ImageProcessor.py

import cv2
import fitz
import numpy as np
import os
import pandas as pd
import pytesseract
import warnings

def pdf2png(folderpath):
    doc = fitz.open(folderpath + '/opinion.pdf')
    zoom = 1
    mat = fitz.Matrix(zoom, zoom)
    for (i, p) in enumerate(doc):
        pix = p.get_pixmap(matrix=mat)
        pix.save(folderpath + '/' + str(i) + '.png')

def get_footnote_bbox(filename):
    footnotes_bbox = (None, None, None, None)
    x1p, y1p, x2p, y2p = get_page_bbox(filename)
    x1h, y1h, x2h, y2h = get_header_bbox(filename)
    image = cv2.imread(filename)
    im_h, im_w, im_d = image.shape
    gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    thresh = cv2.threshold(gray, 240, 255, cv2.THRESH_BINARY_INV)[1]
    kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (20, 1))
    dilate = cv2.dilate(thresh, kernel, iterations=1)
    cnts = cv2.findContours(dilate, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
    cnts = cnts[0] if len(cnts) == 2 else cnts[1]
    cnts = sorted(cnts, key=lambda x: cv2.boundingRect(x)[1])
    for (i, c) in enumerate(cnts):
        x, y, w, h = cv2.boundingRect(c)
        if h < 7 and w > 50 and y > y1p and x - x1p < 30:
            footnotes_bbox = (x, y, x2p, y2p)
    return footnotes_bbox

def get_header_bbox(filename):
    image = cv2.imread(filename)
    im_h, im_w, im_d = image.shape
    base_image = image.copy()
    gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    blur = cv2.GaussianBlur(gray, (9,9), 0)
    thresh = cv2.threshold(blur, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]

    kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (200,10))
    dilate = cv2.dilate(thresh, kernel, iterations=1)

    cnts = cv2.findContours(dilate, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
    cnts = cnts[0] if len(cnts) == 2 else cnts[1]
    cnts = sorted(cnts, key=lambda x: cv2.boundingRect(x)[1])
    for (i,c) in enumerate(cnts):
        x,y,w,h = cv2.boundingRect(c)
        break
    header_bbox = (x, y, x+w, y+40)
    # header_bbox = (145, 45, 465, 155) # For digitized variants
    return header_bbox


def get_page_bbox(filename):
    image = cv2.imread(filename)
    im_h, im_w, im_d = image.shape
    gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    blur = cv2.GaussianBlur(gray, (7, 7), 0)
    thresh = cv2.threshold(blur, 240, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]
    kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (50, 10))
    dilate = cv2.dilate(thresh, kernel, iterations=1)
    cnts = cv2.findContours(dilate, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
    cnts = cnts[0] if len(cnts) == 2 else cnts[1]
    cnts = sorted(cnts, key=lambda x: cv2.boundingRect(x)[1])

    header_bbox = get_header_bbox(filename)
    all_x1 = [cv2.boundingRect(c)[0] for c in cnts]
    all_y1 = [cv2.boundingRect(c)[1] for c in cnts]
    all_x2 = [cv2.boundingRect(c)[0] + cv2.boundingRect(c)[2] for c in cnts]
    all_y2 = [cv2.boundingRect(c)[1] + cv2.boundingRect(c)[3] for c in cnts]
    return min(all_x1), header_bbox[1], max(all_x2), max(all_y2)

def get_case_separator(filename):
    new_case_line = (None, None, None, None)
    x1p, y1p, x2p, y2p = get_page_bbox(filename)
    x1h, y1h, x2h, y2h = get_header_bbox(filename)

    image = cv2.imread(filename)
    im_h, im_w, im_d = image.shape
    gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    blur = cv2.GaussianBlur(gray, (7, 7), 0)
    thresh = cv2.threshold(blur, 240, 255, cv2.THRESH_BINARY_INV)[1]
    kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (20, 1))
    dilate = cv2.dilate(thresh, kernel, iterations=1)
    cnts = cv2.findContours(dilate, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
    cnts = cnts[0] if len(cnts) == 2 else cnts[1]
    cnts = sorted(cnts, key=lambda x: cv2.boundingRect(x)[1])
    for (i, c) in enumerate(cnts):
        x, y, w, h = cv2.boundingRect(c)
        x_center = (x1p + x2p) / 2
        if h < 8 and w > 70 and ((x - x1p) < x_center and (x - x1p) > 0.3 * x_center) and (y > y1p and y > y1h):  #
            new_case_line = (x1p, y, x2p, y)
            break
    return new_case_line

