range(len(fileindices[i])) :
            index = fileindices[i][j]
            ifaddress = addressexists[index]
            iftoCB = toCB[index]
            if ifaddress :
                if len(pages) > 0 :
                    docs.append(pages)
                    types.append(doctype)
                    
                pages = []
                doctype = iftoCB
            
            pages.append(index)
    
        docs.append(pages)
        types.append(doctype)
        docindices.append(docs)
        doctypes.append(types)
    
    cropped = cropped_images
    orig_size = cropped[0].size
    masks = [mask.convert('L').resize((orig_size)) for mask in masks]
    
    if verbose :
        for i in range(len(masks)) :
            img = np.array(masks[i])
            out = np.array(cropped[i])
            
            bw = cv2.inRange(img, 0, 12)
            contours, hierarchy = cv2.findContours(bw, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
            
            aaa = cv2.drawContours(out, contours, -1, (0, 255, 0), 5,  cv2.LINE_AA, hierarchy, 1)
        
            print()
            print(pagenames[i])
            print('Address exists :', addressexists[i])
            print('To CB :', toCB[i])
            # if addressflags[i] :
                
            #     if toCB[i] :
            #         print('text :', texts[i])
            plt.imshow(Image.fromarray(aaa))
            plt.show()
    
    # print recognized text with marks: file - > doc # and doc type -> page number and text
    
    docs_info = []
    for i in range(len(docindices)) :
        docs = []
        if verbose : 
            print('File =', docfilenames[i])
            
        for j in range(len(docindices[i])) :
            doc = {}
            doctype = 'Сопроводительное письмо'
            if doctypes[i][j] :
                doctype = 'Обращение'
    
            doc['Тип документа'] = doctype
            text = ''
            if verbose :
                print('Doc =', j, 'Type =', doctype)
                
            for k in range(len(docindices[i][j])) :
                index = docindices[i][j][k]
                text += fulltexts[index]
                if verbose :
                    print('Page =', pagenames[index])
                    print(fulltexts[index])
                    print('--- end of page ---')
                    print()

            text = re.sub(r'\n +', r'\n', text)
            text = re.sub(r'\n+', r'\n', text)
            doc['Текст документа'] = text
            docs.append(doc)
    
        docs_info.append(docs)
    
    for i in range(len(docindices)) :
        for j in range(len(docindices[i])) :
            for k in range(len(docindices[i][j])) :
                index = docindices[i][j][k]
                if toCB[index] :
                    if verbose :
                        print('Page =', pagenames[index])
                        print(texts[index].strip())
                        print('------------------------')
                        print()

    return docs_info

def processSingleFile(file) :
    return processFiles([file])

# docs_info =  
#  [ 
#    {
#      'Имя поля' : 'Текст поля',
#      ...
#    },
#    ...
#  ]
# то есть это массив документов, содержащихся в файле, для каждого документа задан словарь 'Имя поля' : 'Текст поля' (сейчас там 2 поля для каждого документа)