error with correcting straight images

[jugoprex]

I've run into what I'm guessing is a bug,
I'm running a script that deskews a whole dataset of .tif images, and i've encountered some problems with apparently straight images.
this is the original image(s):

this is the ouput from running the following program:

for file in os.listdir(indir):
    if file.endswith(".jpg") or file.endswith(".jpeg") or file.endswith(".png") or file.endswith(".tif"):
        image = cv2.imread(indir +'/'+ file)
        grayscale = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
        angle = determine_skew(grayscale)
        rotated = rotate(image, angle, (0, 0, 0))

where rotate is the open cv example here.

The output angle is -45 for both images.

[sbrunner]

By adding the following argument, you will have a better result: min_angle=-30, max_angle=30, min_deviation=0.1
If the speed performance is important, keep the min_deviation to 1 (default value) :-)