Im trying to read a file's format so I can correctly assign a new name to it and write it to disk, but when the Image.open() is on the image, I cannot write the image to disk. So for example :
This works:
>>>file = open('708864.jpg')
>>> open('lala.jpeg', 'w').write(file.read())
But, this doesn't
>>>import Image
>>>im = Image.open('708864.jpg')
>>> im.format
>>> open('lala.jpeg', 'w').write(file.read())
It creates a corrupted file (lala.jpeg) which is unable to be opened by any software.
I'm suspecting the culprit is the Image.open(). And after trying to locate an Image.close() statement, I was unable to find one. How would you "close" this image, so I can still write it to disk?
As suggested in my comment, im.save('lala.jpg') is the way to go.
For all the other fun methods on an Image object, you can look at the documentation.
Some workaround, it is just idea:
import Image
import StringIO
file = open('/home/mrok/1.jpg')
output = StringIO.StringIO(file.read())
im = Image.open('/home/mrok/1.jpg')
im.format
open('/home/mrok/2.jpg', 'w').write(output.getvalue())
output.close()
As said in a comment, I ended up using a function I never knew about before, Image.save() , which quickly solves my problem.
Related
using following code to save all tiffs to a single PDF
from PIL import Image
imagelist[0].save(fp=path_to_saving_location+"specified_name.pdf",save_all =True, append_images = imagelist[1:])
instead it is saving the PDF as 001.pdf.
Am I doing anything wrong here?
Create a variable called fullpath in the line above the save statement and set its value how you think.
Print it so you can check it. Then use:
imagelist[0].save(fullpath, save_all =True, append_images = imagelist[1:])
Also, consider deleting 001.pdf before you run your program, so you can be sure if your program really does create it.
I am looking to convert a xml file to an image (ideally a png file) using a python script. I have not found much from my online research. I am trying to use PIL. From this post on StackOverflow I was able to find this code:
from PIL import Image
import ImageFont, ImageDraw
image = Image.new("RGBA", (288,432), (255,255,255))
usr_font = ImageFont.truetype("resources/HelveticaNeueLight.ttf", 25)
d_usr = ImageDraw.Draw(image)
d_usr = d_usr.text((105,280), "MYTEXT",(0,0,0), font=usr_font)
But I do not quite understand what's happening. I tried to replace "MYTEXT" with the actual xml file content and it did not work.
I am basically looking for any solution (ideally using PIL, but it can be another module for python). I came close using imgkit:
import imgkit
imgkit.from_file('example_IN.xml','example_OUT.png')
which returns a png file. The resolution of the image is terrible though, and it lies within a very large white rectangle. I may be missing something. I know you can modify options for imgkit, but I have no idea what modifications to bring, even after checking the documentation. Any help would be deeply appreciated.
Thank you so much!
Best regards.
I had a go in pyvips:
#!/usr/bin/env python3
import sys
import pyvips
from xml.sax.saxutils import escape
# load first arg as a string
txt = open(sys.argv[1], "r").read()
# pyvips allows pango markup in strings -- you can write stuff like
# text("hello <i>sailor!</i>")
# so we need to escape < > & in the text file
txt = escape(txt)
img = pyvips.Image.text(txt)
# save to second arg
img.write_to_file(sys.argv[2])
You can run it like this:
./txt2img.py vari.ws x.png
To make this:
It's pretty quick -- that took 300ms to run on this modest laptop.
The text method has a lot of options if you want higher res, to change the alignment, wrap lines at some limit, change the font, etc. etc.
https://libvips.github.io/libvips/API/current/libvips-create.html#vips-text
The solution suggested above by jcuppit using pyvips definitely works and is quick. I found another solution to make my previous code above work using imgkit (it is slower, I am giving it here just for reference): the resolution of the output image was bad. If this happens, width and height can be changed in the options (this is an easy fix I had missed):
import imgkit
options = {
'width' : 600,
'height' : 600
}
imgkit.from_file('example_IN.xml','example_OUT.png', options=options)
And that will convert a xml file into a png file as well.
I have a .tar file containing several hundreds of pictures (.png). I need to process them via opencv.
I am wondering whether - for efficiency reasons - it is possible to process them without passing by the disc. In other, words I want to read the pictures from the memory stream related to the tar file.
Consider for instance
import tarfile
import cv2
tar0 = tarfile.open('mytar.tar')
im = cv2.imread( tar0.extractfile('fname.png').read() )
The last line doesn't work as imread expects a file name rather than a stream.
Consider that this way of reading directly from the tar stream can be achieved e.g. for text (see e.g. this SO question).
Any suggestion to open the stream with the correct png encoding?
Untarring to ramdisk is of course an option, although I was looking for something more cachable.
Thanks to the suggestion of #abarry and this SO answer I managed to find the answer.
Consider the following
def get_np_array_from_tar_object(tar_extractfl):
'''converts a buffer from a tar file in np.array'''
return np.asarray(
bytearray(tar_extractfl.read())
, dtype=np.uint8)
tar0 = tarfile.open('mytar.tar')
im0 = cv2.imdecode(
get_np_array_from_tar_object(tar0.extractfile('fname.png'))
, 0 )
Perhaps use imdecode with a buffer coming out of the tar file? I haven't tried it but seems promising.
I'm not entirely sure why this is happening but I am in the process of making a program and I am having tons of issues trying to get opencv to open images using imread. I keep getting errors saying that the image is 0px wide by 0px high. This isn't making much sense to me so I searched around on here and I'm not getting any answers from SO either.
