Add support for table areas and regions

camelot/handlers.py

@@ -6,7 +6,7 @@ import sys
 from PyPDF2 import PdfFileReader, PdfFileWriter
 
 from .core import TableList
-from .parsers import Stream, Lattice
+from .parsers import Lattice, Stream, LatticeOCR, StreamOCR
 from .utils import (
     TemporaryDirectory,
     get_page_layout,
@@ -163,14 +163,19 @@ class PDFHandler(object):
             List of tables found in PDF.
 
         """
+        parsers = {
+            "lattice": Lattice,
+            "stream": Stream,
+            "lattice_ocr": LatticeOCR,
+            "stream_ocr": StreamOCR,
+        }
+
         tables = []
         with TemporaryDirectory() as tempdir:
             for p in self.pages:
                 self._save_page(self.filepath, p, tempdir)
-            pages = [
-                os.path.join(tempdir, f"page-{p}.pdf") for p in self.pages
-            ]
-            parser = Lattice(**kwargs) if flavor == "lattice" else Stream(**kwargs)
+            pages = [os.path.join(tempdir, f"page-{p}.pdf") for p in self.pages]
+            parser = parsers[flavor](**kwargs)
             for p in pages:
                 t = parser.extract_tables(
                     p, suppress_stdout=suppress_stdout, layout_kwargs=layout_kwargs

camelot/io.py

@@ -98,9 +98,10 @@ def read_pdf(
     tables : camelot.core.TableList
 
     """
-    if flavor not in ["lattice", "stream"]:
+    if flavor not in ["lattice", "stream", "lattice_ocr", "stream_ocr"]:
         raise NotImplementedError(
-            "Unknown flavor specified." " Use either 'lattice' or 'stream'"
+            "Unknown flavor specified. Use one of the following: "
+            "'lattice', 'stream', 'lattice_ocr', 'stream_ocr'"
         )
 
     with warnings.catch_warnings():

camelot/parsers/__init__.py

@@ -1,4 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from .stream import Stream
 from .lattice import Lattice
+from .stream import Stream
+from .lattice_ocr import LatticeOCR
+from .stream_ocr import StreamOCR

