take_shot.py

import cv2.cv as cv
import numpy
import os

CV_CAP_PROP_FRAME_WIDTH = 3
CV_CAP_PROP_FRAME_HEIGHT = 4

DIR_PREFIX = './pics'
DATE_X = 0 
DATE_Y = 460


def init_camera(rx=640,ry=480):
    setup_uvc_camera()
    camera = cv.CaptureFromCAM(0)
    # set camera properties
    cv.SetCaptureProperty(camera, CV_CAP_PROP_FRAME_WIDTH, rx)
    cv.SetCaptureProperty(camera, CV_CAP_PROP_FRAME_HEIGHT, ry)
    return camera

def setup_uvc_camera():
    command = 'uvcdynctrl -s '
    command += 'Brightness 0'
    os.system(command)
    command = 'uvcdynctrl -s '
    command += 'Contrast 13'
    os.system(command)
    command = 'uvcdynctrl -s '
    command += '"White Balance Temperature, Auto" 0'
    os.system(command)
    command = 'uvcdynctrl -s '
    command += '"White Balance Temperature" 6500'
    os.system(command)
    command = 'uvcdynctrl -s '
    command += '"Backlight Compensation" 0'
    os.system(command)
    command = 'uvcdynctrl -s '
    command += '"Exposure, Auto" 1'
    os.system(command)
    command = 'uvcdynctrl -s '
    command += '"Exposure (Absolute)" 300'
    os.system(command)
    command = 'uvcdynctrl -s '
    command += '"Exposure, Auto Priority" 0'
    os.system(command)

def get_image(camera,filename=None):
    im = cv.QueryFrame(camera)

    
    # take greyscale and compute RMS value
    im2 = cv.CreateImage(cv.GetSize(im),cv.IPL_DEPTH_32F,3)
    cv.Convert(im,im2)
    gray = cv.CreateImage(cv.GetSize(im),cv.IPL_DEPTH_32F,1)
    cv.CvtColor(im2,gray,cv.CV_RGB2GRAY)
    gray_mat = cv.GetMat(gray)
    img = numpy.asarray(gray_mat)

    power = numpy.sqrt(numpy.mean(img**2))

    #save file
    if filename:
        font = cv.InitFont(cv.CV_FONT_HERSHEY_SIMPLEX, 0.8, 0.8, 0, 2, cv.CV_AA)
        cv.PutText(im,filename,(DATE_X,DATE_Y),font,cv.RGB(255,255,0))
        filename = os.path.join(DIR_PREFIX,filename+'.jpg')
        print filename
        cv.SaveImage(filename,im)
        del font
    else:
        filename = ''

    #del(camera)
    del im, im2, gray, img, gray_mat

    return (power,filename)

if __name__ == '__main__':
    if 1:
        camera = init_camera()
        print get_image(camera,'test_file')
    else:
        import pylab
        pylab.ion()
        fig = pylab.figure()
        ax = fig.add_subplot(111)

        p = []
        camera = init_camera()
        p.append(get_image(camera,'test_file')[0])
        ix = []
        ix.append(1)
        line1, = ax.plot(ix,p,'o-')

        while True:
            p.append(get_image(camera,'test_file')[0])
            print p[-1]
            ix.append(ix[-1]+1)
            line1.set_data(ix,p)
            ax.relim()
            ax.autoscale()
            fig.canvas.draw()