We Keep Coding

The document could not be opened, opencv python3

I'm trying to make a video from images with python and OpenCV but when I run the script the video is generated but when I try to open it I give this error:
This is the script:
import cv2
import numpy as np
import glob
frameSize = (1920, 1080)
out = cv2.VideoWriter('output_video.avi',cv2.VideoWriter_fourcc(*'DIVX'), 60, frameSize)
for filename in glob.glob('/folder_path/*.jpg'):
img = cv2.imread(filename)
out.write(img)
out.release()
UPDATE:
If I use
out = cv2.VideoWriter('output_video.avi',cv2.VideoWriter_fourcc(*'MJPG'), 60, frameSize)
Instead
out = cv2.VideoWriter('output_video.avi',cv2.VideoWriter_fourcc(*'DIVX'), 60, frameSize)
The video start but I can see anything

Ok, I have found a solution.
This is the final code:
import cv2,os
from os.path import isfile, join
def convert_pictures_to_video(pathIn, pathOut, fps, time):
# this function converts images to video
frame_array=[]
files=[f for f in os.listdir(pathIn) if isfile(join(pathIn,f))]
#files.remove(".DS_Store")
for i in range (len(files)):
filename=pathIn+files[i]
# reading images
img=cv2.imread(filename)
# img=cv2.resize(img,(1400,1000))
height, width, layers = img.shape
size=(width,height)
for k in range (time):
frame_array.append(img)
out=cv2.VideoWriter(pathOut,cv2.VideoWriter_fourcc(*'mp4v'), fps, size)
for i in range(len(frame_array)):
out.write(frame_array[i])
out.release()
pathIn= '/pathIn-folder/'
pathOut='/pathOut-folder/output.avi'
fps=1
time=20 # the duration of each picture in the video
convert_pictures_to_video(pathIn, pathOut, fps, time)
You can find more info and a tutorial here.
REMEMBER
If you have a mac there are two important things to do.
First you have to uncomment #files.remove(".DS_Store") because when you create a new folder on macOS there is an extra hidden file called .DS_Store
You can't open the output video with Quick Time Player
You have to use another software like VLC

Converting Tiff file to JPG or Png python

Hi i am trying to convert the Tiff file into png or jpg file but the ouput that i am getting is noisy and not what i expected. Below is the code that i have tried :
from PIL import Image
im = Image.open('/content/img.tif')
import numpy as np
imarray = np.array(im)
print(imarray)
from matplotlib import pyplot as plt
plt.imshow(imarray, interpolation='nearest')
plt.show() # To see how the tiff file looks like
import cv2
from PIL import Image, ImageOps
img = (np.maximum(imarray, 0) / imarray.max()) * 255.0
print(img)
img = 255 - img #Inverting the pixel
print("********************************************************************")
print(img)
img = Image.fromarray(np.uint8(img))
img.save(f'/content/img.png')
please find the sample tiff file here
https://drive.google.com/file/d/1Gfyo4dCo_4pfYvUn6_a6lD0SfxZOzUwK/view?usp=sharing
Output png/jpg image i was getting is this
Can anyone please help me in converting the tiff into jpg or png
Thanks

The code below worked for me to read .tiff image and save layers as .jpeg:
from PIL import Image, ImageSequence
#open tiff image
im = Image.open("YOUR IMAGE PATH")
#navigate to the folder were the layers are going to be saved
%cd YOUR DIRECTORY
#loop over layers and export jpeg instances
for i, page in enumerate(ImageSequence.Iterator(im)):
page.mode = 'I'
page.point(lambda i:i*(1./256)).convert('L').save(str(i)+'.jpeg')

How to resize base64 encoded image in python

I want resize base64 encoded image in python.I searched I could not find. I used Pillow package to do it. However, Pillow has no such kind of feature .

This code does the job (Python 3):
import io
import base64
from PIL import Image
base64_str = 'iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg=='
buffer = io.BytesIO()
imgdata = base64.b64decode(base64_str)
img = Image.open(io.BytesIO(imgdata))
new_img = img.resize((2, 2)) # x, y
new_img.save(buffer, format="PNG")
img_b64 = base64.b64encode(buffer.getvalue())
print(str(img_b64)[2:-1])
EDIT: Reducing the size of a base64 image does not imply reducing the file size.

Resize images in python using PIL

I'm trying to resize a set of images, approximatively 366, so I created a script that I tested first on 3 and it was successful.
The issue is when I process the whole folder, it returns me this error :
resizeimage.imageexceptions.ImageSizeError: 'Image is too small, Image size : (275, 183), Required size : (399, 399)'
My script is supposed to iterate an entire folder, resize images then store the output files in another folder:
import os
from PIL import Image
from resizeimage import resizeimage
path = "/Users/sigc2sige/PycharmProjects/helloworld/photos"
size = (399, 399)
for file in os.listdir(path):
with open('/Users/sigc2sige/PycharmProjects/helloworld/photos/'+file, 'r+b') as f:
with Image.open(f) as image:
cover = resizeimage.resize_cover(image, size, Image.ANTIALIAS)
cover.save('/Users/sigc2sige/PycharmProjects/helloworld/photos_2/'+file, image.format)
I did use this instruction:
thumb = ImageOps.fit(image, size, Image.ANTIALIAS) but I believe that it crops images instead of resizing them.
If you have any ideas about how to solve this issue, it would be great.