camelot/parsers/lattice_ocr.py

@@ -0,0 +1,243 @@
+# -*- coding: utf-8 -*-
+
+import os
+import copy
+import logging
+import subprocess
+
+try:
+    import easyocr
+except ImportError:
+    _HAS_EASYOCR = False
+else:
+    _HAS_EASYOCR = True
+
+import pandas as pd
+from PIL import Image
+
+from .base import BaseParser
+from ..core import Table
+from ..utils import TemporaryDirectory, merge_close_lines, scale_pdf, segments_in_bbox
+from ..image_processing import (
+    adaptive_threshold,
+    find_lines,
+    find_contours,
+    find_joints,
+)
+
+
+logger = logging.getLogger("camelot")
+
+
+class LatticeOCR(BaseParser):
+    def __init__(
+        self,
+        table_regions=None,
+        table_areas=None,
+        line_scale=15,
+        line_tol=2,
+        joint_tol=2,
+        threshold_blocksize=15,
+        threshold_constant=-2,
+        iterations=0,
+        resolution=300,
+    ):
+        self.table_regions = table_regions
+        self.table_areas = table_areas
+        self.line_scale = line_scale
+        self.line_tol = line_tol
+        self.joint_tol = joint_tol
+        self.threshold_blocksize = threshold_blocksize
+        self.threshold_constant = threshold_constant
+        self.iterations = iterations
+        self.resolution = resolution
+
+        if _HAS_EASYOCR:
+            self.reader = easyocr.Reader(['en'], gpu=False)
+        else:
+            raise ImportError("easyocr is required to run OCR on image-based PDFs.")
+
+    def _generate_image(self):
+        from ..ext.ghostscript import Ghostscript
+
+        self.imagename = "".join([self.rootname, ".png"])
+        gs_call = "-q -sDEVICE=png16m -o {} -r900 {}".format(
+            self.imagename, self.filename
+        )
+        gs_call = gs_call.encode().split()
+        null = open(os.devnull, "wb")
+        with Ghostscript(*gs_call, stdout=null) as gs:
+            pass
+        null.close()
+
+    def _generate_table_bbox(self):
+        def scale_areas(areas, scalers):
+            scaled_areas = []
+            for area in areas:
+                x1, y1, x2, y2 = area.split(",")
+                x1 = float(x1)
+                y1 = float(y1)
+                x2 = float(x2)
+                y2 = float(y2)
+                x1, y1, x2, y2 = scale_pdf((x1, y1, x2, y2), scalers)
+                scaled_areas.append((x1, y1, abs(x2 - x1), abs(y2 - y1)))
+            return scaled_areas
+
+        self.image, self.threshold = adaptive_threshold(
+            self.imagename, blocksize=self.threshold_blocksize, c=self.threshold_constant
+        )
+
+        image_width = self.image.shape[1]
+        image_height = self.image.shape[0]
+        image_width_scaler = image_width / float(self.pdf_width)
+        image_height_scaler = image_height / float(self.pdf_height)
+        image_scalers = (image_width_scaler, image_height_scaler, self.pdf_height)
+
+        if self.table_areas is None:
+            regions = None
+            if self.table_regions is not None:
+                regions = scale_areas(self.table_regions, image_scalers)
+
+            vertical_mask, vertical_segments = find_lines(
+                self.threshold,
+                regions=regions,
+                direction="vertical",
+                line_scale=self.line_scale,
+                iterations=self.iterations,
+            )
+            horizontal_mask, horizontal_segments = find_lines(
+                self.threshold,
+                regions=regions,
+                direction="horizontal",
+                line_scale=self.line_scale,
+                iterations=self.iterations,
+            )
+
+            contours = find_contours(vertical_mask, horizontal_mask)
+            table_bbox = find_joints(contours, vertical_mask, horizontal_mask)
+        else:
+            vertical_mask, vertical_segments = find_lines(
+                self.threshold,
+                direction="vertical",
+                line_scale=self.line_scale,
+                iterations=self.iterations,
+            )
+            horizontal_mask, horizontal_segments = find_lines(
+                self.threshold,
+                direction="horizontal",
+                line_scale=self.line_scale,
+                iterations=self.iterations,
+            )
+
+            areas = scale_areas(self.table_areas, image_scalers)
+            table_bbox = find_joints(areas, vertical_mask, horizontal_mask)
+
+        self.table_bbox_unscaled = copy.deepcopy(table_bbox)
+
+        self.table_bbox = table_bbox
+        self.vertical_segments = vertical_segments
+        self.horizontal_segments = horizontal_segments
+
+    def _generate_columns_and_rows(self, table_idx, tk):
+        cols, rows = zip(*self.table_bbox[tk])
+        cols, rows = list(cols), list(rows)
+        cols.extend([tk[0], tk[2]])
+        rows.extend([tk[1], tk[3]])
+        # sort horizontal and vertical segments
+        cols = merge_close_lines(sorted(cols), line_tol=self.line_tol)
+        rows = merge_close_lines(sorted(rows), line_tol=self.line_tol)
+        # make grid using x and y coord of shortlisted rows and cols
+        cols = [(cols[i], cols[i + 1]) for i in range(0, len(cols) - 1)]
+        rows = [(rows[i], rows[i + 1]) for i in range(0, len(rows) - 1)]
+
+        return cols, rows
+
+
+    def _generate_table(self, table_idx, cols, rows, **kwargs):
+        table = Table(cols, rows)
+        # set table edges to True using ver+hor lines
+        table = table.set_edges(self.vertical_segments, self.horizontal_segments, joint_tol=self.joint_tol)
+        # set table border edges to True
+        table = table.set_border()
+        # set spanning cells to True
+        table = table.set_span()
+
+        _seen = set()
+        for r_idx in range(len(table.cells)):
+            for c_idx in range(len(table.cells[r_idx])):
+                if (r_idx, c_idx) in _seen:
+                    continue
+
+                _seen.add((r_idx, c_idx))
+
+                _r_idx = r_idx
+                _c_idx = c_idx
+
+                if table.cells[r_idx][_c_idx].hspan:
+                    while not table.cells[r_idx][_c_idx].right:
+                        _c_idx += 1
+                        _seen.add((r_idx, _c_idx))
+
+                if table.cells[_r_idx][c_idx].vspan:
+                    while not table.cells[_r_idx][c_idx].bottom:
+                        _r_idx += 1
+                        _seen.add((_r_idx, c_idx))
+
+                for i in range(r_idx, _r_idx + 1):
+                    for j in range(c_idx, _c_idx + 1):
+                        _seen.add((i, j))
+
+                x1 = int(table.cells[r_idx][c_idx].x1)
+                y1 = int(table.cells[_r_idx][_c_idx].y1)
+
+                x2 = int(table.cells[_r_idx][_c_idx].x2)
+                y2 = int(table.cells[r_idx][c_idx].y2)
+
+                with TemporaryDirectory() as tempdir:
+                    temp_image_path = os.path.join(tempdir, f"{table_idx}_{r_idx}_{c_idx}.png")
+
+                    cell_image = Image.fromarray(self.image[y2:y1, x1:x2])
+                    cell_image.save(temp_image_path)
+
+                    text = self.reader.readtext(temp_image_path, detail=0)
+                    text = " ".join(text)
+
+                table.cells[r_idx][c_idx].text = text
+
+        data = table.data
+        table.df = pd.DataFrame(data)
+        table.shape = table.df.shape
+
+        table.flavor = "lattice_ocr"
+        table.accuracy = 0
+        table.whitespace = 0
+        table.order = table_idx + 1
+        table.page = int(os.path.basename(self.rootname).replace("page-", ""))
+
+        # for plotting
+        table._text = None
+        table._image = (self.image, self.table_bbox_unscaled)
+        table._segments = (self.vertical_segments, self.horizontal_segments)
+        table._textedges = None
+
+        return table
+
+    def extract_tables(self, filename, suppress_stdout=False, layout_kwargs={}):
+        self._generate_layout(filename, layout_kwargs)
+        if not suppress_stdout:
+            logger.info("Processing {}".format(os.path.basename(self.rootname)))
+
+        self._generate_image()
+        self._generate_table_bbox()
+
+        _tables = []
+        # sort tables based on y-coord
+        for table_idx, tk in enumerate(
+            sorted(self.table_bbox.keys(), key=lambda x: x[1], reverse=True)
+        ):
+            cols, rows = self._generate_columns_and_rows(table_idx, tk)
+            table = self._generate_table(table_idx, cols, rows)
+            table._bbox = tk
+            _tables.append(table)
+
+        return _tables

