I have been trying to create a video from still images all in a folder. The file that is written is 0KB in size. I have checked and all files are retrieved by the glob.glob part correctly(That's what the commented print(filename) line is about). I have tried multiple fourcc options and none of them work. Does anyone see an issue that would be causing this? Also this is running on python 3 in Jupyter Notebook.
fold_file = fold +'/*jpg' #fold is just the path to folder containing the images
img_array=[]
for filename in glob.glob(fold_file):
#print(filename)
img=cv2.imread(filename)
height, width, layer = img.shape
size = (width,height)
img_array.append(img)
out = cv2.VideoWriter('pleasework.avi',cv2.VideoWriter.fourcc('X','V','I','D') ,15,size)
for image in range(len(img_array)):
out.write(image)
cv2.destroyAllWindows()
out.release()
This line of code is probably your issue:
for image in range(len(img_array)):
out.write(image)
The len() function counts the number of items in a sequence. Let's presume, for sake of argument that you have five images in img_array. Then len() would return 5. We are then feeding that length value into the range() function to produce a sequence of numbers from 0 to 4 (i.e. up to but not including 5).
We are then parsing through that range using the for loop, and we are dropping the numbers 0 through 4 into the out.write() method instead of dropping in images.
What you probably want is this:
for image in img_array:
out.write(image)
img_array is a Python list and as such, can be parsed by for loops natively without having to use any sort of length calculation, etc.
Related
I'm trying to make GIF from multiple image files, following this thread.
Kris's answer works perfectly when I open a physical file from a directory using Image.open() and then append the list to make a GIF.
imgs = [Image.open(f) for f in os.listdir(os.getcwd())]
imgs[0].save('{}.gif'.format(img_filename),
format='GIF',
append_images=imgs[1:],
save_all=True,
duration=args.duration,
loop=0)
This works fine and the output GIF is infact animated. I noticed that the list glitched_imgs consists of PIL.PngImagePlugin.PngImageFile objects in this case.
However whenever I try to use an Image object returned from a function, The GIF produced is completely static.
imgs = [get_randomized_image() for _ in range(args.frames)]
imgs[0].save('{}.gif'.format(img_filename),
format='GIF',
append_images=imgs[1:],
save_all=True,
duration=args.duration,
loop=0)
Where get_randomized_image() returns a randomized Image object, specifically from a numpy array.
# Inside `get_glitched_image()`
return Image.fromarray(outputarr, img_mode)
I want to directly make a GIF with a list of objects returned from this function, how can I achieve this?
Note: The files I open in the first (working) method, are the files I saved prior using get_randomized_images() so I can assure you they are exactly the same.
I want to superimpose a given set of images of the same size (the AT&T facial images database). I have written the code to do so, which works as follows:
I have assigned the location of the images (for starting I am considering only 4 images).
imstack is used to read one image (as a base image) over which the layover (superimposition) will take place.
A for loop is run that goes through all the images and adds them to the base image (imstack). This adding is done by using the addWeighted() function with the parameters as the current image (im) and the base image (imstack) with the alpha values as 0.5 respectively.
After the loop has run till its completion (all the images are superimposed on the base image) I tried to print the updated imstack as 'compiledimg' by using the imshow().
Further I added the option to save the 'compiledimg' file by pressing 's'.
To fix the error what I have tried is to resize the image after every iteration so that the addWeighted() function receives the images with the same dimensions. First imsize (before entering the for loop) is resized as to set a firm base to the first image with the required size that I have taken as (97(rows),113(columns)).
I don't understand why the addWeighted function is not working because I am using the resize funtion to make sure that the size is kept the same after each iteration. Plus, if also tried to superimpose just two of the images and it worked perfectly fine however it does not work when I try to use the addWeighted() on the third image.
Say I used addWeighted on two images img1 and img2 and stored in img3. Now when I tried to use the addWeighted() on img3 and img4 I am getting the error. Even when I have used the resize function on img3.
