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Fast capture and 2D image stacking as 3D numpy array with Python and Raspberry Pi

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  Fast capture and 2D image stacking as 3D numpy array with Python and Raspberry Pi Agustin Cruz <agustin.cruz@gmail.com> - 2015-07-06 14:31 -0700
    Re: Fast capture and 2D image stacking as 3D numpy array with Python and Raspberry Pi Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-07-06 22:59 +0100
      Re: Fast capture and 2D image stacking as 3D numpy array with Python and Raspberry Pi Agustin Cruz <agustin.cruz@gmail.com> - 2015-07-06 16:16 -0700
        Re: Fast capture and 2D image stacking as 3D numpy array with Python and Raspberry Pi Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-07-07 07:49 +0100

#93540 — Fast capture and 2D image stacking as 3D numpy array with Python and Raspberry Pi

I'm working on a Python - Raspberry Pi project in which I need to take about 30 images per second (no movie) and stack each 2D image to a 3D array using numpy array, without saving each 2D capture as a file (because is slow).

I found this Python code to take images as fast as possible, but i don't know how to stack all images fast to a 3D stack of images.

import io
import time
import picamera
#from PIL import Image

def outputs():
    stream = io.BytesIO()
    for i in range(40):
        # This returns the stream for the camera to capture to
        yield stream
        # Once the capture is complete, the loop continues here
        # (read up on generator functions in Python to understand
        # the yield statement). Here you could do some processing
        # on the image...
        #stream.seek(0)
        #img = Image.open(stream)
        # Finally, reset the stream for the next capture
        stream.seek(0)
        stream.truncate()

with picamera.PiCamera() as camera:
    camera.resolution = (640, 480)
    camera.framerate = 80
    time.sleep(2)
    start = time.time()
    camera.capture_sequence(outputs(), 'jpeg', use_video_port=True)
    finish = time.time()
    print('Captured 40 images at %.2ffps' % (40 / (finish - start)))

Does anyone of you know how to stack the 2D images taken in this code to a 3D numpy array using Python and the Raspberry Pi camera module? Without saving each 2D capture as a file

Best regards, Agustín

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#93541

On 06/07/2015 22:31, Agustin Cruz wrote:
> I'm working on a Python - Raspberry Pi project in which I need to take about 30 images per second (no movie) and stack each 2D image to a 3D array using numpy array, without saving each 2D capture as a file (because is slow).
>
> I found this Python code to take images as fast as possible, but i don't know how to stack all images fast to a 3D stack of images.
>
> import io
> import time
> import picamera
> #from PIL import Image
>
> def outputs():
>      stream = io.BytesIO()
>      for i in range(40):
>          # This returns the stream for the camera to capture to
>          yield stream
>          # Once the capture is complete, the loop continues here
>          # (read up on generator functions in Python to understand
>          # the yield statement). Here you could do some processing
>          # on the image...
>          #stream.seek(0)
>          #img = Image.open(stream)
>          # Finally, reset the stream for the next capture
>          stream.seek(0)
>          stream.truncate()
>
> with picamera.PiCamera() as camera:
>      camera.resolution = (640, 480)
>      camera.framerate = 80
>      time.sleep(2)
>      start = time.time()
>      camera.capture_sequence(outputs(), 'jpeg', use_video_port=True)
>      finish = time.time()
>      print('Captured 40 images at %.2ffps' % (40 / (finish - start)))
>
> Does anyone of you know how to stack the 2D images taken in this code to a 3D numpy array using Python and the Raspberry Pi camera module? Without saving each 2D capture as a file
>
> Best regards, Agustín
>

http://docs.scipy.org/doc/numpy/reference/generated/numpy.dstack.html is 
the first hit on google for "numpy 3d array stack".

