PIL with BytesIO: cannot identify image file - python

I am trying to send an image over socket connection for video chat, but the reconstruction of the image from bytes format is incorrect. Here is my conversion of the image to bytes to send:
pil_im = Image.fromarray(img)
b = io.BytesIO()
pil_im.save(b, 'jpeg')
im_bytes = b.getvalue()
return im_bytes
This sends fine, however, I cannot resolve the reformatting of these bytes into an image file. Here is my code to reformat into image for display:
pil_bytes = io.BytesIO(im_bytes)
pil_image = Image.open(pil_bytes)
cv_image = cv2.cvtColor(np.array(pil_image), cv2.COLOR_RGB2BGR)
return cv_image
The second line there raises the following exception:
cannot identify image file <_io.BytesIO object at 0x0388EF60>
I have looked at some other threads (this one and this one) but no solution has been helpful for me. I am also using this as reference to try to correct myself, but what seems to work fine for them just doesn't for me.
Thank you for any assistance you can provide and please excuse any errors, I am still learning python.

First of all Thank You! as the code in your question helped me to solve the first part of the problem I had. The second part was already solved for me using this simple code (don't convert to array)
dataBytesIO = io.BytesIO(im_bytes)
image = Image.open(dataBytesIO)
Hope this helps

Related

Pass PIL Image to google cloud vision without saving and reading

UPDATE BELOW
Is there a way to pass a PIL Image to google cloud vision?
I tried to use io.Bytes, io.String and Image.tobytes() but I always get:
Traceback (most recent call last):
"C:\Users\...\vision_api.py", line 20, in get_text
image = vision.Image(content)
File "C:\...\venv\lib\site-packages\proto\message.py", line 494, in __init__
raise TypeError(
TypeError: Invalid constructor input for Image:b'Ma\x81Ma\x81La\x81Ma\x81Ma\x81Ma\x81Ma\x81Ma\x81Ma\x81Ma\x81Ma\x81La\x81Ma\x81Ma\x81Ma\x81Ma\x80Ma\x81La\x81Ma\x81Ma\x81Ma\x80Ma\x81Ma\x81Ma\x81Ma\x8 ...
or this if I pass the PIL-Image directly:
TypeError: Invalid constructor input for Image: <PIL.Image.Image image mode=RGB size=480x300 at 0x1D707131DC0>
This is my code:
image = Image.open(path).convert('RGB') # Opening the saved image
cropped_image = image.crop((30, 900, 510, 1200)) # Cropping the image
vision_image = vision.Image(# I passed the different options) # Here I need to pass the image, but I don't know how
client = vision.ImageAnnotatorClient()
response = client.text_detection(image=vision_image) # Text detection using google-vision-api
FOR CLARITY:
I want google text detection to only analyse a certain part of an image saved on my disk. So my idea was to crop the image using PIL and then pass the cropped image to google-vision. But it is not possible to pass an PIL-Image to vision.Image, as I get the error above.
The documentation from Google.
This can be found in the vision.Image class:
Attributes:
content (bytes):
Image content, represented as a stream of bytes. Note: As
with all ``bytes`` fields, protobuffers use a pure binary
representation, whereas JSON representations use base64.
Currently, this field only works for BatchAnnotateImages
requests. It does not work for AsyncBatchAnnotateImages
requests.
A working option is to save the PIL-Image as a PNG/JPG on my disk and load it using:
with io.open(file_name, 'rb') as image_file:
content = image_file.read()
vision_image = vision.Image(content=content)
But this is slow and seems unnecessary. And the whole point for me behind using google-vision-api is the speed comaped to open-cv.
