Help need with python script for PiCamera

Question

I am working with the Raspberry Pi camera and need some help regarding the python script. I need to capture a set of 5 images continuously every 5 minutes interval until I want it to stop. This set of images will be captured with increment in the shutter speed.

Right now, I only have the script written for capturing 5 images.

from picamera import PiCamera
from time import sleep

camera=PiCamera()
camera.resolution=(1024, 768)
camera.start_preview(fullscreen=False, window=(100,200,500,600))
camera.capture_sequence(['image%02d.jpg' % i for i in range (5)])  

Please let me know how to set of images continuously with range of shutter speed. Thanks in advance.

Answer 1

If I've understood correctly, you want to capture 5 images, each with a different shutter speed, wait five minutes, and then repeat. In that case, capture_sequence isn't applicable as it would capture all frames with the same shutter speed.

In that case, the code you want should look something like this:

from picamera import PiCamera
from time import sleep

camera=PiCamera()
camera.resolution=(1024, 768)
camera.start_preview(fullscreen=False, window=(100,200,500,600))

at = 1 # keep track of the current image
while True:
    for shutterspeed in range(250,1500,250): # use shutterspeeds of 250, 500, 750, 1000, and 1250 microseconds, set this to the range of values you're interested in
        camera.shutter_speed = shutterspeed # set the shutter speed to this many microseconds
        sleep(2) # documentation suggests a short 2 second delay for the sensor to adjust
        camera.capture('image%05d.jpg' % at) # save the image in the current folder with 5 leading zeros in the filename
        at = at + 1 # increment the image number
    sleep(5*60) # wait 5 minutes

camera.stop_preview()

Answer 2

I'm trying also to do some HDR images to acquire at the end a whole 8 or super8 film. Every picture of the film will be acquired with different stops. Here the code that I have already tested and that works fine:

from picamera import PiCamera
from time import sleep
from fractions import Fraction

camera = PiCamera()
camera.rotation = 180
camera.resolution = (3280,2464)
camera.framerate= 1/1
sleep(1)
camera.capture('img_0.jpg')
exposure = camera.exposure_speed
camera.exposure_mode = 'off'
i=1
while i < 4:
    camera.shutter_speed = exposure * 2**i
    sleep(1)
    camera.capture('img_plus_'+str(i)+'.jpg')
    camera.shutter_speed = int (exposure / 2**i)
    sleep(1)
    camera.capture('img_minus'+str(i)+'.jpg')
    i+=1

First I take an image at EV0 and I save the exposure_speed so that I know the EV0 value. After that, I change the shutter_speed so that I have under- and over-exposed pictures

Regards

Gian Carlo

Answer 3

The task could be run every five minutes using cron.

Save your script as (e.g) /home/pi/mycapture.py

crontab -e

Then add

*/5 * * * * python /home/pi/mycapture.py

You would need a date/time stamp in the filename to avoid overwriting.