Raspberry Pi - Camera Interface with Python

Take a picture with a button press

import time
import picamera
import RPi.GPIO as GPIO
import numpy as np

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(11,GPIO.IN)

# 8Mpx (3280,2464)
# 5Mpx (2592,1944)
h = 2592 
v = 1944

a = np.zeros((v,h,3), dtype=np.uint8)
a[v/2, :, :] = 0xff
a[:, h/2, :] = 0xff

#set left or right camera

def take_pic():
    with picamera.PiCamera() as camera:
        camera.resolution = (h, v)
        camera.vflip = True
        camera.iso = 800
        #o = camera.add_overlay(np.getbuffer(a), layer=3, alpha=64)
        #camera.start_preview() #0720243637
        time.sleep(2)
        #camera.capture('foo.jpg', resize=(400,240))
        ofile = 'cam%s_%d.jpg' % ('r',time.time())
        camera.capture(ofile)
        #camera.remove_overlay(o)

prev = GPIO.input(11)
while True:
    curr = GPIO.input(11) # take a reading
    if ((not prev) and curr):
        print("button pressed")
        take_pic()
        #take pic
    prev = curr
    time.sleep(0.05)

Add an overlay to a live camera image

import time
import picamera
import numpy as np

h = 800 #2592
v = 480 #1944

a = np.zeros((v,h,3), dtype=np.uint8)
a[v/2, :, :] = 0xff
a[:, h/2, :] = 0xff

with picamera.PiCamera() as camera:
    camera.resolution = (h,v)
    camera.vflip = Ture
    camera.framerate = 24
    camera.start_preview()

    o = camera.add_overlay(np.getbuffer(a), layer=3, alpha=64)
    try:
        while True:
           time.sleep(1)
    finally:
        camera.remove_overlay(o)