Note: Initial size of the images is (97 (rows),113 (columns)) hence I am trying to keep the same image size.
import cv2
import numpy as np
import os
fnames =['~/Downloads/1.pgm','~/Downloads/2.pgm','~/Downloads/3.pgm']
imstack=cv2.imread('~/Downloads/4.pgm')
for path in fnames:
im=cv2.imread(os.path.expanduser(path))
im=cv2.resize(im,(97,113))
imstack=cv2.addWeighted(imstack,0.5,im,0.5,0)
imstack=cv2.resize(imstack,(97,113))
cv2.imshow('compiledimg',imstack)
k = cv2.waitKey(0) & 0xFF
if k == 27:
cv2.destroyAllWindows()
elif k == ord('s'):
cv2.imwrite('compiledimg.pgm',imstack)
cv2.destroyAllWindows()
i have a video where the front view of a car was recorded. The file is an .mp4 and i want to process the single images so i can extract more information (Objects, Lane Lines etc.). The problem is, when i want to create a video out of the processed files, i get an error. Here is what i have done so far:
Opened the video with cv2.VideoCapture() - Works fine
Saved the single frames of the video with cv2.imwrite() - Works fine
Creating a video out of single frames with cv2.VideoWriter() - Works fine
Postprocessing the video with cv2.cvtColor(), cv2.GaussianBlur() and cv2.Canny() - Works fine
Creating a video out of the processed images - Does not work.
Here is the code i used:
enter code here
def process_image(image):
gray = functions.grayscale(image)
blur_gray = functions.gaussian_blur(gray, 5)
canny_blur = functions.canny(blur_gray, 100, 200)
return canny_blur
process_on =0
count =0
video= cv2.VideoWriter("output.avi", cv2.VideoWriter_fourcc(*"MJPG"), 10, (1600, 1200))
vidcap = cv2.VideoCapture('input.mp4')
success,image = vidcap.read()
success = True
while success:
processed = process_image(image)
video.write(processed)
This is the error i get:
OpenCV Error: Assertion failed (img.cols == width && img.rows == height*3) in cv::mjpeg::MotionJpegWriter::write, file D:\Build\OpenCV\opencv-3.2.0\modules\videoio\src\cap_mjpeg_encoder.cpp, line 834
Traceback (most recent call last):
File "W:/Roborace/03_Information/10_Data/01_Montreal/camera/right_front_camera/01_Processed/Roborace_CAMERA_create_video.py", line 30, in
video.write(processed)
cv2.error: D:\Build\OpenCV\opencv-3.2.0\modules\videoio\src\cap_mjpeg_encoder.cpp:834: error: (-215) img.cols == width && img.rows == height*3 in function cv::mjpeg::MotionJpegWriter::write
My suggestion is: The normal images have 3 dimensions because of the RGB-color field. The processed images are only having one dimension. How can i adjust this in the cv2.VideoWriter function.
Thanks for your help
The VideoWriter() class only writes color images, not grayscale images unless you are on Windows, which it looks like you might be judging from the paths in your output. On Windows, you can pass the optional argument isColor=0 or isColor=False to the VideoWriter() constructor to write single-channel images. Otherwise, the simple solution is to just stack your grayscale frames into a three-channel image (you can use cv2.merge([gray, gray, gray]) and write that.
From the VideoWriter() docs:
Parameters:
isColor – If it is not zero, the encoder will expect and encode color frames, otherwise it will work with grayscale frames (the flag is currently supported on Windows only).
So by default, isColor=True and the flag cannot be changed on a non-Windows system. So simply doing:
video.write(cv2.merge([processed, processed, processed])
should patch you up. Even though the Windows variant allows writing grayscale frames, it may be better to use this second method for platform independence.
Also as Zindarod mentions in the comments below there are a number of other possible issues with your code here. I'm assuming you've pasted modified code that you weren't actually running here, or that you would have modified otherwise...if that's the case, please only post minimal, complete, and verifiable code examples.
First and foremost, your loop has no end condition, so it's indefinite. Secondly, you're hard-coding the frame size but VideoWriter() does not simply resize the images to that size. You must provide the size of the frame that you will pass into the VideoWriter(). Either resize the frame to the same size before writing to be sure, or create your VideoWriter using the frame size as defined in your VideoCapture() device (using the .get() methods for the frame size properties).
Additionally, you're reading only the first frame outside the loop. Maybe that was intentional, but if you want to process each frame of the video, you'll need to of course read them in a loop, process them, and then write them.
