Title: VIP: Vortex Image Processing package for high-contrast direct imaging,
Abstract: We present the Vortex Image Processing (VIP) library, a python package
dedicated to astronomical high-contrast imaging. Our package relies on the
extensive python stack of scientific libraries and aims to provide a flexible
framework for high-contrast data and image processing. In this paper, we
describe the capabilities of VIP related to processing image sequences acquired
using the angular differential imaging (ADI) observing technique. VIP
implements functionalities for building high-contrast data processing
pipelines, encompass- ing pre- and post-processing algorithms, potential
sources position and flux estimation, and sensitivity curves generation. Among
the reference point-spread function subtraction techniques for ADI
post-processing, VIP includes several flavors of principal component analysis
(PCA) based algorithms, such as annular PCA and incremental PCA algorithm
capable of processing big datacubes (of several gigabytes) on a computer with
limited memory. Also, we present a novel ADI algorithm based on non-negative
matrix factorization (NMF), which comes from the same family of low-rank matrix
approximations as PCA and provides fairly similar results. We showcase the ADI
capabilities of the VIP library using a deep sequence on HR8799 taken with the
LBTI/LMIRCam and its recently commissioned L-band vortex coronagraph. Using VIP
we investigated the presence of additional companions around HR8799 and did not
find any significant additional point source beyond the four known planets. VIP
is available at this http URL and is accompanied with
Jupyter notebook tutorials illustrating the main functionalities of the
library.