I have a Raspberry on which I want to create a timelapse movie.
All examples I see in the internet FIRST save a bunch of images and THEN converts them into a movie all at once.
I want to create a movie over a long period of time so I can't save thousands of images. What I need is a tool that adds an image to a movie right after the image is captured.
Is there a chance to do that?
There's a flaw in your logic, I think - by adding each image to the movie, you would necessarily be adding a full-frame, rather than only a diff frame. This will result in higher quality, sure - but it will also not save you anything in terms of space as compared to saving the entire image. The space savings you see in adding things to movies is all about that diff, rather than storing a full frame.
Doing a partial diff with check-frames at increments might work, but I'm not sure what format you're targeting, nor what codexes would be needed in order to arbitrarily tack on either a diff frame or a full frame, depending on some external condition - encoding usually takes place as a series of operations rather than singly.
An answer but it isn't finished!
I need your help making this perfect!
Running in python2
import os, cv2
from picamera import PiCamera
from picamera.array import PiRGBArray
from datetime import datetime
from time import sleep
now = datetime.now()
x = now.strftime("%Y")+"-"+now.strftime("%m")+"-"+now.strftime("%d")+"-"+now.strftime("%H")+"-"+now.strftime("%M") #string of dateandtimestart
def main():
imagenum = 100 #how many images
period = 1 #seconds between images
os.chdir ("/home/pi/t_lapse")
os.mkdir(x)
os.chdir(x)
filename = x + ".avi"
camera = PiCamera()
camera.resolution=(1920,1088)
camera.vflip = True
camera.hflip = True
camera.color_effects = (128,128) #makes a black and white image for IR camera
sleep(0.1)
out = cv2.VideoWriter(filename, cv2.cv.CV_FOURCC(*'XVID'), 30, (1920,1088))
for c in range(imagenum):
with PiRGBArray(camera, size=(1920,1088)) as output:
camera.capture(output, 'bgr')
imagec = output.array
out.write(imagec)
output.truncate(0) #trying to get more than 300mb files..
pass
sleep(period-0.5)
camera.close()
out.release()
if __name__ == '__main__':
main()
I've got this configured with with a few buttons and an OLED to select time spacing and frame numbers displayed on a OLED (code not shown above for simplicity but it is also here: https://github.com/gchennell/RPi-PiLapse )
This doesn't make videos larger than 366Mb which is some sort of limit I've reached and I don't know why - if anyone has a good suggestion I would appreciate it
Related
In an old version of my code, I used to do a hardcopy() with a given resolution, ie:
frame = hardcopy(figHandle, ['-d' renderer], ['-r' num2str(round(pixelsperinch))]);
For reference, hardcopy saves a figure window to file.
Then I would typically perform:
ZZ = rgb2gray(frame) < 255/2;
se = strel('disk',diskSize);
ZZ2 = imdilate(ZZ,se); %perform dilation.
Surface = bwarea(ZZ2); %get estimated surface (in pixels)
This worked until I switched to Matlab 2017, in which the hardcopy() function is deprecated and we are left with the print() function instead.
I am unable to extract the data from figure handler at a specific resolution using print. I've tried many things, including:
frame = print(figHandle, '-opengl', strcat('-r',num2str(round(pixelsperinch))));
But it doesn't work. How can I overcome this?
EDIT
I don't want to 'save' nor create a figure file, my aim is to extract the data from the figure in order to mesure a surface after a dilation process. I just want to keep this information and since 'im processing a LOT of different trajectories (total is approx. 1e7 trajectories), i don't want to save each file to disk (this is costly, time execution speaking). I'm running this code on a remote server (without a graphic card).
The issue I'm struggling with is: "One or more output arguments not assigned during call to "varargout"."
getframe() does not allow for setting a specific resolution (it uses current resolution instead as far as I know)
EDIT2
Ok, figured out how to do, you need to pass the '-RGBImage' argument like this:
frame = print(figHandle, ['-' renderer], ['-r' num2str(round(pixelsperinch))], '-RGBImage');
it also accept custom resolution and renderer as specified in the documentation.