UPDATE as of 25/9/2021
from PIL import Image
from io import BytesIO
from google.cloud import vision
with open('images/screenshots/screenshot.png', 'rb') as image_file:
data = image_file.read()
try:
image = vision.Image(content=data)
print('worked')
except TypeError:
print('failed')
im = Image.open('images/screenshots/screenshot.png')
buffer = BytesIO()
im.save(buffer, format='PNG')
try:
image = vision.Image(buffer.getvalue())
print('worked')
except TypeError:
print('failed')
The first version works as expected, but I can't get the second one to work as #Mark Setchell recommended. The first few characters (~50) are the same, the rest is completely different.
UPDATE as of 26/9/2021
Both inputs are of type <class 'bytes'>. The complete error stack can be seen at the top of the question.
Using this code:
print(input_data[:200])
print(type(input_data))
i get the following output:
b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x048\x00\x00\x07\x80\x08\x06\x00\x00\x00+a\xe7\n\x00\x00\x00\x04sBIT\x08\x08\x08\x08|\x08d\x88\x00\x00 \x00IDATx\x9c\xec\xbdy\xd8-\xc7Y\x1f\xf8\xab\xea>\xe7\xdb\xef\xaa\xbbk\xb3%\xcb\x8b\x16[\x12\xc6\xc8\xbb,\x1b\x03\x06\xc6\x8111\x93#2y\xc2381\x8b1\x90\x10\x9e\xf18\x93\x10\x0811\x84\x192\x0c3\x9e\x1020\x03\x03\xc3\xb0\x04\xf0C0\xc6\x96m\xc9\x96m\xed\xb2dI\x96\xaetu\xf7\xed\xdb\xcf\xe9\xae\x9a?j\xe9\xea\xbd\xba\xbb\xbaO\x9f\xef\x9e\xd7\xd6\xfd\xfat\xbf\xf5Vu-o\xbd\xf5\xeb\xb7\xde"\xef\xff\xc7\'8\x1c\x13\x07\x00\xd2\x82\xcc6\xe5\xc6\xa8B&'
<class 'bytes'>
for the working input.
And:
b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x048\x00\x00\x07\x80\x08\x06\x00\x00\x00+a\xe7\n\x00\x01\x00\x00IDATx\x9c\xec\xbdw\x80$\xc7u\x1f\xfc\xab\xea\xeeI\x9bw/\'\x1cr\xce\x04#\x10\x04A\x82`\x84\x95%J"\x95,\xcb\x1f%\x91T\xb0$*}\x1fM\xd9\x96\x95EY\x94(\xc9\xb6\x92i+\x90\x12\x83(3)0\x82\x08$rN\x07\\\xce\xb7\xb7yBw\xd5\xf7G\x85\xaeN3\xdd=\xdd\xb3\xb3{\xfb\xc8\xc3\xceLW\xbd\xca\xaf\xde\xfb\xf5\xabW\xe4{\xdeu\x84\xa3`\xe2\x00#J\xe0Y&\xdf\x00e($\x94\x94\'p\xcc\xc3\xda\xe7Y\x0c\xf1Te\x13\xbf\xcc>\xfa:]Y=x\x84\x7f\xe8\xc23u\x1f\x91l\xfd\x99'
<class 'bytes'>
for the failing input.
As far as I can tell, you start off with a PIL Image and you want to obtain a PNG image in memory without going to disk. So you need this:
#!/usr/bin/env python3
from PIL import Image
from io import BytesIO
# Create PIL Image like you have - filled with red
im = Image.new('RGB', (320,240), (255,0,0))
# Create in-memory PNG - like you want for Google Cloud Vision
buffer = BytesIO()
im.save(buffer, format="PNG")
# Look at first few bytes
PNG = buffer.getvalue()
print(PNG[:20])
It prints this, which is exactly what you would get if you wrote the image to disk as a PNG and then read it back as binary - except this does it in memory without going to disk:
b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x01#'
It would be good to have whole error stack and more accurate code snippet. But form presented information this seems to be confusion of two different "Images". Probably the some copy/paste error, as the tutorials have exactly the same line:
response = client.text_detection(image=image)
But mentioned tutorials image is created by vision.Image() so I think in presented code this should be:
response = client.text_detection(image=vision_image)
As, at least if I understand correctly the code snippet, image is PIL Image, while vision_image is Vision Image that should be passed to text_detection method. So whatever is done in vision.Image() does not have effect on the error massage.