camelot/parsers/stream_ocr.py

@@ -0,0 +1,7 @@
+# -*- coding: utf-8 -*-
+
+from .base import BaseParser
+
+
+class StreamOCR(BaseParser):
+    pass

camelot/plotting.py

@@ -48,7 +48,7 @@ class PlotMethods(object):
         if filename is not None:
             fig.savefig(filename)
             return None
-            
+
         return fig
 
     def text(self, table):

camelot/utils.py

@@ -93,7 +93,6 @@ def download_url(url):
     return filepath
 
 
-stream_kwargs = ["columns", "edge_tol", "row_tol", "column_tol"]
 lattice_kwargs = [
     "process_background",
     "line_scale",
@@ -106,6 +105,7 @@ lattice_kwargs = [
     "iterations",
     "resolution",
 ]
+stream_kwargs = ["columns", "edge_tol", "row_tol", "column_tol"]
 
 
 def validate_input(kwargs, flavor="lattice"):
@@ -116,14 +116,14 @@ def validate_input(kwargs, flavor="lattice"):
                 f"{','.join(sorted(isec))} cannot be used with flavor='{flavor}'"
             )
 
-    if flavor == "lattice":
+    if flavor in ["lattice", "lattice_ocr"]:
         check_intersection(stream_kwargs, kwargs)
     else:
         check_intersection(lattice_kwargs, kwargs)
 
 
 def remove_extra(kwargs, flavor="lattice"):
-    if flavor == "lattice":
+    if flavor in ["lattice", "lattice_ocr"]:
         for key in kwargs.keys():
             if key in stream_kwargs:
                 kwargs.pop(key)

setup.py

@@ -27,6 +27,10 @@ cv_requires = [
     'opencv-python>=3.4.2.17'
 ]
 
+ocr_requires = [
+    'easyocr>=1.1.10'
+]
+
 plot_requires = [
     'matplotlib>=2.2.3',
 ]
@@ -40,7 +44,7 @@ dev_requires = [
     'Sphinx>=3.1.2'
 ]
 
-all_requires = cv_requires + plot_requires
+all_requires = cv_requires + ocr_requires + plot_requires
 dev_requires = dev_requires + all_requires
 
 
@@ -57,10 +61,11 @@ def setup_package():
                     packages=find_packages(exclude=('tests',)),
                     install_requires=requires,
                     extras_require={
-                        'all': all_requires,
                         'cv': cv_requires,
+                        'ocr': ocr_requires,
+                        'plot': plot_requires,
+                        'all': all_requires,
                         'dev': dev_requires,
-                        'plot': plot_requires
                     },
                     entry_points={
                         'console_scripts': [