I think you must specify formattype too (-dtiff in my case). I've tried this in Matlab 2016b with no problem:
print(figHandle,'-dtiff', '-opengl', '-r600', 'nameofmyfig');
EDIT:
If you need the CData just find the handle of the corresponding axes and get its CData
f = findobj('Tag','mytag')
Then depending on your matlab version use:
mycdata = get(f,'CData');
or directly
mycdta = f.CData;
EDIT 2:
You can set the tag of your image programatically and then do what I said previously:
a = imshow('peppers.png');
set(a,'Tag','mytag');
I have a large fits file (over 30,000 x 30,000) pixels. IRAF cannot handle this size of image. How can one crop a file of this size while retaining correct header information, as IRAF does when using its standard cropping mode?
You can do this sort of cropping with astropy.io.fits, though it's not trivial yet. Since astropy.io.fits uses memory mapping by default, it should be able to handle arbitrarily large files (within some practical limits). If you want non-python solutions, look here for details about postage stamp creation.
from astropy.io import fits
from astropy import wcs
f = fits.open('file.fits')
w = wcs.WCS(f[0].header)
newf = fits.PrimaryHDU()
newf.data = f[0].data[100:-100,100:-100]
newf.header = f[0].header
newf.header.update(w[100:-100,100:-100].to_header())
See also this pull request, which implements a convenience Cutout2D function, though this is not yet available in a released version of astropy. Its usage can be seen in the documentation, modified to include WCS:
from astropy.nddata import Cutout2D
position = (49.7, 100.1)
shape = (40, 50)
cutout = Cutout2D(f[0].data, position, shape, wcs=w)
There are more examples here
I'm using Octave to write a script that plots a function at different time periods. I was hoping to create an animation of the plots in order to see the changes through time.
Is there a way to save each plot for each time point, so that all plots can be combined to create this animation?
It's a bit of kludge, but you can do the following (works here with octave 4.0.0-rc2):
x = (-5:.1:5);
for p = 1:5
plot (x, x.^p)
print animation.pdf -append
endfor
im = imread ("animation.pdf", "Index", "all");
imwrite (im, "animation.gif", "DelayTime", .5)
Basically, print all your plots into a pdf, one per page. Then read the pdf's as images and print them back as gifs. This will not work on Matlab (its imread implementation can't handle pdf).
This creates an animated gif
data=rand(100,100,20); %100 by 100 and 20 frames
%data go from 0 to 1, so lets convert to 8 bit unsigned integers for saving
data=data*2^8;
data=uint8(data);
%Write the first frame to a file named animGif.gif
imwrite(data(:,:,1),'/tmp/animGif.gif','gif','writemode','overwrite',...
'LoopCount',inf,'DelayTime',0);
%Loop through and write the rest of the frames
for ii=2:size(data,3)
imwrite(data(:,:,ii),'/tmp/animGif.gif','gif','writemode','append','DelayTime',0)
end
Had to come chime in here because this was the top Google result for me when I was looking for help with this. I had issues with both answers, and some other issues, too. Notably:
For Rick T's answer, the code snippet doesn't write a plot figure, it just writes matrix data. Getting the plot window was a pain.
For carandraug's answer, writing to a PDF took a very long time and made a gigantic PDF.
On my own machine, I'm pretty sure I used apt-install to get Octave, but the getframe function I found referenced in other answers wasn't found. Turns out I had installed version 4.4, which was from 2018 (>3 years old).
I removed the old version of Octave sudo apt remove octave, then installed the new version with snap. If you try octave from a terminal without it installed it should prompt you to the snap install - be sure to include the # 6.4.0 or whatever is included in the command.
Once I had the current version installed, I got access to the getframe command, which is what lets you convert directly from a figure handle to image data - this bypasses the hackey (but previously necessary step) in #carandraug's answer where you had to write to PDF or some other image as a placeholder.
I used #RickT's answer to make my own MakeGif function, which I will share with you all here. Note that MakeGif stores the filename in a persistent variable, meaning it is retained across calls. If you change the filename it will make (or overwrite!!) the new file. If you need to overwrite the current file (i.e., running the same script multiple times and want new results) then you can use clear MakeGif between calls and that will reset the persistentFilename.