Error when trying to convert base64 string to image in Python

I am trying create a Python dashboard in which a user uploads an image and then the image is analyzed. The uploaded image is received as a base64 string and it needs to be converted to an image. I have tried
decoded = BytesIO(base64.b64decode(base64_string))
image = Image.open(decoded)
but I received this error:
cannot identify image file <_io.BytesIO object at 0x00000268954E9888>
Image needs a file-like object, the sort of thing returned by an open. The easiest way to do this is using a with statement:
decoded = base64.b64decode(base64)
with BytesIO(decoded) as fh:
image = Image.open(fh)
# do stuff with image here: when the with block ends
# it's very likely the image will no longer be usable
See if that works better for you. :)

python convert bytes to image

I receive a bytes, which is converted from an image from Android client, how can I convert it to image on Python?
I use these code:
img = Image.open(BytesIO(data))
img.show()
img.save('D:\\1.jpg')
but I can only get an incomplete image like:
The image on the right is what I'm trying to send to Python, and the left is what I get. How can I solve this?
PS:data is complete because I save the image completely by using Eclipse.
I have already solve the problem.I made a stupid mistake that the buffersize I set for socket.recv is too short.
I set a longer buffersize like 100000000, and saving the image is easy like:
f = open('D:\\2.jpg', 'wb')
f.write(data)
f.close()

How can I convert my text string(which I think is a bytearray) to an image?

I am trying to convert, what I think is a bytearray pulled from a database to an image using python PIL.
I have access to the imagetype(jpg, png,..), the image height/width, and the bytearray. The bytearray is of the format
0xffd8ffe000104a46494600010101006000600000ffe111164578.....
I have tried many of the PIL options such as .fromstring and .frombuffer. I've also tried converting the bytearray into other forms (Base64,etc..) and then converting it to an image from there. None of these have worked and the image file is always corrupted.
If i follow the advice from this question:
image = Image.open(io.BytesIO(imagestring))
image.save(imageToSave.jpg)
I get this error: IOError: cannot identify image file
type(imagestring) returns type 'bytearray'
Thanks for reading and for any answers, let me know if I should edit this post with more info.
I can't explain why the 0x is there and if it will be a problem other people run into, but I had to trim off the 0x from the start of the string:
0xffd8ffe000104a46494600010101006000600000ffe111164578....
The code:
image = Image.open(io.BytesIO(imagestring))
image.save(imageToSave.jpg)
worked fine after that

From JPG to b64encode to cv2.imread()

For a program I am writing, I am transferring an image from one computer - using base64.b64encode(f.read(image)) - and trying to read it in the receiving script without saving it to hard drive (in an effort to minimize process time). I'm having a hard time figuring out how to read the image into OpenCV without saving it locally.
Here is what my code for sending the image looks like:
f = open(image.jpg)
sendthis = f.read()
f.close()
databeingsent = base64.b64encode(sendthis)
client.publish('/image',databeingsent,0)
# this is an MQTT publish, details for SO shouldn't be relevant
Meanwhile, here is the code receiving it. (This is in an on_message function, since I'm using MQTT for the transfer.)
def on_message(client, userdata, msg): # msg.payload is incoming data
img = base64.b64decode(msg.payload)
source = cv2.imread(img)
cv2.imshow("image", source)
After the message decodes, I have the error:
"TypeError: Your input type is not a numpy array".
I've done some searching, and I can't seem to find a relevant solution - some exist regarding converting from text files to numpy using b64, but none really relate to using an image and immediately reading that decoded data into OpenCV without the intermediary step of saving it to the harddrive (using the inverse process used to read the file in the "send" script).
I'm still pretty new to Python and OpenCV, so if there's a better encoding method to send the image - whatever solves the problem. How the image is sent is irrelevant, so long as I can read it in on the receiving end without saving it as a .jpg to disk.
Thanks!
You can get a numpy array from you decoded data using:
import numpy as np
...
img = base64.b64decode(msg.payload)
npimg = np.fromstring(img, dtype=np.uint8)
Then you need imdecode to read the image from a buffer in memory. imread is meant to load an image from a file.
So:
import numpy as np
...
def on_message(client, userdata, msg): # msg.payload is incoming data
img = base64.b64decode(msg.payload);
npimg = np.fromstring(img, dtype=np.uint8);
source = cv2.imdecode(npimg, 1)
From the OpenCV documentation we can see that:
imread : Loads an image from a file.
imdecode : Reads an image from a buffer in memory.
Seem a better way to do what you want.

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