Lastly you should have some better error catching in your code. For e.g., see the OpenCV "Getting Started with Video" Python tutorial. The "Saving a Video" section has the proper checks and balances: run the loop while the video capture device is opened, and process and write the frame only if the frame was read properly; then once it is out of frames, the .read() method will return False, which will allow you to break out of the loop and then close the capture and writer devices. Note the ordering here---the VideoCapture() device will still be "opened" even when you've read the last frame, so you need to close out of the loop by checking the contents of the frame.
Add isColor=False argument to the VideoWriter.
Adjusting VideoWriter this way will solve the issue.
Code:
video= cv2.VideoWriter("output.avi", cv2.VideoWriter_fourcc(*"MJPG"), 10, (1600, 1200), isColor=False)
I am writing an image processing program, which works well, but I need to process multiple images.
First, I made an array of images:
images = ((image1.tif),
(image2.tif),
(image3.tif))
Then, I created a for loop:
for image in images:
dna = cv2.imread(image)
{code}
The problem is, whenever I run the code, the console returns an error of
TypeError: expected string or Unicode object, tuple found
At this line:
dna = cv2.imread(image)
It seems that the program is trying to process the whole array at once. I thought that the loop worked by processing one image in the array at a time? Can anybody help me with this?
You should wrap the filenames using single or double quotes:
images = (('image1.tif'),
('image2.tif'),
('image3.tif'))
You can also use list instead of tuples:
images = ['image1.tif', 'image2.tif', image3.tif']
Use:
images = (("image1.tif"),
("image2.tif"),
("image3.tif"))
I'm trying to convert images taken from a capture (webcam) and do some processing on them with OpenCV, but I'm having a difficult time..
When trying to convert the image to grayscale, the program crashes. (Python.exe has stopped working)
Here is the main snippet of my code:
newFrameImageGS = cv.CreateImage ((320, 240), cv.IPL_DEPTH_8U, 1)
for i in range(0,5):
newFrameImage = cv.QueryFrame(ps3eye)
cv.CvtColor(newFrameImage,newFrameImageGS,cv.CV_BGR2GRAY)
golfSwing.append(newFrameImageGS)
When I try using cvConvertScale I get the assertion error:
src.size() == dst.size() && src.channels() == dst.channels()
which makes sense, but I'm pretty confused on how to go about converting the input images of my web cam into images that can be used by functions like cvUpdateMotionHistory() and cvCalcOpticalFlowLK()
Any ideas? Thanks.
UPDATE:
I converted the image to grayscale manually with this:
for row in range(0,newFrameImage.height):
for col in range(0,newFrameImage.width):
newFrameImageGS[row,col] = (newFrameImage8U[row,col][0] * 0.114 + # B
newFrameImage8U[row,col][1] * 0.587 + # G
newFrameImage8U[row,col][2] * 0.299) # R
But this takes quite a while.. and i still can't figure out why cvCvtColor is causing the program to crash.
For some reason, CvtColor caused the program to crash when the image depths where 8 bit. When I converted them to 32 bit, the program no longer crashed and everything seemed to work OK. I have no idea why this is, but at least it works now.
newFrameImage = cv.QueryFrame(ps3eye)
newFrameImage32F = cv.CreateImage((320, 240), cv.IPL_DEPTH_32F, 3)
cv.ConvertScale(newFrameImage,newFrameImage32F)
newFrameImageGS_32F = cv.CreateImage ((320,240), cv.IPL_DEPTH_32F, 1)
cv.CvtColor(newFrameImage32F,newFrameImageGS_32F,cv.CV_RGB2GRAY)
newFrameImageGS = cv.CreateImage ((320,240), cv.IPL_DEPTH_8U, 1)
cv.ConvertScale(newFrameImageGS_32F,newFrameImageGS)
There is a common mistake here:
You're creating a single image in the newFrameImageGS variable before the loop, then overwrite its contents in the loop, which is then appended to a list. The result will not be what you would expect. The list will contain five references to the same image instance at the end, since only the object reference is appended to the list, no copy of the object made this way. This image will contain the very last frame, so you get five of that frame as a result, which is not what you want, I guess. Please review the Python tutorial if it is not clear for you. You can solve this by moving the first line of the above code into the body of the for loop.
Another possibilities if fixing the above would not help you:
The CvtColor function seems to be the correct one for conversion to grayscale, since it can convert to a different number of channels.
According to this manual the CvtColor function requires a destination image of the same data type as the source. Please double check that newFrameImage is a IPL_DEPTH_8U image.