[PIPE2D-462] Create a scattering kernel Created: 11/Oct/19  Updated: 16/Oct/19  Resolved: 15/Oct/19

Status: Done
Project: DRP 2-D Pipeline
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Task Priority: Normal
Reporter: ncaplar Assignee: ncaplar
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Attachments: PNG File Adding_scattering.png    
Issue Links:
Relates
relates to PIPE2D-463 Aliasing effects in 2d PSF Done
Story Points: 3
Sprint: 2DDRP-2019 H
Reviewers: cloomis

 Description   

In order to improve the fidelity of simulations, we want to include the ``long-range'' scattering term that we see in the data. Understanding the impact of this scattering is crucial for understanding how well we can extract data from nearby fibers.

This ticket is to create the simplest kernel, based on observed scatter in LAM, with which to convolve the data to simulate this effect. At this point I am aiming to create only a single kernel, without any spatial dependence.

 Comments   
Comment by ncaplar [ 15/Oct/19 ]

I have placed the representative scattering kernel at /tigress/HSC/PFS/sim_Neven/Scattering_Kernel. This kernel is the median of around 100 examples across the detector. Size is 28x28, where each pixel is the physical pixel (15 microns).

Example usage:

def custom_fftconvolve(array1, array2):
assert array1.shape==array2.shape
return np.fft.fftshift(np.real(np.fft.irfft2(np.fft.rfft2(array1)*np.fft.rfft2(array2))))

#convolve the psf with the scattered light kernel in the final resolution space
scattered_light_in_final_image= custom_fftconvolve(final_image_without_scatter,scattering_kernel)

#add back the scattering to the image
final_image=final_image_without_scatter+scattered_light_in_final_image

I am showing the examples of the procedure below:

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