  Distinguishing signal of young gas rich circumstellar disks from stellar
signal in near infrared light is a difficult task. Current techniques such as
Angular Differential Imaging (ADI) and Polarimetric Differential Imaging (PDI)
cope with drawbacks such as self-subtraction. To address these drawbacks we
explore Iterative Angular Differential Imaging (IADI) techniques to increase
signal throughput in total intensity observations. This work aims to explore
the effectiveness of IADI to recover the self-subtracted regions of disks by
applying ADI techniques iteratively. To determine the effectiveness of IADI a
model of a disk image is made and post-processed with IADI. In addition,
masking based on polarimetric images and a signal threshold for feeding back
signal are explored. Asymmetries are a very important factor in recovering the
disk due to less overlap of the disk in the data set. In some cases, a factor
75 more flux could be recovered with IADI compared to ADI. The Procrustes
distance is used to quantify the impact of the algorithm on the scattering
phase function. Depending on the level of noise and the ratio between the
stellar signal and disk signal, the phase function can be recovered a factor
6.4 in Procrustes distance better than standard ADI. The amplification and
smearing of noise over the image due to many iterations did occur and by using
binary masks and a dynamic threshold this feedback was mitigated, but it still
is a problem in the final pipeline. Lastly observations of protoplanetary disks
made with VLT/SPHERE were processed with IADI giving rise to very promising
results. While IADI has problems with low signal-to-noise observations due to
noise amplification and star reconstruction, higher signal-to-noise
observations show promising results with respect to standard ADI.
