/usr/share/pyshared/gamera/roman_text.py is in python-gamera 3.3.2-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 | # -*- mode: python; indent-tabs-mode: nil; tab-width: 3 -*-
# vim: set tabstop=3 shiftwidth=3 expandtab:
#
# Copyright (C) 2001-2005 Karl MacMillan
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
"""
Usage
=====
(as inferred from the source by Michael Droettboom)
See the docstrings of the classes and functions for more information.
.. code::
from gamera import roman_text
# Load an image and a classifier (see documentation elsewhere)...
# image is a one-bit image
# classifier is a classifier object with a production database loaded
page = roman_text.ocr(image, classifier)
*page* is a ``Page`` object. You can display how the page was
segmenteted in different ways using ``.display_sections``,
``.display_lines``, ``.display_glyphs``, and
``.display_segmentation``.
Once you have a segmented page object, you can convert it to ASCII
using the ``make_string`` function. It takes as input a ``Section``
object, and an optional name-mapping function. The name-mapping
function is any function that takes a string with a symbol id_name and
returns a character (which may be Unicode). This function defines how
the names used in the training data map to characters in the output.
If no name-mapping function is provided a default one is used which
maps Gamera symbol id names to Unicode character names and then to
Unicode characters. All periods ('.') in the Gamera id name are
converted to spaces, and then the result is used as a Unicode
character name. For instance ``latin.capital.letter.a`` maps to
``LATIN CAPITAL LETTER A``. (`Charts of Unicode character names`_).
The version of Unicode used corresponds with that used in your version
of Python. For instance, Python 2.3.x supports Unicode 3.2.0.
.. _: http://www.unicode.org/charts/
.. code::
output = []
for section in page.sections:
output.append(roman_text.make_string(section))
"""
from gamera import core
import unicodedata
import string
class Page:
def __init__(self, image, glyphs):
"""Create a page with the given image."""
self.sections = []
self.image = image
self.glyphs = glyphs
self.section_search_size = 1
self.__fill = 0
self.__noise_size = 0
self.__large_size = 0
def __section_size_test(self, glyph):
"""Filter for section finding - removes very small and
very large glyphs"""
black_area = glyph.black_area()[0]
if black_area > self.__noise_size and \
glyph.nrows < self.__large_size and \
glyph.ncols < self.__large_size:
return 1
else:
return 0
def __avg_glyph_size(self, glyphs):
"""Compute the average glyph size for the page"""
total = 0.0
for g in glyphs:
total += g.nrows
total += g.ncols
return total / (2 * len(glyphs))
def __find_intersecting_rects(self, glyphs, index):
"""For section finding - return the index of glyphs intersecting
the glyph and the index passed in."""
g = glyphs[index]
inter = []
for i in range(len(glyphs)):
if i == index:
continue
if g.intersects(glyphs[i]):
inter.append(i)
return inter
def segment(self):
"""Segment the page into sections and lines. Also computes
all of the statistics for the sections and lines."""
self.find_sections()
self.find_lines()
for s in self.sections:
s.calculate_stats()
for line in s.lines:
line.calculate_stats()
def find_lines(self):
"""Find the lines within all of the sections. Must be called
after find_sections."""
for s in self.sections:
s.find_lines()
def find_sections(self):
"""Find the sections within an image - this finds large blocks
of text making it possible to find the lines within complex
text layouts."""
glyphs = self.glyphs
FUDGE = self.__avg_glyph_size(glyphs) * self.section_search_size
# remove noise and large objects
self.__noise_size = FUDGE
self.__large_size = FUDGE * 20
new_glyphs = []
for g in glyphs:
if self.__section_size_test(g):
new_glyphs.append(g)
else:
if self.__fill:
g.fill_white()
glyphs = new_glyphs
# Sort the glyphs left-to-right and top-to-bottom
glyphs.sort(lambda x, y: cmp(x.ul_x, y.ul_x))
glyphs.sort(lambda x, y: cmp(x.ul_y, y.ul_y))
# Create rectangles for each glyph that are bigger by FUDGE
big_rects = []
for g in glyphs:
ul_y = max(0, g.ul_y - FUDGE)
ul_x = max(0, g.ul_x - FUDGE)
lr_y = min(self.image.lr_y, g.lr_y + FUDGE)
lr_x = min(self.image.lr_x, g.lr_x + FUDGE)
ul_x = int(ul_x); ul_y = int(ul_y)
nrows = int(lr_y - ul_y + 1)
ncols = int(lr_x - ul_x + 1)
big_rects.append(core.Rect(core.Point(ul_x, ul_y), core.Dim(ncols, nrows)))
