cv-analysis-service/vidocp/table_parsing.py
2022-02-06 20:00:38 +01:00

74 lines
2.0 KiB
Python

from functools import partial
import cv2
import numpy as np
from pdf2image import pdf2image
from vidocp.utils.display import show_mpl
from vidocp.utils.draw import draw_stats, draw_rectangles
from vidocp.utils.filters import is_large_enough
from vidocp.utils.post_processing import remove_isolated
def add_external_contours(image, img):
contours, _ = cv2.findContours(img, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
# contours = filter(partial(is_large_enough, min_area=5000000), contours)
for cnt in contours:
x, y, w, h = cv2.boundingRect(cnt)
cv2.rectangle(image, (x, y), (x + w, y + h), 255, 1)
return image
def isolate_vertical_and_horizontal_components(img_bin):
line_min_width = 30
kernel_h = np.ones((1, line_min_width), np.uint8)
kernel_v = np.ones((line_min_width, 1), np.uint8)
img_bin_h = cv2.morphologyEx(img_bin, cv2.MORPH_OPEN, kernel_h)
img_bin_v = cv2.morphologyEx(img_bin, cv2.MORPH_OPEN, kernel_v)
img_bin_final = img_bin_h | img_bin_v
return img_bin_final
def parse_table(image: np.array):
gray_scale = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
th1, img_bin = cv2.threshold(gray_scale, 150, 255, cv2.THRESH_BINARY)
img_bin = ~img_bin
img_bin = isolate_vertical_and_horizontal_components(img_bin)
img_bin_final = add_external_contours(img_bin, img_bin)
_, _, stats, _ = cv2.connectedComponentsWithStats(~img_bin_final, connectivity=8, ltype=cv2.CV_32S)
def is_large_enough(stat):
x1, y1, w, h, area = stat
return area > 3000
stats = np.vstack(list(filter(is_large_enough, stats)))
rects = stats[:, :-1][2:]
# FIXME: For some reason some isolated rects remain.
rects = remove_isolated(rects, input_sorted=True)
return rects
def annotate_tables_in_pdf(pdf_path, page_index=1):
page = pdf2image.convert_from_path(pdf_path, first_page=page_index + 1, last_page=page_index + 1)[0]
page = np.array(page)
stats = parse_table(page)
page = draw_rectangles(page, stats)
show_mpl(page)