Downsampling an image (making it smaller) is one thing, and upsampling (making it bigger) is another thing. If you want to downsample, ANTIALIAS is a good choice, if you want to upsample, there are other filters you could use.
import os
from PIL import Image
from resizeimage import resizeimage
path = "/Users/sigc2sige/PycharmProjects/helloworld/photos"
size = (399, 399)
for file in os.listdir(path):
with open('/Users/sigc2sige/PycharmProjects/helloworld/photos/'+file, 'r+b') as f:
with Image.open(f) as image:
if (image.size) >= size:
cover = resizeimage.resize_cover(image, size, Image.ANTIALIAS)
cover.save('/Users/sigc2sige/PycharmProjects/helloworld/photos_2/'+file, image.format)
else:
cover = image.resize(size, Image.BICUBIC).save('/Users/sigc2sige/PycharmProjects/helloworld/photos_2/'+file, image.format)

Read a base 64 encoded image from memory using OpenCv python library

I'm working on an app that to do some facial recognition from a webcam stream. I get base64 encoded data uri's of the canvas and want to use it to do something like this:
cv2.imshow('image',img)
The data URI looks something like this:
data:image/gif;base64,R0lGODlhEAAQAMQAAORHHOVSKudfOulrSOp3WOyDZu6QdvCchPGolfO0o/XBs/fNwfjZ0frl3/zy7////wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACH5BAkAABAALAAAAAAQABAAAAVVICSOZGlCQAosJ6mu7fiyZeKqNKToQGDsM8hBADgUXoGAiqhSvp5QAnQKGIgUhwFUYLCVDFCrKUE1lBavAViFIDlTImbKC5Gm2hB0SlBCBMQiB0UjIQA7
So, for clarity I've shown what the image looks like so the base64 string is not broken.
<img src="data:image/gif;base64,R0lGODlhEAAQAMQAAORHHOVSKudfOulrSOp3WOyDZu6QdvCchPGolfO0o/XBs/fNwfjZ0frl3/zy7////wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACH5BAkAABAALAAAAAAQABAAAAVVICSOZGlCQAosJ6mu7fiyZeKqNKToQGDsM8hBADgUXoGAiqhSvp5QAnQKGIgUhwFUYLCVDFCrKUE1lBavAViFIDlTImbKC5Gm2hB0SlBCBMQiB0UjIQA7">
The official doc says, that imread accepts a file path as the argument. From this SO answer, if I do something like:
import base64
imgdata = base64.b64decode(imgstring) #I use imgdata as this variable itself in references below
filename = 'some_image.jpg'
with open(filename, 'wb') as f:
f.write(imgdata)
The above code snippet works and the image file gets generated properly. However I don't think so many File IO operations are feasible considering I'd be doing this for every frame of the stream. I want to be able to read the image into the memory directly creating the img object.
I have tried two solutions that seem to be working for some people.
Using PIL reference:
pilImage = Image.open(StringIO(imgdata))
npImage = np.array(pilImage)
matImage = cv.fromarray(npImage)
I get cv not defined as I have openCV3 installed which is available to me as cv2 module. I tried img = cv2.imdecode(npImage,0), this returns nothing.
Getting the bytes from decoded string and converting it into an numpy array of sorts
file_bytes = numpy.asarray(bytearray(imgdata), dtype=numpy.uint8)
img = cv2.imdecode(file_bytes, 0) #Here as well I get returned nothing
The documentation doesn't really mention what the imdecode function returns. However, from the errors that I encountered, I guess it is expecting a numpy array or a scalar as the first argument. How do I get a handle on that image in memory so that I can do cv2.imshow('image',img) and all kinds of cool stuff thereafter.
I hope I was able to make myself clear.

This is my solution for python 3.7 and without using PIL
import base64
def readb64(uri):
encoded_data = uri.split(',')[1]
nparr = np.fromstring(base64.b64decode(encoded_data), np.uint8)
img = cv2.imdecode(nparr, cv2.IMREAD_COLOR)
return img
i hope that this solutions works for all

This worked for me on python 2, and doesn't require PIL/pillow or any other dependencies (except cv2):
Edit: for python3 use base64.b64decode(encoded_data) to decode instead.
import cv2
import numpy as np
def data_uri_to_cv2_img(uri):
encoded_data = uri.split(',')[1]
nparr = np.fromstring(encoded_data.decode('base64'), np.uint8)
img = cv2.imdecode(nparr, cv2.IMREAD_COLOR)
return img
data_uri = "data:image/jpeg;base64,/9j/4AAQ..."
img = data_uri_to_cv2_img(data_uri)
cv2.imshow(img)

You can just use both cv2 and pillow like this:
import base64
from PIL import Image
import cv2
from StringIO import StringIO
import numpy as np
def readb64(base64_string):
sbuf = StringIO()
sbuf.write(base64.b64decode(base64_string))
pimg = Image.open(sbuf)
return cv2.cvtColor(np.array(pimg), cv2.COLOR_RGB2BGR)
cvimg = readb64('R0lGODlhEAAQAMQAAORHHOVSKudfOulrSOp3WOyDZu6QdvCchPGolfO0o/XBs/fNwfjZ0frl3/zy7////wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACH5BAkAABAALAAAAAAQABAAAAVVICSOZGlCQAosJ6mu7fiyZeKqNKToQGDsM8hBADgUXoGAiqhSvp5QAnQKGIgUhwFUYLCVDFCrKUE1lBavAViFIDlTImbKC5Gm2hB0SlBCBMQiB0UjIQA7')
cv2.imshow(cvimg)

I found this simple solution.
import cv2
import numpy as np
import base64
image = "" # raw data with base64 encoding
decoded_data = base64.b64decode(image)
np_data = np.fromstring(decoded_data,np.uint8)
img = cv2.imdecode(np_data,cv2.IMREAD_UNCHANGED)
cv2.imshow("test", img)
cv2.waitKey(0)
Source : https://gist.github.com/HoweChen/7cdd09b08147133d8e1fbe9b52c24768