"ValueError: Not a bracketing interval." on some images

[liorazi]

Tried to run the program on some images, for some it worked, but on many I get this error:

python3 unproject_text.py lp8.png

abs_area_cutoff = 18.7572
got 6 contours with 1 small.
got bounding rect -281 163 583 58
got bounding rect -305 186 586 12
got bounding rect 263 197 3 1
Traceback (most recent call last):
File "unproject_text.py", line 503, in
main()
File "unproject_text.py", line 495, in main
SRH = skew_detect(img, contours, RH)
File "unproject_text.py", line 468, in skew_detect
res = scipy.optimize.minimize_scalar(f, (-2.0, 0.0, 2.0))
File "/usr/local/lib/python3.6/site-packages/scipy/optimize/_minimize.py", line 653, in minimize_scalar
return _minimize_scalar_brent(fun, bracket, args, **options)
File "/usr/local/lib/python3.6/site-packages/scipy/optimize/optimize.py", line 2108, in _minimize_scalar_brent
brent.optimize()
File "/usr/local/lib/python3.6/site-packages/scipy/optimize/optimize.py", line 1892, in optimize
xa, xb, xc, fa, fb, fc, funcalls = self.get_bracket_info()
File "/usr/local/lib/python3.6/site-packages/scipy/optimize/optimize.py", line 1880, in get_bracket_info
raise ValueError("Not a bracketing interval.")
ValueError: Not a bracketing interval.

The image I tried was:
https://liorazi.github.io/lp8.png

[krishna81m]

Reproduced, not sure if version incompatibility

python unproject_text.py dg-1.png
abs_area_cutoff = 130.48
got 254 contours with 0 small.
got bounding rect 453 731 12 1
got bounding rect 380 772 11 2
got bounding rect 382 772 4 1
Traceback (most recent call last):
File "unproject_text.py", line 503, in
main()
File "unproject_text.py", line 495, in main
SRH = skew_detect(img, contours, RH)
File "unproject_text.py", line 468, in skew_detect
res = scipy.optimize.minimize_scalar(f, (-2.0, 0.0, 2.0))
File "/usr/local/lib/python2.7/site-packages/scipy/optimize/_minimize.py", line 773, in minimize_scalar
return _minimize_scalar_brent(fun, bracket, args, **options)
File "/usr/local/lib/python2.7/site-packages/scipy/optimize/optimize.py", line 2108, in _minimize_scalar_brent
brent.optimize()
File "/usr/local/lib/python2.7/site-packages/scipy/optimize/optimize.py", line 1892, in optimize
xa, xb, xc, fa, fb, fc, funcalls = self.get_bracket_info()
File "/usr/local/lib/python2.7/site-packages/scipy/optimize/optimize.py", line 1880, in get_bracket_info
raise ValueError("Not a bracketing interval.")
ValueError: Not a bracketing interval.

[saikat-sarkar]

Anyone found any solution to this error. I am getting the same error.

[IonutQo2]

I got the same error.
Has someone got any ideas?

root@ad9f76f47988:/var/www/deskew# python unproject_text.py deskew0.jpg
Traceback (most recent call last):
  File "unproject_text.py", line 503, in <module>
    main()
  File "unproject_text.py", line 490, in main
    contours, hierarchy = get_contours(img)
  File "unproject_text.py", line 135, in get_contours
    cv2.CHAIN_APPROX_NONE)
ValueError: need more than 2 values to unpack

[adithya-sama]

I got the same error.
Has someone got any ideas?

root@ad9f76f47988:/var/www/deskew# python unproject_text.py deskew0.jpg
Traceback (most recent call last):
  File "unproject_text.py", line 503, in <module>
    main()
  File "unproject_text.py", line 490, in main
    contours, hierarchy = get_contours(img)
  File "unproject_text.py", line 135, in get_contours
    cv2.CHAIN_APPROX_NONE)
ValueError: need more than 2 values to unpack

you can fix this by gng to line 134 and removing the _.
plus this is not the same error as everybody else.

[dipanshunagar]

Bracket value is an optional parameter for these optimizers. So you could remove the second parameter (-2.0, 0.0, 2.0) on line 468, and it will work.
But I'm not sure how good the result would be without this bracket value, haven't tested it a lot yet.