VIDIOC_S_FMT error 16, Device or resource busy - Raspberry Pi Forums

dear all,
working on image processing using raspberry pi, have installed intex usb web camera on raspberry pi.
have used basic python script of image processing https://www.cl.cam.ac.uk/projects/raspb ... first.html required libraries installed on raspberry pi.

script code:
import imgproc
imgproc import *


# open webcam take pictures
camera = camera(160, 120)

# open viewer window display images
viewer = viewer(160, 120, "the first step")

# take picture camera
img = camera.grabimage()

# display image in viewer
viewer.displayimage(img)


# iterate on each pixel in image
x in range(0, img.width):
for y in range(0, img.height):
# value @ xth column , yth row, place intensities variables
red, green, blue = img[x, y]

# test find colour dominant
if red > green , red > blue:
# red dominant, set pixel red
img[x, y] = 255, 0, 0
elif green > red , green > blue:
img[x, y] = 0, 255, 0
else:
# if red or green isn't dominant, blue must be
img[x, y] = 0, 0, 255


# display image again
viewer.displayimage(img)

# delay 5000 milliseconds give time see changes, exit
waittime(5000)


# end of script
when run script giving error "vidioc_s_fmt error 16, device or resource busy"


installed : $ sudo apt-get install gtk2-engines-pixbuf

please me
vidioc_s_fmt error 16, device or resource busy

thank you

raspberrypi