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence

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#93542

On Monday, July 6, 2015 at 6:00:42 PM UTC-4, Mark Lawrence wrote:
> On 06/07/2015 22:31, Agustin Cruz wrote:
> > I'm working on a Python - Raspberry Pi project in which I need to take about 30 images per second (no movie) and stack each 2D image to a 3D array using numpy array, without saving each 2D capture as a file (because is slow).
> >
> > I found this Python code to take images as fast as possible, but i don't know how to stack all images fast to a 3D stack of images.
> >
> > import io
> > import time
> > import picamera
> > #from PIL import Image
> >
> > def outputs():
> >      stream = io.BytesIO()
> >      for i in range(40):
> >          # This returns the stream for the camera to capture to
> >          yield stream
> >          # Once the capture is complete, the loop continues here
> >          # (read up on generator functions in Python to understand
> >          # the yield statement). Here you could do some processing
> >          # on the image...
> >          #stream.seek(0)
> >          #img = Image.open(stream)
> >          # Finally, reset the stream for the next capture
> >          stream.seek(0)
> >          stream.truncate()
> >
> > with picamera.PiCamera() as camera:
> >      camera.resolution = (640, 480)
> >      camera.framerate = 80
> >      time.sleep(2)
> >      start = time.time()
> >      camera.capture_sequence(outputs(), 'jpeg', use_video_port=True)
> >      finish = time.time()
> >      print('Captured 40 images at %.2ffps' % (40 / (finish - start)))
> >
> > Does anyone of you know how to stack the 2D images taken in this code to a 3D numpy array using Python and the Raspberry Pi camera module? Without saving each 2D capture as a file
> >
> > Best regards, Agustín
> >
> 
> http://docs.scipy.org/doc/numpy/reference/generated/numpy.dstack.html is 
> the first hit on google for "numpy 3d array stack".
> 
> -- 
> My fellow Pythonistas, ask not what our language can do for you, ask
> what you can do for our language.
> 
> Mark Lawrence

Hi Mark,
I know the dstack function can do the job, but i don't know how to implement it in this case.

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#93550

On 07/07/2015 00:16, Agustin Cruz wrote:
> On Monday, July 6, 2015 at 6:00:42 PM UTC-4, Mark Lawrence wrote:
>> On 06/07/2015 22:31, Agustin Cruz wrote:
>>> I'm working on a Python - Raspberry Pi project in which I need to take about 30 images per second (no movie) and stack each 2D image to a 3D array using numpy array, without saving each 2D capture as a file (because is slow).
>>>
>>> I found this Python code to take images as fast as possible, but i don't know how to stack all images fast to a 3D stack of images.
>>>
>>> import io
>>> import time
>>> import picamera
>>> #from PIL import Image
>>>
>>> def outputs():
>>>       stream = io.BytesIO()
>>>       for i in range(40):
>>>           # This returns the stream for the camera to capture to
>>>           yield stream
>>>           # Once the capture is complete, the loop continues here
>>>           # (read up on generator functions in Python to understand
>>>           # the yield statement). Here you could do some processing
>>>           # on the image...
>>>           #stream.seek(0)
>>>           #img = Image.open(stream)
>>>           # Finally, reset the stream for the next capture
>>>           stream.seek(0)
>>>           stream.truncate()
>>>
>>> with picamera.PiCamera() as camera:
>>>       camera.resolution = (640, 480)
>>>       camera.framerate = 80
>>>       time.sleep(2)
>>>       start = time.time()
>>>       camera.capture_sequence(outputs(), 'jpeg', use_video_port=True)
>>>       finish = time.time()
>>>       print('Captured 40 images at %.2ffps' % (40 / (finish - start)))
>>>
>>> Does anyone of you know how to stack the 2D images taken in this code to a 3D numpy array using Python and the Raspberry Pi camera module? Without saving each 2D capture as a file
>>>
>>> Best regards, Agustín
>>>
>>
>> http://docs.scipy.org/doc/numpy/reference/generated/numpy.dstack.html is
>> the first hit on google for "numpy 3d array stack".
>>
>> --
>> My fellow Pythonistas, ask not what our language can do for you, ask
>> what you can do for our language.
>>
>> Mark Lawrence
>
> Hi Mark,
> I know the dstack function can do the job, but i don't know how to implement it in this case.
>

Sadly I don't know how either, but if I can find the above link in 
seconds, I'm fairly certain that with a little searching you could find 
something.  Specific sites like nullege or koders might offer solutions.

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence

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