# Search for intersecting glyphs and merge them. This is
# harder than it seems at first because we want everything
# to merge together that intersects regardless of the order
# in the list. It ends up being similar to connected-component
# labeling. This is prone to be kind-of slow.
current = 0
rects = big_rects
while(1):
# Find the indexexes of any rects that interesect with current
inter = self.__find_intersecting_rects(rects, current)
# If we found intersecting rectangles merge them with them current
# rect, remove them from the list, and start the whole process
# over. We start over to make certain that everything that should
# be merged is.
if len(inter):
g = rects[current]
new_rects = [g]
for i in range(len(rects)):
if i == current:
continue
if i in inter:
g.union(rects[i])
else:
new_rects.append(rects[i])
rects = new_rects
current = 0
# If we didn't find anything that intersected move on to the next
# rectangle.
else:
current += 1
# Bail when we are done.
if current >= len(rects):
break
# Create the sections
sections = []
for rect in rects:
sections.append(Section(rect))
# Place the original (small) glyphs into the sections
for glyph in self.glyphs:
if self.__section_size_test(glyph):
for s in sections:
if s.bbox.intersects(glyph):
s.add_glyph(glyph)
break
# Fix up the bounding boxes
for s in sections:
s.calculate_bbox()
self.sections = sections
def display_sections(self, clear=1):
"""Display the sections found by placing a box around them
in a display. If clear is true then any boxes already on
the displayed are cleared first."""
# display the sections
result = self.sections
if self.image._display == None:
self.image.display()
display = self.image._display
if clear:
display.clear_all_boxes()
for rect in result:
b = rect.bbox
display.add_box(core.Rect(core.Point(b.ul_x, b.ul_y), core.Dim(b.ncols, b.nrows)))
def display_lines(self, clear=1):
"""Display the lines found by placing a box around them
in a display. If clear is true then any boxes already on
the displayed are cleared first."""
if self.image._display == None:
self.image.display()
display = self.image._display
if clear:
display.clear_all_boxes()
for s in self.sections:
for line in s.lines:
b = line.bbox
display.add_box(core.Rect(core.Point(b.ul_x, b.ul_y), core.Dim(b.ncols, b.nrows)))
def display_glyphs(self, clear=1):
if self.image._display == None:
self.image.display()
display = self.image._display
if clear:
display.clear_all_boxes()
for rect in self.glyphs:
b = rect
display.add_box(b.ul_y, b.ul_x, b.nrows, b.ncols)
def display_segmentation(self):
self.display_lines()
self.display_sections(0)
class Section:
def __init__(self, bbox):
self.bbox = core.Rect(bbox)
self.lines = []
self.glyphs = []
# stats
self.avg_glyph_area = 0
self.avg_glyph_height = 0
self.avg_glyph_width = 0
self.avg_line_height = 0
self.agv_line_width = 0
def find_tall_glyphs(self, stdev=20):
from gamera import stats
tall = []
for i in range(len(self.glyphs)):
g = self.glyphs[i]
if stats.samplestdev([g.nrows, self.avg_glyph_height]) > stdev:
tall.append(i)
return tall
def add_line(self, line):
self.lines.append(line)
self.lines.sort(lambda x, y: cmp(x.bbox.ul_y, y.bbox.ul_y))
def add_glyph(self, glyph):
self.glyphs.append(glyph)
def calculate_bbox(self):
assert(len(self.glyphs) > 0)
self.bbox = core.Rect(self.glyphs[0])
for glyph in self.glyphs:
self.bbox.union(glyph)
def calculate_stats(self):
self.calculate_glyph_stats()
self.calculate_line_stats()
def calculate_glyph_stats(self):
# calculate glyph stats
total_area = 0.0
total_gheight = 0.0
total_gwidth = 0.0
for g in self.glyphs:
nrows = g.nrows
ncols = g.ncols
total_area += nrows * ncols
total_gheight += nrows
total_gwidth += ncols
l = len(self.glyphs)
self.avg_glyph_area = total_area / l
self.avg_glyph_height = total_gheight / l
self.avg_glyph_width = total_gwidth / l
def calculate_line_stats(self):
# calculate line stats
total_lheight = 0.0
total_lwidth = 0.0
for line in self.lines:
total_lheight += line.bbox.nrows
total_lwidth += line.bbox.ncols
l = len(self.lines)
self.avg_line_height = total_lheight / l
self.avg_line_width = total_lwidth / l
def __find_intersecting_lines(self, glyphs, index):
g = glyphs[index]
inter = []
for i in range(len(glyphs)):
if i == index:
continue
if g.bbox.intersects(glyphs[i].bbox):
inter.append(i)
return inter
def find_lines(self):
# Remove abnormally tall glyphs that might interfer with
# line finding
self.calculate_glyph_stats()
tall_indexes = self.find_tall_glyphs()
tall = []
glyphs = []
for i in range(len(self.glyphs)):
if i in tall_indexes:
tall.append(self.glyphs[i])
else:
glyphs.append(self.glyphs[i])
orig_glyphs = self.glyphs
self.glyphs = glyphs
# find the lines - this is very basic for now
lines = []
for glyph in self.glyphs:
found = 0
for line in lines:
if line.contains_glyph(glyph):
line.add_glyph(glyph)
found = 1
break
if not found:
new_line = Line(glyph)
lines.append(new_line)
# Merge any overlapping lines
current = 0
while(1):
inter = self.__find_intersecting_lines(lines, current)
if len(inter):
new_lines = [lines[current]]
for i in range(len(lines)):
if i == current:
continue
if i in inter:
new_lines[0].merge(lines[i])
else:
new_lines.append(lines[i])
current = 0
lines = new_lines
else:
current += 1
if current >= len(lines):
