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I need to rotate around 150 images different amounts so that I can properly annotate my data with bounding boxes. The issue is that for some reason the image files aren't being saved rotated after running through my code and entering some values. How do I save these images in a rotated fashion so when I reopen the image file it's already rotated?

The file should be properly overwritten given I've gone as far as actually deleting the file entirely and saving a new one under the same name.

import os
from skimage import io, transform
import cv2
from scipy import ndimage
import scipy.misc

folder_name = r'C:\Users\admin\Desktop\Pedro_Database\Setup_Data\test'
with os.scandir(folder_name) as folder:
    for file in folder:
        if (file.name.endswith('.bmp')):
            path = folder_name + '/' + file.name
            img = cv2.imread(path)
            rotate = 360
            rotated_img = img
            while(rotate != 0):
                cv2.imshow('image',rotated_img)
                cv2.waitKey(0)
                cv2.destroyAllWindows()
                rotate = int(input("Rotate By: "))
                rotated_img = ndimage.rotate(img, rotate, reshape=False)
            #os.remove(path)
            cv2.imwrite(path, rotated_img)
            print(file.name + " saved")

After running this code over two photos and terminating normally I reopen the image files and they are 100% unchanged.

John Gordon
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Dawson
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  • _I reopen the image files and they are 100% unchanged_ Are the file timestamps updated? – John Gordon Jun 18 '19 at 17:11
  • Yes the timestamp is updated, even with the os.remove() command still commented out – Dawson Jun 18 '19 at 17:20
  • How are you checking to see if they have changed? Lots of programs do some type of buffering and maybe the viewer is not updating properly? (ie, your code above is working??). – brechmos Jun 18 '19 at 17:33
  • The image is saved as a .bmp. I've opened it in the default microsoft viewer, as well as paint, and the application that's actually important to me LabelImg from https://github.com/tzutalin/labelImg. – Dawson Jun 18 '19 at 17:37
  • Try changing the `rotate = 360` to something else (e.g., `rotate = 180`) just to be sure the while and rotate (angle) is all input correctly. If there is some odd mistake, a default `rotate = 360` means you won't see an actual rotation. If your images are all rotated 180 degrees, then there is something odd about the while conditional and loop. – brechmos Jun 18 '19 at 17:49
  • Omg I just noticed I'm changing my rotation to 0 before I move to the next image every time XD ooooops. – Dawson Jun 18 '19 at 18:02
  • As a slight aside, you could consider doing: `for file in glob.glob(os.path.join(folder_name, '*.bmp')):` instead of the `with`, `for` and `if bmp` lines. (I am not a Windows person, but I think this should work there too. Save a few lines). – brechmos Jun 18 '19 at 18:06

1 Answers1

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I'm not used to opencv but I think the problem is in this line 

cv2.imwrite(path, rotated_img)

It must be put inside the while loop so that when the image is rotated by rotated_img = ndimage.rotate(img, rotate, reshape=False), it is written (saved). If it's not, your rotated_img will remain the same, as rotate = 0 when it exits the while loop.

Also, if you want to save all rotated images, you should consider changing the path, for example: path = path + str(i), where i is increased by 1.

i = 0
while(rotate != 0):
    cv2.imshow('image',rotated_img)
    cv2.waitKey(0)
    cv2.destroyAllWindows()
    rotate = int(input("Rotate By: "))
    rotated_img = ndimage.rotate(img, rotate, reshape=False)
    i += 1
    path_of_rotated_image = path + str(i)
    cv2.imwrite(path_of_rotated_image, rotated_img)
    print(file.name + " saved") # if you want to print
AcaNg
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