Here is the code for the MakeGif function; code to test it with is provided after this:
function MakeGif(figHandle, filename)
persistent persistentFilename = [];
if isempty(filename)
error('Can''t have an empty filename!');
endif
if ~ishandle(figHandle)
error('Call MakeGif(figHandle, filename); no valid figHandle was passed!');
endif
writeMode = 'Append';
if isempty(persistentFilename)|(filename!=persistentFilename)
persistentFilename = filename;
writeMode = 'Overwrite';
endif
imstruct = getframe(figHandle);
imwrite(imstruct.cdata, filename, 'gif', 'WriteMode',writeMode,'DelayTime',0);
endfunction
And here is the code to test the function. There's a commented-out call to clear MakeGif between the blue and green colors. If you leave it commented out it will append the green sine wave to the blue sine wave, resulting in alternating colors after every cycle - again the filename is persistent in the function. If you uncomment that call then the MakeGif function will treat the green's call as "new" and trigger the overwrite of the blue sine wave and all you'll see is green.
clear all;
time = 0:0.1:2*pi;
nSamples = numel(time);
figHandle = figure(1);
for i=1:nSamples
plot(time,sin(time + time(i)),'Color','blue');
drawnow;
MakeGif(figHandle, 'test.gif');
endfor
% Uncomment the 'clear' command below to clear the MakeGif persistent
% memory, which will trigger the green sine wave to overwrite the blue.
% Default behavior is to APPEND a green sine wave because the filename
% is the same.
%clear MakeGif;
for i=1:nSamples
plot(time,sin(time + time(i)),'Color','green');
drawnow;
MakeGif(figHandle, 'test.gif');
endfor
I spent several hours on this after being super dissatisfied with laggy screen captures so I really hope this helps someone in the future! Good luck and best wishes from the Age of Covid lol.
#Chuck thanks for that code; I've been using it to save 1500-frame GIFs of simulation output, and I find that after maybe ~500 frames the time to save the next frame to the output during the call to MakeGif starts to become ... unnerving. I guess imwrite reads and writes the entirety of the output file at each call that includes the 'WriteMode','Append' pair. At frame 1500 my output is 480Mb so that becomes untenable.
An apparent rescue for this is hinted at in the doc for Octave 7.1.0's imwrite, with the suggestion that you can pass it a 4-dimensional array and write the entire image sequence with one call. I haven't been able to make this work, though: Calling imwrite that way seems to simply write the very first image in the sequence into every frame in the output file.
Using python 3.4 in linux and windows, I'm trying to create qr code images from a list of string objects. I don't want to just store the image as a file because the list of strings may change frequently. I want to then tile all the objects and display the resulting image on screen for the user to scan with a barcode scanner. For the user to know which code to scan I need to add some text to the qr code image.
I can create the list of image objects correctly and they are in a list and calling .show on these objects displays them properly but I don't know how to treat these objects as a file object to open them. The object that is given to the open function, (img_list[0] in my case), in my add_text_to_img needs to support read, seek and tell methods. When I try this as is I get an attribute error. I've tried BytesIO and StringIO but I get an error message that Image.open does not support buffer interface. Maybe I am not doing that part correctly.
I'm sure there are several ways to do this, but what is the best way to open in memory objects as a file object?
from io import BytesIO
import qrcode
from PIL import ImageFont, ImageDraw, Image
def make_qr_image_list(code_list):
"""
:param code_list: a list of string objects to encode into QR code image
:return: a list of image or some type of other data objects
"""
img_list = []
for item in code_list:
qr = qrcode.QRCode(
version=None,
error_correction=qrcode.ERROR_CORRECT_L,
box_size=4,
border=10
)
qr.add_data(item)
qr_image = qr.make_image(fit=True)
img_list.append(qr_image)
return img_list
def add_text_to_img(text_list, img_list):
"""
While I was working on this, I am only saving the first image. Once
it's working, I'll save the rest of the images to a list.
:param text_list: a list of strings to add to the corresponding image.
:param img_list: the list containing the images already created from
the text_list
:return:
"""
base = Image.open(img_list[0])
# img = Image.frombytes(mode='P', size=(164,164), data=img_list[0])
text_img = Image.new('RGBA', base.size, (255,255,255,0))
font = ImageFont.truetype('sans-serif.ttf', 10)
draw = ImageDraw.Draw(text_img)
draw.text((0,-20),text_list[0], (0,0,255,128), font=font)
# include some method to save the images after the text
# has been added here. Shouldn't actually save to a file.
# Should be saved to memory/img_list
output = Image.alpha_composite(base,text_img)
output.show()
if __name__ == '__main__':
test_list = ['AlGaN','n-AlGaN','p-AlGaN','MQW','LED AlN-AlGaN']
image_list = make_qr_image_list(test_list)
add_text_to_img(test_list, image_list)
im = image_list[0]
im.save('/my_save_path/test_image.png')
im.show()
Edit: I've been using python for about a year and I feel like this is a pretty common thing to do but I'm not even sure that I'm looking up/searching for the right terms. What topics would you search for to answer this? If anyone can post a link or two to what I need to read up on regarding this, that would be very appreciated.
