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Message ID: 512     Entry time: Tue Jun 3 02:15:29 2008
Author: Andrey 
Type: Summary 
Category: Cameras 
Subject: Fitting results 

There have been a lot of work going on related to the processing of images captured by the cameras GC-650 and GC-750 recently.

In the end of the week of May 30 Joseph and me (Andrey) installed the two cameras capturing the images of the pick-off of the main beam on the PSL optical table. The cameras are located after the picked-off beam going towards the "PSL position QPD", after the 33-66 beamsplitter (33% of reflection and 66% of transmission).

Initially (on May 30) the GC-650 camera was taking the images of reflected beam, while the camera GC-750 was taking images of transmitted beam. On Monday June 2 we switched the positions of the cameras, so GC-650 appeared to be on the path of the transmitted beam and GC-750 on the path of the reflected beam.

I (Andrey Rodionov) was able in the weekend to succeed in writing a Matlab program that performs the two-dimensional Gaussian fitting of the captured images, and I used that program to fit the images from the cameras.

The program fits the camera data by a two-dimensional Gaussian surface:

Z = A * exp[ - 2 * (X - X_Shift)^2 / (Waist_X)^2 ] * exp[ - 2 * (Y - Y_Shift)^2 / (Waist_Y)^2 ] + CONST_Shift,

where A, X_Shift, Waist_X, Y_Shift, Waist_Y, CONST_Shift are 6 parameters of the fit.

Attached are the pdf-files showing the results: images taken with our cameras, the 2-dimensional Gaussian fit for these images and the surfaces of residuals. Residuals are differences between the exact beam profile and the result of fitting. In normalized version of residual graph I normalize it by the first coefficient of fitting A, the factor in front of the exponents.
Attachment 1: May30-GC650.pdf  711 kB  | Show | Hide all | Show all
Attachment 2: May30-GC750.pdf  648 kB  | Hide | Hide all | Show all
May30-GC750.pdf May30-GC750.pdf May30-GC750.pdf May30-GC750.pdf May30-GC750.pdf May30-GC750.pdf
Attachment 3: June02-GC650.pdf  783 kB  | Hide | Hide all | Show all
June02-GC650.pdf June02-GC650.pdf June02-GC650.pdf June02-GC650.pdf June02-GC650.pdf June02-GC650.pdf
Attachment 4: June02-GC750.pdf  589 kB  | Show | Hide all | Show all
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