def get_page_elements(filename):
    page_bbox = get_page_bbox(filename)
    header_bbox = get_header_bbox(filename)
    fn_bbox = get_footnote_bbox(filename)
    case_separator_bbox = get_case_separator(filename)
    if fn_bbox[0] is not None:
        body_bbox = (page_bbox[0], header_bbox[3], page_bbox[2], fn_bbox[1])
    else:
        body_bbox = (page_bbox[0], header_bbox[3], page_bbox[2], page_bbox[3])

    image = cv2.imread(filename)
    cv2.rectangle(image, (page_bbox[0], page_bbox[1]), (page_bbox[2], page_bbox[3]), (0, 0, 0), 4)
    cv2.rectangle(image, (header_bbox[0], header_bbox[1]), (header_bbox[2], header_bbox[3]), (0, 255, 0), 2)
    cv2.rectangle(image, (body_bbox[0], body_bbox[1]), (body_bbox[2], body_bbox[3]), (255, 0, 0), 2)
    if fn_bbox[0] is not None:
        cv2.rectangle(image, (fn_bbox[0], fn_bbox[1]), (fn_bbox[2], fn_bbox[3]), (0, 0, 255), 2)
    if case_separator_bbox[0] is not None:
        cv2.rectangle(image, (case_separator_bbox[0], case_separator_bbox[1]),
                      (case_separator_bbox[2], case_separator_bbox[3]), (255, 0, 255), 2)

    return page_bbox, header_bbox, fn_bbox, body_bbox, case_separator_bbox, image

def process_file(folderpath):
    pdf2png(folderpath)
    files = [f for f in os.listdir(folderpath) if '.png' in f.lower() and "processed" not in f.lower()]
    data = {'Pg Ind':[],
            'Header X1':[], 'Header Y1': [], 'Header X2': [], 'Header Y2':[],
            'Body X1':[], 'Body Y1': [], 'Body X2': [], 'Body Y2':[],
            'Footer X1':[], 'Footer Y1': [], 'Footer X2': [], 'Footer Y2':[],
            'Page X1':[], 'Page Y1': [], 'Page X2': [], 'Page Y2':[],
            'Case Separator Y': [],
           }
    data_df = pd.DataFrame(data)
    for (i,f) in enumerate(files):
        page_bbox, header_bbox, fn_bbox, body_bbox, case_separator_bbox, image = get_page_elements(folderpath +'/' + f)
        ind = int(f.split('.png')[0])
        row = {'Pg Ind':[ind],
                'Header X1':[header_bbox[0]], 'Header Y1': [header_bbox[1]], 'Header X2': [header_bbox[2]], 'Header Y2':[header_bbox[3]],
                'Body X1':[body_bbox[0]], 'Body Y1': [body_bbox[1]], 'Body X2': [body_bbox[2]], 'Body Y2':[body_bbox[3]],
                'Footer X1':[fn_bbox[0]], 'Footer Y1': [fn_bbox[1]], 'Footer X2': [fn_bbox[2]], 'Footer Y2':[fn_bbox[3]],
                'Page X1':[page_bbox[0]], 'Page Y1': [page_bbox[1]], 'Page X2': [page_bbox[2]], 'Page Y2':[page_bbox[3]],
                'Case Separator Y': [case_separator_bbox[1]]
               }
        row_df = pd.DataFrame(row)
        data_df = pd.concat([data_df, row_df], ignore_index=True)
        cv2.imwrite(folderpath + '/' + str(ind) + '-processed.png', image)
    data_df['Pg Ind'] = data_df['Pg Ind'].astype('int')
    data_df.to_csv(folderpath +'/data.csv', index=False)