I have taken about 20 pictures and they are all using the same device. Probably 8 of them actually open and work correctly, the rest don't. They aren't corrupted either because they open in other programs. I have triple checked the paths and they are using full paths.
Is anyone else having issues like this? All of my files are .jpgs and I am not seeing any problems on my end. Is this a bug or am I doing something wrong?
Here is a snippet of the code that I am using that is reproducing the error on my end.
imgloc = "F:\Kyle\Desktop\Coinjar\Test images\ten.png"
img = cv2.imread(imgloc)
cv2.imshow('img',img)
When I change the file I just adjust the name of the file itself the entire path doesn't change it just refuses to accept some of my images which are essentially the same ones.
I am getting this error from a later part of the code where I try to use img.shape
Traceback (most recent call last):
File "F:\Kyle\Desktop\Coinjar\CoinJar Test2.py", line 14, in <module>
height, width, depth = img.shape
AttributeError: 'NoneType' object has no attribute 'shape'
and I am getting this error when I try to show a window from the code snippet above.
Traceback (most recent call last):
File "F:\Kyle\Desktop\Coinjar\CoinJar Test2.py", line 11, in <module>
cv2.imshow('img',img)
error: ..\..\..\..\opencv\modules\highgui\src\window.cpp:261: error: (-215) size.width>0 && size.height>0 in function cv::imshow
Probably you have problem with special meaning of \ in text - like \t or \n
Use \\ in place of \
imgloc = "F:\\Kyle\\Desktop\\Coinjar\\Test images\\ten.png"
or use prefix r'' (and it will treat it as raw text without special codes)
imgloc = r"F:\Kyle\Desktop\Coinjar\Test images\ten.png"
EDIT:
Some modules accept even / like in Linux path
imgloc = "F:/Kyle/Desktop/Coinjar/Test images/ten.png"
From my experience, file paths that are too long (OS dependent) can also cause cv2.imread() to fail.
Also, when it does fail, it often fails silently, so it is hard to even realize that it failed, and usually something further the the code will be what sparks the error.
Hope this helps.
Faced the same problem on Windows: cv.imread returned None when reading jpg files from a subfolder. The same code and folder structure worked on Linux.
Found out that cv.imread processes the same jpg files, if they are in the same folder as the python file.
My workaround:
copy the image file to the python file folder
use this file in cv.imread
remove redundant image file
import os
import shutil
import cv2 as cv
image_dir = os.path.join('path', 'to', 'image')
image_filename = 'image.jpg'
full_image_path = os.path.join(image_dir, image_filename)
image = cv.imread(full_image_path)
if image is None:
shutil.copy(full_image_path, image_filename)
image = cv.imread(image_filename)
os.remove(image_filename)
...
I had i lot of trouble with cv.imread() not finding my Image. I think i tryed everything involving changing the path. The os.path.exists(file_path) function also gave me back a True.
I finaly solved the problem by loading the images with imageio.
img = imageio.imread('file_path')
This also loads the img in a numpy array and you can use funktions like cv.matchTemplate() on this object. But i would recomment if u are doing stuff with multiple images that you then read all of them with imageio because i found diffrences in the arrays produced by .imread() from the two libs (opencv, imageio) on a File both of them could open.
I hope i could help someone
Take care to :
try imread() with a reliable picture,
and the correct path in your context like (see Kyle772 answer). For me either //or \.
I lost a couple of hours trying with 2 images saved from a left click in a browser. As soon as I took a personal camera image, it works fine.
Spyder screen shot
#context windows10 / anaconda / python 3.2.0
import cv2
print(cv2.__version__) # 3.2.0
imgloc = "D:/violettes/Software/Central/test.jpg" #this path works fine.
# imgloc = "D:\\violettes\\Software\\Central\\test.jpg" this path works fine also.
#imgloc = "D:\violettes\Software\Central\test.jpg" #this path fails.
img = cv2.imread(imgloc)
height, width, channels = img.shape
print (height, width, channels)
python opencv image-loading imread
I know that the question is already answered but in case anybody still is not able to load images with imread. It may be because there are letters in the string path witch imread does not accept.
For exmaple umlauts and diacritical marks.
My suggestion for everyone facing the same problem is to try this:
cv2.imshow("image", img)
The img is keyword. Never forget.
When you get error like this AttributeError: 'NoneType' object has no attribute 'shape'
Try with new_image=image.copy
I need open an image, verify the image, then reopen it (see last sentence of below quote from PIL docs)
im.verify()
Attempts to determine if the file is broken, without actually decoding
the image data. If this method finds any problems, it raises suitable
exceptions. This method only works on a newly opened image; if the
image has already been loaded, the result is undefined. Also, if you
need to load the image after using this method, you must reopen the
image file.
This is what I have in my code, where picture is a django InMemoryUploadedFile object:
img = Image.open(picture)
img.verify()
img = Image.open(picture)
The first two lines work fine, but I get the following error for the third line (where I'm attempting to "reopen" the image):
IOError: cannot identify image file
What is the proper way to reopen the image file, as the docs suggest?
This is no different than doing
f = open('x.png')
Image.open(f)
Image.open(f)
The code above does not work because PIL advances in the file while reading its first few bytes to (attempt to) identify its format. Trying to use a second Image.open in this situation will fail as noted because now the current position in the file is past its image's header. To confirm this, you can verify what f.tell() returns. To solve this issue you have to go back to the start of the file either by doing f.seek(0) between the two calls to Image.open, or closing and reopening the file.
Try doing a del img between the verify and second open.