  Radial velocity and transit methods are effective for the study of short
orbital period exoplanets but they hardly probe objects at large separations
for which direct imaging can be used. We carried out the international deep
planet survey of 292 young nearby stars to search for giant exoplanets and
determine their frequency. We developed a pipeline for a uniform processing of
all the data that we have recorded with NIRC2/Keck II, NIRI/Gemini North,
NICI/Gemini South, and NACO/VLT for 14 years. The pipeline first applies
cosmetic corrections and then reduces the speckle intensity to enhance the
contrast in the images. The main result of the international deep planet survey
is the discovery of the HR 8799 exoplanets. We also detected 59 visual multiple
systems including 16 new binary stars and 2 new triple stellar systems, as well
as 2,279 point-like sources. We used Monte Carlo simulations and the Bayesian
theorem to determine that 1.05[+2.80-0.70]% of stars harbor at least one giant
planet between 0.5 and 14M_J and between 20 and 300 AU. This result is obtained
assuming uniform distributions of planet masses and semi-major axes. If we
consider power law distributions as measured for close-in planets instead, the
derived frequency is 2.30[+5.95-1.55]%, recalling the strong impact of
assumptions on Monte Carlo output distributions. We also find no evidence that
the derived frequency depends on the mass of the hosting star, whereas it does
for close-in planets. The international deep planet survey provides a database
of confirmed background sources that may be useful for other exoplanet direct
imaging surveys. It also puts new constraints on the number of stars with at
least one giant planet reducing by a factor of two the frequencies derived by
almost all previous works.
