picamera to Numpy : File like helper class to read an image from picamera into numpy ndarray , usefull for image processing, especially with opencv

rpi2numpy.py

# Copyright (c) 2016 Laxmianarayan G Kamath A [email protected]
# 
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
# 
# You should have received a copy of the GNU Lesser General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

#Usage:
# import rpi2numpy 
# rn = rpi2numpy.Rpi2Numpy()
# .. code here .. probably start a loop
# i = rn.read()
# .. process it
# rn.capture.close()

# capture = picamera.PiCamera()
# width, height = capture.resolution
# rpif = Rpi2NumpyFile(width,height)
# capture.capture(rpif, format='bgr'
# image = rpif.get_image()


#Points to note if you are trying to understand this code:
# % The function "capture" from "picamera" module expects a *file-like* object which has the "write" method to dump it's data into
# % It will dump the format expected by opencv when you as for capture in 'bgr' format.
# % numpy can read data from string using the "fromstring" function into its array.
import picamera
import time
import numpy

class Rpi2NumpyFile(object):
    def __init__(self,width,height,format='bgr',videoport=True,depth=3):
        self.image = None
        self.data = None
        self.width = width
        self.height = height
        self.format = format
        self.depth = depth
        self.videoport = videoport
    def open(self):
        return True
    def write(self,data):
        self.data = data
    def get_image(self):
        assert self.data is not None, "No Image read yet"
        return numpy.frombuffer(self.data,dtype=numpy.uint8).reshape(self.height, self.width, self.depth)
    def close(self):
        return True

class Rpi2Numpy(object):
    def __init__(self,*cameraParams, **cameraKeyParams):
        self.capture = picamera.PiCamera(*cameraParams, **cameraKeyParams)
        width,height = self.capture.resolution
        self.r2n = Rpi2NumpyFile(width,height)
    def read(self):
        self.capture.capture(self.r2n,format=self.r2n.format, use_video_port = self.r2n.videoport)
        return self.r2n.get_image()

if __name__ == '__main__':
    rn = Rpi2Numpy(resolution=(1024,768))
    rn.capture.video_denoise = False
    rn.capture.video_stabilization = False
    rn.capture.image_denoise = False
    rn.capture.exposure_mode ='off'

    numframes = 100
    t1 = time.time()

    for i in xrange(0,numframes):
        j = rn.read()
    t2 = time.time()

    
    t3 = time.time()
    j = rn.read()
    t4 = time.time()

    print "Num of Frames: %d" %(numframes)
    print "Time Taken %f seconds" % (t2 - t1)
    print "FPS: %f " % (numframes/ (t2 - t1))

    print "Time Taken for single shot %f seconds" % (t4 - t3)