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Add support for table areas and regions

add-ocr
Vinayak Mehta 2020-12-06 07:04:47 +05:30
parent 1287abeeaf
commit 6612a2f58d
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GPG Key ID: 2170CDB940114C1D
1 changed files with 54 additions and 25 deletions
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57
camelot/parsers/lattice_ocr.py
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@ -17,7 +17,7 @@ from PIL import Image
from .base import BaseParser
from ..core import Table
from ..utils import TemporaryDirectory, merge_close_lines, scale_image, segments_in_bbox
from ..utils import TemporaryDirectory, merge_close_lines, scale_pdf, segments_in_bbox
from ..image_processing import (
adaptive_threshold,
find_lines,
@ -32,6 +32,7 @@ logger = logging.getLogger("camelot")
class LatticeOCR(BaseParser):
def __init__(
self,
table_regions=None,
table_areas=None,
line_scale=15,
line_tol=2,
@ -41,6 +42,7 @@ class LatticeOCR(BaseParser):
iterations=0,
resolution=300,
):
self.table_regions = table_regions
self.table_areas = table_areas
self.line_scale = line_scale
self.line_tol = line_tol
@ -59,7 +61,7 @@ class LatticeOCR(BaseParser):
from ..ext.ghostscript import Ghostscript
self.imagename = "".join([self.rootname, ".png"])
gs_call = "-q -sDEVICE=png16m -o {} -r300 {}".format(
gs_call = "-q -sDEVICE=png16m -o {} -r900 {}".format(
self.imagename, self.filename
)
gs_call = gs_call.encode().split()
@ -69,13 +71,51 @@ class LatticeOCR(BaseParser):
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",
@ -89,19 +129,8 @@ class LatticeOCR(BaseParser):
iterations=self.iterations,
)
if self.table_areas is not None:
areas = []
for area in self.table_areas:
x1, y1, x2, y2 = area.split(",")
x1 = int(float(x1))
y1 = int(float(y1))
x2 = int(float(x2))
y2 = int(float(y2))
areas.append((x1, y1, abs(x2 - x1), abs(y2 - y1)))
areas = scale_areas(self.table_areas, image_scalers)
table_bbox = find_joints(areas, vertical_mask, horizontal_mask)
else:
contours = find_contours(vertical_mask, horizontal_mask)
table_bbox = find_joints(contours, vertical_mask, horizontal_mask)
self.table_bbox_unscaled = copy.deepcopy(table_bbox)