break
# Put the tall glyphs back in by assigning them to the first line
# we come to that intersects.
for i in range(len(tall)):
for line in lines:
found = 0
if line.bbox.contains_y(tall[i].ul_y):
line.add_glyph(tall[i])
found = 1
break
if not found:
print "Did not find lines for all tall glyphs"
self.glyphs = orig_glyphs
self.lines = lines
class Line:
def __init__(self, glyph):
self.center = 0
self.bbox = core.Rect(core.Point(glyph.ul_x, glyph.ul_y), core.Dim(glyph.ncols, glyph.nrows))
self.glyphs = []
self.add_glyph(glyph)
def add_glyph(self, glyph):
self.glyphs.append(glyph)
self.glyphs.sort(lambda x, y: cmp(x.ul_x, y.ul_x))
self.bbox.union(glyph)
def calculate_stats(self):
total_center = 0
for glyph in self.glyphs:
total_center += (glyph.ul_y + glyph.lr_y) / 2
self.bbox.union(glyph)
self.center = total_center / len(self.glyphs)
def contains_glyph(self, glyph):
center = (glyph.ul_y + glyph.lr_y) / 2
if self.bbox.contains_y(center):
return 1
else:
return 0
def merge(self, line):
self.glyphs.extend(line.glyphs)
self.calculate_stats()
def name_lookup_old(id_name):
"""Converts a symbol name into a single character."""
split_string = string.split(id_name, '.')
l = len(split_string)
if l > 1:
if split_string[0] == "lower":
return string.lower(split_string[-1])
elif split_string[0] == "upper":
return string.upper(split_string[-1])
elif split_string[0] == "symbol":
if l == 2:
s = split_string[1]
if s == "comma":
return ","
elif s == "dot":
return ""
elif s == "plus":
return "+"
elif s == "lessthan":
return "<"
else:
print "ERROR: Name not known about:", id_name
return ""
elif l == 3:
if split_string[1] == "paren":
if split_string[2] == "close":
return ")"
else:
return "("
elif split_string[1] == "bracket":
if split_string[2] == "close":
return "]"
else:
return "["
else:
print "ERROR: Name not known about:", id_name
return ""
else:
print "ERROR: Name not known about:", id_name
return ""
elif split_string[0] == "digit":
return split_string[1]
elif split_string[0] == "line":
return ""
elif split_string[0] == "punctuation":
if split_string[1] == "comma":
return ","
else:
return ""
else:
print "ERROR: Name not known about:", id_name
return ""
else:
return ""
def name_lookup_unicode(id_name):
name = id_name.replace(".", " ")
name = name.upper()
try:
return unicodedata.lookup(name)
except KeyError:
print "ERROR: Name not found:", name
return ""
def make_string(lines, name_lookup_func=name_lookup_unicode):
s = ""
for line in lines:
glyphs = line.glyphs
total_space = 0
for i in range(len(glyphs) - 1):
total_space += glyphs[i + 1].ul_x - glyphs[i].lr_x
average_space = total_space / len(glyphs)
for i in range(len(glyphs)):
if i > 0:
if (glyphs[i].ul_x - glyphs[i - 1].lr_x) > (average_space * 2):
s = s + " "
s = s + name_lookup_func(glyphs[i].get_main_id())
s = s + "\n"
return s
def output(lines, filename="text.txt"):
s = make_string(lines)
f = file(filename, "w")
f.write(s)
f.flush()
f.close()
def ocr(image, classifier = None, glyphs = None):
"""Performs basic OCR segmentation.
*image*: OneBit image
*classifier*: a classifier with a production database loaded (optional)
*glyphs*: a list of glyphs from the image (optional)
Returns a ``Page`` object.
"""
if glyphs is None:
glyphs = image.cc_analysis()
if classifier is not None:
#classifier.classify_list_automatic(glyphs)
glyphs = classifier.group_and_update_list_automatic(glyphs)
page = Page(image, glyphs)
page.segment()
return page
|