need help in error of crop image in python

Question

I'm new to Python and for homework, I wrote a function that supposed to crop a image.

When I try to run the code u get an error that points to line that isn't even found in my code.

The error is

OSError: cannot write mode F as JPEG

Also another little question. it force me to put in the command of imagio.read, imageio.v2.read and I don't know why.

Every help will be appreciated. Thank you very much.

Full error:

Traceback (most recent call last):
File "C:\\Users\\מחשב\\AppData\\Roaming\\Python\\Python310\\site-packages\\PIL\\JpegImagePlugin.py", line 650, in \_save
rawmode = RAWMODE\[im.mode\]
KeyError: 'F'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "C:\\Users\\מחשב\\Desktop\\python\\עיבוד תמונה\\חיתוך.py", line 16, in \<module\>
imageio.v2.imwrite('crop_img.jpg', new_pic)
File "C:\\Users\\מחשב\\AppData\\Roaming\\Python\\Python310\\site-packages\\imageio\\v2.py", line 396, in imwrite
with imopen(uri, "wi", \*\*imopen_args) as file:
File "C:\\Users\\מחשב\\AppData\\Roaming\\Python\\Python310\\site-packages\\imageio\\core\\v3_plugin_api.py", line 367, in __exit__
self.close()
File "C:\\Users\\מחשב\\AppData\\Roaming\\Python\\Python310\\site-packages\\imageio\\plugins\\pillow.py", line 144, in close
self.\_flush_writer()
File "C:\\Users\\מחשב\\AppData\\Roaming\\Python\\Python310\\site-packages\\imageio\\plugins\\pillow.py", line 485, in \_flush_writer
primary_image.save(self.\_request.get_file(), \*\*self.save_args)
File "C:\\Users\\מחשב\\AppData\\Roaming\\Python\\Python310\\site-packages\\PIL\\Image.py", line 2439, in save
save_handler(self, fp, filename)
File "C:\\Users\\מחשב\\AppData\\Roaming\\Python\\Python310\\site-packages\\PIL\\JpegImagePlugin.py", line 653, in \_save
raise OSError(msg) from e
OSError: cannot write mode F as JPEG

My code is:

import numpy as np
import imageio

def pic_crop(img,height,dy,width,dx):
    new_img=np.zeros((dy,dx))
    for row in range(0,dy):
        for column in range(0,dx):
            new_img[row,column]=img[height+row,width+column]
return new_img

pic=imageio.v2.imread('myimageGR.jpg')
new_pic= pic_crop(pic,30,90,50,80)
print(new_pic.shape)
imageio.v2.imwrite('crop_img.jpg', new_pic)

Answer 1

new_img.dtype is float64, imageio.v2.imwrite expects uint8 for jpeg format, so either do

new_img=np.zeros((dy,dx),dtype='uint8')

or do

imageio.v2.imwrite('crop_img.jpg', new_pic.astype('uint8'))

also you can simplify pic_crop to avoid this problem

def pic_crop(img,height,dy,width,dx):
    new_img = np.array(img[height:height+dy, width:width+dx])
    return new_img