  Spatially entangled twin photons provide a test of the
Einstein-Podolsky-Rosen (EPR) paradox in its original form of position (image
plane) versus impulsion (Fourier plane). We show that recording a single pair
of images in each plane is sufficient to safely demonstrate an EPR paradox. On
each pair of images, we have retrieved the fluctuations by subtracting the
fitted deterministic intensity shape and then have obtained an intercorrelation
peak with a sufficient signal to noise ratio to safely distinguish this peak
from random fluctuations. A 95% confidence interval has been determined,
confirming a high degree of paradox whatever the considered single pairs. Last,
we have verified that the value of the variance of the difference between twin
images is always below the quantum (poissonian) limit, in order to ensure the
particle character of the demonstration. Our demonstration shows that a single
image pattern can reveal the quantum and non-local behavior of light, without
any need of averaging after repeating the experiment.