You already have PIL image objects; qr.make_image() returns the (a wrapper around) the right type of object and you do not need to open them again.
As such, all you need to do is:
base = img_list[0]
and go from there.
You do need to match image modes when compositing; QR codes are black-and-white images (mode 1), so either convert that or use the same mode in your text_img image object. The Image.alpha_composite() operation does require that both images have an alpha channel. Converting the base is easy:
base = img_list[0].convert('RGBA')
I have a folder of jpg files and I want to make them into a movie. I am using this script:
% Create video out of list of jpgs
clear
clc
% Folder with all the image files you want to create a movie from, choose this folder using:
ImagesFolder = uigetdir;
% Verify that all the images are in the correct time order, this could be useful if you were using any kind of time lapse photography. We can do that by using dir to map our images and create a structure with information on each file.
jpegFiles = dir(strcat(ImagesFolder,'\*.jpg'));
% Sort by date from the datenum information.
S = [jpegFiles(:).datenum];
[S,S] = sort(S);
jpegFilesS = jpegFiles(S);
% The sub-structures within jpegFilesS is now sorted in ascending time order.
% Notice that datenum is a serial date number, for example, if you would like to get the time difference in hours between two images you need to subtract their datenum values and multiply by 1440.
% Create a VideoWriter object, in order to write video data to an .avi file using a jpeg compression.
VideoFile = strcat(ImagesFolder,'\MyVideo');
writerObj = VideoWriter(VideoFile);
% Define the video frames per second speed (fps)
fps = 1;
writerObj.FrameRate = fps;
% Open file for writing video data
open(writerObj);
% Running over all the files, converting them to movie frames using im2frame and writing the video data to file using writeVideo
for t = 1:length(jpegFilesS)
Frame = imread(strcat(ImagesFolder,'\',jpegFilesS(t).name));
writeVideo(writerObj,im2frame(Frame));
end
% Close the file after writing the video data
close(writerObj);
(Courtesy of http://imageprocessingblog.com/how-to-create-a-video-from-image-files/)
But it gives me this error:
Warning: No video frames were written to this file. The file may be invalid.
> In VideoWriter.VideoWriter>VideoWriter.close at 289
In Movie_jpgCompilation at 37
I'm sure my jpg files are fine, and they are in the folder I specify. What is the problem?
(This is my first post ever, so I hope it helps).
If you're on Linux, don't the backslashes need to be forward slashes? When I ran it on my Mac, my jpegFiles was an empty Struct. When I changed them around it worked:
% Create video out of list of jpgs
clear
clc
% Folder with all the image files you want to create a movie from, choose this folder using:
ImagesFolder = uigetdir;
% Verify that all the images are in the correct time order, this could be useful if you were using any kind of time lapse photography. We can do that by using dir to map our images and create a structure with information on each file.
jpegFiles = dir(strcat(ImagesFolder,'/*.jpg'));
% Sort by date from the datenum information.
S = [jpegFiles(:).datenum];
[S,S] = sort(S);
jpegFilesS = jpegFiles(S);
% The sub-structures within jpegFilesS is now sorted in ascending time order.
% Notice that datenum is a serial date number, for example, if you would like to get the time difference in hours between two images you need to subtract their datenum values and multiply by 1440.
% Create a VideoWriter object, in order to write video data to an .avi file using a jpeg compression.
VideoFile = strcat(ImagesFolder,'/MyVideo.avi');
writerObj = VideoWriter(VideoFile);
% Define the video frames per second speed (fps)
fps = 1;
writerObj.FrameRate = fps;
% Open file for writing video data
open(writerObj);
% Running over all the files, converting them to movie frames using im2frame and writing the video data to file using writeVideo
for t = 1:length(jpegFilesS)
Frame = imread(strcat(ImagesFolder,'/',jpegFilesS(t).name));
writeVideo(writerObj,im2frame(Frame));
end
% Close the file after writing the video data
close(writerObj);
Edit: You can also use filesep so that the file separator is OS-specific. http://www.mathworks.com/help/matlab/ref/filesep.html
It would be simpler to use Windows Movie Maker [windows] or iMovie [mac]. For your purposes though you should use PowerPoint.