cv-analysis-service/vidocp/figure_detection.py

import cv2
import numpy as np
from pdf2image import pdf2image

from vidocp.utils.detection import detect_large_coherent_structures
from vidocp.utils.display import show_mpl
from vidocp.utils.draw import draw_rectangles
from vidocp.utils.post_processing import remove_included
from vidocp.utils.filters import is_large_enough, has_acceptable_format
from vidocp.utils.text import remove_primary_text_regions


def is_likely_figure(cont, min_area=5000, max_width_to_hight_ratio=6):
    return is_large_enough(cont, min_area) and has_acceptable_format(cont, max_width_to_hight_ratio)


def detect_figures(image: np.array):

    image = image.copy()

    image = remove_primary_text_regions(image)
    cnts = detect_large_coherent_structures(image)

    cnts = filter(is_likely_figure, cnts)
    rects = map(cv2.boundingRect, cnts)
    rects = remove_included(rects)

    return rects


def detect_figures_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)

    redaction_contours = detect_figures(page)
    page = draw_rectangles(page, redaction_contours)

    show_mpl(page)